Split (2)

train · 33.5k rows

patent_number stringlengths 0 9	section stringclasses 4 values	raw_text stringlengths 0 954k
	summary
	abstract	The present invention provides an optical semiconductor device including a semiconductor thin film (4) having photoconductivity and a pair of electrodes (5) and (10) for applying an electric field to an inside of the semiconductor thin film (4) in a direction approximately vertical to a surface of the semiconductor thin film (4), wherein the semiconductor thin film (4) generates an electromagnetic wave when light is applied to a region thereof to which the electric field is applied. The electrodes are provided to a front surface and a back surface of the semiconductor thin film (4) with the semiconductor thin film interposed therebetween.
	summary
044617224	abstract	A method of solidifying waste materials, such as radioactive or toxic matals, which are contained in aqueous solutions. To accomplish this solidification, an inorganic, non-metallic binding agent such as gypsum is intermixed with the aqueous solution and a substance such as pumice or ceramic tile which promotes the intermixing of the binding agent and the aqueous solution.
	claims	1. An electron microscope system, comprising:electron beam image obtaining means for obtaining an image of a specimen having a resist pattern formed on a surface thereof using a scanning electron microscope;quantifying means for quantifying a feature of variations in brightness of the image at a desired area of the resist pattern by processing the obtained image;index value calculating means for calculating an index value for relating the feature of variations in brightness of the image quantified by the quantifying means to an amount of reduction from a reference value of a film thickness of the resist pattern; andestimation means for estimating the amount of reduction from the reference value of the film thickness of the resist pattern using the index value calculated by the index value calculating means,wherein the index value is correlated with changes in roughness of a surface of the resist pattern at the desired area, andfurther comprising means for verifying the calculated index value against a database which registers a relationship between film thickness reduction index values and amounts of film thickness reduction of resist patterns or a relationship between an etching bias and film thickness reduction index values. 2. The electron microscope system according to claim 1, wherein the index value calculating means calculates the index value for relating the feature of variations in brightness of the image quantified by the quantifying means to the amount of reduction from the reference value which is the film thickness of the resist pattern formed by being exposed under a normal exposure condition. 3. The electron microscope system according to claim 1, wherein the estimation means estimates an amount of film thickness reduction of the resist pattern by applying the index value calculated by the index value calculation means to a database previously made and stored for relating an index value for a resist pattern having a reference film thickness to an amount of film thickness reduction of the resist pattern. 4. The electron microscope system according to claim 1, wherein the index value having a correlation with the amount of film thickness reduction calculated from the electron microscope image is a quantified degree of roughness of the desired area of the resist pattern caused by a phenomenon of the film thickness of the resist pattern with respect to the reference thickness of the resist pattern as a reference. 5. The electron microscope system according to claim 1, wherein the index value having the correlation with the amount of film thickness reduction calculated from the electron microscope image is a quantified average brightness of the desired area of the resist pattern. 6. The electron microscope system according to claim 1, wherein the index value having the correlation with the amount of film thickness reduction calculated by the electron microscope image is a quantified distribution of the brightness of the desired area of the resist pattern. 7. The electron microscope system according to claim 1,wherein the film thickness reduction index values comprise standard deviations of a brightness variation of projected waveform of the image of a specimen. 8. The electron microscope system according to claim 1,wherein the film thickness reduction index values comprise σ values or centers of a normal distribution applied to a brightness histogram of the image of a specimen. 9. The electron microscope system according to claim 1,wherein the film thickness reduction index values comprise minimum values of a center of a waveform of the image of a specimen. 10. The electron microscope system according to claim 1, wherein the roughness of the surface of the resist pattern is determined by a texture analysis in which a power spectrum of an area corresponding to an upper position in image is determined, and the roughness of a texture is quantified from frequency properties of the power spectrum. 11. A method for evaluating film thickness reduction of a resist pattern using an electron microscope system, comprising:obtaining an image of a specimen having a resist pattern formed on a surface thereof using a scanning electron microscope;quantifying a feature of variations in brightness of the image at a desired area of the resist pattern by processing the obtained image;calculating an index value for relating the feature of variations in brightness of the image quantified by the quantifying step to an amount of reduction from a reference value of a film thickness of the resist pattern; andestimating the amount of reduction from the reference value of the film thickness of the resist pattern using the index value calculated by the index value calculating step,wherein the index value is correlated with changes in roughness of a surface of the resist pattern at the desired area, andfurther comprising verifying the calculated index value against a database which registers a relationship between film thickness reduction index values and amounts of film thickness reduction of resist patterns or a relationship between an etching bias and film thickness reduction index values. 12. The method according to claim 11, wherein the index value calculating step calculates the index value for relating the feature of variations in brightness of the image quantified by the quantifying step to the amount of reduction from the reference value which is the film thickness of the resist pattern formed by being exposed under a normal exposure condition. 13. The method according to claim 11, wherein the estimation step estimates an amount of film thickness reduction of the resist pattern by applying the index value calculated by the index value calculation step to a database previously made and stored for relating an index value for a resist pattern having a reference film thickness to an amount of film thickness reduction of the resist pattern. 14. The method according to claim 11, wherein the index value having a correlation with the amount of film thickness reduction calculated from the electron microscope image is a quantified degree of roughness of the desired area of the resist pattern caused by a phenomenon of the film thickness of the resist pattern with respect to the reference thickness of the resist pattern as a reference. 15. The method according to claim 11, wherein the index value having the correlation with the amount of film thickness reduction calculated from the electron microscope image is a quantified average brightness of the desired area of the resist pattern. 16. The method according to claim 11, wherein the index value having the correlation with the amount of film thickness reduction calculated by the electron microscope image is a quantified distribution of the brightness of the desired area of the resist pattern. 17. The method according to claim 11,wherein the film thickness reduction index values comprise standard deviations of a brightness variation of projected waveform of the image of a specimen. 18. The method according to claim 11,wherein the film thickness reduction index values comprise σ values or centers of a normal distribution applied to a brightness histogram of the image of a specimen. 19. The method according to claim 11,wherein the film thickness reduction index values comprise minimum values of a center of a waveform of the image of a specimen. 20. The method according to claim 11, wherein the roughness of the surface of the resist pattern is determined by a texture analysis in which a power spectrum of an area corresponding to an upper position in image is determined, and the roughness of a texture is quantified from frequency properties of the power spectrum.
	summary
	abstract	Configurations of molten fuel salt reactors are described that include an auxiliary cooling system which shared part of the primary coolant loop but allows for passive cooling of decay heat from the reactor. Furthermore, different pump configurations for circulating molten fuel through the reactor core and one or more in vessel heat exchangers are described.
	description	1. Field of the Invention The present invention relates to a method, computer program and device for determining the crystal structure and/or the range of crystal structures of one or more crystalline tubular molecules from a set of calibration-free properties of a diffraction pattern of the one or more crystalline tubular molecules. 2. Description of the Related Art Various crystalline tubular molecules have been discovered in recent years including carbon Nanotubes and nanobuds and boron-nitride Nanotubes. Carbon Nanotubes have received the most attention because of their unique physical, chemical, thermal and electrical properties. A fundamental problem in both basic and applied research on crystalline tubular molecules such as single-walled carbon nanotubes (SWCNTs) exists because many physical properties of nanotubes can be extremely sensitive to their atomic structure. For instance, the structure of a SWCNT can be conveniently described by a pair of integers known as the chiral indices (n, m). A well-known example of the sensitivity of structure to properties is that a carbon nanotube can be metallic if (n−m) is divisible by 3, otherwise they are semiconducting. A slight change in the value n or m can, thus, dramatically alter the electronic properties of a nanotube. For instance, a (13, 1) tube is metallic while a (14, 1) tube is semiconducting though they are geometrically very similar to each other. Therefore, unambiguous (n, m) determination of individual SWCNTs is of crucial value for progressing CNT-based nanotechnology. Current efforts for structural characterization of SWCNTs can be categorized into two broad classes, i.e., optical and non-optical. Optical spectroscopy includes, for example, resonant Raman scattering and photoluminescence, where (n, m) are identified by using the characteristic optical transition energies and photon frequencies (in Raman scattering) or optical absorption and emission energies (in photoluminescence). Optical measurements are usually limited in that they require a range of laser wavelengths for detecting a variety of tubes and they are only valid for a limited range of tube diameters. Laborious tasks are usually involved for both measurement and data interpretation. Photoluminescence has an additional drawback since the method can only detect semiconducting nanotubes. In addition, the insufficient spatial resolution of optical measurements makes it impossible to probe individual SWCNTs for analysis without considering effects from the tube environment. Moreover, there is no known calibration technique to correlate the intensity of excitations for tubes of given chiral indices to their concentrations, thus it is difficult to accurately map the chirality distribution in a SWCNT sample with optical measurements. In the non-optical communities, the chiral indices are usually assigned by first determining the characteristic tube diameter D0 and chiral angle α by means of direct imaging techniques in real space (e.g. scanning tunneling microscopy (STM) and high-resolution transmission electron microscopy (HRTEM)), or in reciprocal space by the electron diffraction technique. Direct imaging techniques are faced with the problem that the tubes are usually not stable enough for acquiring high-quality images with atomic-resolution and at a high magnification. Electron diffraction was the first technique to be used to characterize SWCNTs at the time of their discovery and has remained one of the most powerful means for their structural analysis. Advanced nano-beam electron diffraction techniques uniquely allow direct probing of individual nanotubes and characterization of their structure. However, the measurements are typically made by assuming a normal incidence condition or a small tube tilting angle, e.g. less than 6°. In contrast, it is not rare for a nanotube to have a tilt angle of 20° from the horizontal plane. In practice, it is difficult to establish an experimental setup to ensure such small tilt angle requirements. Although determination of the chiral angle α from electron diffraction patterns (EDPs) was shown to be independent of tube inclination, evaluation of the tube diameter may rely on the tilt of the tube unless the diffraction patterns are actually calibrated by internal standard materials, which are in practice unavailable in the measurement. In the absence of such standards, absolute calibration of an EDP of a SWCNT depends on the value of the carbon-carbon (C—C) bonding distance, which has uncertainty between 0.142 nm and 0.144 nm. Additionally the C—C bond can be stretched when the tube diameter is small. Also, calibration of the EDP by using the C—C bonding distance is either tilt sensitive or complicated by the curvature of the tube. In order to take into account the tilting effect of the tube on the determination, a tedious trial-and-error simulation procedure has to be applied. Moreover, when D0 and α are required to be determined prior to (n, m) assignment, as by previous methods, they must both be determined with high accuracy in order to determine chiral indices n and m unambiguously. For instance, the metallic (13, 1) tube where D0=1.06 nm and α=3.7°, is very similar to the semi-conducting (14, 1) tube where D0=1.14 nm and α3.4°. Obviously, a slight error in either D0 or α easily leads to an ambiguity in indexing a SWCNT. To overcome these deficiencies, we introduce a new invention: a method for determining the atomic structure of at least one tubular crystalline molecule, wherein the method comprises the following steps: obtaining a diffraction pattern of at least one tubular crystalline molecule, and calculating at least one feature of the atomic structure and/or range of atomic structures using at least one calibration-free property of the diffraction pattern. In one embodiment of the invention, the diffraction pattern is an electron diffraction pattern. In one embodiment of the invention, the diffraction pattern is obtained from a sample of at least one tubular crystalline molecule using a transmission electron microscope. In one embodiment of the invention, the at least one tubular crystalline molecule comprises a nanotube. In one embodiment of the invention, the at least one molecule is a carbon nanotube and/or a carbon nanobud. In one embodiment of the invention, the crystal structure and/or crystal orientation of the tubular crystalline molecule is uniquely specified by at least two mathematically independent parameters. In one embodiment of the invention, the mathematical parameters uniquely specifying the nanotube or nanobud based molecule are chiral indices. In one embodiment of the invention, the calibration-free property of the diffraction pattern is the pseudo-periodicity of the diffraction intensity along a layer line and/or the distance between at least two pairs of layer lines and/or the distance between the first pair of minima in the diffraction intensity along a layer line and/or the distance between the first pair of maxima in the diffraction intensity along a layer line and/or the area under the layer line intensity curve, and/or, the inner limit of the diffraction layer cloud, and/or the out limit of the diffraction layer cloud and/or the inner limit of the gap in the diffraction layer cloud and/or the outer limit of the gap in the diffraction layer cloud. In one embodiment of the invention, the at least one calibration-free property is non-dimensionalized by dividing by at least one non-equivalent calibration-free property. In one embodiment of the invention, the chiral indices are determined by simultaneously solving at least two coupled equations which relate at least two non-dimensionalized calibration-free properties to the non-tilt-corrected chiral indices. In one embodiment of the invention, the at least two calibration-free properties to be non-dimensionalized are the distances between non-equatorial layer lines and the equatorial layer line and the non-dimensionalizing calibration-free property is the pseudo-periodicity of the diffraction intensity along the equatorial layer line. In one embodiment of the invention, the non-tilt-corrected chiral indices are determined by simultaneously solving at least two coupled algebraic equations which relate the tilt-corrected chiral indices to the order of at least two Bessel functions corresponding to the vertices of at least two hexagons indexed based on a honeycomb lattice structure of the wall of the tubular crystalline molecule. In one embodiment of the invention, the order of each Bessel function describing the variation in intensity of a signal from a given layer line is determined from at least one non-dimensionalized calibration-free property. In one embodiment of the invention, the calibration-free property to be non-dimensionalized is the distance between the first pair of maxima in the diffraction intensity along at least one non-equatorial layer line and the non-dimensionalizing calibration-free property is the pseudo-periodicity of the diffraction intensity along the same layer line. In one embodiment of the invention, the non-tilt-corrected chiral indices are tilt-corrected. In one embodiment of the invention, the tilt-correction is achieved by truncating the non-tilt-corrected chiral indices to the nearest lower integer. In one embodiment of the invention, the upper or lower limit of the chiral angle in a bundle of crystalline tubular molecules is determined by non-dimensionalizing the inner limit of the diffraction layer cloud and/or the inner limit of the gap in the diffraction layer cloud by the outer limit of the diffraction layer cloud and/or the outer limit of the gap in the diffraction layer cloud and solving an equation relating the non-dimensionalized inner limit to the molecule's chiral angle to determine the maximum and/or minimum chiral angle present in the bundle. Furthermore, the inventive idea includes a computer program for determining the atomic structure of at least one tubular crystalline molecule, which computer program is further adapted to perform the above mentioned method steps, when executed on a data-processing device. Furthermore, the inventive idea includes a device for determining the atomic structure of at least one tubular crystalline molecule, which device comprises means for performing the above mentioned method steps. The presented method according to the invention allows the direct determination of (n, m) chiral indices of SWCNTs from their EDPs. Uniquely, the method is absolutely calibration-free and errors in structure determination due to the tubular crystalline molecule inclination with respect to the incident beam are specified. The tilt angle of the carbon tubular crystalline molecule with respect to the incident electron beam can be simultaneously evaluated, thus the effect of the tube inclination can be compensated for in the determination of the structure. In addition, several independent procedures are proposed to cross-check the results based on the new perceptions of the diffraction pattern. The current invention, for the first time, allows the structure of tubular crystalline molecules to be unambiguously determined, and thus provides a means to exactly characterize the material. This is of enormous importance for both the scientific study and commercial application of such molecules in materials, components and devices. The method for determining the atomic structure of one or more tubular crystalline molecules is presented in FIG. 1. First, a diffraction pattern of one or more tubular crystalline molecules is obtained 10. Next one or more calibration-free properties, together with one or more non-dimensionalizing calibration-free properties are measured from the diffraction pattern 11. Next, the calibration-free properties are non-dimensionalized with the one or more non-dimensionalizing calibration-free properties 12. Finally, the structure-defining properties or the range of structure defining properties are obtained by solving one or more equations correlating the calibration-free properties to the structure defining properties 13. The invention is described for determining the chirality of one or more single-walled carbon Nanotubes as an example of a typical tubular crystalline molecule, but the method is easily applicable to any molecule which can be uniquely defined by one or more independent parameters. For carbon Nanotubes, these are the chiral indices, or equivalently, the diameter and chiral angle. The relationship between the two is shown schematically in FIG. 2 which depicts a graphene sheet where each hexagon 20 represents a ring of six carbon atoms. The hexagons referenced from an origin (0,0) 21 have chiral indices (n, m). Each additional hexagon is indexed as shown in the FIG. 2. A particular carbon nanotube can then be represented by a particular chiral index in which the sheet is rolled such that the origin overlaps the given indexed hexagon. The diameter Do 22 and the chiral angle α 23 of the nanotube are thus specified which in the example of FIG. 2 are shown for chiral indices (n, m)=(10, 5). In the method, at first, a diffraction pattern of one or more crystalline tubular molecules is obtained by, for instance, the use of a transmission electron microscope (TEM) or mathematical simulation. Typical measured and simulated diffraction patterns for single walled carbon nanotube are shown in FIGS. 3a and 3b where 30 is the equatorial layer line and 31 are non-equatorial layers lines. From such an image, one or more independent calibration-free properties can be measured which scale linearly when the image is scaled and so do not need to be calibrated with respect to each other. From the original diffraction pattern, the distance between pairs of layer lines satisfy this criterion. Shown are several layer line distances with respect to the equatorial layer line d1, d2, d3, d4, d5 and d6. Furthermore, as shown in FIG. 4, additional independent calibration-free properties are available from the intensity profile along any particular layer line 40. Each layer line represents a squared Bessel function of a particular order as will be explained in the examples. Independent calibration-free properties available from the intensity profile along any particular layer line i include, but are not limited to, Bi, the distance between the first pair of minima of the diffraction intensity along the layer line 41, Ai, the distance between the first pair of maxima in the diffraction intensity along a layer line 42, the pseudo-periodicity, δi, of the diffraction intensity along a layer line 43 and the area under the layer line intensity curve. Other possible properties of the diffraction pattern according to the method and the above list do not, in any way, limit the scope of the invention. These constitute the possible calibration-free properties to be non-dimensionalized. Subsequently, a third and independent calibration-free property is chosen from the same list. This becomes the non-dimensionalizing calibration-free property. By dividing the calibration-free properties to be non-dimensionalized by the non-dimensionalizing calibration-free property, a set of one or more non-dimensionalized calibration-free properties is obtained. Importantly, these are independent of the scaling of the diffraction pattern and so need not be absolutely or independently calibrated, by, for instance, a measured reference distance such as a ruler or a chemical bond length. Subsequently, a set of equations is chosen which relates the non-dimensionalized calibration-free property to the properties to be determined which define the structure of the molecule. In the case of carbon Nanotubes, two chiral indices are required, or equivalently, the Nanotube diameter and the chiral angle and, consequently, two non-dimensionalized calibration-free properties are needed to uniquely define the nanotube. For other crystal structures, other parameters are possible and the preceding examples, in no way, limit the scope of the invention. Subsequently, the structure defining properties are determined by solving the coupled equations relating them to the non-dimensionalized calibration-free properties. A number of mathematical means for achieving this are possible according to the invention including, but not limited to, solving a system of algebraic equations or minimizing the error between ideal and measured diffraction patterns. This will be made clearer in the following examples. In general, if the diffraction pattern is obtained from a molecule or a group of molecules not perpendicular to the incident beam generating the diffraction pattern, there will be an error in the calculated structure defining properties. The present invention allows this error to be corrected by truncation. This will be made clearer in the following examples where the method is applied to single walled carbon nanotubes to illustrate the execution of the method. This in no way limits the scope of the invention for other crystalline tubular molecules. In the preferred embodiment of the method according to the invention, the two or more calibration-free properties to be non-dimensionalized are the distances between non-equatorial layer lines and the equatorial layer line and the non-dimensionalizing calibration-free property is the pseudo-periodicity of the diffraction intensity along the equatorial layer line. FIG. 3a shows the EDP taken by a Philips CM200-FEG TEM operating at the highest possible accelerating voltage of 200 kV and a simulated EDP from a (23,10) SWCNT in a normal incidence. The microscope is equipped with a Gatan 794 multiscan CCD camera (1 k×1 k) for digital recording. The diffraction pattern is composed of many separate layer-lines parallel to each other but perpendicular to the tube axis. According to the kinematical diffraction theory of carbon nanotubes, the intensity profile along a certain layer-line is described by the sum of a series of squared Bessel functions. In particular, along the equatorial line 30 at the center, the dominant Bessel function is J0(πD0R), where R is the radial distance measured along the equatorial line from the diffraction center. Mathematically, Bessel functions have an infinite number of minima (alternately termed zeros or roots) pseudo-periodically spaced. In practice, when x=πD0R>>0, the zeroth-order Bessel function J0(πD0R) or simply J0(x), can be approximated by J 0 ⁡ ( x ) = 2 π ⁢ ⁢ x ⁢ cos ⁡ ( x - π 4 ) ,of which the roots are given by x j = π ⁢ ⁢ D 0 ⁢ R j = ( j - 1 4 ) ⁢ π ,where j is an integer greater than 1, and the interval between the neighboring roots is xj+1−xj=π. By this approximation we have then:D0·δ0=1, where δ0=Rj+1−Rj (1)It is worth remarking that the intensity profile on the equatorial line is totally independent of tube tilting, and thus so is the measurement of the value δ0. The spacing di (FIG. 1) of each non-equatorial layer-line measured from the equatorial line is subject to scaling by a tilt factor 1 cos ⁢ ⁢ τ ,where τ represents the tilt angle of the nanotube with τ=0° in the normal incidence condition. di of the three layer-lines for the first-order hexagons are assigned d1, d2, d3; and d4, d5, d6 for the second-order hexagons. Now by introducing a new term, the intrinsic layer-line spacing (ξi), which corresponds to each non-equatorial layer-line, is defined by:ξi=D0·di (2)By geometrical considerations, expressions for ξi of the six most important layer-lines corresponding to di(i=1, 2, . . . , 6) can be derived as ξ 1 = n - m 3 ⁢ π , ξ 2 = n + 2 ⁢ m 3 ⁢ π , ξ 3 = 2 ⁢ n + m 3 ⁢ π , ⁢ ξ 4 = 3 ⁢ m π , ξ 5 = 3 ⁢ n π , ξ 6 = 3 ⁢ ( n + m ) π . ( 3 ) For example, since D 0 = n 2 + m 2 + n ⁢ ⁢ m π · a , ⁢ d 3 = 1 d 010 · cos ⁢ ⁢ α ,where d 010 = 3 2 ⁢ a , and ⁢ ⁢ cos ⁢ ⁢ α = 2 ⁢ n + m 2 ⁢ n 2 + m 2 + n ⁢ ⁢ m ,we have ξ 3 = D 0 · d 3 = 2 ⁢ n + m 3 ⁢ π . Parameter α is the graphite lattice constant. ξi are nondimensional parameters and they are functions of only the chiral indices (n, m). On the other hand, ξi can be readily measured from the diffraction pattern by ξ i = d i δ if Eq. (1) and Eq. (2) are combined. It is obvious that the measured values of the intrinsic layer-line spacings (ξiτ) are scaled by 1 cos ⁢ ⁢ τ . The simultaneous solution of any two expressions of ξi from Eq. (3) will give chiral indices (n, m). For instance, the solution of n and m from ξ2 and ξ3 is: n = π 3 · ( 2 ⁢ ⁢ ξ 3 - ξ 2 ) , ⁢ m = π 3 · ( 2 ⁢ ξ 2 - ξ 3 ) ( 4 ) Or equivalently from ξ3 and ξ6, we have n = π 3 · ( 3 ⁢ ξ 3 - ξ 6 ) , ⁢ m = π 3 · ( 2 ⁢ ξ 6 - 3 ⁢ ξ 3 ) ( 5 ) In this way, the structure defining properties (the chiral indices) are determined by solving an algebraic system of equations relating them to the non-dimensionalized calibration-free properties of the diffraction pattern (ξ2 and ξ3 or ξ3 and ξ6) which are two pairs of distances between the non-equatorial layer lines and the equatorial layer line (d2 and d3 or d3 and d6) that are non-dimensionalized by δ, the pseudo-periodicity of the equatorial layer line. Other combinations are possible according to the invention. In more general cases, when the tilt angle τ is non-zero, the actual measured results (nτ,mτ) are given by: n τ = n · 1 cos ⁢ ⁢ τ = n + ɛ n , m τ = m · 1 cos ⁢ ⁢ τ = m + ɛ m ( 6 ) where εn and εm are tilt-effect errors, which are positive numbers. It is calculated that εi<2 (i=n or m) for nanotubes with n or m being approximately at value 30 at a tilt angle of τ=20°. When the tilt angle is small, so that 0≦εi<1, then:n=TRUNC(nτ) or m=TRUNC(mτ); (7)when the tilt angle becomes relatively large, so that 1≦εi<2, then:n=TRUNC(nτ)−1 or m=TRUNC(mτ)−1. (8) Here, TRUNC is a function to truncate a number into an integer by removing the fractional part of that number. After (n, m) is determined, the tilt angle τ can be calculated from Eq. (6) by cos ⁢ ⁢ τ = n n τ ⁢ ⁢ or ⁢ ⁢ cos ⁢ ⁢ τ = m m τ . Since the intrinsic layer-line spacings ξi are more sensitive to the tube tilting, the tilt angle is more robustly evaluated by cos ⁢ ⁢ τ = ξ i ξ i τ ,for instance, cos ⁢ ⁢ τ = ξ 3 ξ 3 τ = 2 ⁢ n + m 3 ⁢ π · ξ 3 τ = ξ 6 ξ 6 τ = 3 ⁢ ( n + m ) π · ξ 6 τ ( 9 ) With the tilt angle τ taken into account, the absolute calibration of the diffraction pattern can be carried out a posteriori by any of the layer-line spacings di, for example, d 3 = 2 ⁢ 3 3 ⁢ a · cos ⁢ ⁢ α ⁢ cos ⁢ ⁢ τ ( 10 ) Here, the graphite lattice constant α is known to be 0.246 nm. The major sources of error in the method arise from the intrinsic measurement errors of δ0=Rj+1−Rj and di, especially the relatively small magnitude of δ as a divisor to calculate the intrinsic layer-line spacing ξiτ. Another error source arises when the tilt angle is large so that there is no confident criterion in practice to make a correct selection between Eq. (7) or Eq. (8) to determine (n, m). In order to stay in the range where Eq. (7) is valid (i.e. so as not to invoke Eq. (8)), we introduce the tolerated tilt angle τmax for nanotubes of different (n, m). Theoretically τmax for a certain n can be estimated by cos ⁡ ( τ max ) = lim ɛ max → 1 - ⁢ ( n n + ɛ max ) . As the integer n increases, the tolerated tilt angle τmax decreases. For instance, supposing εmax=0.9, the tolerated tilt angle is allowed to be as large as 20° for n=15. In addition, based on Eq. (6), an intrinsic index ratio β, which is a function of (n, m), is introduced where β = m n = m + ɛ m n + ɛ n = ɛ m ɛ n ≤ 1 ,hence εm≦εn. It can be seen that the method allows equal or higher tilt angle to be tolerated when determining m (compared to n). In other words, it is favorable to first calculate m based on Eq. (7). n can then be more reliably derived by applying the intrinsic index ratio β, since β can be tilt-independently measured by β = m n = 2 ⁢ ξ 2 - ξ 3 2 ⁢ ξ 3 - ξ 2 according to Eq. (4); or by β = m n = 2 ⁢ ξ 6 - 3 ⁢ ξ 3 3 ⁢ ξ 3 - ξ 6 according to Eq. (5). By this procedure, in general situations when the tilt angle is not larger than 20°, SWCNTs with chiral indices (n, m) (n≧15≧m) can be directly measured without ambiguity by using Eq. (7) to first derive m. As before, n can be calculated by using the parameter β. If m or n is incorrectly determined due to, for example, pixelation errors, the mistake should be recognized easily from the resultant unreasonable tilt angle; or the results can be cross-checked by the n measurement based on Eq. (7) or Eq. (8). For example, from FIG. 2a (τ=5°), if m is incorrectly determined to be 6, n then should be 10 by applying the parameter β. The resultant tilt angle is then approximately 33°, which is too large to be a normal case. On the other hand, if n is incorrectly calculated to be 11, while m is correctly determined to be 7, this will signal a serious mismatch of the intrinsic ratio β between the measured value from ξiτ and the calculated value by m n .Determination of the tube diameter D0 after calibration of the EDP based on Eq. (10) can also be independently employed to verify the results. Of course, the results can further be cross-checked by measuring different layer-lines separately. When the tilt angle is beyond the tolerated limit, in addition to the above-mentioned cross-checking procedure, a trial-and-error procedure around all adjacent (n, m) candidates can be applied. It is worth noting that this method is also applicable for (n, m) determination of achiral nanotubes (i.e., armchair and zigzag tubes), with d1=0, d2=d3=d4=d5, d6=2d2 for an armchair nanotube; and d1=d2, d3=2d1, d4=0, d5=d6=3d1 for a zigzag tube. Since only the layer-line spacings di and the interval δ0 between the zeros along the equatorial line are involved in the measurement, the present method has no significant limitations. In contrast, the method has a high degree of flexibility and verifiability in that (n, m) can be determined by using many combinations of layer-line spacings. One important remark is that the EDP is required to resolve the zeros on the equatorial line so that δ0 can be measured with confidence. In the present alternate embodiment of the method, the chiral indices are determined by simultaneously solving two or more coupled algebraic equations which relate the tilt-corrected chiral indices to the order of two or more Bessel functions corresponding to the vertices of two or more hexagons indexed based on the honeycomb lattice structure of the wall of the tubular crystalline molecule. Here the calibration-free properties are first used to define the order of each Bessel function describing the variation in intensity of the signal from a given layer line. The calibration-free property to be non-dimensionalized is the distance between the first pair of maxima in the diffraction intensity along one or more non-equatorial layer lines and the non-dimensionalizing calibration-free property is the pseudo-periodicity of the diffraction intensity along the same layer line. Other combinations and choices of calibration-free properties to be non-dimensionalized and non-dimensionalizing calibration-free properties are possible according to the invention. The chiral indices (n, m) of a SWCNT are correlated with the orders of Bessel functions (squared) that act as shape factors for the diffraction from the nanotube. This enables direct evaluation of the chiral indices of carbon nanotubes. Unambiguous determination of (n, m) then depends on reliably retrieving the Bessel orders from the corresponding Bessel functions. Bessel factors have a mirror symmetry about x=0. For a Bessel factor having a non-zero order, there is always an “intensity-gap” around x=0, where the intensity is approaching zero. The width of the gap is also a function of the Bessel factor order. A higher order Bessel factor has a wider intensity-gap than a lower order Bessel factor. On the other hand, the interval between the first two positive roots δi of a Bessel factor increases much more slowly with the absolute value of the Bessel order \|ν\|. Therefore, non-dimensional characteristic ratios for each individual Bessel factor can be calculated by dividing Ai or Bi by δi as: R A i = A i δ i ⁢ ⁢ or ( 11 ) R B i = B i δ i ( 12 ) As examples, for Bessel factors of orders ν=9 and ν=10, RAi is 5.51 and 5.95 respectively, with an absolute difference of 0.44. Likewise, RBi is 6.87 and 7.31, also with a difference of 0.44. The corresponding differential precision for distinguishing these two Bessel factors is then 7.9% when using RAi, or 6.2% when using RBi. In the case of Bessel factors of higher orders ν=29 and ν=30, the absolute differences of their RAi ratios and of their RBi ratios are both as large as 0.31, with differential precisions being 2.4% and 2.2%, respectively. Therefore, the introduction of RAi and RBi allows much higher differential precisions for distinguishing adjacent Bessel factors, thus allowing the use of layer-lines dominated by high-order Bessel functions. Bessel function, which is associated with (n, m) by:ν=nh−mk, (13) Characteristic ratios RAi and RBi for Bessel factors of orders from ν=0 to 30 have been tabulated and listed in Table 1. By comparing the ratios measured from the intensity profiles along diffraction layer-lines with those listed in Table 1, Bessel orders can immediately be recognized, which are then ascribed to the chiral indices of the nanotube. By using several combinations of RAi and RBi from different layer-line measurements to complement and verify each other in a measurement, a high level of confidence can be achieved. TABLE 1Characteristic ratios RAi and RBi forBessel factors of orders from ν = 0 to 30.\|ν\|RARB11.1562.40721.8593.13032.4853.77443.0614.36653.6004.91864.1065.44074.5955.93785.0626.41395.5116.871105.9477.315116.3737.744126.7848.162137.1878.569147.5818.966157.9639.355168.3389.735178.70710.11189.07010.47199.42710.83209.77911.192110.1211.532210.4611.882310.8012.212411.1312.552511.4612.872611.7813.202712.1013.522812.4113.832912.7214.153013.0314.46 The method can be applied to determine range of chiral angles present in a bundle of SWCNTs. FIG. 5a shows a measured EDP of a bundle of SWCNTs taken by a Philips CM200-FEG TEM with chiral angels clustered near 30 degrees. The inner and outer limits (din and dout) of the diffraction layer cloud 50 correspond to the limits of the minimum chiral angle present in the bundle. By non-dimensionalizing din by dout according to equation (14): tan ⁢ ⁢ α = 1 3 ⁢ ( 2 ⁢ d i ⁢ ⁢ n d out - 1 ) , ( 14 ) the minimum chiral angle in the bundle is determined. FIG. 5b shows a simulated EDP of a bundle of SWCNTs with chiral angels clustered near zero. Here the inner and outer limits (din and dout) of the gap in the diffraction layer cloud 51 correspond to the limits of the maximum chiral angle present in the bundle. By non-dimensionalizing din by dout according to equation (14), the maximum chiral angle in the bundle can be determined. The method according to the invention is demonstrated on both simulated and experimental diffraction patterns of single-walled carbon nanotubes. The technique can be readily extended to structural analysis of nanotubes of other materials with structure analog to carbon nanotubes, such as boron nitride Nanotubes and carbon nanobuds. Material: (12,7) SWCNT Diffraction pattern from: Simulation Structure defining property: Chiral indices (n,m) Calibration-free properties to be non-dimensionalized: d3 and d6 Non-dimensionalizing calibration-free property: δ In order to test the method, we simulate a tilt-series of EDPs of a (12,7) SWCNT. Two of them are shown in FIG. 6 at tilt angels of 5 and 30 degrees. By applying the (ξ3,ξ6) set of equations, chiral indices (n, m) and the tilt angles τ are determined as summarized in Table 2, in which 2ξiτ (i=3 or 6) are measured from the simulated patterns; 2ξi(n,m) are calculated from Eq. (3). The tilt angles, τi (i=3 or 6), are determined by using the intrinsic layer-line spacings based on Eq. (9). It is clearly seen that, when the tilt angle is less than 20°, the chiral indices can be directly measured without ambiguity. The error for the case when the tilt is 5° (FIG. 2a) and εn=−0.02<0 is due to the pixel resolution limitation, which can be avoided by improving the pixel resolution of the EDP. As the tilt angle increases as large as 25°, εn=1.21>1, while εm=0.74<1; when the tilt angle reaches 30°, both εn and εm become larger than 1. In such situations, one must be cautious when calculating (n, m) from Eq. (7) or Eq. (8). This will be discussed later in more detail. TABLE 2Determination of chiral indices, (n, m), and tilt angles, τ, from a tilt-series of simulated EDPs of a (12, 7) tube by measuring d3 and d6 layer-lines.The listed tilt angles, τi (i = 3, or 6) are calculated based on Eq. (9).Simulated(n, m)tilt angles2ζ3τ2ζ3(12, 7)τ32ζ6τ2ζ6(12, 7)τ6nτnεnmτmεm(12, 7) 0°11.41311.3943.30°20.97920.9503.01°12.03120.037.0070.00 5°11.4133.30°21.0335.09°11.98(11 + 1)−0.02a7.1070.1010°11.5499.40°21.2509.64°12.15120.157.1270.1215°11.79314.93°21.68514.96°12.42120.427.2570.2520°12.12019.92°22.28319.92°12.77120.777.4470.4425°12.55424.83°23.09824.90°13.21(13 − 1)1.217.7470.7430°13.15229.97°24.18529.98°13.85(13 − 1)1.858.08(8 − 1)1.08aεn < 0 is due to the pixel resolution limitation (see the text). Material: (12,7) SWCNT Diffraction pattern from: TEM Structure defining property: Chiral indices (n,m) Calibration-free properties to be non-dimensionalized: d2, d3 and d6 Non-dimensionalizing calibration-free property: δ To apply the method to real problems, high-quality EDPs of individual SWCNTs are essential but in reality difficult to obtain because of their weak scattering power and the tendency for the tubes to be easily modified by the electron beam. FIG. 3a shows a high-resolution TEM image of an individual SWCNT. The (ξ2,ξ3) set of equations and the (ξ3,ξ6) set of equations are independently employed for the calculations with results summarized in Table 2 (a) and Table 2 (b), respectively. The chiral indices (n, m) of the SWCNT are thus determined to be (23, 10) and the tilt angle τ is determined to be approximately 10° from both equation sets. With the tilt angle τ=10° taken into account, we can accurately calibrate the diffraction pattern by using, for instance, d 3 = 2 ⁢ 3 3 ⁢ a · cos ⁢ ⁢ α cos ⁢ ⁢ τ ⁢ 4.554 ⁢ ⁢ nm - 1 ;hence the tube diameter is determined to be 2.29 nm from the EDP based on Eq. (1), which accurately matches the (23, 10) tube. Material: (23,10) SWCNT Diffraction pattern from: Simulation Structure defining property: Chiral indices (n,m) Calibration-free properties to be non-dimensionalized: d3 and d6 Non-dimensionalizing calibration-free property: δ A simulated EDP of the (23, 10) nanotube at a tilt of 10° is presented in FIG. 3b, on which a similar measurement is performed. The corresponding results are also listed in Table 2 (a) and 2 (b) for comparison. Again, there is an excellent match between results from the simulated diffraction pattern and the experimental pattern. Material: (25,2) SWCNT Diffraction pattern from: Simulation Structure defining property: Chiral indices (n,m) Calibration-free properties to be non-dimensionalized: Ai and Bi Non-dimensionalizing calibration-free property: δi As an example, FIG. 7a presents a simulated normal-incidence diffraction pattern of a chiral (25,2) single-walled carbon nanotube. FIGS. 7c and 7b show the corresponding intensity profiles along the L2 and L3 layer-lines. Table 3 lists the ratios RAi and RBi calculated from both the L2 and L3 layer-lines. By comparing with their nearest characteristic values in Table 1, the Bessel orders are directly recognizable as νn=25 and νm=2 accordingly for L2 and L3 layer-lines with little ambiguity. TABLE 3Ratios RAi and RBi determined from L2 and L3 layer-lines on thediffraction patterns of a (25, 2) nanotube, and the correspondingbest fit values of the Bessel orders.L2 Layer-lineL3 Layer-lineDetermineddeterminedνmRatiosvaluesνn of the best fitvaluesof the best fitRAi11.5251.882RBi13.0253.202 Material: (18,11) SWCNT Diffraction pattern from: TEM Structure defining property: Chiral indices (n,m) Calibration-free properties to be non-dimensionalized: Ai and Bi Non-dimensionalizing calibration-free property: δi The proposed method has been applied to determine the chiral indices of real single-walled carbon nanotubes. FIG. 8a shows the EDP of an individual SWCNT taken by a Philips CM200-FEG TEM operating at the highest possible accelerating voltage of 200 kV. The microscope is equipped with a Gatan 794 multiscan CCD camera (1 k×1 k) for digital recording. The layer-lines passing through (0, 1) and (1, 1) reflections as labeled L3 and L6 in FIG. 8a are employed for (n, m) determination. The intensity profiles along L3 and L6 layer-lines are shown in FIGS. 8 (c) and (b), respectively. From L3 layer-line, RAi is calculated to be 6.53, based on which the chiral index m is confidently identified as 11. Likewise, from L6 layer-line RAi is calculated to be 4.0, giving the value n−m=7, thus n is recognized to be 18. This (23, 10) tube is a semiconducting nanotube of diameter D0=2.29 nm, and chiral angle α=17.2°. TABLE 4Ratios and determined from L3 and L6 layer-lines on the diffractionpatterns of a (25, 2) nanotube, and the corresponding best fit valuesof the Bessel orders.L3 Layer-lineL6 Layer-lineDetermineddeterminedνn−mRatiosvaluesνm of the best fitvaluesof the best fitRAi4.0114.47RBi5.5116.17 Material: Bundle of SWCNTs having a high chiral angle Diffraction pattern from: TEM Structure defining property: Minimum chiral angle (α) in the bundle Calibration-free properties to be non-dimensionalized: din Non-dimensionalizing calibration-free properties: dout The proposed method is applied to determine range of chiral angles present in a bundle of SWCNTs. FIG. 5a shows a measured EDP of a bundle of SWCNTs with chiral angels clustered near 30 degrees. The inner and outer limits (din and dout) of the diffraction layer cloud correspond to the limits of the minimum chiral angle present in the bundle. By non-dimensionalizing din by dout according to equation (14), the minimum chiral angle in the bundle is determined to be 23.9 degrees. Material: Bundle of SWCNTs having a low chiral angle Diffraction pattern from: Simulation Structure defining property: Maximum chiral angle (α) in the bundle Calibration-free properties to be non-dimensionalized: din Non-dimensionalizing calibration-free properties: dout FIG. 5b shows a simulated EDP of a bundle of SWCNTs with chiral angles clustered near zero. Here the inner and outer limits (din and dout) of the gap in the diffraction layer cloud correspond to the limits of the maximum chiral angle present in the bundle. By non-dimensionalizing din by dout according to equation (14), the maximum chiral angle in the bundle is determined to be 13.9 degrees. It is obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways. The invention and its embodiments are thus not limited to the examples described above; instead they may vary within the scope of the claims.
047568771	abstract	A core support system for a core barrel of a nuclear reactor, which core barrel has a bottom core support plate wherein the core support plate has apertures therethrough about the periphery thereof which communicate with recesses in engagement means for the core support plate, and keys inserted into the core support plate apertures and secured thereto with the lower section of the key extending into the recess of the engagement means. The method of installation enables alignment and securement of the core barrel in the pressure vessel without need for an assembler to enter the area between the core barrel support plate and the bottom of the vessel.
	abstract	There is provided a collector. The collector includes a first mirror shell positioned inside a second mirror shell that has a chamfered end.
	description	The invention relates to a protective screen for the screening off of a suction space and of a suction duct connected to it. A reactor in a nuclear power plant is surrounded by a safety container of concrete and steel, the so-called containment. Furthermore, the reactor is equipped with an emergency cooling system (termed Emergency Core Cooling or ECC in English) in order to cool the reactor core in the event of a malfunction or incident. In such a case the water is sucked in from the lowermost part of the safety container, the so-called sump, by emergency cooling pumps via suction ducts and circulated through the reactor core. In the design scenario for the emergency cooling system it is assumed that insulation debris and chunks of concrete which arise in an incident can fall down into the sump and/or be washed down into the sump by the downwardly flowing water. In order that the debris do not impair the ability of the emergency cooling system to operate, special screen elements, referred to as protective screens herein, are provided in front of the inlet openings of the suction ducts which lead to the emergency cooling pumps. These protective screens have the task of keeping back the debris resulting from the incident and simultaneously ensuring an adequate through-flow of water. In this connection it must be ensured that the pressure drop caused by the debris does not exceed the permissible limiting value. Previously known protective screens used in nuclear power plants with pressure water reactors (PWR) are mainly formed as flat grid segments which have only a small screen surface and which in the event of contamination with fibrous debris materials produce an impermissibly high pressure drop. Protective screen elements of corrugated and perforated sheet metal offer a larger effective screen area. However, deformations occur under pressure loading which restrict the size of such protective screen elements. A cylindrical suction screen is described in EP 0 818 227 A1 which admittedly has a very large effective screen area but can only be used in rare cases in the sump region of a PWR nuclear power plant, because the direct environment of the inlet openings of the suction ducts is constructed in such a way that it is unsuitable for the use of cylindrical suction screens. A suction space for the installation of protective screen elements with a suitable screen area is mainly provided in front of the inlet openings of the suction ducts. For space reasons the suction space in the sump region of a PWR nuclear power plant is, on average, relatively shallow. An object of the present invention is to make available a protective screen the effective screen area of which is substantially larger, for example several times larger, than the area which results from the external dimensions and which can be used for the screening off of the suction space and of a suction duct connected to it in the sump region of a PWR nuclear power plant. This object is satisfied with the protective screen described in accordance with the embodiments of the present invention. The protective screen in accordance with the invention for the screening off of the suction space and of the suction duct connected thereto, in particular of a suction space and a suction duct in an emergency cooling system of a nuclear power plant, includes at least one screen wall element which has a suction side and an outflow side. The screen wall element is built up from one or more modular rectangular (or four-cornered) cassette units, with the cassette units each containing a plurality of suction pockets open towards the suction side, wherein the screen pockets are surrounded by outflow gaps, the outflow gaps being connected to the outflow side or open towards the outflow side. The cassette units can preferably be placed in a row, for example in one direction in order to assemble the screen wall element in the desired size. The screen pockets are preferably each surrounded on four sides by outflow gaps. In a preferred embodiment the cassette units contain spaced-apart walls and/or intermediate walls and bent perforated wall segments, in particular essentially U-shaped, bent, perforated wall segments between the walls and/or the intermediate walls in order to form suction pockets. A plurality of U-shaped bent wall sections can advantageously be formed in an elongate, meander-shaped part. The walls and/or the intermediate walls of the cassette units are preferably formed as double walls and/or outflow gaps. The suction pockets preferably have a depth of greater than 0.1 m, in particular greater than 0.2 m. In a preferred embodiment the walls and/or the intermediate walls of the cassette units are clamped against one another by connection elements such as for example bolts or pins. The spacing between two walls and/or intermediate walls and/or the spacing between the two sides of a double wall is preferably determined by spacer elements. In a further preferred embodiment the walls and/or the intermediate walls and/or the U-shaped bent wall segments are manufactured from perforated, preferably pierced sheet metal. The protective screen in accordance with the invention has the advantage that relatively large area and comparatively shallow screen wall elements can be assembled with the cassette units. I.e. the length and width of the screen wall elements can be selected in a wide range, while the thickness is typically significantly smaller in comparison to the length and/or width. Furthermore, it is possible to assemble a plurality of screen wall elements into a larger protective screen and/or a protective screen with a complex shape. Thus, the protective screens in accordance with the invention are particularly suited for the screening off of the suction space and of a suction duct connected to it in the sump region of a PWR nuclear power plant, where suction spaces of different sizes have to be screened off and the height which is available is restricted. The protective screen in accordance with the invention is particularly suited for the retro-fitting to existing plants in which the protective screen with an inadequate screen area is intended to be replaced or has to be replaced by a protective screen with a larger effective screen area. It is particularly advantageous that the pocket-like design of the screen surface enables a penetration flow which can flow away in five directions. The protective screens in accordance with the invention typically have an effective screen area which is five to twenty times larger than a protective screen consisting of a planar screen surface with corresponding outer dimensions. Thanks to the larger effective screen area, the debris and materials which cover the screen area and the water penetration speed give rise to a substantially lower through-flow resistance, so that the pressure drop which arises across the protective screen is correspondingly reduced. A further advantage of the protective screen in accordance with the invention is the pressure loadability of the screen wall elements assembled from the cassette units. The walls and intermediate walls respectively of the cassette units which are held under stress and the limbs of the U-shaped bent wall segments form a grid-like network of reinforcing ribs so that the cassette units have a high degree of shape stability and can be loaded with a higher pressure than, for example, a corrugated sheet metal of corresponding size. Further advantageous embodiments can be understood from the following description taken in conjunction with the accompanying drawings. FIG. 1 shows a section through an embodiment of a suction position for cooling water, in particular a suction position in the sump region of a nuclear power plant, in particular of a PWR power plant. In the embodiment, a protective screen 1 in accordance with the present invention is arranged above a suction space 3 which is connected by a suction duct 5 to a pump, which is not shown in FIG. 1. A suction flow 7 produced by the pump out of the suction space 3 passes into an inlet opening 6 of the suction duct 5 arranged in the suction space. The suction space 3 is bounded towards the top by the protective screen 1 and in the other directions by a wall 4, which can for example consist of concrete. The protective screen 1 screens the suction space 3 off from the top and prevents debris and disturbing parts, such as for example pieces of insulation materials, which are carried along by the cooling water from being able to enter into the suction space 3 and the suction line 5. Support elements 1a are provided in the upper part of the suction space 3 on which the protective screen 1 is arranged. They can for example consist of steel sections, such as for example angle sections, T-sections or H-sections. In the embodiment the protective screen 1 and the suction space 3 are arranged below a water level 8 which covers over the sump region of a safety container not shown in FIG. 1. A protective roof 9 is provided in the embodiment above the protective screen 1 and spaced from it. The protective roof protects sidewise beyond the protective screen in order to protect the protective screen from mechanical damage. Furthermore debris rakes 9a are provided in the inlet region to the side of the protective screen 1 between the protective roof 9 and the wall 4 in order to keep back larger pieces of debris. FIG. 2 shows a further embodiment of a suction position with a screen wall element of a protective screen in accordance with the present invention seen in a perspective view. The screen wall element 2 is assembled from four modular rectangular cassette units 11.1-11.4 which are arranged sidewise in a row in one direction. It should be noted that the number and the arrangement of the cassette units can be varied in order to assemble screen wall elements of the desired size. The layout of the cassette units 11.1-11.4 is explained in more detail in the following sections. The screen wall element 2 has a suction side 12 and an outflow side which is not visible in the present perspective view. The screen wall element 2 is arranged above a suction space 3 which is formed on one side by the screen wall element 2 and on the opposite side by a wall element 4 which can for example be a concrete plate. A base plate of a safety container, or a different constructional part at or in the safety container of a nuclear power plant, can also be used as the wall element 4. In the embodiment two parallel beams and/or spacer elements 1a are arranged on the wall element 4 on which the screen wall element 2 is secured. The beam elements or spacer elements, which can for example be executed as H-like steel sections, serve simultaneously as a lateral boundary for the suction space 3. In FIG. 2 the suction space 3 is shown open in the two remaining directions, so that the construction of the suction position can be better recognized. In order to complete the construction the suction space 3 must be closed at the open sides by means of wall elements and must in addition be correspondingly lengthened if the inlet opening of the suction duct is located outside the region shown. In a preferred embodiment a plurality of boundary surfaces of a suction space are screened off by means of screen wall elements. In this manner it is, for example, possible to form a suction body, or a screen body, which is matched to the constructional environment. FIG. 3 shows a perspective view of a cassette unit of the embodiment shown in FIG. 2. The cassette unit 11 has a suction side 12 and an outflow side 13 and includes outer walls 14.1, 14.2 and, depending on the requirements, one or more intermediate walls 15.1, 15.2, the outer walls and intermediate walls being arranged spaced from one another. Furthermore the cassette unit 11 includes bent and perforated wall segments 16.1, 16.2 between the outer wall 14.1, 14.2 and intermediate walls 15.1, 15.2 respectively in order to form suction pockets 17.1, 17.2. The bent wall segments can for example be U-shaped, V-shaped or similarly shaped. Advantageously, wall segments 16.1, 16.2 arranged in a row are formed as elongate meandering parts. The walls 14.1, 14.2 and/or intermediate walls 15.1, 15.2 and/or the bent wall segments (16, 16.1, 16.2) are preferably manufactured from perforated sheet metal. The diameter of the perforation holes typically lies in the range from 1 to 10 mm, preferably from 2 to 5 mm. The suction pockets 17.1, 17.2 preferably have a depth of greater than 0.1 m, in particular greater than 0.2 m. The walls 14.1, 14.2 and/or intermediate walls 15.1, 15.2 are connected and clamped together in the embodiment by means of connection elements 18.1, 18.2. FIG. 4 shows an enlarged section of an embodiment of the cassette unit shown in FIG. 3 in a perspective view. In this variant the walls and/or intermediate walls of the cassette units 11 are perforated and formed as double walls 14.1′, 14.1″, 14.2′, 14.2″, 15.1′, 15.1″, 15.2′, 15.2″. The double walls are preferably closed off towards the suction side and open to the outflow side so that they form outflow gaps 21, 21.1, 21.2. Due to the double walls, the suction pockets 17 are surrounded on at least two sides by the named outflow gaps 21, 21.1, 21.2 through which the water flowing out of the suction pocket into the double walls can flow away. FIG. 5a shows a cross-section through two suction pockets lying alongside one another in accordance with a further variant of the present invention. The walls and the intermediate walls are likewise executed in this variant as double walls 14.1′, 14.1″, 14.2′, 14.2″, 15.1′, 15.1″. The double walls are for example each formed from two, perforated, spaced-apart wall parts which are designed so that the double walls are closed off towards the suction side whereas they are open towards the outflow side. Respective, perforated, U-shaped, bent wall segments 16.1, 16.2 are arranged between double walls 14.1′, 14.1″, 14.2′, 14.2″, 15.1′, 15.1″ and form suction pockets 17.1, 17.2 together with the double walls. The double walls serve in this arrangement as lateral outflow gaps 21, 21.1, 21.2 through which lateral penetration flows can flow away out of the suction pockets. The reference numeral 25 thereby designates the suction side inflow direction and the reference numeral 26 the outflow direction. Further penetration flows out of the suction pockets flow through the perforated, U-shaped, bent wall segments 16.1, 16.2. The double walls 14.1′, 14.1″, 14.2′, 14.2″, 15.1′, 15.1″ and/or the wall parts of the same are connected by means of connection elements 18.1, 18.2, which can for example be formed as screws, threaded bolts or pins, and can be clamped against one another. The mutual spacing of the wall parts in the double walls can for example be fixed by spacer elements 24, 24.1, 24.2, while the distance between the double walls is determined by the perforated, U-shaped, bent wall segments 16.1, 16.2. FIG. 5b shows a longitudinal section through a row of suction pockets in accordance with the variant shown in FIG. 5a. A row of perforated U-shaped bent wall segments are formed in an elongate-shaped meandering part 16. This part can be favorably manufactured by bending operations, for example from perforated sheet metal. In the meandering part 16 outflow gaps 22, 22.1 are formed between the U-shaped bent wall segments which are closed towards the suction side and open towards the outflow side. The reference numeral 25 thereby designates the suction side inflow direction and the reference numeral 26 the outflow direction. The U-shaped bent wall segments, together with the walls or double walls 15.1, form the suction pockets 17.1, 17.2, 17.n. The suction pockets in accordance with the variant shown in FIGS. 5a and 5b have the advantage that they are surrounded on four sides by outflow gaps 22, 22.1, 21.2, 21, 21.1. In addition, the penetration flow which is sucked through the base of the suction pockets can flow away direct to the outflow side; i.e. the outflow of the penetration stream from the suction pockets takes place to all sides without disturbing resistance. FIG. 5c shows a perspective view of such a suction pocket 17 with a marking of the outflow directions 26, 26.1, 26.2, 26.3, 26.4 of the penetration flows. In comparison to planar protective screens of conventional construction the protective screens in accordance with the present invention have a substantially larger effective screen area for the same length and width. Debris and materials which cover the suction surface thus cause a substantially lower through-flow resistance, so that the pressure drop which arises across this protective screen of the invention is correspondingly reduced. A further advantage of the protective screen in accordance with the invention is the comparatively high shape stability and ability to be loaded with pressure as well as the robust structure which facilitates installation work and repair work.
	claims	1. A mask data generation method, comprising:arranging first and second auxiliary patterns adjacent to a device pattern, andperforming, by a computer, an optical proximity correction (OPC) process,wherein a first distance at which the first auxiliary pattern is spaced from a short side of the device pattern is set to be longer than a second distance at which the second auxiliary pattern is spaced from a long side of the device pattern upon arranging auxiliary patterns. 2. The mask data generation method according to claim 1, wherein:the first distance varies depending upon a dimension of the short side of the device pattern. 3. The mask data generation method according to claim 1, wherein:the first distance is predetermined with a table lookup method by a dimension of the short side of the device pattern. 4. The mask data generation method according to claim 1, wherein:the first distance falls within a range from a minimum dimension to 1.6 times the minimum dimension. 5. The mask data generation method according to claim 1, wherein:the auxiliary pattern spaced from the short side of the device pattern is located a minimum separation dimension away from a position of an OPC pattern obtained by an OPC process without the auxiliary patterns. 6. A mask produced by the mask data generation method according to claim 1. 7. A mask produced by the mask data generation method according to claim 2. 8. A mask produced by the mask data generation method according to claim 3. 9. A mask produced by the mask data generation method according to claim 4. 10. A mask produced by the mask data generation method according to claim 5. 11. A mask data generation method, comprising:arranging first and second auxiliary patterns adjacent to a device pattern, andperforming, by a computer, an optical proximity correction (OPC) process,wherein a first distance at which the first auxiliary pattern is spaced from a first side of the device pattern is set to be longer than a second distance at which the second auxiliary pattern is spaced from a second side of the device pattern upon arranging auxiliary patterns. 12. The mask data generation method according to claim 11, wherein:the first distance varies depending upon a dimension of the first side of the device pattern. 13. The mask data generation method according to claim 11, wherein:the first distance is predetermined with a table lookup method by a dimension of the first side of the device pattern. 14. The mask data generation method according to claim 11, wherein:the first distance falls within a range from a minimum dimension to 1.6 times the minimum dimension. 15. The mask data generation method according to claim 11, wherein:the auxiliary pattern spaced from the first side of the device pattern is located a minimum separation dimension away from a position of an OPC pattern obtained by an OPC process without the auxiliary patterns. 16. A mask produced by the mask data generation method according to claim 11. 17. A mask, comprising:first and second auxiliary patterns being arranged adjacent to a device pattern,wherein a first distance at which the first auxiliary pattern is spaced from a first side of the device pattern is set to be longer than a second distance at which the second auxiliary pattern is spaced from a second side of the device pattern upon arranging auxiliary patterns. 18. The mask according to claim 17, wherein:the first distance varies depending upon a dimension of the first side of the device pattern, and wherein said first side comprises a short side and said second side comprises a long side of the device pattern. 19. The mask method according to claim 17, wherein:the first distance is predetermined with a table lookup method by a dimension of the first side of the device pattern. 20. The mask according to claim 17, wherein:the first distance falls within a range from a minimum dimension to 1.6 times the minimum dimension.
	abstract	Provided is a scanning probe microscope (SPM), a probe of which can be automatically replaced and the replacement probe can be attached onto an exact position. The SPM includes a first scanner that has a carrier holder, and changes a position of the carrier holder in a straight line; a second scanner changing a position of a sample on a plane; and a tray being able to store a spare carrier and a spare probe attached to the spare carrier. The carrier holder includes a plurality of protrusions.
	claims	1. A Fourier ptychographic imaging system employing embedded pupil function recovery, comprising:a variable illuminator configured to illuminate a sample at a plurality of oblique illumination incidence angles;an objective lens configured to filter light issuing from the sample based on its numerical aperture;a radiation detector configured to receive light filtered by the objective lens and capture a plurality of intensity images corresponding to the plurality of oblique illumination incidence angles; anda processor configured to iteratively and simultaneously update a pupil function and a separate sample spectrum, wherein the sample spectrum is updated iteratively for each illumination incidence angle at overlapping regions in the Fourier domain with Fourier transformed intensity image data, wherein the overlapping regions correspond to the plurality of illumination incidence angles and the numerical aperture of the objective lens. 2. The Fourier ptychographic imaging system of claim 1, wherein the processor further configured to inverse transform the updated sample spectrum to determine an image of the sample, wherein the image has a higher resolution than the captured intensity images. 3. The Fourier ptychographic imaging system of claim 1,wherein the processor is further configured to determine an aberration from the updated pupil function; andfurther comprising a wavefront modulator configured to adaptively correct an incident wavefront based on the determined aberration. 4. The Fourier ptychographic imaging system of claim 1, wherein the objective lens has a numerical aperture between about 0.02 and 0.13. 5. The Fourier ptychographic imaging system of claim 1, wherein the objective lens has a numerical aperture of about 0.08. 6. The Fourier ptychographic imaging system of claim 1, wherein the variable illuminator comprises a plurality of discrete light elements, wherein the plurality of oblique illumination incidence angles are associated with different discrete light elements. 7. The Fourier ptychographic imaging system of claim 1, wherein the variable illuminator comprises a circular array of discrete light elements. 8. The Fourier ptychographic imaging system of claim 1, wherein the overlapping regions overlap by between 20% and 90% in area. 9. The Fourier ptychographic imaging system of claim 1, wherein the overlapping regions overlap by between 2% and 99.5% in area. 10. The Fourier ptychographic imaging system of claim 1, wherein the overlapping regions overlap by about 66% in area. 11. A method of Fourier ptychographic imaging employing embedded pupil function recovery, the method comprising:illuminating a sample from a plurality of incidence angles using a variable illuminator;filtering light issuing from the sample using an optical element;capturing a plurality of variably-illuminated intensity image distributions of the sample using a radiation detector;simultaneously updating a pupil function and a separate sample spectrum, wherein the sample spectrum is updated in overlapping regions with Fourier transformed variably-illuminated intensity images measurements, wherein the overlapping regions corresponds to the plurality of incidence angles and the numerical aperture of the lens; andinverse Fourier transforming the recovered sample spectrum to recover an image having a higher resolution than the intensity images. 12. The method of Fourier ptychographic imaging employing embedded pupil function recovery of claim 11, the method further comprising inverse transforming the updated sample spectrum to determine an image of the sample, wherein the image has a higher resolution than the captured intensity images. 13. The method of Fourier ptychographic imaging employing embedded pupil function recovery of claim 11, the method further comprising:determining an aberration from the updated pupil function; andadaptively correcting for the determined aberration using a wavefront modulator. 14. The method of Fourier ptychographic imaging employing embedded pupil function recovery of claim 11, wherein the objective lens has a numerical aperture between about 0.02 and 0.13. 15. The method of Fourier ptychographic imaging employing embedded pupil function recovery of claim 11, wherein the objective lens has a numerical aperture of about 0.08. 16. The method of Fourier ptychographic imaging employing embedded pupil function recovery of claim 11, wherein the variable illuminator comprises a circular array of discrete light elements. 17. The method of Fourier ptychographic imaging employing embedded pupil function recovery of claim 11, wherein the overlapping regions overlap by between 20% and 90% in area. 18. The method of Fourier ptychographic imaging employing embedded pupil function recovery of claim 11, wherein the overlapping regions overlap by between 2% and 99.5% in area. 19. The method of Fourier ptychographic imaging employing embedded pupil function recovery of claim 11, wherein the overlapping regions overlap by about 66% in area.
	claims	1. A deflector array comprising:a plurality of deflectors, which deflect charged particle beams, arrayed on a substrate,wherein each of said plurality of deflectors includes a single opening formed in the substrate, and each of said plurality of deflectors including a pair of electrodes that oppose each other through the opening and being configured to deflect a single charged particle beam, andwherein said plurality of deflectors are arrayed such that a length of said pair of electrodes in a longitudinal direction thereof is not less than a distance between centers of two of said plurality of deflectors that are located nearest to each other, said plurality of deflectors being arrayed to form a checkerboard lattice, and two openings of the two of said plurality of deflectors overlapping in the longitudinal direction. 2. The deflector array according to claim 1, wherein said pair of electrodes are formed such that a distance between said pair of electrodes shortens from centers toward end portions of said pair of electrodes. 3. An exposure apparatus which exposes a wafer with a charged particle beam, the apparatus comprising:a charged particle source which emits the charged particle beam;a first electron optical system which forms a plurality of intermediate images of said charged particle source;a second electron optical system which projects the plurality of intermediate images formed by said first electron optical system onto the wafer; anda positioning apparatus which holds and positions the wafer,wherein said first electron optical system includes a deflector array defined in claim 1. 4. A method of manufacturing a device, the method comprising:exposing a wafer with a charged particle beam using an exposure apparatus defined in claim 3;developing the exposed wafer; andprocessing the developed wafer to manufacture the device. 5. The deflector array according to claim 1, wherein the deflector array includes deflectors with three rows and three columns.
	description	The invention relates to a method and an imaging system for generating X-ray images with an X-ray source and an X-ray detector. Moreover, it relates to an X-ray generator for such an imaging system. From the WO 2010/0055930 A1, an X-ray imaging apparatus is known which comprises a plurality of X-ray sources, a collimator with a plurality of slits, and an X-ray detector with a plurality of detecting elements. Selective activation of an X-ray source and modification of the collimator geometry allows to vary the projection view without a physical movement of detector or X-ray source. It was an object of the present invention to provide improved means for the X-ray imaging of an object with a pixelated detector, wherein it is particularly desirable to achieve a better exploitation of the X-ray dose the object is exposed to. This object is achieved by an X-ray imaging system according to claim 1, a method according to claim 2, and an X-ray generator according to claim 11. Preferred embodiments are disclosed in the dependent claims. According to a first aspect, the invention relates to an X-ray imaging system for generating X-ray images of an object, for example of a patient in a medical X-ray laboratory, or of a piece of luggage in a security system, wherein the X-ray detector has for technical reasons radiation insensitive areas between pixels inside the illuminated area. The generated images will in general consist of projections of the object, which may optionally be synthesized to sectional images by Computed Tomography (CT). The X-ray imaging system comprises the following components: a) At least one X-ray source for generating an X-ray beam. In this context, the term “X-ray” shall in a broad sense comprise any high-energy electromagnetic radiation, typically radiation with a wavelength between about 10−8 and 10−12 m. The generated X-ray beam may in general have any geometry, consisting for example of (approximately) parallel X-rays. Most preferably, each X-ray source is however approximately point-like (in relation to the other components of the imaging system), yielding a fan-shaped or cone-shaped X-ray beam.b) An X-ray detector that comprises an array of X-ray sensitive units or elements separated by X-ray insensitive regions between said units (i.e. regions that do not convert received radiation into useful measurement signals). As the detection signal of these units usually corresponds to image information at a particular point of the generated projection, these sensitive units will in the following as usual be called “pixels”. The array comprises at least two of these pixels, typically however a large number of several thousands of pixels that are arranged in a one- or two-dimensional pattern. The X-ray detector is arranged in the field of view of the X-ray source such that the pixels can be reached by the generated X-ray beam.c) A collimator that comprises at least two openings, wherein the geometry of X-ray source, X-ray detector, and collimator is such that the at least two openings allow the passage of X-rays from at least one X-ray source such that at least two neighboring pixels of the detector are illuminated while the radiation-insensitive region between said pixels is at least partially shielded from X-rays by the material of the collimator, i.e. it is illuminated with a weaker intensity. Typically, the intensity between the pixels is less than 75%, preferably less than 50%, most preferably less than 10% of the intensity within the pixels (when no object is present). The considered two openings are usually neighboring openings of the collimator.d) An object space where an object to be imaged can be accommodated, said object space being located between the collimator and the X-ray detector. According to a second aspect, the invention relates to a method for generating an X-ray image with an X-ray imaging system, particularly with an X-ray imaging system of the kind described above. The method comprises the following steps, which are typically executed simultaneously: a) Generating an X-ray beam with at least one X-ray source. b) Detecting X-rays of said beam at the positions of pixels of an array of pixels of an X-ray detector. c) Allowing the passage of X-rays from said X-ray beam through at least two openings of a collimator such that at least two neighboring pixels of the detector are illuminated while the radiation-insensitive region between said pixel positions is at least partially shielded.d) Accommodating an object to be imaged between the collimator and the detector. In some X-ray imaging systems (as for example those commonly used in Computed Tomography), the region between two (neighboring) pixels of a pixelated X-ray detector is insensitive to X-radiation due to the design of the detector. Insensitive separation components may for example be located in these regions, or the regions may be occupied by an anti-scatter grid. X-rays that are directed towards such regions between two pixels will therefore not contribute to an image but only increase the dose an object is exposed to. Furthermore, such rays may even be counterproductive as they contribute to scattered radiation which compromises image quality. These negative effects are avoided in the imaging system and the method described above due to the collimator that shields the region between two pixels and that allows the passage of X-radiation only towards the sensitive pixel areas. In the following, various preferred embodiments of the invention will be described that relate both to an imaging system and a method of the kind described above. Thus the openings in the collimator may preferably be slits having an elongated geometry (e.g. with a rectangular shape) with a diameter in length-direction being several times larger than a diameter in the orthogonal width-direction. Preferably the slits may be such that they generate fan-shaped beams which illuminate a stripe on the pixel array extending from one border of the detector to the opposite. In an alternative embodiment, the openings may be holes, i.e. they have a compact (e.g. circular, square or rectangular) shape. Most preferably, the holes have a shape that corresponds substantially to the shape of the pixels of the detector. In this case the complete X-ray sensitive area of one pixel can optimally be illuminated through such an opening with an adequate small source. It was already mentioned that the pixel array of the X-ray detector will typically comprise (much) more than two radiation sensitive pixels. In a preferred embodiment, these pixels are aligned in a quasi-periodical array and, by means of the collimator, are illuminated with a higher intensity than radiation insensitive regions between them in at least one direction of (quasi-) periodicity of the array. In general, a large multi-pixel sub-area of the detector can be illuminated by an X-ray source through one opening of the collimator. To optimize the shielding of insensitive regions between the pixels, it is however preferred that the size and arrangement of at least one opening of the collimator and of at least one X-ray source is such that substantially only one pixel or substantially only one row of pixels is illuminated through said opening. Most preferably, all openings of the collimator fulfill these conditions. While the advantages of the invention can already be achieved with just two openings in the collimator, it is preferred that the collimator comprises an array typically having a higher number of openings which are one- or two-dimensionally aligned with the pixels of the detector. In this context, “alignment” of the openings with the pixels shall mean that any two neighboring openings allow the passage of X-rays towards two neighboring pixels while the region between said pixels is substantially shielded. To put it in other words, radiation from the X-ray source projects the openings of the collimator onto a pattern on the detector area that corresponds to (or preferentially is identical to) the pattern of pixels in this area. The size (mean diameter) of the pixels of the X-ray detector typically ranges between about 0.1 mm and about 2 mm. Typical geometries of the pixels are rectangular, square, hexagonal, or any other shape that allows for a smart tiling of a one- or two-dimensional area. The pitch of the pixels, i.e. the mean distance between two characteristic points (e.g. the centers) of neighboring pixels, preferably ranges between about 0.5 mm and 2 mm. The pitch of the pixels contributes to the image resolution that can be achieved with the imaging system for a given size and arrangement of the X-ray source. The width of the openings of the collimator preferably ranges between about 100 μm and 500 μm. For noncircular openings, said width is defined as the diameter of the largest circle which can completely be inscribed in the opening. The pitch of the openings of the collimator preferably ranges between about 100 μm and 500 μm. The advantages of the present invention can in principle be achieved with just a single X-ray source. As a real X-ray source has however some finite spatial extension, the illumination of the pixels through the openings of the collimator will necessarily be somewhat blurred due to penumbra effects. Limitation of such effects requires that the X-ray source should be as small as possible, which reduces however also the available intensity of the X-ray illumination. A solution to this dilemma is achieved if the imaging system comprises an “X-ray generator” with a plurality of X-ray sources that fulfill the conditions of the invention, i.e. for each X-ray source there are at least two openings of the collimator which allow the passage of X-rays towards two neighboring pixels while the region between said pixels is substantially shielded from radiation of the considered X-ray source. It is preferred that all X-ray sources are arranged within an area which is limited by a maximal diameter such that the spatial resolution of the image of the examined object is kept within a preferred specification. Typically this means that said area has a maximum diameter which corresponds to the diameter of the emission area of a focal spot of commonly used X-ray sources. On the other hand it is preferred that the X-ray sources are not as close together that they illuminate a pixel through the same collimator opening, as this would increase the effective beam penumbra per opening and thus have no benefit compared to the use of a single focal spot with extended emission area. Considering said arguments it is most preferred that the X-ray sources are aligned to the collimator openings in a way, that each X-ray source uses a different collimator opening for the illumination of a particular pixel or pixel set, thus implying that the X-ray sources keep some minimum distance from each other. By using a plurality of X-ray sources, the available intensity of radiation can be increased accordingly without increasing blurring effects. In the aforementioned embodiment, there is preferably at least one pixel that is simultaneously illuminated by radiation passing through at least two different openings (said radiation coming from different X-ray sources). According to a further development of the aforementioned embodiment, the geometry of the imaging system is chosen such that any two X-ray sources of the X-ray generator illuminate the same set of pixels through the openings of the collimator. Most preferentially, one can align all X-ray sources and all collimator openings quasi-periodically in a way that each individual X-ray source illuminates the detector array through the collimator openings with a pattern for which the X-ray sensitive pixel regions are illuminated with a higher intensity than the insensitive regions between the pixels. The illumination patterns of all X-ray sources then superpose to build a total illumination pattern which again fulfills the condition that X-ray sensitive pixel regions are illuminated with a higher intensity than the insensitive regions between the pixels. In an idealized case, each X-ray source illuminates all detector pixels, or, in an equivalent formulation, each detector pixel is illuminated simultaneously by all available X-ray sources. Preferably the total size of the area containing the plurality of X-ray sources of the X-ray generator is comparatively small, so that—within the resolution limits of the detector—the projections through an object generated from all the X-ray sources are substantially the same. As already said, the total area covered by the X-ray sources is preferably comparable to the size of focal spots in conventional X-ray tubes. Most preferably, the plurality of all X-ray sources covers an area of less than about 10 mm2. The (maximal) diameter of the individual X-ray sources of the X-ray generator is typically smaller than 100 μm, preferably smaller than 50 μm. According to a third aspect, the invention relates to an X-ray generator for an imaging system of the kind described above, said generator comprising a plurality of X-ray sources. The X-ray generator is characterized in that it comprises an emission area with modulated emission intensity. Peaks of emission intensity will then functionally constitute different X-ray sources. In a first preferred embodiment of the X-ray generator, said generator comprises electron optics and/or a structured electron emitter for bombarding the emission area with electrons in a pattern that generates an array of emission peaks. While in conventional X-ray tubes the focal spot on the target is uniformly bombarded with electrons, the present invention creates some micro-structure in the target area with a plurality of emission peaks. The aforementioned structured electron emitter may preferably be structured in a pattern that is a scaled copy of the pattern of the X-ray source array. In this case only a simple linear “optical” imaging of the emitted electrons onto the emission area is required. An electron emitter with a sufficiently fine structure may particularly be realized by carbon nanotube emitters. More information on carbon nanotubes and X-ray sources that can be built with them can for example be found in the U.S. 2002/0094064 A1 or U.S. Pat. No. 6,850,595. According to another embodiment, the X-ray generator comprises a spatially extended X-ray emitter that is disposed behind a mask with holes. The extended X-ray emitter can for example be the focal spot of a conventional X-ray tube, having a size of typically several square millimeters. The holes of the mask will function in this embodiment as the required multitude of point-like X-ray sources. Like reference numbers or numbers differing by integer multiples of 100 refer in the Figures to identical or similar components. In many conventional X-ray imaging modalities (especially in CT), the X-ray detector has inactive regions characterized as gaps between pixels. For a CT detector, the gaps are currently unavoidable as they are necessarily used for the absorption lamellae of an anti-scatter collimator (also known as anti-scatter-grid). During operation, the X-ray cone beam also illuminates the inactive detector areas. This results in an unnecessary dose exposure to the patient. In view of this, a method is suggested here which allows to spatially modulate the X-ray cone beam such that the active detector areas (pixels) are almost fully illuminated and the inactive gaps between the pixels are at least less intense illuminated. Basically, the suggested method applies a multitude of needle beams instead of a more or less homogeneous illuminating cone beam. FIG. 1 schematically shows a side view of an imaging system 100 according to a first embodiment of the aforementioned concepts. The imaging system 100 comprises the following components: an X-ray generator 101 with an array of separate X-ray sources 101a, . . . 101d for generating X-ray beams Xa, . . . Xd; a collimator 102 with pin-holes P; an X-ray detector 103 with a (one- or two-dimensional) array of sensitive pixels 103a, . . . 103e. An object to be imaged (not shown) may be disposed in the “object space” between the collimator 102 and the detector 103. The basic idea of the imaging system 100 is to use the pin-hole mask 102 as a collimator to create an array of needle beams, each beam reaching exactly one of the pixels 103a, . . . 103e. The pin-hole collimator 102 works already excellent with a single X-ray source (e.g. source 101a), if an ideal point-like X-ray source is (would be) used. For an X-ray source spot size of typically (effective, e.g. as seen by the detector) 0.5 mm×1 mm, however, one can easily prove that such a spatially extended source creates a penumbra, which in practical cases (source-detector distance of 1 m and source-collimator distance of 20 cm) has a width of at least 2 mm. Compared to typical detector pixel pitches of about 1.2 mm this is too broad. To decrease the needle beam extension, two actions must be taken: Firstly, the focal spot size must be decreased. Secondly, the pin-holes P of the collimator 102 must be decreased in size. To create a needle beam extension of 1 mm full-width-half-maximum (FWHM) at the detector 103 with 200 μm wide gaps d between pixels, for the above mentioned distances a pin-hole collimator 102 with a pitch of 240 μm and a hole size of 200 μm has to be used. To ensure an adequate small penumbra of 200 μm width, a single focal spot has to be reduced to a size of 50 μm. FIG. 2 illustrates the resulting ray geometry for a single X-ray source 101a and a single pin-hole P of the collimator 102, allowing the passage of a central beam Xa′ with a penumbra Xa″. A single focal spot of the aforementioned size is likely to suffer from too low total intensity. It is therefore preferred to use not only one small source, but an array of several small X-ray sources 101a, . . . 101d. Preferably, the total area including these small X-ray sources 101a, . . . 101d corresponds to common focal spot sizes. Moreover, the pitch of the small X-ray sources 101a, . . . 101d is adapted such that the projected image of the source array on the detector 103 fits the pixel pitch (i.e., for 1.2 mm detector pixel pitch, the source array would require a pitch of about 300 μm). The fine-structured X-ray generator 101 thus provides an array of very small focal spots, which assures that a multitude of needle beams get sharp enough to illuminate only the active pixel regions. Practically, the array of X-ray sources 101a-101d could be realized with the help of electron optics similar to those already used in common X-ray tubes; however, the electron emitter has to be structured such that electrons are emitted only in those areas which correspond to a scaled copy of the X-ray source array. This is feasible for example with structured carbon nanotube emitters. The pin-hole mask of the collimator 102 can be fabricated as an etched metal foil which is added into the path of rays somewhere in front of the object (not shown). Potentially the collimator 102 can be combined with common pre-filtering or beam shapers. It has to be taken into account that the distance between the collimator 102 and the X-ray generator 101 as well as the local hole pitch of the collimator must be always adapted such that the projected image of each of the X-ray sources 101a, . . . 101d fits the detector pixel pitch. FIG. 3 shows a second embodiment of an imaging system 200 with an X-ray generator 201 which allows the use of a common X-ray tube with a single focal spot 211 (optionally with dual or quattro focal spot technology). This approach can be implemented with reasonable effort into already available CT scanners. The focal spot 211 of a common X-ray tube (not shown in detail) is pre-patient collimated by a (second) mask 212 or grating with pinholes 213. Basically, the indicated point sources shown in FIG. 1 are replaced by openings 213 of the second mask 212, while the X-ray focal spot 211 needs not to be structured any more. As seen in FIG. 3, the pitch of the mask 212 is larger than that of the collimator 202, therefore this mask 212 is even easier to produce than the collimator 202. The optimal structure of the grating 212 depends on whether one wants to create a set of fan beams (useful in case that the detector pixel gaps are negligible small in one direction), or a set of needle beams (useful for common CT detectors having pixel arrays with inactive gaps in each direction). For the fan beam case, one has to produce line gratings, while for the second case one has to produce masks with rectangular openings. It is an advantage of the present invention that the total exposure to a patient is reduced by the part of X-rays absorbed by the pin-hole collimator, but without loss of image quality, ideally even with maintaining the tube intensity received per active pixel area in absence of a pin-hole collimator. As a positive side effect, less X-ray scattered radiation is generated, leading to an improvement of the image quality. The invention can be applied especially with X-ray Computed Tomography systems, but also more generally to all X-ray imaging systems characterized by inactive areas between detector pixels. Finally it is pointed out that in the present application the term “comprising” does not exclude other elements or steps, that “a” or “an” does not exclude a plurality, and that a single processor or other unit may fulfill the functions of several means. The invention resides in each and every novel characteristic feature and each and every combination of characteristic features. Moreover, reference signs in the claims shall not be construed as limiting their scope.
	description	This application is a divisional application of U.S. patent application Ser. No. 13/567,243 (filed Aug. 6, 2012), which claims priority to U.S. Provisional Application No. 61/515,151 (filed Aug. 4, 2011), the entire disclosures of which are incorporated by reference herein. Field of the Invention The present invention relates generally to nuclear technologies. More specifically, particular embodiments of the invention claimed herein relates to nuclear fuels and related methods for use in various types of nuclear reactors. Description of Related Art Nuclear fuel is what is “consumed” by fission to produce energy in a nuclear reactor. Nuclear fuels are very high-density energy sources and it is clear from the initial analysis of the March 2011 Fukushima accident that the failure of the nuclear fuel after shutdown has been the most important cause of the damage to the reactors and the environment. The immediate reason for the fuel failure was the lack of adequate cooling for the decay heat generated after reactor shutdown. The fact that the fuel failed rather rapidly and uncontrollably soon after cooling was compromised, however, points to substantial inherent weaknesses in this component of the nuclear reactor. Oxide fuels such as uranium dioxide are commonly used in today's reactors because they are relatively simple and inexpensive to manufacture and can achieve very high effective uranium densities, have a high melting point and are inert to air. They also provide well-established pathways to reprocessing. The thermal conductivity of these fuels, however, is very low and goes down as the temperature goes up. The low thermal conductivity can lead to overheating of the center part of the pellets during use and difficulty in heat dissipation during loss of coolant events. Virtually all fuel used in light water reactors (LWRs) is uranium dioxide (UO2). The uranium dioxide powder is compacted into cylindrical pellets and sintered at high temperatures to produce ceramic nuclear fuel pellets with a high density. Such fuel pellets are then stacked into metallic tubes (cladding). Cladding prevents radioactive fission fragments from escaping from the fuel into the coolant and contaminating it. The metal used for the tubes depends on the design of the reactor. Stainless steel was used in the past, but most reactors now use a zirconium alloy which, in addition to being highly corrosion-resistant, has low neutron absorption. The use of zirconium instead of stainless steel allows lower enrichment fuel to be used for similar operating cycles. Zirconium, however, is much more prone to react with steam to produce hydrogen at high temperatures. Recently, micro-encapsulated tristructural-isotropic (TRISO) fuel particles compacted within a graphite matrix have been proposed for the next generation gas-cooled reactors. A TRISO fuel particle comprises a kernel of fissile/fertile material coated with several isotropic layers of pyrolytic carbon (PyC) and silicon carbide (SiC). These TRISO particles are combined with a graphite matrix material and pressed into a specific shape. While the TRISO fuel forms offer better fission product retention at higher temperatures and burnups than metallic fuel forms, they also provide only one containment shell (i.e., SiC layer) against fission product release to the coolant, and some fission products may migrate out of the kernel and through the outer layers and escape into the graphite matrix and coolant. The sealed tubes containing the fuel pellets are called fuel rods. The fuel rods are grouped into fuel assemblies that are used to build up the core of a power reactor. The fuel assemblies consist of fuel rods bundled in arrangements of 14×14 to 17×17 depending on the core design. One type of fuel is known as pressurized water reactor fuel, or PWR. PWR bundles are about 4 meters in length. In PWRs, control rods are inserted through the top directly into the fuel bundle. Another type of fuel is known as boiling water reactor fuel, or BWR. The fuel assemblies in BWRs are “canned” within a thin tube surrounding each bundle. As the water physically changes phase and boils as it moves up through the BWR assemblies, the canned arrangement is adopted to prevent local density variations from affecting neutronics and thermal hydraulics of the overall reactor. There are typically 91 to 96 fuel rods per assembly and 400-800 assemblies in the reactor core. Control rods are inserted from the bottom as cruciform blades surrounding the canned assemblies. Nuclear fuel, like any material in a high-radiation environment, can undergo substantial changes in its properties during reactor operations. Moreover, the occurrence of nuclear reactions will cause significant changes in the fuel stoichiometry over time, leading to cracking and fission gas release. As the fuel is degraded and cracks, the more volatile fission products trapped within the uranium dioxide may become free to move into the fuel-clad gap. As the fuel pin is sealed, the pressure of the gas filling the gap will increase and it is possible to deform and burst the cladding. The swelling of the fuel can also impose mechanical stresses on the cladding. Once the geometry of the fuel rod is changed by excessive swelling, its heat transfer behavior may be degraded, with significant increase in the temperature of the cladding possible. The common failure process of fuel in the water-cooled reactors is a transition to film boiling and subsequent ignition of zirconium cladding in the steam. In a loss-of-coolant accident (LOCA) the surface of the cladding could reach a temperature between 800 and 1400° K, and the cladding will be exposed to steam for some time before water is re-introduced into the reactor to cool the fuel. During this time when the hot cladding is exposed to steam, some oxidation of the zirconium will occur to form a zirconium oxide and produce hydrogen. The oxidation can produce breaching of the fuel clad and subsequent release of the radioactive fission products. The vast majority of nuclear fuels used today consist of uranium dioxide (UO2) pellets stacked inside a sealed cladding tube of zirconium alloy to make a fuel rod. Such fuels have three main weaknesses, however: (1) the presence of large amounts of zirconium in the clad that can react with steam at high temperature to produce hydrogen, (2) the fact that the fission products are only loosely bound to the fuel after they are produced, and (3) the very low conductivity of the fuel itself, which causes very high temperatures in the fuel and impedes the cooling of the fuel during off-normal situations. A fuel clad with a less reactive metal (like stainless steel) or a non-metal, having a higher conductivity (like a carbide or nitride fuel) and tightly bound fission products, would not have produced the large amounts of hydrogen responsible for the explosions at the Fukushima plant or the high temperatures responsible for the rapid failures after loss of cooling and the large releases of radioactivity that occurred after fuel failure. It is clear that oxide fuels in zirconium cladding, the form most commonly used in LWRs, are vulnerable to LOCA conditions and can fail in catastrophic ways, due to (1) the adverse combination of a chemically active cladding, (2) loosely bound fission products, and (3) poor heat transfer capabilities. Thus, there exists a need for alternatives to oxide fuels that can be used to mitigate these concerns. Although the present invention may obviate one or more of the above-mentioned needs, it should be understood that some aspects of the invention might not necessarily obviate one or more of those needs. In the following description, certain aspects and embodiments will become evident. It should be understood that these aspects and embodiments are merely exemplary and the invention, in its broadest sense, could be practiced without having one or more features of these aspects and embodiments. To attain the advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, one aspect of the invention may provide a nuclear fuel comprising a dispersion ceramic micro-encapsulated (DCM) nuclear fuel pin. In order to obtain a feasible fuel replacement in nuclear reactors, the DCM fuel pin needs to behave in essentially the same way as standard UO2 fuel pins in terms of power generation, thermo-hydraulics and neutronics, so that a UO2 fuel assembly could be one-for-one replaced with a DCM fuel assembly. It is therefore necessary to achieve comparable levels of linear fissile density and reactivity behavior in the DCM fuel as in the original low-enrichment uranium fuel throughout the operational fuel life in the reactor. Dispersion ceramic micro-encapsulated (DCM) fuel is manufactured from kernels of uranium bearing material of the highest possible density, such as uranium nitride (UN), uranium carbide (UC), uranium silicide (U3Si), or an equivalent material. The methods for obtaining these materials are well-known in the art and may include a sol-gel method or other. Similarly, methods for coating the kernels are well-known and may include: (1) a layer of porous carbon to provide a suitable absorptive buffer for fission products and other gases generated during operations, (2) a thin layer of dense pyrolitic carbon, (3) a dense layer of silicon carbide, and (4) an external layer of pyrolitic carbon to provide structural strength and a pressure tight containment of fission products generated in the kernel. The coated particles containing the fissile uranium may then be overcoated in a slurry of silicon carbide and finally enclosed in a mixture of silicon carbide (over 90%) and yttrium and aluminum oxide nano-powders that is compressed and heated to produce a uniform high density sintered compact. The compact maintains good mechanical strength at high temperatures, has excellent radiation tolerance and high thermal conductivity, due to the continuous high density SiC matrix. It is also non-reactive with water and high temperature steam. Because of its good heat conductivity, the maximum temperature reached in the fuel is well below 1000° K, not high enough to drive diffusion mechanisms that would lead to migration and dispersion of the fission products out of the fuel coatings. In some exemplary embodiments, the invention may replace UO2 nuclear fuel material with uranium nitride (UN), uranium carbide (UC) or uranium silicide (U3Si), all of which provide substantially higher heavy metal density than UO2. In other exemplary embodiments, the nuclear fuel may use two or more sizes of TRISO particles in the compacts, which will increase the achievable packing fraction. In another exemplary embodiment of the invention, the fuel will use a very dense SiC matrix, obtained by the use of a low-temperature nano-powder sintering process such as a nano infiltration transient eutectic phase (NITE) or equivalent process to provide near-complete filling of the space between TRISO particles. In still another exemplary embodiment of the invention, the TRISO particles may include a SiC overcoat prior to sintering of the compact in order to provide a suitable interface between the TRISO particle and the compact matrix. In yet another exemplary embodiment of the invention, the nuclear fuel pellets may have an increased diameter of about 15%, thereby decreasing the pellet-to-clad gap. This is possible due to the higher thermal conductivity and good radiation stability of the DCM fuel. Yet another exemplary embodiment of the invention may increase the fuel enrichment to between 10 and 20% or more if allowed by regulations. Another exemplary embodiment of the invention may provide adequate amounts of burnable poison in the fuel pins by means of resonant absorbers gadolinium (Gd) or erbium (Er) to counteract the larger initial excess reactivity and the softer spectrum. It is one purpose of the invention to maintain the same lattice configuration and overall dimensions in the fuel assemblies during operation. 10 Fuel Element 15 Silicon Carbide (SiC) Matrix 20 Micro-Encapsulated Fuel Particles 22 Porous Carbon Buffer Layer 24 Inner Pyrolytic Carbon (PyC) Layer 25 Fuel Kernel 26 Ceramic Layer 28 Outer PyC Layer 30 Fuel Rod 35 Cladding Tube 40 Fuel Bundle 100 Elongated Rod Fuel Element 130 Graphite Prism 135 Hole Reference will now be made in detail to the exemplary embodiments consistent with the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference characters will be used throughout the drawings to refer to the same or like parts. Dispersion fuels consist of a distribution of discrete fuel particles embedded in a non-fuel matrix. Ideally, the matrix remains largely not affected by neutron and fission fragment damage from the fission events that take place in the fuel particles. The best composite fuel uses fully encapsulated coated fuel particles embedded in an inert heat-conductive matrix and surrounded by a metallic or ceramic clad. In a well-designed dispersion fuel, there are three very strong barriers to fission product release to the coolant. These are the coating around the particle, the dense matrix, and the cladding around the dispersion fuel block, each of them independently capable of containing the fission products and chemically inactive. Given the available irradiation behavior database, the concept most likely to minimize fission gas release to the coolant will incorporate “buffered” particles in a dense matrix. This “buffer” material serves the dual role of providing volume for fission gas and providing volume for fuel particle swelling. The buffer layer is protected by a dense coating layer, also designed to provide for fission product retention. These are essentially TRISO coated fuel particles. TRISO fuel is a type of micro fuel particle that can be used effectively as the discrete fuel particles of a dispersion fuel concept. The term “TRISO,” as used herein, may refer to any type of micro fuel particle consisting of a fuel kernel composed of UC or uranium oxycarbide (UCO) in the center, coated with one or more layers surrounding one or more isotropic materials. In one preferred embodiment, TRISO particles include four layers of three isotropic materials. In that embodiment, the four layers are a porous buffer layer made of carbon, followed by a dense inner layer of pyrolytic carbon (PyC), followed by a ceramic layer of SiC to retain fission products at elevated temperatures and to give the TRISO particle a strong structural integrity, followed by a dense outer layer of PyC. TRISO fuel particles are designed not to crack due to the stresses or fission gas pressure at temperatures beyond 1600° C., and therefore can contain the fuel in the worst of accident scenarios. TRISO fuel was designed for use in high temperature gas cooled reactors, to be operating at temperatures much higher than the temperatures of LWRs. Of the possible matrix materials, silicon carbide (SiC) offers the largest existing database in terms of material properties, irradiation behavior, and fabrication. SiC has excellent oxidation resistance due to rapid formation of a dense, adherent silicon dioxide (SiO2) surface scale on exposure to air at elevated temperature, which prevents further oxidation. The low irradiation swelling behavior of SiC is well documented. Processing of SiC into dense shapes is currently done on an industrial scale at a reasonable cost, although major modifications will be required for processing of particle fueled composites. The use of coated particles makes it more difficult to achieve high heavy metal density in the fuel, since the net heavy metal density within a fuel particle falls rapidly with increasing coating thickness. This fact requires that the coating thickness to kernel diameter ratio be kept as small as possible while maintaining utility as a fission product barrier. It is however clear that the use of dispersion fuels in LWRs will demand higher enrichment and a lower power density. The most likely fissile particle types for composite fuels are uranium/plutonium carbides (UC or PuC) and uranium/plutonium nitrides (UN or PuN) due to the combination of high melting temperature and high actinide density. Uranium silicides could provide an even higher density of fissile uranium, but may be unstable under the expected fabrication and operation conditions. The dispersion fuel consisting of the combination of TRISO fuel particles and silicon carbide matrix in a ceramic cladding is known as dispersion ceramic micro-encapsulated (DCM) fuel. FIG. 6 conceptually illustrates the fabrication process of DCM fuel for use in the LWRs. DCM fuel consists of UN or UC TRISO particles that are embedded inside a SiC matrix. This fuel design differs significantly from the previous dispersion type fuel approaches, since the damage due to 100 MeV fission fragments and noble gas release is fully contained within the TRISO particle and the inert SiC matrix is solely exposed to neutron irradiation. In addition to offering exceptional stability under neutron irradiation conditions (less than 1% swelling), the thermal conductivity of the SiC matrix is on the order of about 10 times higher than that of uranium dioxide. The fuel development and qualification process for DCM fuel has benefited from and will significantly be facilitated by decades of gas reactor TRISO fuel development and optimization activities. FIGS. 1-3 illustrate an exemplary nuclear fuel element consistent with various aspects of the present invention. While the invention may be described in connection with particular reactor types (e.g., light water reactors, boiling water reactors, and gas-cooled reactors), embodiments of the invention may be used, or modified for use, in any other types of nuclear reactors, such as heavy water reactors, liquid metal reactors, and thermoionic nuclear converters. Referring to FIG. 1, a fuel element 10, according to one exemplary embodiment, may comprise a plurality of micro-encapsulated fuel particles 20 embedded in a silicon carbide (SiC) matrix 15. The fuel element 10 may be formed by compressing a mixture of the fuel particles 20 and a SiC-based matrix precursor material in a mold. The mold may have any desired shape for the fuel element 10. In one exemplary embodiment, the SiC-based matrix precursor material may comprise SiC powder mixed with sintering additives and may be in a form of powder-based slurry, ceramic slurry for tape casting, or any other mixture type known in the art. Because the SiC matrix 15 is a ceramic material, the fuel element 10 is sometimes referred to as a fully ceramic micro-encapsulated fuel element. While the fuel element 10 of FIG. 1 has a shape of a cylindrical pellet, particularly suitable for use in a conventional light water reactor, the fuel element may have a variety of other shapes, such as, for example, a sphere or an elongated rod, depending on the type and/or operational characteristics of the nuclear reactor in which the fuel element is intended to be used. The fabrication process and the resulting properties and characteristics of the fuel element 10 will be described in more detail later. The fuel particles 20 dispersed in the SiC matrix 15 may be tristructuralisotropic (TRISO) fuel particles. The term “TRISO fuel particle,” as used herein, may refer to any type of micro fuel particle comprising a fuel kernel and one or more layers of isotropic materials surrounding the fuel kernel. By way of example only, the fuel particle 20 may have a diameter of about 1 millimeter. As shown in FIG. 1, the fuel particle 20 may comprise a fuel kernel 25 at its center. The fuel kernel 25 may comprise fissile and/or fertile materials (e.g., uranium, plutonium, thorium, etc.) in an oxide, carbide, or oxycarbide form. In one exemplary embodiment, the fuel kernel 25 may comprise low enriched uranium (LEU) of any suitable enrichment level. The fuel kernel 25 may be coated with four distinct layers: (1) a porous carbon buffer layer 22; (2) an inner pyrolytic carbon (PyC) layer 24; (3) the ceramic layer 26; and (4) an outer pyrolytic carbon (PyC) layer 28. The modeled behavior of DCM fuel is illustrated in FIG. 7, highlighting the much lower fuel temperature during operations relative to oxide fuels (due to the much higher heat conductivity of the SiC matrix and the UC or UN fuel particle). As shown in FIG. 8, the oxide fuel will swell, crack and release the volatile fission products into the clad enclosure, whereas the DCM fuel will retain all fission products inside the TRISO particles and will not swell under irradiation. As shown in FIGS. 9-10, the nuclear fuel may use two or more sizes of TRISO particles in the compacts, which will increase the achievable packing fraction. The results of using different material and kernel sizes are reproduced in Tables 1-4 of FIGS. 14-17 and in FIGS. 11-13. The porous carbon buffer layer 22 surrounds the fuel kernel 25 and serves as a reservoir for accommodating buildup of fission gases diffusing out of the fuel kernel 25 and any mechanical deformation that the fuel kernel 25 may undergo during the fuel cycle. The inner PyC layer 24 may be formed of relatively dense PyC and seals the carbon buffer layer 22. The ceramic layer 26 may be formed of a SiC material and serve as a primary fission product barrier and a pressure vessel for the fuel kernel 25, retaining gaseous and metallic fission products therein. The ceramic layer 26 also provides overall structural integrity of the fuel particle 20. In some exemplary embodiments, the SiC layer 26 may be replaced or supplemented with zirconium carbide (ZrC) or any other suitable material having similar properties as those of SiC and/or ZrC. The outer PyC layer 28 protects the SiC layer 26 from chemical attack during operation and acts as an additional diffusion boundary to the fission products. The outer PyC layer 28 may also serve as a substrate for bonding to the surrounding matrix material. The configuration and/or composition of the fuel particle are not limited to the embodiments described above. Instead, it should be understood that a fuel particle consistent with the present disclosure may include one or more additional layers, or omit one or more layers, depending on the desired properties of the fuel particle. For example, the fuel particle 20 may be overcoated with the SiC matrix material (i.e., SiC layer) prior to being mixed and compressed with the SiC powder. An exemplary method of fabricating the fuel element 10, according to another aspect of the present invention, will be described herein. To form the fuel particles 20, according to one exemplary embodiment, the material for the fuel kernel 25 may be dissolved in a nitric acid to form a solution (e.g., uranyl nitrate). The solution is then dropped through a small nozzle or orifice to form droplets or microspheres. The dropped microspheres are then gelled and calcined at high temperature to produce the fuel kernels 25. The fuel kernels 25 may then be run through a suitable coating chamber, such as a CVD furnace, in which desired layers are sequentially coated onto the fuel kernels 25 with high precision. It should be understood that any other fabrication method known in the art may be additionally or alternatively used to form the fuel kernels 25. Once the fuel particles 20 are prepared, the fuel particles 20 are mixed with SiC powder, which comprises the precursor for the SiC matrix 15. Prior to the mixing, the fuel particles 20 may be coated with a suitable surface protection material. The SiC powder may have an average size of less than 1 μm and/or a specific surface area greater than 20 m2/g. By way of example only, the size of the SiC powder may range from about 15 nm to about 51 nm with the mean particle size being about 35 nm. During or prior to mixing, sintering additives, such as, for example, alumina and rare earth oxides, may be added to the SiC powder and/or coated onto the SiC powder surface. In one exemplary embodiment, the amount of additives may range from about 6 weight % to 10 weight %. When mixing with the fuel particles 20, the SiC-based precursor material containing the SiC powder may be in a variety of physical states (e.g., powder, liquid, slurry, etc.) depending on the mixing and/or fabrication method used. The SiC-based precursor mixed with the fuel particles 20 may then be pressed to stress at a predetermined pressure and temperature to form the fuel element 10. According to one exemplary embodiment, the sintering pressure and temperature during the press may be less than about 30 MPa and 1900° C., respectively. Preferably, the sintering pressure and temperature may be about 10 MPa and 1850° C., respectively. The duration of the press may be less than or equal to about one hour, but it may take more than one hour. The small size or large specific surface area of the SiC powder, with the limited mass fraction of the sintering additives, may enable the formation of highly crystalline, near-full density, SiC matrix at conditions sufficient to ensure the integrity of the fuel particles 20. The SiC matrix provides an additional barrier to fission products that may be released during normal operation and accident temperatures and contaminate the coolant of the reactor. The SiC matrix also helps contain fission products after disposal. For example, FIG. 2 shows a microscopic, partial cross-sectional view of the fuel element 10 fabricated with a method consistent with the present invention. As can be seen from the figure, the fuel element 10 has very clean interfaces between the fuel particles 20 and the SiC matrix 15. Further, the SiC matrix 15 has a very low porosity (e.g., only about 3˜4% closed microporosity), forming a gas-impermeable barrier that acts as a secondary barrier to fission products/actinides diffusion and other radioactivity releases from the fuel particles 20. In addition, the SiC matrix 15 has very low permeability to helium (e.g., in the order of about 10−10 10−11 m2/s), which is substantially lower than that of graphite and makes it particularly suitable for a gas cooled reactor that uses helium as a coolant. Low permeability of the SiC matrix 15 may also ensure retention of fission product gas. FIG. 3 illustrates a temperature gradient inside the fuel element 10 at an operating condition, with a comparison to a conventional UO2 fuel element. As shown in the figure, the fuel element 10 consistent with the present invention may have substantially higher thermal conductivity than that of the UO2 fuel element. Higher thermal conductivity has many beneficial effects. For example, higher thermal conductivity may permit operating the nuclear reactor at higher temperature. Operating a reactor at higher temperature may increase the efficiency and the power density, which may permit reduction of the reactor size. Higher thermal conductivity may also permit higher burnup of the fuel element while maintaining the overall fuel integrity. Moreover, as briefly mentioned above, higher burnup may not only reduce the overall waste volume but also limit possible nuclear proliferation and diversion opportunities. Furthermore, fuel with high thermal conductivity may undergo less severe temperature transients during an accident condition, such as a loss of coolant accident (LOCA). In light water reactor operating conditions, migration of fission products (including gases) outside the TRISO fuel particles and the SiC matrix is not expected to occur. Further, the SiC matrix 15 has higher fracture strength, higher irradiation resistance, and lower irradiation swelling than graphite or UO2. The combination of better irradiation performance and better thermal conductivity may result in better mechanical performance as compared to graphite or UO2 fuel element. The resulting matrix 15 is considered a near-stoichiometric, radiation-resistant, form of SiC, allowing the fuel element 10 to be repository-stable for direct disposal even after substantial burnup (e.g., 60˜99% burnup). Now, with reference to FIGS. 4 and 5, exemplary applications of the fuel element 10, according to various aspects of the present invention, are described. In one exemplary embodiment, one or more fuel elements 10 may be enclosed in a metallic cladding tube 35 or any other suitable enclosure to form a fuel rod 30, as shown in FIG. 4. When the fuel elements 10 are enclosed inside the cladding tube 35 or an enclosure, the cladding tube 35 or the enclosure may provide an additional barrier (i.e., in addition to the pressure-bearing ceramic coating around the fuel kernel 25 and the fully ceramic SiC matrix 15) to fission products and actinide transport from the fuel particles 20. One or more fuel rods 30 may then be placed in a fuel bundle 40 for use in, for example, a light water reactor. Thus, according to one exemplary aspect, the fuel element 10 consistent with the present invention may be used in a conventional light water reactor, as replacement fuel for conventional UO2 fuel pellets, which may provide enhanced thermal conductivity and irradiation stability, as well as added barriers to fission product and actinide transport. According to another aspect of the present invention, the fuel element may be provided as an elongated rod fuel element 100, as shown in FIG. 5. The fuel element 100 may be placed in a hole 135 drilled in a graphite prism 130 or block for use in a gas-cooled reactor. As mentioned above, the fully ceramic fuel element 100, consistent with the present invention, may exhibit higher fracture strength, higher irradiation resistance, and lower irradiation swelling than the conventional graphite matrix-based fuel. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
047529474	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primary radiation diaphragm for X-ray examination devices, and in particular to such a radiation diaphragm having at least one pair of diaphragm plates adjustable in opposite directions relative to each other. 2. Description of the Prior Art A primary radiation diaphragm having two diaphragm plates movable in opposite directions relative to each other for limiting the extent of an X-ray beam is described in German OS 1,800,879. In this known radiation diaphragm, the edges of the adjustable plates are wedge-shaped so that the x-radiation is not completely absorbed by the diaphragm at the region close to the edge thereof. This serves two purposes. First, a good gating of the diagnostically relevant image region is possible, so that substantially no image regions not containing useful image information are bright enough to interfere with viewing of the relevant image. Second, when using a picture reproduction device, such as a monitor, for introducing instruments into the examination subject, it is assured that the instrument can be seen before entry into the diagnostically relevant region. In this known primary radiation diaphragm, the diaphragm edges limiting the X-ray beam are straight. In practice, such a straight edge does not always correspond to the desired limitation of the image field. Particularly, for gating the regions surrounding the heart, a curved edge contour is desirable so that the image field can be optimally adpated to the shape of the heart. A diaphragm system having plates with differently shaped edges which can be moved above each other is described in USLP 3,980,407. Different shapes at the gated field can be achieved using the same diaphragm plates in this manner. SUMMARY OF THE INVENTION It is an object of the present invention to provide a primary radiation diaphragm which permits a plurality of different image field shapes to be achieved by the use of two diaphragm plates. It is a further object of the present invention to provide a primary radiation diaphragm which permits rectangular gating as well as gating corresponding to the heart contour using the same set of plates as may optionally be needed. Another object of the present invention is to provide such a primary radiation diaphragm which is capable of individual adaptation for examination of respective patients. The above objects are achieved in accordance with the system disclosed herein wherein the diaphragm plates are adjustably mounted in two spaced planes and the path of adjustment is selected large enough such that the X-ray beam is optionally limitable by each diaphragm plate with one of two edges disposed perpendicular to the path of movement during adjustment. Individual adjustment means are provided for each of the diaphragm plates. In the primary radiation diaphragm described herein, the diaphragm plates are arranged in pairs, with the plates in each pair being capable of movement past each other over each other, so that different shapes of gating are possible by selective use of the different shaping of the two edges of a single diaphragm plate. These edges are disposed perpendicular to the path of adjustment movement of the plates.
054065984	claims	1. A system for monitoring a power of a nuclear reactor in accordance with a change of a neutron flux distribution mode, comprising: a plurality of neutron flux measuring means disposed in a reactor core for measuring neutron flux and generating neutron flux signals; means for calculating a neutron flux distribution in the core in response to the neutron flux detection signals from the neutron flux measuring means; means for calculating a higher mode of the neutron flux distribution in accordance with the results of calculations performed by the neutron flux distribution calculating means; a filter calculating means for obtaining a filter for extracting characteristics of change of the neutron flux detection signal in accordance with a phase difference and an amplitude difference between neutron flux detection signals without cancelling; and an input/output means for transmitting the neutron flux detection signal filtered by the filter obtained by the filter calculating means. a plurality of neutron flux measuring means disposed in a reactor core for measuring neutron flux and generating neutron flux signals; means for calculating a fundamental mode distribution of the neutron flux in response to the neutron flux detection signals from the neutron flux measuring means; a subcriticality evaluating means for estimating a subcriticality of a state of the core in accordance with the neutron flux distribution in the calculated fundamental mode and in comparison to a value as a primary moment of the power distribution with respect to a distance with a predetermined value; and an input/output means for transmitting a result of an evaluation made by the subcriticality evaluation means. a core present state data measuring means for measuring an operational state of a core of the nuclear reactor and generating a core operational state signal; means for calculating a neutron flux distribution in a fundamental mode in response to the core operational state signal; means for calculating a higher mode of the neutron flux in a state of the core realized when insertion of a selected control rod is initiated in accordance with the calculated neutron flux distribution and discriminating whether or not a subcriticality of the higher mode is smaller than a predetermined limit value; and an input/output means for transmitting results of calculations performed by the higher mode calculating means. a plurality of neutron flux measuring means disposed in a core of the reactor for measuring neutron flux in the core and generating a signal representing a local power range monitor measured data from the neutron flux measuring means; means for calculating neutron flux distribution in response to the signal from the neutron flux measuring means; a higher mode calculating means for calculating neutron higher modes in accordance with the calculation results of the neutron flux distribution calculating means; and an input/output means for outputting calculation results from the neutron flux distribution calculating means and the higher mode calculating means. 2. A system according to claim 1, wherein said filter calculating means is operatively connected at one side to the neutron flux measuring means through a data sampler and at another side to the higher mode calculating means, and said filter calculating means obtains a filter reflecting a state of the core realized due to change of an operational state in accordance with the higher mode of the neutron flux distribution calculated by the higher mode calculating means and a filter obtained in accordance with differences in amplitudes and phases between signals occurring due to change of the neutron flux detection signal measured actually. 3. A system according to claim 1, further comprising a stability monitoring means connected to an output side of said filter calculating means, and wherein said stability monitoring means has a structure for evaluating a core stability index in response to a power signal filtered by the filter calculating means to monitor the stability of the state of the core. 4. A system according to claim 1, wherein said neutron flux distribution calculating means is constituted by a process control computing means which is provided in association with the higher mode calculating means. 5. A system according to claim 4, wherein said process control computing means includes the higher mode calculating means. 6. A system according to claim 4, further comprising a power distribution monitoring device connected at input side to the process control computing means and at output side to a display means. 7. A system for monitoring a power of a nuclear reactor in accordance with a change of a neutron flux distribution mode, comprising: 8. A system according to claim 7, further comprising a higher mode calculating means for calculating a higher mode of the neutron flux distribution in accordance with results of calculations performed by the neutron flux distribution calculating means and a filter calculating means for obtaining a filter for extracting characteristics of change of the neutron flux detection signal in accordance with the neutron flux detection signal, and wherein results of calculations performed by said filter calculating means is transmitted to the input/output means. 9. A system according to claim 7, wherein said neutron flux distribution calculating means is constructed by a process control computing means connected at input side to the neutron flux measuring means through a data sampler and at output side to the subcriticality evaluation means. 10. A system according to claim 9, wherein said process control computing means is further connected at output side to the high mode calculating means. 11. A system according to claim 10, further comprising a filter calculating means operatively connected to the neutron flux measuring means for obtaining a filter for extracting characteristics of change of the neutron flux detection signal in response to the neutron flux detection signal and a stability monitoring means connected to an output side of said filter calculating means, and wherein said stability monitoring means has a structure for evaluating a core stability index in response to a power signal filtered by the filter calculating means to monitor the stability of the state of the core. 12. A system for monitoring power of a nuclear reactor in accordance with a change of a neutron flux distribution mode, comprising: 13. A system for monitoring power of a nuclear reactor in accordance with the change of the neutron flux distribution mode, comprising: 14. A system according to claim 13, wherein said higher mode calculating means is provided with a magnitude variation calculating means for calculating a variation in magnitude in each mode on the basis of the higher mode modes and the local power range monitor measured data. 15. A system according to claim 13, wherein said neutron flux distribution calculating means is constructed by a process control computing means operatively connected at input side to the neutron flux measuring means through a data sampler and at output side to the higher mode calculating means.
062663860	abstract	An apparatus and method are provided for inverting the lower internal assembly of a nuclear reactor. The apparatus includes a frame which is sized to receive the lower internal assembly. The frame supports the lower internal assembly as it is being inverted. The apparatus also includes a spider assembly which fits within the lower internal assembly and provides support for a baffle assembly located therein. The method includes the steps of removing the lower internal assembly from a reactor vessel and rotating the lower internal assembly prior to performing maintenance.
	abstract	Disclosed are system and method embodiments for determining the root-causes of a performance objective violation, such as an end-to-end service level objection (SLO) violation, in a large-scale system with multi-tiered applications. This determination is made using a hybrid of component-level snapshots of the state of the system during a period in which an abnormal event occurred (i.e., black box mapping) and of known events and their causes (i.e., white-box mapping). Specifically, in response to a query about a violation (e.g., why did the response time for application a1 increase from r1 to r2), a processor will access and correlate the black-box and white-box mappings to determine a short-list of probable causes for the violation.
	claims	1. A grating for X-ray differential phase-contrast imaging, comprising:a first sub-grating; andat least a second sub-grating, the sub-gratings each comprising a body structure with bars, and gaps, arranged periodically with a pitch,said sub-gratings being arranged consecutively for receiving an X-ray beam and being positioned laterally displaced from each other, said grating being configured as one of a phase grating, an analyzer grating, and an absorption grating. 2. The grating of claim 1, projections of said sub-gratings resulting in an effective grating with a smaller effective pitch than the pitches of said sub-gratings. 3. The grating of claim 1, said sub-gratings having the same pitch. 4. The grating of claim 3, wherein the displacement of one of said sub-gratings from another one of said sub-gratings is an offset amounting to a fraction of half the pitch. 5. The grating of claim 1, wherein the sub-gratings have an equal bars/gap ratio. 6. A grating for X-ray differential phase-contrast imaging, comprising:a first sub-grating; andat least a second sub-grating, the sub-gratings each comprising a body structure with bars, and gaps, arranged periodically with a pitch,said sub-gratings being arranged consecutively for receiving an X-ray beam and being positioned laterally displaced from each other, wherein the pitch of one of said sub-gratings is a multiple of the pitch of another one of said sub-gratings. 7. A grating for X-ray differential phase-contrast imaging, comprising:a first sub-grating; andat least a second sub-grating, the sub-gratings each comprising a body structure with bars, and gaps, arranged periodically with a pitch,said sub-gratings being arranged consecutively for receiving an X-ray beam and being positioned laterally displaced from each other, wherein said sub-gratings each has a height that creates a π-phase shift at a design wavelength. 8. A grating for X-ray differential phase-contrast imaging, comprising:a first sub-grating; andat least a second sub-grating, the sub-gratings each comprising a body structure with bars, and gaps, arranged periodically with a pitch,said sub-gratings being arranged consecutively for receiving an X-ray beam and being positioned laterally displaced from each other, said sub-gratings being arranged on a single wafer. 9. A detector arrangement of an X-ray system for generating phase-contrast images of an object, said arrangement comprising:an X-ray source;a source grating;a phase grating;an analyzer grating; anda detector,wherein the X-ray source is adapted to generate polychromatic spectrum of X-rays; andwherein at least one of the phase and analyzer gratings is a grating according to claim 1. 10. An X-ray system for generating phase-contrast data of an object, said system comprising the detector arrangement of claim 9. 11. A method of phase-contrast imaging for examining an object of interest, comprising:applying X-ray radiation beams of an X-ray source to a source-grating splitting the beams;applying the splitted beams to a phase grating recombining the splitted beams in an analyzer plane;applying the recombined beams to an analyzer grating; andrecording raw image data with a sensor while stepping the analyzer grating transversely over one period of the analyzer grating,wherein at least one of the phase and analyzer gratings is a grating according to claim 1. 12. A non-transitory computer-readable medium embodying a computer program for examination of an object of interest via phase-contrast imaging, said program having instructions executable by a processor of an X-ray system for causing the system to carry out a plurality of acts, among said plurality there being the acts of:applying (52) X-ray radiation beams of an X-ray source to a source-grating splitting the beams;applying the splitted beams to a phase grating recombining the splitted beams in an analyzer plane;applying the recombined beams to an analyzer grating; andrecording raw image data with a sensor while stepping the analyzer grating transversely over one period of the analyzer grating;wherein at least one of the phase and analyzer gratings is a grating according to claim 1. 13. The grating of claim 1, said sub-gratings having respective front surfaces and being arranged so that said surfaces are disposed normal to said beam and face in a direction of arrival of said beam. 14. The grating of claim 1, a given sub-grating from among said sub-gratings comprising silicon, and an additional gold layer covering said bars, and said gaps, of the body structure of said given sub-grating. 15. The grating of claim 2, said effective grating being defined by sidewalls in a propagation direction of an X-ray beam, in which direction said sub-gratings face. 16. The grating of claim 15, a given sub-grating from among said sub-gratings comprising silicon, and an additional gold layer covering said bars, and said gaps, of the body structure of said given sub-grating. 17. The computer readable medium of claim 12, among said plurality of acts there being a further act of computing the recorded raw image data into display data. 18. The grating of claim 1, said sub-gratings facing in a same direction. 19. The grating of claim 18, the displacement being normal to said direction. 20. The grating of claim 18, the respective displacements of each of said sub-gratings from the other one or more of said sub-gratings being normal to said direction.
	summary
052689484	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Looking now in greater detail at the accompanying drawings, FIG. 1 is a perspective view illustrating the upper end of a typical assembly for a nuclear fuel bundle of the general type that is described in greater detail in the aforementioned U.S. Pat. No. 4,064,004. The details of the fuel bundle itself are not important to the present invention, except to note that a typical fuel bundle includes a plurality of vertically extending control rod guide tubes 10, the lower ends of which are secured to a lower support plate or tie plate (not shown) and the upper ends of which are received within an upper end fitting or upper support plate 12. As explained above, it is necessary from time to time to remove the fuel rods (not shown) which normally extend vertically at a position beneath the upper support plate 12, and these fuel rods are removed by first disconnecting, and then removing, the upper support plate 12 from its mounting on the upper ends of the guide tubes 10. The present invention relates to a locking assembly, which is generally indicated by the reference numeral 14 in FIG. 1, that normally locks the upper support plate 12 in position on the guide tubes 10, but which can be easily manipulated to unlock or disconnect the upper support plate 12 from the guide tubes 10 for removal therefrom. One embodiment of the locking assembly 14 of the present invention is illustrated in FIGS. 2-4 and includes a collar 16 that is fixed to the upper end of each guide tube 10, the collar including a radially extending shoulder 18 that normally is received within a recess at the bottom surface of the support plate 12 as best seen in FIGS. 3 and 4, whereby the support plate 12 is supported on the upper ends of the shoulders 18 of each collar 16 in the fuel bundle. The collar 16 also includes a sleeve 20 that extends axially up through a cylindrical opening 22 in the support plate 12, the opening 22 also being provided with a generally rectangular slot 24 extending radially outwardly in opposite directions from the opening 22. The upper end of the sleeve 20 is provided with two oppositely extending projections 26 which correspond generally in shape to the slots 24 in the support plate 12. A generally annularly shaped locking member 28 is rotatably mounted on the sleeve 20, and is provided with depending feet 30 which are flared outwardly at the lower ends thereof for engaging an interior annular surface of the support plate opening 22 (see FIGS. 3 and 4), whereby the locking member 28 is freely rotatable within the opening 22 but is restrained from any axial movement relative to the support plate 12. The locking member 28 is provided with a transversely extending slot 32, the outer ends of which correspond generally in shape to the support plate slots 24, and the upper surface of the locking member 28 is provided with two apertures 34 for receiving the prongs 36 of a operating tool 38 for a purpose to be described in greater detail presently. The annular body portion of the locking member 28 presents an exterior annular surface 40 that is formed with two pairs of oppositely disposed detents 42 and 42' which are preferably arranged in circumferentially spaced relationship to one another, as best seen in FIG. 2. A locking cup 44 is provided which consists of a relatively thin annular wall portion 46 formed of a suitable metal, and being provided with a pair of oppositely disposed spring biased ears 48. The locking cup 44 is also provided with a generally flat lower wall portion 50 having an opening therein for receiving the sleeve 20, and the locking cup 44 is provided with oppositely disposed depending tabs 49, only one of which is visible in FIG. 2, which are received within recesses 51 (see FIG. 2) in the support plate opening 22 to anchor the locking cup 44 against rotational movement. As best seen in FIGS. 3 and 4, the rotatable locking member 28 is received within the confines of the annular wall 46 of the locking cup 44, with the exterior annular surface 40 of the locking member 28 closely adjacent the interior surface of the locking cup annular wall 46, and with the bottom wall 50 of the locking cup 44 contained between the body portion of the locking member 28 and the upper surface of the support plate 12. Since, as described above, the locking member 28 is retained on the support plate 12 by the depending feet 30, the locking cup 44 is likewise maintained as an integral part of the operating unit by virtue of the bottom wall 50 being positioned between the locking member 28 and the support plate 12. In operation, the collar 16 is welded or otherwise fixed to the upper end of the guide tubes 10 and is disposed with the radially extending projections 26 aligned with the slots 24 in the support plate 12, and the rotatable locking member 28 is normally at its locking position illustrated in FIG. 3, at which position the locking member slot 32 is out of alignment with the projections 26 and the support plate slots 24, and the body portion of the locking member 28 is positioned between the projections 26 and the slots 24 to lock the support plate 12 in place on the guide tubes 10. At this locking position, the spring biased ears 48 in the locking cup 44 are deflected inwardly and positively engage one pair of detents 42 to resiliently maintain the locking member 28 against rotation. When it is desired to remove the support plate 12 from the guide tubes 10 for purposes described above, the tool 38 is manipulated to insert the prongs 36 thereof in the apertures 34 of the locking member 28, and the tool 38 is then rotated to impose a predetermined torsional force on the locking member 28 which results in the spring biased ears 48 being deflected outwardly by the camming action of the moving detents 42, whereby the locking member 28 is easily rotatable about the sleeve 20 until the second pair of detents 42' are positioned adjacent the spring biased ears 48, which then deflect inwardly to engage the detents 42' and resiliently maintain the rotatable locking member 28 at its unlocked or release position with the slot 32 therein aligned with both the projections 26 and the support plate slots 24. It will be apparent that this procedure for rotating the locking member 28 is quick and simple, and when all of the locking members 28 for each of the locking assemblies 14 associated with the support plate 12 have been rotated to their unlocked positions, the support plate 12 can be easily removed from the upper ends of the guide tubes 10 by lifting it upwardly so that the projections 26 can pass through the openly aligned slots 24 and 32. It will also be apparent that after the support plate 12 has been removed from the guide tubes 10, the locking assembly 14 remains integrally fixed to the support plate 12 and guide tubes 10 so that there are no loose parts which must be kept track of, and the rotatable locking member 28 is resiliently and positively maintained at its unlocked position by virtue of the spring biased ears 48 engaging the detents 42', so that when the support plate 12 is again to be positioned on the guide tubes 10, the locking member 28 of each of the locking assemblies 14 will be properly positioned to permit passage of the projections 26 through the aligned slots 24 and 32, all without any manipulation or adjustment of the various locking assemblies 14. Moreover, once the support plate 12 is properly positioned on the guide tubes 10, it is again a relatively simple matter to manipulate the tool 38 so that the prongs 36 engage the apertures 34, whereupon the locking member can be rotated back to its locked position with the spring biased ears again engaging the detents 42. A second embodiment of the present invention is illustrated in FIGS. 5-8, and it consists of a locking assembly 52 that includes a collar 54 having a radially extending shoulder 56 that supports the support plate 12 in the same manner as that described above, and a cylindrical sleeve portion 58 that is welded or otherwise secured at the upper end of the guide tube 10, the sleeve portion extending up through the opening 22 in the support plate 12 so as to be coextensive therewith. A rotatable locking member 60 includes an annular wall portion 62 formed of suitable metal, and has a pair of oppositely disposed spring biased ears 64 that are deflected inwardly from the interior surface of the annular wall portion 62. A pair of projections 66 extend outwardly from the annular wall portion, and they have a shape corresponding generally to that of the support plate slots 24. The rotatable locking member 60 also includes a flat bottom surface 68 that is slidably mounted between the top surface of the sleeve 58 and an end portion 70 that is welded or otherwise secured at the upper end of the guide tube 10 whereby the rotatable locking member 60 is axially contained between the sleeve 58 and the fixed end portion 70, while still being freely rotatable about the guide tube 10. The end portion 70 is provided with an outwardly extending shoulder 72, and a depending annular portion 74 that extends within the confines of the annular wall 62, the exterior surface of the annular portion 74 being formed with two pairs of opposed detents 76,76', only one detent in each pair being visible in FIG. 5. In operation, the rotatable locking member 60 is normally positioned as shown in FIG. 6 with the projections 66 thereof engaging the upper surface of the support plate 12 and maintaining it in a locked position between such projections and the shoulder 56. At this locked position, the spring biased ears 64 resiliently engage one pair of detents 76 to resiliently maintain the rotatable locking portion 60 at its locked position. When it is desired to remove the support plate 12 from the guide tubes 10, a hollow cylindrical tool 78 having notches 80 formed in the bottom edge thereof is passed over the end portion 70 and the rotatable locking portion 60 until the notches 80 receive therein the projections 66, whereupon the tool 78 is rotated to impose a predetermined torsional force on the rotatable locking member 60 which, by virtue of the camming action of the detents 76, causes the spring biased ears 64 to be deflected outwardly and permit rotation of the rotatable locking portion 60 until the spring biased ears 64 reach the other pair of detents 76' and deflect inwardly to resiliently maintain the rotatable locking portion 60 at its unlocked position as shown in FIG. 7. At this unlocked position, the projections 66 are aligned with the support plate slots 24, and when all of the locking assemblies 52 in the fuel bundle are moved to, and maintained at, their unlocked positions, the support plate 12 can be lifted off of the guide tubes 10 with the slots 24 passing over the aligned projections 66. Again, as was the case with the first embodiment, it will be noted that after the support plate has been removed, all of the locking assemblies 52 remain integrally fixed at the end of the guide tubes 10 without any loose parts, and the rotatable locking members 60 of each locking assembly 52 are maintained in their unlocked position by the spring biased ears 64 so that the support plate can be repositioned on the guide tubes 10 without any movement or adjustment of the locking assembly components. If for some unforeseen reason, use of the second embodiment should result in the spring biased ears 64 losing some of their resiliency through constant expansion and deflection, a further feature of the present invention allows for additional spring biased ears 64 to be crimped into the annular wall 62 using a crimping tool 82 as illustrated in FIG. 8. Even though the shoulder 72 of the fixed end portion 70 extends over the annular wall 62, this shoulder 72 is formed with opposed apertures 84 located directly above one of the pairs of detents 76 and aligned therewith. Accordingly, since the annular wall 62 has a circular configuration as illustrated in FIG. 8, the depending prongs 86 of the crimping tool 82 can be moved downwardly through the apertures 84 in the shoulder 72 and through the aligned detents 76 until the prongs 86 engage and crimp the annular wall 62 to form new spring biased ears 64 therein, all without any necessity of disassembling the locking assembly 52 for this purpose. A third embodiment of the present invention is illustrated in FIGS. 9-11 which illustrate a locking assembly 88 that includes a collar 89 that is welded or otherwise secured at the upper end of a guide tube 10, the collar 89 including a shoulder 90 for supporting the support plate 12, a sleeve portion 92 extending upwardly therefrom, and a plurality of curved fingers 94 that project upwardly from the sleeve 92 with spacings 96 between each of the fingers 94. A relatively thin annular snap ring 98, preferably made from a suitable resilient metal, is formed with a pair of opposed spring biased ears 100 and a spacing 102 between its two ends, and the snap ring 98 is positioned over the upstanding fingers 94 to encircle such fingers with the ears 100 being positioned in two of the opposed spacings 96 between the fingers 94. A movable locking member 104 is provided with an annular sleeve portion 106 that is positioned over, and receives therein, the snap ring 98, and the interior annular surface of the sleeve portion is provided with an inwardly directed protrusion 108 that is received within the spacing 102 of the snap ring 98. The rotatable locking member 104 also includes a pair of oppositely disposed projections 110 having a shape corresponding generally to the support plate openings 24, and the locking member 104 is held in place by a fixed end portion 112 that is welded or otherwise secured at the upper end of the guide tube 10 with the rotatable locking member 104 being sandwiched between the fixed end portion 112 and the sleeve 92 so that it is free to rotate, but is held against axial movement, or separation from the other components. In operation, the rotatable locking member 104 is positioned at its locked position as shown in FIG. 10 with the projections 110 extending over the upper surface of the support plate 12 to lock it in place on the guide tube 10. At this position, the locking member 104 is maintained at its locked position by the spring biased ears 100 resiliently engaging two of the opposed spacings 96 between the fingers 94, and with the snap ring 98 being movable with the rotatable locking member 104 by virtue of the protrusion 108 extending into the snap ring spacing 102. When it is desired to remove the support plate 12 from the guide tube 10, a tool 78 identical to that described above is positioned over the fixed end piece 112 until the notches 80 receive therein the projections 110, whereupon the tool 78 is rotated to cause the spring biased ears 100 to deflect outwardly and permit rotational movement of the locking member 104 until the spring biased ears 100 resiliently engage the other two opposed spacings 96 between the fingers 94, and the locking member 104 is then positioned at its unlocked position as shown in FIG. 11. At its unlocked position, the projections 110 are openly aligned with the support plate slots 24 and the support plate can then be moved upwardly with the projections 110 passing through the slots 24. As with the other two embodiments, the rotatable locking member 104 is resiliently maintained at its unlocked position by the spring biased ears 100 so no adjustment is necessary when the support plate is repositioned on the guide tubes 10, and each locking assembly 88 is integrally fixed on the end of the guide tubes 10 with no loose parts. It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of a broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.
048250899	claims	1. Radiant barrier apparatus for reflecting long wave radiation, comprising, in combination: base means, including a flexible chip having a first substantially clear film substrate having a first side and a second side; and metallized layer means including first and second layer secured to one of each of the first and second sides of the substrate for reflecting long wave infra red radiation. 2. The apparatus of claim 1 in which the chip is crinkled and the metallized layer means comprises a first metallized layer on the first side and a second metallized layer on the second side. 3. The apparatus of claim 1 in which the chip is fan folded, and the metallized layer means comprises a first metallized layer on the first side and a second metallized layer on the second side. 4. The apparatus of claim 1 in which the chip includes a second substantially clear film substrate, and each substantially clear film substrate has a first side and a second side. 5. The apparatus of claim 4 in which the first and second substantially clear film substrates include outer peripheries, and they are sealed together at their outer peripheries to defined bag means. 6. The apparatus of claim 5 in which the bag means is filled with a gas. 7. The apparatus of claim 6 in which the metallized layer means includes the first layer secured to the first side of the first film substrate and the second layer secured to the first side of the second film substrate. 8. The apparatus of claim 7 in which metallized layer means further includes a third layer secured to the second side of the first film substrate and a fourth layer secured to the second side of the second film substrate. 9. The apparatus of claim 6 in which the bag means comprises a plurality of gas filled bags. 10. The apparatus of claim 9 in which the plurality of gas filled bags are secured together at their outer peripheries to comprise a sheet of gas filled bags. 11. The apparatus of claim 4 in which the first and second clear film substrates are secured together at a plurality of horizontal connecting lines and a plurality of vertical connecting lines to define a plurality of bags in a sheet configuration. 12. The apparatus of claim 9 in which each bag is filled with a gas. 13. The apparatus of claim 4 in which the metallized layer means is disposed between the first and second substantially clear film substrate. 14. The apparatus of claim 13 in which the first substantially clear film substrate has a first thickness, and the second substantially clear film substrate has a second thickness, and the second thickness is greater than the first thickness. 15. The apparatus of claim 13 in which the base means further includes a support base, and the first substantially clear film substrate is disposed on the support base. 16. The apparatus of claim 1 in which the base means includes a first grooved surface, and the metallized layer means includes a first metallized layer secured to the first grooved surface. 17. The apparatus of claim 16 in which the base means includes a second grooved surface, and the metallized layer means includes a second metallized layer secured to the second grooved surface. 18. The apparatus of claim 17 in which the first and second metallized layers are secured together to define a single radiant barrier block. 19. The apparatus of claim 18 in which the base means further includes a first rectangular block and a second rectangular block, and the first grooved surface extends diagonally on the first rectangular block and the second grooved surface extends diagonally on the second rectangular block. 20. The apparatus of claim 1 in which the base means includes a first mesh layer. 21. The apparatus of claim 20 in which the base means further includes a second mesh layer, and the metallized layer means is secured to the first and second mesh layers.
047160080	abstract	A control device for a PWR includes a plurality of clusters arranged for insertion into and removal from the core and each having a plurality of rods connected to a common carrier vertically slidable in a stationary guide structure and connectable to a drive shaft. First clusters contain neutron absorbing material and are each individually associated with electromagnetic actuation means for adjusting the amount of insertion of the associated one of the first clusters. Second clusters contain a different material and are each individually associated with hydraulic actuation means controllable to cause upward and downward movement. A set of one first cluster and one second cluster is associated with some of said fuel assemblies, with the drive shafts of the two clusters in each set being arranged symmetrically with respect to the axis of a single stationary structure located above the associated fuel assembly and arranged for authorizing mutually independent movement of the first and second clusters.
	abstract	The inventions relates to a lithography system in which an electronic image pattern is delivered to a exposure tool for projecting an image to a target surface, said exposure tool comprising a control unit for controlling exposure projections, said control unit at least partly being included in the projection space of the said exposure tool, and being provided with control data by means of light signals, said light signals being coupled in to said control unit by using a free space optical interconnect comprising modulated light beams that are emitted to a light sensitive part of said control unit, wherein the modulated light beams are coupled in to said light sensitive part using a holed mirror for on axis incidence of said light beams on said light sensitive part, the hole or, alternatively, holes of said mirror being provided for passage of said exposure projections.
046648747	description	DETAILED DESCRIPTION OF THE INVENTION In the following description, like reference characters designate like or corresponding parts throughout the several views. Also in the following description, it is to be understood that such terms as "forward", "rearward", "left", "right", "upwardly", "downwardly", and the like, are words of convenience and are not to be construed as limiting terms. In General Referring now to the drawings, and particularly to FIG. 1, there is shown an upper end of a reconstitutable fuel assembly, being generally designated by the numeral 10, on which the reusable locking tube insertion and removal fixture of the present invention, generally indicated at 12, is employed. Basically, the fuel assembly 10, being of conventional construction, includes an array of fuel rods 14 held in spaced relationship to one another by a number of transverse support grids 16 (only one being shown) spaced along the fuel assembly length. Each fuel rod 14 includes nuclear fuel pellets (not shown) and is sealed at its opposite ends. The fuel pellets composed of fissile material are responsible for creating the reactive power of the nuclear reactor core in which the assembly 10 is placed. A liquid moderator/coolant such as water, or water containing boron, is pumped upwardly through the fuel assemblies of the core in order to extract heat generated therein for the production of useful work. The reconstitutable fuel assembly 10 also includes a number of longitudinally extending guide tubes or thimbles 18 along which the grids 16 are spaced and to which they are attached. The opposite ends of the guide thimbles 18 extend a short distance past the opposite ends of the fuel rods 14 and are attached respectively to a bottom nozzle (not shown) and a top nozzle 20. To control the fission process, a number of control rods (not shown) are reciprocally movable in the guide thimbles 18 located a predetermined positions in the fuel assembly 10. Specifically, a rod cluster control mechanism (not shown) interconnected to the control rods and associated with the top nozzle 20 is operable to move the control rods vertically in the guide thimbles 18 to thereby control the fission process in the fuel assembly 10, all in a well-known manner. Top Nozzle Attaching Structure As illustrated in FIG. 1, the top nozzle 20 comprises a housing 22 having a lower adapter plate 24 surrounded by four interconnected, upstanding side walls 26 with raised sets of pads 28,30 (only one pad in each set being shown) located respectively at pairs of diagonal corners 32,34 formed by the side walls 26. The control rod guide thimbles 18 have their uppermost end portions 36 coaxially positioned within the control rod passageways 38 formed through the adapter plate 24 of the top nozzle 20. For gaining access to the fuel rods 14, the adapter plate 24 of the top nozzle 20 is removably connected to the upper end portions 36 of the guide thimbles 18 by an attaching structure, generally designated 40. As partly seen in FIGS. 1, 3 and 4, and better seen in FIGS. 5 to 8, the top nozzle attaching structure 40 of the reconstitutable fuel assembly 10 includes a plurality of outer sockets 42 (only one being shown) defined in the top nozzle adapter plate 24 by the plurality of passageways 38 (also only one being shown) which each contains an annular circumferential groove 44 (only one being shown), a plurality of inner sockets 46 (only one being shown) defined on the upper end portions 36 of the guide thimbles 18, and a plurality of removable reusable locking tubes 48 (only one being shown) inserted in the inner sockets 46 to maintain them in locking engagement with the outer sockets 42. Each inner socket 46 is defined by an annular circumferential bulge 50 on the hollow upper end portion 36 of one guide thimble 18 only a short distance below its upper edge 52. A plurality of elongated axial slots 53 are formed in the upper end portion 36 of each guide thimble 18 to permit inward elastic collapse of the slotted end portion to a compressed position so as to allow the annular bulge 50 thereon to be inserted within and removed from the annular groove 44 via the adapter plate passageway 38. The annular bulge 50 seats in the annular groove 44 when the guide thimble upper end portion 36 is inserted in the adapter plate passageway 38 and has assumed an expanded position. In such manner, the inner socket 46 of each guide thimble 18 is inserted into and withdrawn from locking engagement with one of the outer sockets 42 of the adapter plate 24. Finally, each reusable locking tube 48 is inserted from above the top nozzle 20 into its respective locking position in the hollow upper end portion 36 of one guide thimble 18 forming one inner socket 46. When the locking tube 48 is inserted in its locking position, it retains the bulge 50 of the inner socket 46 in the latter's expanded locking engagement with the annular groove 44 and prevents the inner socket 46 from being moved to its compressed releasing position in which it could be withdrawn from the outer socket 42. In such manner, each locking tube 48 maintains its respective one inner socket 46 in locking engagement with the outer socket 42, and thereby the attachment of the top nozzle 20 on the upper end portion 36 of each guide thimble 18. Each locking tube 48 has at least a pair of small dimples 60 (FIGS. 5 to 8) preformed on the exterior thereof during manufacture and thus prior to insertion of the tube 48 to its locking position. The dimples 60 are so preformed by any suitable method, such as be die forming, by being coined or by spot welding, and so configured to have a generally pyramidal shape such that the metal forming the dimples substantially resists yielding and dimensional change regardless of the number of insertions and withdrawals of the tube 48 into and from the locking position. Thus, the whole locking tube per se yields, rather than the dimples 60, and then springs back to its original shape. Also, the dimples 60 are located along the exterior of the tube 48 and have outer tips diametrically displaced from one another across the tube at a distance greater than the inside diameter of the guide thimble upper edge 52 such that when the tube is inserted to the locking position, as seen in FIGS. 5 to 7, the dimples extend into the annular bulge 50 in the guide thimble upper end portion 36 which in turn fits into the annular groove 44 defined in the passageway 38 of the adapter plate 24. In such manner, the dimples 60 provide a positive interference fit with the guide thimble upper end portion 36 above the annular bulge 50 therein and with the upper portion of the adapter plate passageway 38 which prevents inadvertent withdrawal of the locking tube 48 from the locking position. Fixture for Inserting and Removing Reusable Locking Tubes For effectuating inspection, removal, replacement and/or rearrangement of fuel rods 14 contained in the reconstitutable fuel assembly 10, the assembly must be removed from the reactor core and lowered into a work station (not shown) by means of a standard fuel assembly handling tool (not shown). In the work station, the fuel assembly is submerged in coolant and thus maintenance operations are performed by manipulation of remotely-controlled submersible equipment. One component of such equipment is the fixture 12 of the present invention for removing and reinserting the reusable locking tubes 48 as the first and third steps in removing and replacing the top nozzle 20. Another component of such equipment is the fixture (not shown) forming the invention illustrated and described in the third patent application cross-referenced above. After the locking tubes have been removed in the first step by the fixture of the present invention, the fixture of the cross-referenced application is used for removing the top nozzle 20 of the reconstitutable fuel assembly 10 in the second step. Then after the locking tubes have been reinserted in the third step, the latter fixture is again used for replacing the top nozzle 20 back on the guide thimbles 18. Referring to FIGS. 1 to 8, there is shown the fixture 12 useful in inserting and removing the reusable locking tubes 48 into and from their locking positions within the top nozzle 20. The fixture 12 basically includes locking tube engaging means, generally designated 62, and actuating means, generally indicated 64. The locking tube engaging means 62 includes a lower traveling plate 66 and a plurality of hollow flexure tubes 68 attached to and projecting downward from the lower plate 66. The lower plate 66 has a generally square configuration and a plurality of openings 70 arranged in a pattern which matches that of the plurality of guide thimbles 18 and adapter plate passageways 38 of the fuel assembly 10. Each flexure tube 68 is anchored in one of the openings 70 defined through the lower plate 66 and has a lower axially segmented sleeve portion 72 which terminates in a lower segmented rim 74. An annular exterior shoulder 76 on the flexure tube 68 above its lower segmented portion 72 provides a stop such that when the shoulder 76 is disposed on an upper surface 78 of the adapter plate 24, the length of the lower sleeve portion 72 of the flexure tube 68 compared to that of the locking tube 48 is such that its segmented rim 74 will be positioned just below a lower end 80 of the locking tube 48. The segmented sleeve portion 72 is normally in a circumferentially collapsed condition in which its segmented rim 74 has an outside diameter less than the inside diameter of the reusable locking tube 48. Thus, the segmented rim 74 is normally contracted or collapsed inwardly toward the central axis of the flexure tube 68 sufficiently to allow the flexure tube 68 to be inserted into and withdrawn from the locking tube 48. The actuating means 64 includes an upper traveling plate 82 and a plurality of elongated solid actuating rods 84 attached to and projecting downward from the upper plate 82. The upper plate 82 has a generally square configuration matching that of the lower plate 66 and a plurality of taped holes 86 arranged in a pattern which matches that of the openings 70 in the lower plate 66. Each actuating rod 84 is anchored in one of the tapped holes 86 in the upper plate and has a shaft portion 86 which extends through one of the flexure tubes 68 and terminates in a lower enlarged nose 88 having a conical configuration. When the upper and lower plates 82,66 are positioned in contact next to one another, as seen in FIG. 1, the length of the actuating rod 84 compared to that of the flexure tube 68 is such that the enlarged nose 88 of the rod 84 is displaced a short distance below the segmented rim 74 of the tube 68 (see FIGS. 5 and 6). The outside diameter of the enlarged nose 88 of the actuating rod 84 is larger than the inside diameter of the segmented rim 74 of the flexure tube 68 such that as seen in FIG. 3, when the upper plate 82 is moved upwardly away from the lower plate 66, in an exemplary embodiment through a distance of approximately 0.35 inch, the inner annular tapered surface 90 of the enlarged nose 88 engages and expands the segmented rim 74 to a circumferentially expanded condition as the nose is forcibly inserted into the flexure tube 68, as seen in FIG. 7. The rim 74 is expanded to have an outside diameter greater than that of the inside diameter of the locking tube 48. Then, when the upper and lower plates 82,66 are moved together away from the adapter plate 24, as seen in FIG. 4, the rim 74 engages the lower end 80 of the locking tube 48 and carries the tube 48 with it, withdrawing the tube 48 from the remainder of the attaching structure 40 in the top nozzle 20, as seen in FIG. 8. Conversely, when the upper plate 82 is moved toward the lower plate 66, the enlarged nose 88 disengages and withdraws from segmented rim 74, allowing the rim 74 to contract back to its normal collapsed condition. The fixture 12 also includes mounting means, aligning means and biasing means, being generally designated 92, 94 and 96, respectively. The mounting means 92 includes a mounting plate 98 and a central shaft 100 rotatably journalled by a bushing 102 in the mounting plate 98. The lower portion 104 of the central shaft 100 is externally threaded and threadably engaged in a center tapped hole 106 in the upper plate 82. The lower end 108 of the lower threaded portion 104 of the central shaft 100 extends through a bore 110 in the center of the lower plate 66. In such arrangement, the central shaft 100 supports the upper plate 82, but not the lower plate 66, from the mounting plate 98. The mounting plate 98 has a generally square configuration approximately equal in size to that of the fuel assembly top nozzle 10. Four corner legs 112 on the bottom of the mounting plate 98 rest against the corner pairs of pads 28,30 of the top nozzle 20 such that the mounting plate 98 is stationarily supported on the top nozzle while operations are performed, as will be described later below, to remove and reinsert the reusable locking tubes 48. Two diagonally disposed ones of the four corner legs 112 of the mounting plate and one pad pair 28 of the top nozzle 20 include means for releasably locking the mounting plate 98 on the top nozzle 20. The releasable locking means includes a pair of hollow expandable split sleeves 114 fixedly mounted in the pair of diagonal corner legs 112 and a pair of wedge pins 116 mounted for rotational and axial movement in the respective sleeves 114. The sleeves 114 are adapted for insertion within respective bores 118 defined in the pair of diagonal corner pads 28 of the top nozzle housing 22. The wedge pins 116 having nuts 120 on their upper ends adapted to receive a suitable long-handled socket tool (not shown) for rotating the pins 116. When the pins 116 are rotated and thereby axially moved in a first direction, the sleeves 114 are caused to expand into frictional engagement with the bores 118 which secures the mounting plate 98 on the top nozzle housing 22. Conversely, when the pins 116 are rotated and thereby axially moved in an opposite second direction, the sleeves 114 are allowed to contract and release their frictional engagement with the bores 118, allowing removal of the mounting plate 98 from the top nozzle. The aligning means 94 of the fixture 12 includes a pair of elongated pins 122 which extend between and interconnect the stationary mounting plate 98 and the lower and upper traveling plates 66,82. Aligned holes 124,126,128 are formed in the respective plates 66,82,98 for receipt of the pins 122. Upper and lower retaining rings 130,132 are attached to opposite ends of the pins 122 for preventing the pin ends from slipping through the holes 124,128 of the respective lower and stationary plates 66,98. Each of the holes 124 through the lower plate 66 have a larger diameter counterbore 134 which opens toward the upper surface 78 of the adapter plate 24 and defines a ledge 136. Also, each of the pins 122 has a shouler 138 defined at the transition between a lower smaller diameter shaft portion 140 which extends through the holes 124,126 of the lower and upper plates 66,82 and an upper larger diameter shaft portion 142 which extends from the upper plate 82 through the hole 128 in the mounting plate 98. Thus, the aligning pins 122 not only keep the plates 66,82,98 aligned with one another, but also the lower plate ledge 136 and upper side of the upper plate 82 together in combination with the lower retaining ring 132 and pin shoulder 138 define the maximum limit of movement of the upper plate 82 away from the lower plate 66. Such maximum limit is designed to equate to the point at which the enlarged nose 88 on the actuating rod 84 expands the diameter of the segmented rim 74 on the flexure tube 68 to its circumferentially expanded condition in which it extends under the lower end 80 of the locking tube 48. The biasing means 96 of the fixture 12 includes a plurality of pairs of opposing pockets or recesses 144,146 formed respectively in the facing surfaces of the lower and upper plates 66,82 and a plurality of coil springs 148, one of which is disposed in each pair of the opposing recesses. The springs 148 thus interengage the plates 66,82 and normally bias them for movement away from one another so as to displace them at their aforementioned maximum limit. However, the springs 148 are yieldable for allowing the plates to move toward one another to the adjacent contacting positions, as seen in FIG. 1. Additionally, the fixture 12 includes a pair of spring-loaded shafts 150 which extend between the mounting plate 98 and the lower and upper plates 66,82. The plates 66,82,98 have respective holes 152,154,156 therein for receipt of the shafts 150. Each hole 154 in the upper plate 82 has a larger diameter counterbore 158 which opens facing toward the lower plate 66 and defines a ledge 160. The bottom ends 162 of the shafts 150 are externally threaded and adapted to threadably engage the internal threads in the holes 152 in the lower plate 66. Also, each of the shafts 150 has a shoulder 164 defined at the transition between a lower smaller diameter shaft portion 166 which extends through the holes 152,154 of the lower and upper plates 66,82 and an upper larger diameter shaft portion 168 which extends from the upper plate 82 through the hole 156 in the mounting plate 98. Further, a spring 170 is captured about each of the shafts 150 between the upper side of the mounting plate and a washer 172 retained on the upper end of the shaft 150 below a hex head 174 thereon. The spring 170 biases the shaft in a direction away from the lower plate. Still further, each shaft 150 is slidable axially relative to the plates 66,82,98 and against the bias of the spring 170 so that the bottom end 162 of the shaft 150 can be brought into the threaded hole 152 and threaded therein for attaching and maintaining the upper plate 82 against the lower plate 66 between the shoulder 164 and the attached bottom end 162 of the shaft 150. The hex head 174 is adapted to receive a suitable long-handled tool (not shown) for forcing the shaft 150 downward to overcome the bias of the spring 170 and to rotate the shaft to thread and unthread its bottom end 162. A retainer ring 176 on the lower shaft portion 166 prevents the shaft 150 from slipping out of the hole 154 through the upper plate 82 when the bottom end 162 of the shaft 150 is unthreaded and detached from the lower plate 66 and the spring 170 then causes the shaft 150 to move axially away from the lower plate. When the shafts 150 are detached from the lower plate 66, the biasing springs 148 in the recesses 144,146 of the plates 66,82 try to force the plates 66,82 apart to their maximum limit and thus will provide the positive plate separation necessary to cause the enlarged noses 88 on the actuating rods 84 to align with the segmented rims 74 on the flexure tubes 68, expanding the rims beneath the lower ends 80 of the reusable locking tubes 48 for removal of the tubes. Thus, when the central shaft 100 is rotated, by a suitable long-handled socket tool (not shown) connected to its hex head 178, so as to move the upper plate 82 upwardly away from the lower plate 66, the biasing springs 148 assist in their positive separation. Once the maximum limit of the upper plate 82 away from the lower plate 66 is reached, further rotation of the central shaft 100 raises both the upper and lower plates 82,66 together away from the adapter plate 24. Also, central shaft 100 has an externally threaded section 180 below its hex head 178 adapted to connect with a long-handled fixture handling tool (not shown) for installing and removing the mounting plate 98 onto and from the top nozzle 20. The procedures for removing and reinstalling the reusable locking tubes 48 are as follows. Removal of the locking tubes 48 from the removable top nozzle 20 for reconstitution of the fuel assembly 10 is initiated by lowering the fixture 12 (see in phantom in FIG. 1) toward the top nozzle when the fuel assembly is housed in a submerged work station. The lowering of the fixture 12 is accomplished using a long-handled tool (not shown) connected to the threaded section 180 of the central shaft 100 to guide the wedge pins 116 into the bores 118 of the top nozzle housing 22. Note that the upper and lower plates 82,66 are attached together, as seen in FIG. 1, by threading the bottom ends 162 of the shafts 150 into the tapped holes 152 in the lower plate 66 before lowering of the fixture 12. Once the mounting plate 98 is resting on the top nozzle 20, using a suitable long-handled socket tool connected to the nuts 120 on wedge pins 116, the fixture 12 can be locked on the top nozzle. Next, another long-handled socket took (not shown) is used to engage the hex head 178 of the central shaft 100 and rotate it, causing the attached upper and lower plates 82,66 to lower until the enlarged shoulders 76 on the flexure tubes 68 rests on the adapter plate upper surface, as seen in FIG. 1. At this point, the flexure tubes 68 (and actuating rods 84) extend through the reusable locking tubes 48 and the segmented bottom rims 74 of the flexure tubes 68 are located below the lower ends 80 of the locking tubes 48. Also, the enlarged noses 88 of the actuating rods 84 protrude below the flexure tube rims 74, as seen in FIG. 6. The flexure tubes 48 remain in their collapsed conditions which enabled them to have clear passage through the hollow locking tubes. Now, a long-handled socket tool (not shown) is used to engage the hex head 174 on each of the spring-loaded shafts 150 which are threaded at their bottom ends 162 into the holes 152 in the lower plate 66. Turning the shafts 150 the appropriate direction, the threads are disengaged and the spring 170 raises the shaft 150 away from the lower plate 66. Following next, a long-handled socket tool (not shown) is again connected to the hex head 178 on the central shaft 100 and the shaft is turned so as to cause the upper plate 82 and the actuating rods 84 attached thereon to rise. When the upper plate 82 travels through its maximum displacement or limit (for instance 0.35 inch) away from the lower plate 66 at which point the lower retaining rings 132 on the aligning pins 122 contact the ledges 136 in the counterbores 134 in the lower plate 66, as seen in FIG. 3, the lower plate 66 is then moved upward also. At the point where both plates 66,82 begin to travel upward, as seen in FIG. 4, the segmented rims 74 on the flexure tubes 68 are expanded beneath the locking tubes 48 by the noses 88 on the actuating rods 84, as seen in FIGS. 7 and 8, thus engaging and withdrawing the locking tubes 48 simultaneously from the removable top nozzle adapter plate 24. The central shaft 100 is turned until the end of mechanical travel is reached at which elevation the locking tubes are disengaged from the remainder of the top nozzle attaching structure 40 and the top nozzle 20 is then free to be raised off the upper end portions 36 of the guide thimbles 18. For reinstallation of the reusable locking tubes 48 back into the top nozzle attaching structure 40 after the fuel assembly 10 has been reconstituted and the top nozzle 20 has been replaced on the guide thimbles 18 of the fuel assembly 10, a long-handled socket tool (not shown) is engaged with the hex head 178 on the central shaft 100. The central shaft 100 is then turned in the appropriate direction to lower the two plates together and the captured locking tubes 48 until the enlarged shoulders 76 on the flexure tubes 68 rests against the adapter plate 24. At this point, the locking tubes 48 have been reinserted into their corresponding attaching structures 40. Turning of the central shaft 100 is continued until the upper plate 82 rests against the lower plate 66. Now, the rims 74 on the flexure tubes 68 have contracted from under the locking tubes 48. The hex head 174 on the shafts 150 are now engaged and the weight of the tool is used to compress the springs 170, forcing the shafts downward so that the bottom ends 162 can be threaded into the holes 152 in the lower plate 66. When the shafts 150 have been so threaded to the lower plate 66, the upper plate 82 is attached to the lower plate 66 so as to prevent expansion of the flexure tubes 68 by the actuating rods 84 during removal thereof which happens next. With a suitable long-handled socket tool engaged to the hex head 178 on the central shaft 100, the shaft is turned, raising the plates together and the flexure tubes 68 and actuating rods 84 therewith out of the locking tubes 48 and clear of the top nozzle adapter plate 24. Finally, using suitable tools (not shown) the wedge pins 116 are released and the fixture 12 unlocked from the top nozzle 20, and the fixture 12 is then removed from the reconstituted fuel assembly 10. It is thought that the present invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement thereof without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred or exemplary embodiment thereof.
	claims	1. A cylindrical nuclear fuel compact having an upper end, a lower end and a peripheral surface comprising an integral mold of a plurality of coated fuel particles which have an overcoat layer provided thereon, wherein a chamfer is formed in a corner of both of the upper end and the lower end of said nuclear fuel compact, said chamfer having a straight or curved vertical cross-section and said chamfer is formed by cutting or compression so as to intersect the overcoat layer, but so as not to damage said coated fuel particles. 2. A fuel compact as set forth in claim 1, wherein said chamfer has two or more stepped planes of different chamfering angles. 3. A fuel compact as set forth in claim 1, wherein said chamfer has said straight vertical cross-section and wherein a distance t or t′ is 0.10 mm or more, said distance t is a height distance between a top point and a bottom point of an inclination of said straight vertical cross-section of said chamfer, and said distance is a horizontal distance between said top point and said bottom point of said inclination of said straight vertical cross-section of said chamfer. 4. A fuel compact as set forth in claim 3, wherein said chamfer has a chamfering angle in a range of 30° to 60°. 5. A fuel compact as set forth in claim 1, wherein said chamfer has a straight cross-section, and said chamfer has a chamfering angle in a range of 30° to 60°. 6. A fuel compact as set forth in claim 3, wherein said chamfer has a chamfering angle other than 45°, and the distance t is not equal to the distance t′. 7. A method of manufacturing a fuel compact as set forth in claim 1 comprising integrally molding coated fuel particles by a die and forming a plane or curved taper on a corner of said die to thereby form a chamfer having a straight or curved cross-section. 8. A method of manufacturing a fuel compact as set forth in claim 7, wherein said taper is formed on said corner of said die by attaching a ring-like taper member having a taper surface on said die. 9. A fuel compact as set forth in claim 5, wherein said chamfering angle of said chamfer is other than 45°, and a distance t is not equal to a distance t′, said distance t is a height distance between a top point and a bottom point of an inclination of said straight vertical cross-section of said chamfer, and said distance t′ is a horizontal distance between said top point and said bottom point of said inclination of said straight vertical cross-section of said chamfer.
	abstract	Cores include different types of control cells in different numbers and positions. A periphery of the core just inside the perimeter may have higher reactivity fuel in outer control cells, and lower reactivity cells may be placed in an inner core inside the inner ring. Cores can include about half fresh fuel positioned in higher proportions in the inner ring and away from inner control cells. Cores are compatible with multiple core control cell setups, including BWRs, ESBWRs, ABWRs, etc. Cores can be loaded during conventional outages. Cores can be operated with control elements in only the inner ring control cells for reactivity adjustment. Control elements in outer control cells need be moved only at sequence exchanges. Near end of cycle, reactivity in the core may be controlled with inner control cells alone, and control elements in outer control cells can be fully withdrawn.
	abstract	A nuclear fuel assembly bottom nozzle, of the type including a perforated plate to allow water to pass through it, the nozzle having lateral faces, and at least one anti-debris element positioned on a lateral face to block out debris likely to infiltrate between the bottom nozzle and another adjacent bottom nozzle, characterized in that, in the free state, the or each anti-debris element permanently projects from the lateral face on which it is positioned, the or each anti-debris element being elastically deformable so as to retract towards the lateral face in the event of a force being exerted on the anti-debris element towards the lateral face.
045499853	claims	1. A method for solidifying and separating constituents from phosphoric acid solutions containing uranium and dissolved metals, comprising the steps of: (a) adding an alkali metal carbonate to a solution of phosphoric acid containing uranium and dissolved metals in at least about stoichiometric proportions to the acid content of the solution, and separating precipitated insolubles therefrom; (b) adding a calcium salt to the solution in amount of about 10 to about 50 percent in excess of stoichiometric proportions with the phosphate content; and (c) adding an alkali metal hydroxide to the solution and adjusting the pH of said solution to at least about 10, and separating precipitated insolubles therefrom. (a) adding an alkali metal carbonate to a solution of phosphoric acid containing uranium and dissolved metals in at least about stoichiometric proportions to the acid content of the solution, and separating precipitated insolubles therefrom; (b) adding sodium hydrosulfite to the solution, and separating precipitated insolubles therefrom; (c) adding a calcium salt to the solution; and (d) adding an alkali metal hydroxide to the solution and adjusting the pH of said solution to at least about 10, and separating precipitated insolubles therefrom. (a) adding at least one metal carbonate selected from the group consisting of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate to a solution of phosphoric acid containing uranium and dissolved metals in at least about stoichiometric proportions to the acid content of the solution, and adjusting the phosphate concentration thereof to about 1.1.+-.0.2 molar, and separating precipitated insolubles therefrom; (b) adding sodium hydrosulfite to the solution, and separating precipitated insolubles therefrom; (c) adding at least one calcium salt selected from the group consisting of calcium nitrate and calcium chloride to the solution in amount of about 10 to about 50 percent in excess of stoichiometric proportions with the phosphate content; and (d) adding sodium hydroxide to the solution and adjusting the pH of said solution to at least about 10, and separating precipitate insolubles therefrom. (a) contacting a solution of phosphoric acid containing uranium and dissolved metals with an anion exchange material and removing phosphate ions therefrom to thereby increase the concentration ratio of the dissolved metals to the acid; (b) adding an alkali metal carbonate to the solution in at least about stoichiometric proportions to the acid content of the solution, and separating insolubles therefrom; (c) adding a calcium salt to the solution in amount of about 10 to about 50 percent in excess of stoichiometric proportions with the phosphate content; and (d) adding an alkali metal hydroxide to the solution and adjusting the pH of said solution to at least about 10, and separating insolubles therefrom. (a) contacting a solution of phosphoric acid containing uranium and dissolved metals with an anion exchange medium and removing phosphate ions therefrom to thereby increase the concentration ratio of the dissolved metals to the acid; (b) adding at least one metal carbonate selected from the group consisting of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate to the solution in at least about stoichiometric proportions to the acid content of the solution, and separating insolubles therefrom; (c) adding at least one calcium salt selected from the group consisting of calcium nitrate and calcium chloride to the solution in amount of about 10 to about 50 percent in excess of stoichiometric proportions with the phosphate content; and (d) adding sodium hydroxide to the solution and adjusting the pH of said solution to at least about 10, and separating insolubles therefrom. (a) contacting a solution of phosphoric acid containing uranium and dissolved metals with an anion exchange material and removing phosphate ions therefrom to thereby increase the concentration ratio of the dissolved metal to the acid; (b) adding sodium carbonate to the solution in at least about stoichiometric proportions to the acid content of the solution, and separating the insolubles precipitated therefrom; (c) adding calcium nitrate to the solution in amount of about 10 to about 50 percent in excess of stoichiometric proportions with the phosphate content; and (d) adding sodium hydroxide to the solution and adjusting the pH of said solution to at least about 10, and separating the insolubles precipitated therefrom. (a) contacting a solution of phosphoric acid containing dissolved metals with an anion exchange material and removing phosphate ions therfrom to thereby increase the concentration ratio of the dissolved metals to the acid; (b) adding an alkali metal carbonate to the solution in at least about stoichiometric proportions to the acid content of the solution, and separating precipitated insolubles therefrom; (c) adding sodium hydrosulfite to the solution, and separating precipitated insolubles therefrom; (d) adding a calcium salt to the solution in amount of about 10 to about 50 percent in excess of the stoichiometric proportions with the phosphate content; and (e) adding an alkali metal hydroxide to the solution and adjusting the pH of said solution to at least about 10, and separating precipitated insolubles therefrom. (a) contacting a solution of phosphoric acid containing dissolved metals including uranium compounds with an anion exchange material and removing phosphate ions therefrom to thereby increase the concentration ratio of the dissolved metals to the acid; (b) adding at least one metal carbonate selected from the group consisting of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate to the solution in at least about stoichiometric proportions to the acid content of the solution, and separating precipitated insolubles therefrom; (c) adding sodium hydrosulfite to the solution, and separating precipitated insolubles therefrom; (d) adding at least one calcium salt selected from the group consisting of calcium nitrate and calcium chloride to the solution in amount of from about 10 to about 50 percent in excess of stoichiometric proportions with the phosphate content; and (e) adding sodium hydroxide to the solution and adjusting the pH of said solution to at least about 10, and separating precipitated insolubles therefrom. (a) contacting a solution of phosphoric acid containing dissolved metals with an anion exchange material and removing phosphate ions therefrom to thereby increase the concentration ratio of the dissolved metals to the acid; (b) adding an alkali metal carbonate to the solution in at least about stoichiometric proportions to the acid content of the solution and adjusting the phosphate concentration thereof to about 1.1.+-.0.2 molar, and separating precipitated insolubles therefrom; (c) adding sodium hydrosulfite to the solution, and separating precipitated insolubles therefrom; (d) adding a calcium salt to the solution in amount of about 10 to about 50 percent in excess of stoichiometric proportions with the phosphate content; and (e) adding an alkali metal hydroxide to the solution and adjusting the pH of said solution to at least about 10, and separating precipitated insolubles therefrom. (a) contacting a solution of phosphoric acid containing dissolved metals including uranium compounds with an anion exchange material and removing phosphate ions therefrom to thereby increase the concentration ratio of the dissolved metals to the acid; (b) adding at least one metal carbonate selected from the group consisting of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate to the solution in at least about stoichiometric proportions to the acid content of the solution and adjusting the phosphate concentration thereof to about 1.1.+-.0.2 molar, and separating precipitated insolubles therefrom; (c) adding sodium hydrosulfite to the solution, and separating precipitated insolubles therefrom; (d) adding at least one calcium salt selected from the group consisting of calcium nitrate and calcium chloride to the solution in amount of about 10 to about 50 percent in excess of stoichiometric proportions with the phosphate content; and (e) adding sodium hydroxide to the solution and adjusting the pH of said solution to at least about 10, and separating precipitated insolubles therefrom. (a) adding an alkali metal carbonate to a solution of phosphoric acid containing uranium and at least one dissolved metal selected from the group consiting of iron, nickel, molybdenum, copper, zinc, chromium, aluminum, cobalt and magnesium in at least about stoichiometric proportions to the acid content of the solution, and separating precipitated metal insolubles therefrom; (b) adding a calcium salt to the solution in amount of about 10 to about 50 percent in excess of stoichiometric proportions with the phosphate content; and (c) adding an alkali metal hydroxide to the solution and adjusting the pH of said solution to at least about 10, and separating precipitated metal insolubles therefrom. 2. The solidifying and separating method of claim 1, wherein the alkali metal carbonate added to the solution comprises at least one metal carbonate selected from the group consisting of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate. 3. The solidifying and separating method of claim 1, wherein the calcium salt added to the solution comprises at least one calcium salt selected from the group consisting of calcium nitrate and calcium chloride. 4. The solidifying and separating method of claim 1, wherein the alkali metal hydroxide added to the solution to adjust the pH thereof comprises sodium hydroxide. 5. A method for solidifying and separating constituents from phosphoric acid solutions containing dissolved metals including uranium compounds, comprising the steps of: 6. A method for solidifying and separating constituents from phosphoric acid solutions containing dissolved metals including uranium compounds, comprising the steps of: 7. The solidifying and separating method of claim 6, wherein the carbonate added to the solution comprises sodium carbonate. 8. The solidifying and separating method of claim 6, wherein the calcium salt added to the solution comprises calcium nitrate. 9. The solidifying and separating method of claim 6, wherein the separated precipitated insolubles from each step are combined and dehydrated for disposal. 10. A method for solidifying and separating constituents from phosphoric acid solutions containing uranium and dissolved metals, comprising the steps of: 11. The solidifying and separating method of claim 10, wherein the carbonate added to the solution comprises at least one metal carbonate selected from the group consisting of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate. 12. The solidifying and separating method of claim 10, wherein the calcium salt added to the solution comprises at least one calcium salt selected from the group consisting of calcium nitrate and calcium chloride. 13. The solidifying and separating method of claim 10, wherein the alkali metal hydroxide added to the solution to adjust the pH thereof comprises sodium hydroxide. 14. A method of solidifying and separating constituents from phosphate acid solutions containing uranium and dissolved metals, comprising the steps of: 15. The solidifying and separating method of claim 14, wherein the metal carbonate added to the solution comprises sodium carbonate. 16. The solidifying and separating method of claim 14, wherein the calcium salt added to the solution comprises calcium nitrate. 17. The solidifying and separating method of claim 14, wherein the separated insolubles from each step are combined and dehydrated. 18. A method for solidifying and separating constituents from phosphoric acid solution containing uranium and dissolved metals, comprising the steps of: 19. A method for solidifying and separating constituents from phosphoric acid solutions containing dissolved metals including uranium compounds, comprising the steps of: 20. The solidifying and separating method of claim 19, wherein the alkali metal carbonate added to the solution comprises at least one metal carbonate selected from the group consisting of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate. 21. The solidifying and separating method of claim 19, wherein the calcium salt added to the solution comprises at least one calcium salt selected from the group consisting of calcium nitrate and calcium chloride. 22. The solidifying and separating method of claim 19, wherein the alkali metal hydroxide added to the solution to adjust the pH thereof comprises sodium hydroxide. 23. The solidifying and separating method of claim 19, wherein the separated precipitated insolubles from each step are combined and dehydrated for disposal. 24. A method for solidifying and separating constituents from phosphoric acid solutions containing dissolved metals including uranium compounds, comprising the steps of: 25. The solidifying and separating method of claim 24, wherein the carbonate added to the solution comprises sodium carbonate. 26. The solidifying and separating method of claim 24, wherein the calcium salt added to the solution comprises calcium nitrate. 27. The solidifying and separating method of claim 24, wherein the separated precipitated insolubles from each step are combined and dehydrated for disposal. 28. A method for solidifying and separating constituents from phosphoric acid solutions containing dissolved metals including uranium compounds, comprising the steps of: 29. A method for solidifying and separating constituents from phosphoric acid solutions containing dissolved metals including uranium compounds, comprising the steps of: 30. The solidifying and separating method of claim 29, wherein the carbonate added to the solution comprises sodium carbonate. 31. The solidifying and separating method of claim 29, wherein the calcium salt added to the solution comprises calcium nitrate. 32. The solidifying and separating method of claim 29, wherein the separated precipitated insolubles from each step are combined and dehydrated for disposal. 33. A method for solidifying and separating constituents from phosphoric acid solutions containing uranium and dissolved metals, comprising the steps of:
	claims	1. A method of determining a shape of a radiation beam at a target position of a radiotherapy system, the system comprising:a radiation source for projecting the radiation beam towards the target position along a beam axis; anda multi-leaf collimator disposed between the radiation source and the target position, the multi-leaf collimator comprising a defocused array of moveable leaves configured to be positioned to intersect and block a part of the radiation beam so as to define the shape of the radiation beam at the target position, each leaf having a plane extending through a plane perpendicular to the beam axis and a width extending in a direction perpendicular to the plane of the respective leaf, wherein at least a first leaf and a second leaf are aligned such that the plane of the first leaf converges with the plane of the second leaf at a line, wherein a point within the line is displaced laterally from the beam axis;the method comprising:determining a projected width, with respect to the radiation beam, for each leaf positioned to intersect the radiation beam, the projected width being greater than a width of the respective leaf, wherein the determined projected width for a leaf further from the beam axis is wider than the determined projected width for a leaf closer to the beam axis;determining the shape of the radiation beam at the target position using the projected width of at least one leaf;positioning the leaves of the multi-leaf collimator based on the determined shape of the radiation beam; andirradiating the target position with the beam. 2. The method as claimed in claim 1, wherein all of the leaves of the multi-leaf collimator have substantially the same width, the method comprising:determining a progressively wider projected width for a leaf as a distance between the leaf and the beam axis increases. 3. The method as claimed in claim 1, comprising:determining the position of an edge of the radiation beam at the target position using the projected width of at least one leaf. 4. The method as claimed in claim 1, wherein the projected width is determined as a distance, in the plane perpendicular to the beam axis and passing through the leaf, between (i) a lateral edge extremity of the leaf furthest from the beam axis in a plane extending through the radiation source, and (ii) a plane extending through the radiation source and including a lateral edge extremity of the leaf closest to the beam axis. 5. The method as claimed in claim 1, comprising:storing values of the projected width for each leaf in a lookup table, andconsulting the values stored in the lookup table when determining the shape of the radiation beam at the target position. 6. The method as claimed in claim 1, wherein the target position is defined for a subject that is moveable into and out of the radiation beam. 7. The method as claimed in claim 6, further comprising:identifying a target position in the subject;determining an initial desired beam shape to irradiate the target position;positioning the subject for irradiation by the radiation beam;positioning the leaves of the mufti-leaf collimator based on the initial beam shape at the target position;irradiating the target position with the beam;determining a revised beam shape at the target position; andadjusting the position of one or more leaves of the multi-leaf collimator to change the beam shape from the initial beam shape to the revised beam shape. 8. The method as claimed in claim 7, wherein the radiation source is at a first position when the initial beam is determined and at a second position when the revised beam shape is determined, the first position being different from the second position. 9. A radiotherapy system comprising:a radiation source for projecting the radiation beam towards a target position along a beam axis;a multi-leaf collimator disposed between the radiation source and the target position, the multi-leaf collimator comprising a defocused array of moveable leaves configured to be positioned to intersect and block a part of the radiation beam so as to define the shape of the radiation beam at the target position, each leaf having a plane extending through a plane perpendicular to the beam axis and a width extending in a direction perpendicular to the plane of the respective leaf, wherein at least a first leaf and a second leaf are aligned such that the plane of the first leaf converges with the plane of the second leaf at a line, wherein a point within the line is displaced laterally from the beam axis; anda control system for controlling the multi-leaf collimator to move the leaves to provide a desired beam shape at the target position;wherein the control system is configured to:determine a projected width, with respect to the radiation beam, for each leaf positioned to intersect the radiation beam, the projected width being, greater than a width of the respective leaf, wherein the determined projected width for a leaf further from the beam axis is wider than the determined projected width for a leaf closer to the beam axis;determine the shape of the radiation beam at the target position using, the projected width of at least one leaf;position the leaves of the multi-leaf collimator based on the determined shape of the radiation beam; andirradiate the target position with the beam. 10. The system as claimed in claim 9, wherein all of the leaves of the mufti-leaf collimator have substantially the same width. 11. The system as claimed in claim 9, wherein the control system is configured to:determine a progressively wider projected width for a leaf as a distance between the leaf and the beam axis increases. 12. The system as claimed in claim 9, wherein the control system is configured to:determine the position of an edge of the radiation beam at the target position using the projected width of at least one leaf. 13. The system as claimed in claim 9, wherein the projected width is determined as a distance, in the plane perpendicular to the beam axis and passing through the leaf, between (i) a lateral edge extremity of the leaf furthest from the beam axis in a plane extending through the radiation source, and (ii) a plane extending through the radiation source and including a lateral edge extremity of the leaf closest to the beam axis. 14. The system as claimed in claim 9, wherein the control system is configured to:store values of the projected width for each leaf in a lookup table, andconsult the values stored in the lookup table when determining the shape of the radiation beam at the target position. 15. The system as claimed in claim 9, wherein the target position is defined for a subject that is moveable into and out of the radiation beam. 16. The system as claimed in claim 15, wherein the control system is configured to:identify a target position in the subject;determine an initial desired beam shape to irradiate the target position;position the subject for irradiation by the radiation beam;position the leaves of the multi-leaf collimator based on the initial beam shape at the target position;irradiate the target position with the beam;determine a revised beam shape at the target position; andadjust the position of one or more leaves of the multi-leaf collimator to change the beam shape from the initial beam shape to the revised beam shape. 17. The system as claimed in claim 16, wherein the radiation source is at a first position when the initial beam is determined and at a second position when the revised beam shape is determined, the first position being different from the second position.
	description	The present invention relates generally to nuclear fuel, and specifically to systems and methods for reducing the storage time of spent nuclear fuel. Spent nuclear fuel rods and other spent nuclear materials, if not reprocessed, require storage for about 100,000 years until their radioactivity abates. No one is willing to guarantee that any geologic formation is absolutely stable for that period of time. Thus at present in the United States alone there is −45,500 metric tonnes of spent fuel rods cumulated after 40 years cooling in large water-filled cooling pools near operating reactors. This burden of nuclear waste will become largely unsustainable because the cooling ponds are not designed as facilities to permanently store the rods. European states, such as France, reprocess their fuel rods to recover fissile atoms such as unburned 235U and 239Pu. While that works for a while, there seems to be a limit of about three reprocessing passes before the spent rod becomes too contaminated with neutron absorbers. Reprocessing was ruled out in this country by President Carter because it recovers plutonium and therefore, represents a proliferation hazard. Chemical separation is a possibility, but it is extremely hazardous because of the intense radioactivity of the daughter products. There are two epochs that dominate spent rod storage—daughter product radioactivity and actinide/transuranic radioactivity. If the latter can be eliminated, the total storage time required would be reduced by at least two possibly three orders of magnitude. Each 1000 MW nuclear power station in the U.S. produces about 30 metric tonnes of high level radioactive waste per year. There are about 104 U.S. nuclear power plants accounting for 20% of our electrical power that generate roughly 3,120 metric tonnes of spent fuel rods a year. The Department of Energy recently cancelled the Yucca Mountain Storage facility, and Secretary Chu has formed an esteemed commission to search for alternatives. But at present there is no means established for fuel rod disposal apart from the cooling pools at each power plant. Clearly opposition to the Yucca Mountain facility was centered on the stability of that formation over a significant geologic time (100,000 years). Nuclear waste storage times over hundreds to a thousand years appear to have little opposition. Although nuclear power plant safety remains an issue in some minds, removal of the storage problem will be the great enabler of fission nuclear power—an available, reliable, constant, greenhouse gas-free power source. Naturally if the restrictions on nuclear power plant construction were removed by showing a clear and safe path for fuel rod treatment and storage, a large number of new jobs will be created and nuclear component industries such as N-rated precision valves as an example will be re-invigorated. More and better power plants will require improvement and better control of the national power grid and also provide a source of new jobs and industries. In accordance with an aspect a method is providing of reducing the storage time of spent nuclear fuel. The method comprises providing a sample of spent nuclear fuel and irradiating the spent nuclear fuel with substantially collimated gamma ray photons having energy levels of about 10 MeV to about 15 MeV for a predetermined time period to initiate a photofission reaction in the remaining fertile fissile material in the spent nuclear fuel. In accordance with an aspect of the present invention, a method of reducing the storage time of spent nuclear fuel rods is provided. The method comprises placing a spent nuclear fuel rod in a nuclear reactor with a plurality of active nuclear fuel rods and a plurality of control rods and removing one or more of the plurality of control rods until the reactor reaches near criticality. The method further comprises irradiating the spent nuclear fuel with substantially collimated gamma ray photons having energy levels of about 10 MeV to about 15 MeV for a predetermined time period to initiate a photofission reaction in the remaining fertile fissile material in the spent nuclear fuel rod. In accordance with yet a further aspect of the invention, a system is provided for reducing the storage time of spent nuclear fuel. The system comprises a chamber configured to hold a sample of spent nuclear fuel and a gamma ray free electron laser (FEL) spaced apart from the nuclear reactor and positioned to irradiate the spent nuclear fuel with substantially collimated gamma ray photons having energy levels of about 10 MeV to about 15 MeV for a predetermined time period to initiate a photofission reaction in the remaining fertile fissile material in the spent nuclear fuel. Systems and methods are disclosed for reducing the radioactivity lifetime and thus the storage time of spent nuclear fuel. The systems and methods employ a gamma ray free electron laser (FEL) that can provide photons having energies of about 10 MeV to about 15 MeV to irradiate the spent nuclear fuel with gamma photons that penetrate the spent nuclear fuel in portions of the spent nuclear fuel that are inaccessible to thermal neutrons. The irradiation initiates a photofission reaction in the remaining fertile fissile material in the rod such as actinides (unused 235U, formed 239Pu, 241PU) in addition to other transuranics that are present in the spent nuclear fuel. This can reduce the storage time of the spent nuclear fuel from approximately 105 years to approximately 103 years or less. The spent nuclear fuel can be spent nuclear fuel rods. The major neutron absorbers that block the fission process in spent nuclear fuel rods are highly concentrated at or near the cylindrical surface of the rod and have substantially no effect on gamma ray penetration into the fuel rod in a direction along the longitudinal axis of the fuel rod. The gamma ray FEL differs from other sources of gamma ray photons in that it provides near collimation and has a relatively narrow energy spectrum. Therefore, the gamma ray FEL can be positioned to provide collimated photons having energies of about 10 MeV to about 15 MeV along the longitudinal axis of the nuclear spent fuel rod. In one aspect of the present invention, a spent nuclear fuel rod can be inserted into an active pile of nuclear fuel rods to act as an inefficient control rod in a light water pile nuclear reactor that can generate energy that can also be used to power the laser while the laser is irradiating the spent nuclear fuel rod. The active control rods and the photofission reaction induced by the 10-15 MeV gamma ray FEL provide a fission gain (i.e., chain fission reaction) that can be controlled to increase the fission of the remaining fissile material in the spent nuclear fuel rods at a reasonable rate (e.g., 1-10 hours) such that the spent rods can be processed faster than depletion of the active fuel rods. FIG. 1 illustrates a system 10 for reducing the storage time of spent nuclear fuel in accordance with an aspect of the present invention. A sample of spent nuclear fuel 14 is disposed in a chamber, for example, a nuclear reactor 16. The spent nuclear fuel 14 can be a spent nuclear fuel rod, radioactive material removed from a spent nuclear fuel rod or other spent nuclear fuel from another source. A gamma ray FEL that provides photons with energies of about 10 MeV to about 15 MeV is positioned to irradiate the spent nuclear fuel 14 with collimated gamma rays for a predetermined time period. The nuclear reactor 16 can include active nuclear fuel 18 and control material 20 that is employed to absorb the thermal neutrons generated by the active nuclear fuel 18. An amount of control material 20 is removed from the nuclear reactor 16 until the nuclear reactor 16 is brought near criticality, so as to keep the production of new fissile material to a minimum The substantially collimated gamma beam irradiates the spent nuclear fuel 14 with gamma photons that penetrate the spent nuclear fuel in portions of the spent nuclear fuel that are nearly inaccessible to the thermal neutrons because of the local thermal neutron absorber concentration. The irradiation initiates a photofission reaction in the remaining fertile fissile material (actinides/transuranics) in the spent nuclear fuel 14 that are present in the spent nuclear fuel 14. The thermal neutrons generated by the active nuclear fuel 18 and the photofission reaction induced by the 10-15 MeV gamma ray FEL 12 provide a fission gain (i.e., chain fission reaction) that can be controlled to increase the fission of the remaining fissile material in the spent nuclear fuel at a reasonable rate such that the spent nuclear fuel 14 can be processed faster than depletion of the active nuclear fuel 18. It is to be appreciated that the systems and methods of the present invention can be employed to reduce the storage time of spent nuclear fuel rods employed at nuclear power plants without any separation process of the radioactive material in the spent nuclear fuel rod. FIG. 2 illustrates a schematic illustration of graph 24 that shows the microstructure and the distribution of actinides and fission products of a spent nuclear fuel rod. A nuclear spent fuel rod does not have a uniform distribution of neutron-absorber poisons. The neutron-absorber poisons are distributed where the highest thermal neutron flux was located—at or near the cylindrical surface of the rod. Moreover, at least in the case of light water reactors using LEU (low-enriched uranium—a mixture of about 4˜5% of 235UO2 with 95% 238UO2), the uranium oxide is in the form of ceramic pellets encased in a metal sleeve (zirconium alloy). With use this ceramic becomes crazed with many fine-line cracks increasing in density towards the pellet rim, resulting from, among other things, the high thermal stress the pellet is subjected. The two major neutron absorbers (poisons) are xenon and samarium. As a result of crazing, a spent rod may release quite a bit of xenon over a period of weeks or months after being retired from an active pile. Thus it is stable samarium's concentration that largely determines the thermal neutron penetrability in a spent rod. Therefore both plutonium along with other fissile atoms and samarium, have roughly the same concentration profile with possibly a bump in the middle of the rod for the fissile atoms as a result of thermal neutron shielding. Each spent rod has, on average about 1023 fissile atoms of all kinds remaining. These contribute to a long-lived radioactivity tail. FIG. 3 illustrates a graph 26 of relative radioactivity of spent nuclear fuel versus time (years). According to the graph 26, storage times can be roughly divided into a fission product epoch and an actinide and transuranics epoch. Without the actinide tail, storage times could be reduced to a little less than a 1000 years. After that time, the spent rod would be about as radioactive as mined uranium ore. A 10 MeV-15 MeV collimated source of gamma ray photons will induce photofission in odd uranium and plutonium isotopes. Since it is presumed that the thermal poisons have a small cross section (of the order of millibarns), their distribution will have substantially no effect on the gamma ray penetration into the fuel rod in a direction along its longitudinal axis. Thus the gamma ray beam will fission atoms in some annulus about the center made inaccessible to thermal neutrons. FIG. 4 illustrates a system 30 for reducing the storage time of spent nuclear fuel rods in accordance with an aspect of the present invention. The system 30 includes a gamma ray FEL 32 spaced apart from a light water pile nuclear reactor 34. The gamma ray FEL 32 is configured to provide substantially collimated gamma photons at energies of about 10 MeV to about 15 MeV. FIG. 5 illustrates a top cross-sectional view of the nuclear reactor 34 of FIG. 4. A spent nuclear fuel rod 36 is disposed in a central region of the nuclear reactor 34 surrounded by a plurality of active nuclear control rods 38 and a plurality of control rods 37 that absorb thermal neutrons. The spent rod 36 can act as an inefficient control rod. The gamma ray FEL 32 is aligned along a longitudinal axis of the spent nuclear fuel rod 36 to provide gamma ray photons at energies of about 10 MeV to about 15 MeV that burn fissile materials and that remain in the spent fuel rod 36 by photofission. A typical spent fuel rod (˜3.3 m long) consists of uranium oxide ceramic pellets approximately 1 cm in diameter and 1 cm in height. When fresh the UO2 is enriched to about 4% with 235U, but after the rod becomes too thermal neutron absorbent (‘poisoned’) to function, it still consists of about 1% thermally fissile atoms—mostly plutonium formed by neutron absorption from 238U. The greatest deposits are around the rim of the pellets that experience the greatest concentration of thermal neutrons. The major neutron absorbers that block the fission process have substantially no effect on gamma ray penetration into the spent nuclear fuel rod 36 in a direction along the longitudinal axis of the spent nuclear fuel rod 36. Unlike thermal neutrons, the gamma ray beam is not selectively absorbed by common neutron poisons, such as samarium and xenon. Although a spent nuclear fuel rod is no longer is useful in a power-producing pile with its heavy buildup of neutron poisons, some thermal fissions occur if it is placed in a thermal neutron flux. Moreover it is not feasible to solely depend on laser-induced photofission to burn up 1023 atoms in any reasonable time. To be specific: suppose the laser has a 10 mJ pulse at a rate of 1/sec. Each spent 3.7 m long fuel rod has about 1023 thermally fissionable atoms left in it comprising about 1% of the number of atoms. Photofission cross sections for uranium isotopes as well as plutonium and the other actinides are about 0.3 barn at 10 MeV. Hence 92.7% of the photons are absorbed and a total of 5.79·109 photo-fissions per laser pulse are created. Of these about 1% are photofissions in the desired isotopes. Depending on the laser alone to split these atoms may lead to an unacceptably long process. Therefore, one or more control rods of the plurality of control rods 37 can be removed from the nuclear reactor 34 until the nuclear reactor 34 is brought to near criticality so as to keep production of new fissile material to a minimum. The thermal neutrons generated by the active nuclear fuel rods 38 and the photofission reaction induced by the 10 MeV-15 MeV gamma ray FEL provide a fission gain (i.e., chain fission reaction) that can be controlled to increase the fission of the remaining fissile material and actinides in the spent nuclear fuel rod 36 at a reasonable rate such that the spent nuclear fuel rod 36 can be processed faster than depletion of the active fuel rods 38. Each photofission event triggers a number of thermal neutron generations determined by the control rods 37. Some fraction of the thermal neutron flux will induce splitting in remaining fissile atoms in the spent nuclear fuel rod 36, but is limited by the presence of neutron poisons. For example suppose that G represents the thermal neutron ‘gain’ that follows fast neutron fission production in the spent rod from laser-induced fission. The total number of desired fissile atoms split per pulse becomes 0.01×5.79×109*(1+G). According to the Department of Energy, a typical MWe power plant must replace 66 fuel rod assemblies, consisting of, say 90 rods, each year, for a total of 5940 rods. To keep up with this rate, the system would have to process one rod every 1.5 hours. This rate seems problematical because of the very high thermal neutron flux required. Therefore more than one of these installations will be needed for each power plant (of course, the laser pulse rate can be increased and more than one rod processed at a time). It is necessary to fission at least 1017 fissile atoms per shot if this spent fuel rod soaking process is to be practical. Assuming no absorption (neutron poisons), the minimum gain required is 1.73·107. A boiling water reactor (thermal efficiency: 0.7) would generate about 3.9 MW of electrical power at this fission rate. Now the soak time is 11.57 days. A 60 day soak time would run the reactor at a 750 kW electrical power rate. These soak times will increase (but the electrical power level will not) when full neutron poisoning is taken into account. Note that the power generation is about 1/1000 or less than that of a full power plant. The nuclear reactor 34 is also employed as a power source for the gamma ray FEL 32. Therefore, the energy derived from the process of reducing the storage time of the spent nuclear fuel rod 36 can be employed to offset the energy cost of performing the process. The system 30 further includes a heat exchanger 40 coupled to the nuclear reactor 34, a turbine 42 coupled to the heat exchanger 40 and a generator 44 coupled to the turbine 42. The heat generated by the nuclear reactor 34 is captured by the heat exchanger 40 and employed to drive the turbine 42. The turbine 42 drives the generator 44 to provide electricity. The electricity is in turn utilized to power the gamma ray FEL 32. FIG. 6 illustrates a block diagram of a laser driven gamma ray self-amplified stimulated-emission (SASE) FEL 60 in accordance with an aspect of the present invention. The gamma ray SASE FEL 60 can provide substantially collimated gamma ray photons with relatively narrow energy spectrum at energies of about 10 MeV to about 15 MeV. The gamma ray SASE FEL 60 includes a laser driven electron injector 62 that provides a source of electrons to a laser-driven particle accelerator 64. The laser-driven particle accelerator 64 accelerates the electrons to high speeds, which are then provided to a laser driven undulator 66. The laser-driven undulator 66 oscillates the accelerated electrons to generate substantially collimated high gamma ray photons at energies of about 10 MeV to about 15 MeV. The laser-driven electron injector 62 can include a field emission nanotip electron source driven by a short pulse laser 68. The short pulse laser 68 is also employed by the laser-driven particle accelerator 64 and the laser driven dielectric undulator 66 to generate the required electromagnetic fields to accelerate and oscillate the electrons that result in the production of substantially collimated gamma rays. A typical radio frequency (RF) driven gamma ray source can be several kilometers long. By employing a laser source to generate the required electromagnetic fields, the gamma ray SASE FEL 60 can be built with a length of about 1 to about 5 meters and therefore can be assembled on a tabletop. A gamma ray FEL differs from other sources of 10-15 MeV photons in two respects its substantial collimation and its relatively narrow energy spectrum. Although a Linear Accelerator (LINAC) that generates 10 MeV-15 MeV photons could be used, the beams are quite divergent (relative to an FEL source) and have a wide energy spectrum. The skirts of the photofission cross section for the transuranics are steep so that photons with less than 10 MeV energy will create little photofission. Therefore, such a source substitution will greatly reduce the efficiency of the clean-up process. In view of the foregoing structural and functional features described above, a methodology in accordance with various aspects of the present invention will be better appreciated with reference to FIG. 7. While, for purposes of simplicity of explanation, the methodology of FIG. 7 is shown and described as executing serially, it is to be understood and appreciated that the present invention is not limited by the illustrated order, as some aspects could, in accordance with the present invention, occur in different orders and/or concurrently with other aspects from that shown and described herein. Moreover, not all illustrated features may be required to implement a methodology in accordance with an aspect the present invention. FIG. 7 illustrates a method 100 for reducing the storage time of spent nuclear fuel rods in accordance with an aspect of the present invention. The method begins at 110 where a spent nuclear fuel rod is positioned in an active pile of nuclear fuel rods and control rods in a nuclear reactor. At 120, control rods are removed until the nuclear reactor is brought to near criticality, so as to keep production of new fissile material to a minimum. At 130, a gamma ray FEL is disposed spaced apart from the nuclear reactor and positioned to provide gamma ray photons having an energy of about 10 MeV to about 15 MeV along the longitudinal axis of the spent nuclear rod. At 140, energy is extracted from the nuclear reactor and converted to electricity to power the gamma ray FEL. At 150, the laser is powered up to irradiate the spent nuclear fuel rod for a predetermined time period concurrently with the thermal neutron bombardment by the active control rods. What have been described above are examples of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims.
	abstract	A tool for inspecting a cell formed by grid beams of a top guide structure in a nuclear reactor is provided. The tool includes a camera; a support structure coupled to the camera for contacting at least one of the grid beams to support the camera within the cell; and at least one actuator moving the camera with respect to the support structure and along one of the grid beams, the at least one actuator coupling the camera to the support structure. A method for inspecting a cell formed by grid beams of a top guide structure in a nuclear reactor is also provided.
	description	This application is a national stage entry under 35 U.S.C. 371 of International Application No. PCT/SE2008/050615, filed 26 May 2008, designating the United States. This application claims foreign priority under 35 U.S.C. 119 and 365 to Swedish Patent Application No. 0701280-0, filed 25 May 2007. The present invention relates to a canister for final repository of radioactive waste, particularly for spent nuclear fuel in the form of fuel elements. More specifically, the invention relates to canisters with spent nuclear fuel, which are intended to be deposited in deep subterranean repository for at least a hundred thousand years. No prior art exists today for rendering spent nuclear fuel harmless in large scale. Hence, various concepts have been developed in order to bury the spent nuclear fuel in primary rock. The spent nuclear fuel may have to rest in the primary rock for hundreds of thousands of years before the radioactivity has abated to a level that is harmless to man and animal. It is important during this long period of time to ensure that the fuel does not dissolve such that radioactive particles rise to ground surface via the ground water. Water is needed in order for the spent fuel to dissolve and spread. It is hence important for the final repository to ensure that the spent fuel is maintained encapsulated in a tight canister and thereby is prevented from contacting the surrounding water until the radioactivity has abated to a low level. In most of the hitherto developed concepts the final repository comprises a system of barriers (canister, buffer and rock) that together are intended to prevent the radioactive species of the fuel from reaching ground surface. If one barrier does not work as planned, the other barriers will nevertheless guarantee safety, according to SKB, the Swedish Nuclear Fuel and Waste Management Co (www.skb.se). The canister (with an insert) is closest to the fuel. It is this barrier that is primarily intended to isolate the fuel from the surroundings. The objective of the canister in the repository is to completely encapsulate the spent fuel for a very long time, since no radioactive species can reach ground surface as long as the canister is tight. The Swedish Nuclear Fuel and Waste Management Co has developed a concept, the KBS-3 method, that is based on encapsulation of spent nuclear fuel in a protective copper casing that is thereafter embedded in bentonite clay at a depth of 500 meters in the primary rock. Hereby, the bentonite clay acts as a buffer against mechanical stress in the canister caused by rock movements and will also limit the ground water flow. Inside the protective copper casing there is a nodular iron insert in order to increase strength. The copper casing is joined together by e.g. friction welding or electron beam welding or some other welding method. Countries such as Sweden, Finland and Canada are planning to deposit their spent nuclear fuel according to this concept or a similar one. Copper is classified as a corrosion allowing metal in water that contains O2. SKB is of the opinion that the rate of corrosion in anoxic (free from gaseous oxygen) ground water only depends on accessible sulphur and that it hence is extremely low. It is thereby considered that the copper will give a perfect protection against corrosion until the radioactivity has abated. On page 28, second paragraph of the SKB report Encapsulation—When, where, how and why? (SKB Art. 141 2008) the following statement can be read: Today we really know all we need to know about corrosion in order to design the canister and the respitory to be safe for much more than 100,000 years. The present consensus about copper corrosion is also summarised in SKB Technical report Tr-01-23. Other countries have chosen another concept according to which a corrosion resistant metal such as titanium, titanium alloys, high-alloy stainless steel or nickel alloys has been chosen for the casing, instead of a corrosion allowing metal. It is characteristic for such alloys that their excellent resistance to corrosion is achieved by the formation of a thin passive layer of oxide (so called passive film) that forms on the outer surface of the metal. Irrespective of the choice of material for the canister casing, the demands are very high since they will be exposed to hard environments for a long time, such as: ground water that contains sulphide and chloride. ground water that contains O2 (oxidising) for 1-3,000 years. Anoxic environment for the following 100,000-1,000,000 years. Elevated temperatures (30-100° C.) for 10,000 years due to radioactive decay of the fuel. For the alloys that form passive films there is a certain risk of pitting corrosion, particularly if the chloride content of the ground water gets very high. This is a problem for the concepts based on the corrosion resistance of a passive layer. Accordingly, there is a risk that the barrier that is to be constituted by the canister is prematurely penetrated. The applicant has surprisingly found that copper is not immune in water free from O2 (anoxic water). This means that the rate of corrosion of copper in contact with anoxic ground water is much higher than previously assumed. Moreover, it has surprisingly been found that the rate of corrosion of copper in an anoxic water environment is very temperature sensitive and completely unacceptable rates of corrosion are achieved at 60-90° C. with the formation of a high hydrogen-containing, porous and non-protective oxide. Such temperatures may exist for up to 10,000 years due to the activity of the fuel. This means that none of the above mentioned concepts will result in a corrosion protection that, with adequate safety margins, will cope with the conditions that the canisters may be exposed to, until the radioactivity has abated to levels that are harmless to man and animal. It should also be noted that the canisters in question for spent nuclear fuel are relatively large. The canisters according to the KBS-3 method are almost five meters high and have a diameter of slightly more than one meter. The casing consists of copper with a thickness of five centimeters. In order to enhance strength, it has an insert of nodular iron which is a type of cast iron, on the inside. When the canister is full of spent fuel it will weigh between 25 and 27 metric ton. SE 425,707 and U.S. Pat. No. 4,834,917 are both based on hot isostatic pressing (HIP) of copper powder for the manufacturing of the outer canister. However, hot isostatic pressing of copper powder for this purpose has several drawbacks: 1) A HIP:ed copper powder may result in worse corrosion and mechanical properties than the KBS-3 method with hot formed (forged) OFP copper alloy as suggested by the SKB. 2) It is expensive and technically difficult to HIP such large canisters as are required by the KBS-3 concept (diameter of about 1 m, height of about 5 m). 3) All methods that require for the radioactive material to be positioned inside the inner canister during the sintering process/HIP are completely out of the question in order to achieve an improvement over the KBS-3 concept, since the fuel rods do not withstand high temperatures. That is because it is very hard to avoid oxidation of the main component of the spent nuclear fuel pellets, UO2, to higher oxides at elevated temperatures. Such a conversion is risky since it may result in a 35% volume expansion and pulverization of the pellets. In addition, the solubility of the higher oxides is too high in this context. 4) It is estimated that a certain percentage of the fuel rods (zircaloy tubes with uranium dioxide pellets) will contain water absorbed/adsorbed in the porous UO2 pellets during the interim storage that takes place in a water reservoir for 30-40 years (alternatively from the time period in the reactor). It is not considered to be technically/economically possible to dry the fuel rods after the interim storage, to a guaranteed dryness. This means that if the UO2 pellets are exposed to heat treatment they will rapidly react with moisture and water during heating, which must not take place (see paragraph 3). SE 509,177 shows an example on how to produce a canister for the KBS-3 method, i.e. a canister comprising an inner steel canister and an outer copper canister. The outer copper canister is formed by electrolytic copper coating of the inner steel canister. U.S. Pat. No. 4,562,001 shows a container that comprises at least three layers of different metals, which, from the outside inwardly, are always more noble. In one example, the outer layer consists of cast iron, the intermediate layer consists of nickel or a nickel alloy, and the inner layer consists of copper or a copper alloy. The problem of having an outermost non-noble metal such as cast iron or carbon steel, is the strong development of gaseous hydrogen due to anoxic corrosion. In this corrosion reaction, the thermodynamic equilibrium pressure of hydrogen is about 700 bar (Thermo Calc software, SSUB-database 2006). In all repository methods in which bentonite clay is to be used as external buffer around the metal canister (such as in KBS-3), there must not be any build-up of hydrogen gas pressure since that may ruin the buffer protection by the formation of holes and channels in the bentonite clay, which in turn results in far too fast transport paths for gas, water and ions in the same. The hydrogen released from anoxic corrosion of iron furthermore results not only in hydrogen gas (H2) but also in a considerable amount of atomic hydrogen (H) that migrates into the metal. This electrochemical hydrogen load due to corrosion of iron is harmful also to nickel and copper alloys that are not per se classified as particularly hydrogen sensitive alloys. The problem is that hydrogen load due to corrosion of iron can be said to correspond to a hydrogen gas pressure in the magnitude of 700 bar. A strong hydrogen activity will degrade virtually all metals (including copper and nickel alloys) in terms of mechanical properties (strength, creep ductility, toughness, etc.), and in addition the corrosion resistance will decrease for copper and nickel alloys at the same time as the risk of stress corrosion cracking (SCC) and hydrogen embrittlement increases. Contrary to U.S. Pat. No. 4,562,001, the applicant's patent is based on a copper canister with an outer metal alloy that forms a passive film based on chromium oxide, zirconium oxide or titanium oxide. Note that copper is less noble in the electromotive series than the oxide forming alloys containing Zr, Ti, Cr in their passive state (normal state). The object of the present invention is to provide a canister for spent nuclear fuel, which solves at least one of the above mentioned problems. Yet an object is to provide a canister that offers excellent protection against corrosion for at least 100,000 years. Another object of the present invention is that the concepts developed for final repository of the copper canister, according to the KBS-3 method, can be used completely or partly also for the novel canister. It would e.g. be preferable for the canister to provide a good protection against corrosion also when embedded in bentonite clay. Yet a purpose of the present invention is to provide a canister that need not be sealed by HIP:ing. At least one of the above mentioned objects or problems is achieved or solved by a canister for used nuclear fuel according to the present invention, which comprises spent fuel elements enclosed in a copper casing in combination with at least one outer metal layer of a passive-film-forming metal or metal alloy. It is preferable, in order to achieve an excellent protection against corrosion, that the outer metal layer forms an essentially hydrogen free passive film in anoxic ground water and hence it is suggested that the outer metal layer comprises an alloy that forms a zirconium, titanium or chromium rich oxide also in anoxic water. The passive-film-formers get completely passivated in anoxic water and can withstand elevated temperatures as well as the oxidising conditions that initially prevail. The rate of corrosion of copper is however unacceptably high at elevated temperatures, also in water that is completely free from gaseous oxygen (anoxic water). Hence, the object of the passive film layer is to protect the outside of the copper casing for at least the first 10,000 years during which an elevated temperature is assumed to prevail. When the temperature has decreased enough due to the abating radioactivity, copper will however give a good protection against corrosion also in environments with high levels of chlorides. In best case, if the ground water environment does not change to promote pitting corrosion (e.g. in case of high levels of Cl−) of the passive-film-forming alloys, the outer casing as such can form a complete protection against corrosion for 100,000 years or more, particularly if it is made of a zirconium or titanium alloy. Zirconium or titanium alloys form nearly hydrogen free passive films also in anoxic water, i.e. the oxygen is taken from the water molecule without allowing the hydrogen to penetrate into the oxide or metal. This is most valid for zirconium (Corrosion Science, Volume 31, 1990, P. 149-154, G. Hultquist, et al.). Accordingly, a harmful Zr hydride can scarcely form in anoxic water below 100° C. The conditions of the surrounding environment may change during the geological eras and in time unfavourable conditions could possibly lead to the formation of a small hole in the outer casing with the passive-film-forming metal or metal alloy. Even if this happens it is a process that will take a very long time and the elevated temperature due to the activity in the radioactive waste will be considerably much lower than in the beginning since the activity abates in time. That is, if a hole forms in the outer casing due to pitting corrosion, the temperature will have decreased to such a level that the rate of corrosion of the copper is low at that time, which means that the copper casing will provide an excellent protection against corrosion at a later point of time when the temperature is lower. For alloys that form a passive film of chromium oxide it is also the case that if very high levels of Cl− are accumulated in the deep subterranean repository and the outer casing is penetrated due to Cl− induced pitting corrosion, the corrosion of the inner copper casing will be dampened since the slowly corroding outer casing constitutes a weak source of hydrogen. If a high enough hydrogen pressure, i.e. more than 1×10−3 bar is built up, the copper will namely be virtually immune against corrosion in anoxic water even if the temperature is high. (It is probable that the hydrogen pressure will exceed 10−3 bar due to local corrosion of chromium oxide-forming alloys in anoxic water. It can be mentioned that in the atmosphere there is only 5×10−7 bar of gaseous hydrogen). It is furthermore assumed that also chloride induced copper corrosion is counteracted by an increased hydrogen pressure. A titanium rich passive film can be achieved by forming the outer metal layer of titanium or an alloy thereof, and a zirconium rich passive film can be achieved by forming the outer metal layer of zirconium or an alloy thereof. A chromium rich passive film can be achieved by forming the outer metal layer from a nickel-based alloy (a cobalt-based alloy is also conceivable) with at least 12% by weight of Cr, preferably at least 14% by weight of Cr, or a stainless steel with a chromium content of at least 18% by weight of Cr. The stainless steel alloys should preferably be alloyed with molybdenum and/or tungsten in order to increase the repassivation of the passive film, where W+Mo>0.15% by weight. In the choice of an austenitic stainless steel it is furthermore preferred that the nickel content is at least 12% Ni by weight. For the duplex stainless steel it is preferred that the nickel content is less than 10% by weight and it can be down to about 4% by weight of Ni or even 1.5% by weight of Ni, by the replacement of nickel with manganese and/or nitrogen. Also ferritic stainless steels with chromium contents above 22% by weight can come in question. The outer layer of the passive-film-forming alloy (here called PFA) can be applied on the copper canister according to at least two methods: 1) A copper sleeve that contains an insert with spent fuel is sealed and forms a copper canister, after which the sealed copper canister including fuel is introduced into a PFA tube that includes a welded bottom (as an alternative, the bottom is welded onto the tube after introduction of the copper canister in the same). Preferably, the copper canister is introduced with a gap that is as small as possible in order to avoid overly reduction of thermal conductivity. A PFA cover is applied in order to be joined with the PFA tube by robotic welding, thereby to seal the outer casing. The tube can have a longitudinal weld or be seamlessly manufactured. For stainless steels and nickel alloys e.g., it is advantageous for cost reasons to produce with a longitudinal weld, while seamless production by extrusion or press piercing is more expensive. 2) Two PFA sheet halves or alternatively one PFA sheet are/is shaped and pressed tightly around an empty copper casing, after which longitudinal welding takes place (optionally with a thin weld root plate in order to prevent the copper from contaminating the PFA seam). This method will result in a small or even non-existing gap, a shrink fit is e.g. possible to achieve as shrinking takes place in the welded seam. The insert with the spent fuel is thereafter introduced into the copper sleeve that is sealed by welding a copper lid thereupon. It is preferred in order to enable welding of the copper lid by e.g. friction stir welding, that the upper rim of the copper sleeve is arranged some distance above the upper rim of the outer, surrounding, PFA sheet. Accordingly, the PFA lid will have the shape of a sleeve (FIG. 3) that is slipped over and welded together with the surrounding PFA sheet. If there is also a gap, somewhat impaired heat conduction may result. This can mean that the copper casing reaches a maximum temperature that exceeds 100° C., which will impair its strength and somewhat increase its creeping. This is however not a problem as the outer casing of the passive-film-forming metal or metal alloy, irrespective of which passive-film-former that is used, will have a much better strength (including creeping strength) even if its thickness is only half or even a third of the thickness of the copper layer. The gap between the copper casing and the passive film casing can be eliminated if it is filled with a low melting and corrosion slow metal, such as a tin or lead alloy. Different types of robotic welding can be used to weld the outer PFA casing, depending on which alloy that is chosen. TIG welding as well as plasma welding are e.g. suitable welding methods. For stainless steel and Ni based alloys, MAG or MIG welding is also suitable. The material thickness of the outer casing can be varied depending on which passive-film-forming metal or metal alloy that is used, since different metals or alloys have different corrosion resistance. If the casing is made of titanium or a titanium alloy, it is preferred that the casing has a material thickness in the range of 4-30 mm, more preferred in the range of 6-20 mm. For zirconium or zirconium based alloys, it is preferred to have a material thickness in the range of 3-20 mm. Titanium, zirconium and alloys thereof have the best corrosion properties, which means that they can be made thinner. For cobalt based alloys and nickel based alloys, it is preferred to have a material thickness in the range of 8-40 mm, more preferred in the range of 10-30 mm. For stainless steel it is preferred to have a material thickness in the range of 8-50 mm, more preferred in the range of 10-40 mm. Given that an additional barrier has been added in the form of the outer casing of the passive-film-forming metal or metal alloy, it could be conceivable to reduce the material thickness of the copper casing from the 50 mm intended for the KBS-3 method to 30 mm, e.g. The copper casing should however at least exceed 25 mm and the corrosion protection will naturally be better the larger the material thickness. An important advantage of having a thinner material thickness is however that it will be easier to achieve good welded seams and accordingly sealing of the copper casing could be easier as well as with a better result. For the same reason, it could come into question in case of a thinner material thickness to make the copper casing from a tube with a longitudinal weld without appreciably impairing the properties of the copper casing. The outer casing will moreover result in a considerably increased structural stability that will considerably relieve a copper casing with an insert, meaning e.g. that the strength requirements for the insert can be lowered. Given that it is possible that the chemical environment can vary several times during different time epochs (ice age, interglaciers), a third metal layer internal of the copper casing can possibly be motivated in connection with additionally increased safety thinking. In that case, such a layer should also be a passive-film-forming alloy (titanium, titanium alloys, zirconium, zirconium alloys, cobalt alloys, nickel alloys or stainless steel). This can also be achieved by the insert with a tight lid being made of stainless cast steel with at least 18% by weight of chromium, which results in several advantages (see below in connection with a load bearing insert). The canister according to the present invention is preferably also embedded in bentonite clay when it is to be placed in final repository. The load bearing insert can for example also be manufactured of cast iron, as is suggested in the KBS-3 method. Safety may however be increased by manufacturing the insert from e.g. cast steel with at least 18% chromium, as an alternative to cast iron. This is because hydrogen pressures that are potentially very high can build up inside the canister if water contacts the cast iron (see the discussion above concerning U.S. Pat. No. 4,562,001), whereby the copper casing could crack. This scenario is furthermore accelerated if the mechanical properties of the copper (static strength and creep ductility e.g.) are degraded by the hydrogen, so called hydrogen embrittlement. Naturally, the insert can be formed from other materials. A canister 1 is shown in FIGS. 1 and 2. The canister has an inner copper casing 4a, 4b, 4c comprising a copper tube 4a with a copper lid 4b and a copper bottom 4c. The copper tube 4a and the copper bottom 4c are joined together by welding (such as friction stir welding or electron beam welding) and form a copper sleeve 4a, 4c, but the copper sleeve 4a, 4c can also be made from a single piece by press piercing e.g. An insert 2 is introduced into the copper casing 4a, 4c, which insert 2 has a number of longitudinal cavities 3 intended for spent fuel rods. An insert lid 6 seals the insert 2. The copper casing 4b has been joined together with the copper casing 4a, 4b only after the insert has been filled with spent fuel rods. FIG. 2 shows an insert intended for 12 fuel elements with fuel rods, but more as well as fewer can naturally be conceived. For fuel elements of larger cross-section it may e.g. suffice to have one insert 2 that may contain just 4 fuel elements. An outer casing 5a, 5b, 5c of a passive-film-forming metal or metal alloy encloses the inner copper casing 4a, 4b, 4c. The outer casing 5a, 5b, 5c comprises an outer tube 5a that has an outer lid 5b and an outer bottom 5c, which all three are manufactured from the same passive-film-forming metal or metal alloy (titanium, titanium alloy, zirconium, zirconium alloy, cobalt based alloy, nickel based alloy or stainless steel). In this embodiment, the outer casing 5a, 5b, 5c has been applied over the copper casing 4a, 4b, 4c after the copper lid 4b has been joined together with the copper casing 4a, 4c, i.e. according to method no. 1) above. FIG. 3 shows an embodiment in which an outer sleeve 5a, 5c of a passive-film-forming metal or metal alloy, comprising an outer sleeve 5a, joined together with an outer bottom 5c, has been applied over the copper sleeve 4a, 4c, before the copper lid 4b has been joined together with the copper sleeve 4a, 4c. Here, it can be seen that the upper edge of the outer sleeve 5a, 5c is positioned below the upper edge of the copper sleeve 4a, 4c, thus enabling for the copper lid 4b to be welded together with the copper sleeve 4a, 4c. Thereafter, an outer lid 5b can be slipped over the copper lid 4b and welded together with the outer sleeve 5a, 5c. Since the upper edge of the outer sleeve 5a, 5c is positioned below the upper edge of the copper sleeve 4a, 4c, the outer lid 5b will also be shaped as a sleeve. This corresponds to method no. 2) according to the above and it is the preferred embodiment of the canister according to the present invention. Naturally, it is realised that the invention is not limited to the above mentioned embodiment examples but can be varied within the scope defined by the claims.
	claims	1. A method of removing a radioactivated reactor pressure vessel from a reactor building of a nuclear plant, comprising: carrying a radiation shield for shielding radiations from said reactor pressure vessel into said reactor building; positioning said radiation shield onto a reactor shield wall shielding said reactor pressure vessel inside said reactor building; abutting said reactor pressure vessel and said radiation shield by raising said reactor pressure vessel; and carrying said reactor pressure vessel together with said radiation shield out of said reactor building by raising said reactor pressure vessel. 2. A method of removing a radioactivated reactor pressure vessel from a reactor building of a nuclear plant, comprising: carrying a radiation shield for shielding radiation from said reactor pressure vessel into said reactor building; positioning said radiation shield onto a reactor shield wall shielding said reactor pressure vessel inside said reactor building; attaching a hanger to said reactor pressure vessel; abutting a part of the upper end portion of said reactor pressure vessel and a part of the upper portion of said radiation shield by raising said reactor pressure vessel; and carrying said reactor pressure vessel together with said radiation shield out of said reactor building by raising said reactor pressure vessel. 3. A method of removing a radioactivated reactor pressure vessel from a reactor building of a nuclear plant according to claim 2 , wherein said hanger is attached to a head of said reactor pressure vessel. claim 2 4. A method of removing a radioactivated reactor pressure vessel from a reactor building of a nuclear plant, comprising: carrying a radiation shield for shielding radiation from said reactor pressure vessel into said reactor building; positioning said radiation shield onto a reactor shield wall shielding said reactor pressure vessel inside said reactor building; abutting said reactor pressure vessel and said radiation shield by raising said reactor pressure vessel; and carrying said reactor pressure vessel together with said radiation shield out of said reactor building by raising said reactor pressure vessel. 5. A method of removing a radioactivated reactor pressure vessel from a reactor building of a nuclear power plant, comprising: carrying a radiation shield for shielding radiation from said reactor pressure vessel into said reactor building; positioning said radiation shield onto a reactor shield wall shielding said reactor pressure vessel inside said reactor building; abutting a head of said reactor pressure vessel and said radiation shield by raising said reactor pressure vessel; and carrying said reactor pressure vessel together with said radiation shield out of said reactor building by raising said reactor pressure vessel. 6. A method of removing a radioactivated reactor pressure vessel from a reactor building of a nuclear power plant, comprising: carrying a radiation shield for shielding radiation from said reactor pressure vessel into said reactor building; positioning said radiation shield onto a reactor shield wall shielding said reactor pressure vessel inside said reactor building; abutting a part of the upper end portion of said reactor pressure vessel and a part of the upper portion of said radiation shield by raising said reactor pressure vessel; and carrying said reactor pressure vessel together with said radiation shield out of said reactor building by raising said reactor pressure vessel. 7. A method of removing a radioactivated reactor pressure vessel from a reactor building of a nuclear power plant, comprising: carrying a radiation shield for shielding radiation for said reactor pressure vessel into said reactor building; positioning said radiation shield onto a reactor shield wall shielding said reactor pressure vessel inside said reactor building; raising said reactor pressure vessel into said radiation shield until said reactor pressure vessel comes into contact with means through which said reactor pressure vessel bears the weight of said radiation shield; and carrying said reactor pressure vessel together with said radiation shield out of said reactor building by raising said reactor pressure vessel. 8. A method of removing a radioactivated reactor pressure vessel from a reactor building of a nuclear plant according to claim 7 , wherein said means are stoppers mounted on an upper lid of said radiation shield. claim 7 9. A method of removing a radioactivated reactor pressure vessel from a reactor building of a nuclear plant according to claim 7 , wherein said means are stopper beams fixed to an upper portion of said radiation shield. claim 7 10. A method of removing a radioactivated reactor pressure vessel from a reactor building of a nuclear plant according to claim 9 , wherein said stopper beams contact an upper flange of said reactor pressure vessel. claim 9
	abstract	Exemplary embodiments provide automated nuclear fission reactors and methods for their operation. Exemplary embodiments and aspects include, without limitation, re-use of nuclear fission fuel, alternate fuels and fuel geometries, modular fuel cores, fast fluid cooling, variable burn-up, programmable nuclear thermostats, fast flux irradiation, temperature-driven surface area/volume ratio neutron absorption, low coolant temperature cores, refueling, and the like.
	abstract	A nuclear reactor instrumentation system monitors a nuclear power system that includes a reactor core within a reactor vessel and one or more sensors for monitoring parameters of the nuclear power system. The nuclear reactor instrumentation system includes a computer having a processor and configured to be powered by a normal power source and a backup power source; a wireless transmitter operable under the control of the processor; and a memory coupled to the processor and containing stored programming instructions. The stored programming instructions are executable by the processor to cause the processor to receive data from the sensors; identify a loss of normal power from the normal power source; and in response to identifying the loss of normal power, cause the wireless transmitter to transmit the received data.
	abstract	An electron beam exposure apparatus has a first shaping aperture having a plurality of rectangular openings, each having sizes different from each other and shaping a beam shape of an electron beam, a rectangular opening selection deflector which controls a path of the electron beam to irradiate the electron beam on one of the plurality of rectangular openings, a second shaping aperture having a plurality of character openings, each having sizes different from each other and shaping a beam shape of the electron beam passing through the first shaping aperture, and a character beam deflector which controls the path of the electron beam to irradiate the electron beam on character openings corresponding to the rectangular openings in the first shaping aperture.
	description	Shown in FIG. 1 is a prior art guide tube 1 of a fuel assembly for a pressurized-water nuclear reactor. The prior art guide tube 1 is of zirconium alloy and has a cylindrical external surface whose diameter is constant along the length of the tube, except for the upper part 2 of the tube which is bell-mouthed and has for example a tapped inner bore. This upper part of the tube permits fixing the tube in the upper terminal element of the fuel assembly, optionally by the use of detachable fixing means. The guide tube 1 further comprises an internally tapped lower end by means of which the tube may be fixed to the lower terminal element of the fuel assembly. The guide tube 1 comprises a main or body part 1a and a lower end part 1b which differ from each other in that the main part 1a has a first wall thickness e1 and the lower end part 1b a second thickness e2 exceeding the thickness e1. Consequently, the part 1b constitutes a reinforced part of the tube. In some cases, the guide tube may comprise a reinforced part of increased thickness between two main parts which have a thickness less than the reinforced part, instead of a reinforced end part. The outside diameter of the tube is constant and identical in the main part of the tube and in the reinforced part 1b. The inside diameter of the tube in the main part 1a is therefore larger than the inside diameter of the tube in the part 1b and the guide tube 1 has a transition region 1c between its parts 1a and 1b. In the transition region 1c, the internal surface of the tube is formed by a conical or tapered chamfer whose vertex angle is around 10xc2x0. The wall of the lower end part of the tube may have through openings, such as 3, which permit limiting the overpressure of the cooling liquid of the reactor in the lower part of the guide tube upon the dropping of the absorber rod guided by the guide tube rendering more progressive the braking of the absorber rod upon the dropping of a cluster. The increased thickness e2 of the wall of the guide tube in the lower end part 1b of the guide tube permits reinforcing the lower part of the guide tube and avoiding deterioration of this lower part by the effect of the overpressure upon the dropping of the absorber rod of the control cluster and in the course of the transitional periods of the nuclear reactor. However, the presence of an intermediate region 1c whose internal wall has the shape of a conical or tapered chamfer creates a discontinuity as concerns the guiding of the absorber rod in the guide tube. Further, the intermediate region may be a weak region of the tube. Further, to produce the tube shown in FIG. 1, there must be employed a forming process, such as a rotary hammering, for reducing the thickness of the wall in the main part of the guide tube, i.e. along the major part of the length of the tube, then for inwardly upsetting the thick wall of the lower part of the tube. Such a forming process is delicate to carry out and requires a relatively long operating time. The process according to the invention permits producing a tube which is in a single piece and has a reinforced part, by a rolling technique on a pilgrim or pilger rolling mill. Shown diagrammatically in FIG. 2 are the main elements of a pilgrim rolling mill for forming a tube from a tubular blank. The pilgrim rolling mill designated by the general reference numeral 5 mainly comprises a first die 6a and a second die 6b in the form of splined cylinders mounted to be rotatable about their axes, and a mandrel 7 having a symmetrical shape of revolution. The dies 6a and 6b are rotatively mounted by means of their respective shafts 8a and 8b in a movably mounted cage associated with driving means so as to be capable of travelling in the axial direction of the mandrel 7 in one direction or the other with a constant amplitude, as diagrammatically shown by the double arrow 9. Each of the dies 6a and 6b comprises a respective peripheral groove 10a or 10b, named spline, which has a cross-sectional shape in the radial direction of the die which is close to a semi-circular shape. The cross section of the grooves 10a and 10b of the dies 6a and 6b has a dimension which varies continuously along the periphery of the groove, the section having a maximum dimension in an entrance part and a minimum section in the exit part of the groove. The dies 6a and 6b are driven in rotation about their respective axis in one direction or the other owing to the displacement of the cage in one direction or the other during the reciprocating displacement diagrammatically represented by the double arrow 9. The pilgrim rolling mill shown in FIG. 2 permits effecting the rolling of the wall of a tubular blank 11 engaged on the mandrel 7 in such manner as to progressively reduce the diameter and the thickness of the wall of the blank and obtain, at the ouput end of the mill, a tube 12 whose diameter and wall thickness are less than the diameter and wall thickness of the blank 11. owing to the rolling, the blank 11 undergoes an elongation which may be considerable in the axial direction. The mandrel 7 on which the blank 11 is engaged is connected to a rod 13 which permits moving the mandrel 7 in translation and in rotation about its axis. The pilgrim rolling mill 5 further comprises a carriage (not shown) which may be fixed to the blank 11 by clamps. The carriage permits. advancing the blank in the rolling direction after each of the steps effected by the pilgrim rolling mill. The device for advancing the blank also permits rotating it about its axis at the end of each of the rolling steps. The mandrel 7 comprises a first cylindrical part 7a whose diameter is less than the inside diameter of the blank 11, a second symmetrical part 7b of revolution whose meridian curves have substantially the shape of parabolas and a slightly conical or tapered end part 7c whose diameter is the final inside diameter of the tube 12 to be produced or close to said final inside diameter. The dies 6a and 6b are disposed on opposite sides of the mandrel 7 on which the blank 11 and the tube 12 in the course of rolling are engaged, in such manner that the grooves 10a and 10b constitute, during the travel in the axial direction and the rotation of the dies, a tube-forming surface having a roughly circular section. Owing to the fact that the dimension of the cross sections of the grooves 10a and 10b vary in a continuous manner along the periphery of the dies, the dimensions of the cylindrical forming surface of the tube themselves vary between a maximum dimension and a minimum dimension during the displacements of the cage and dies. The cage travels in the axial direction with an amplitude substantially corresponding to the length of the mandrel, along the region 7b of reduction of the blank and the region 7c of the calibration of the tube 12; the diameter and the thickness of the blank 11 are progressively reduced to the values of the diameter and wall thickness of the tube 12. At the end of each of the displacements of the rolling cage, the blank is advanced along the mandrel with a certain amplitude in the axial direction, and the blank is made to turn about its axis through a certain angle. Simultaneously, the mandrel 7 is made to turn about its axis by the rod 13. The rolling can be effected in a substantially continuous manner by engaging blanks one after the other on the rod 13 and the mandrel 7 and collecting the tubes 12 at the output end of the rolling mill. The pilgrim rolling method just described can be applied to the production of guide tubes comprising a lower end part having a wall of increased thickness relative to the wall thickness of the main part of the tube. To carry out the process for producing guide tubes according to the invention, there is employed a pilgrim or pilger rolling mill comprising a mandrel of a special shape, such as that shown in FIG. 3. The mandrel 14 having a symmetrical shape of revolution comprises a screw-threaded end 15 for connecting the mandrel to a holding and actuating rod. Following on the threaded part in the axial direction 16, the mandrel comprises a first cylindrical part 17 whose diameter is less than the inside diameter of the starting blank used for forming the guide tube, a first part 18 having a symmetrical decreasing section of revolution and a meridian in the shape of a parabola or a shape which approaches a parabola, and a third slightly conical or tapered part 21 whose diameter is equal to roughly the inside diameter of the reinforced lower end part of the guide tube to be produced. The mandrel 14 therefore comprises a plurality of successive forming sections in the axial direction constituting different guide tube-forming stages. The stepped forming mandrel 14 is used for producing guide tubes according to the invention in the course of two successive stages respectively represented in FIGS. 4A and 4B effected in this order or in the opposite order which may possibly be carried out on successive sections of a tube blank so as to produce in a single operation a rolled product from which it is possible to obtain, by cutting off, a plurality of guide tubes having a reinforced part. FIG. 4A shows the mandrel 14 in the course of a first pilgrim rolling stage of a tubular blank 22 of which both the diameter and the wall thickness exceed the diameter and the wall thickness of the guide tube to be produced. The pilgrim rolling mill comprises two dies 10a and 10b which are similar to the dies described in the case of the pilgrim rolling mill 5 shown in FIG. 2. The pilgrim rolling mill used for carrying out the process of the invention and shown in FIGS. 4A and 4B differs from the pilgrim rolling mill of the conventional type shown in FIG. 2 only in respect of the use of the stepped mandrel 14 and the mechanization of the axial displacement of the mandrel. The dies 10a and 10b freely rotatively mounted in a cage which may be displaced in the axial direction 16 of the mandrel 14, permit reducing the diameter and the thickness of the blank 22. The blank 22 was obtained by prior production and shaping operations which may themselves include pilgrim rolling operations. The blank 22 has an inside diameter slightly larger than the outside diameter of the cylindrical part 17 of the mandrel 14 and a wall thickness exceeding the wall thickness of the guide tube in its lower end part where the wall thickness is maximum. As can be seen in FIG. 4A, the pilgrim rolling is effected during the first rolling stage with the mandrel 14 placed in such manner that the dies 10a and 10b rotatively mounted in the cage of the rolling mill are displaced in a reciprocating manner along the parts 18 and 19 of the mandrel 14. In this way, the inside diameter and the outside diameter of the tubular product 24 obtained at the output end of the rolling mill, i.e. on the downstream side of the region 19 of the mandrel 14, are identical to the inside diameter and the outside diameter of the main part of the guide tube to be produced. In particular, the part 19 of the mandrel 14 constitutes a part for calibrating the product 24 so that its inside diameter has for precise dimension the required inside diameter for producing the guide tube. The dimension and the arrangement of the dies 10a and 10b are such that the outside diameter of the product 24 at the output end of the rolling mill precisely corresponds to the required outside diameter for producing the guide tube. The first rolling stage is carried out by effecting a certain number of successive rolling steps between which the blank 22 is advanced and rotated about its axis, the mandrel 14 being also rotated through a certain angle between the successive rolling steps. A coding device associated with the pilgrim rolling mill permits determining in a very precise manner the length of the product 24 obtained at the output end of the rolling mill. When a predetermined length of the product has been obtained at the output end of the rolling mill, the coding device delivers a signal for displacing the mandrel 14 in the axial direction and possibly stopping the rolling mill. The second rolling stage, shown in FIG. 4B, is indeed effected after a displacement of the mandrel 14 in the axial direction toward the upstream end of the pilgrim rolling mill so as to place the parts 20 and 21 of the mandrel in the working region of the rolling mill, i.e. in the region of the displacement of the dies 10a and 10b. The displacement of the mandrel 14 from its position shown in FIG. 4A for carrying out the first rolling stage to its position shown in FIG. 4B for carrying out the second rolling stage, can be achieved after having stopped the pilgrim rolling operation, the cage in which the dies 10a and 10b are mounted being stationary, or without stopping the rolling, in which case the cage in which the dies are mounted remains in motion. In the second stage of the rolling, the rotative dies 10a and 10b displaced in the axial direction by the cage of the rolling mill, reduce the dimensions of the blank in such manner as to obtain at the output end of the rolling mill, i.e. on the downstream side of the part 21 of the mandrel, a rolled tubular product 25 whose inside diameter calibrated by the part 21 of the mandrel is equal to the required inside diameter for producing the guide tube, in its reinforced lower end region. The outside diameter of the product 25 is identical to the outside diameter of the product 24 obtained in the first rolling stage owing to the fact that the dies 10a and 10b employed are the same as those used in the first stage of the rolling. The mandrel 14 must comprise, generally, a first part whose cross-sectional diameter diminishes in the axial direction from a value less than the inside diameter of the blank to a value equal to the inside diameter of the main part of the tube to be produced, and a second part whose cross-sectional diameter diminishes, in the axial direction of the mandrel, from a value equal to the inside diameter of the main part of the tube to be produced to a value equal to the inside diameter of the lower end part of the tube to be produced. The wall thickness of the product 25 at the output end of the rolling mill therefore very precisely corresponds to the wall thickness to be obtained in the lower end part of the guide tube. The coding device permits, as before, stopping the second rolling stage as soon as a predetermined length of the product 25 has been obtained at the output end of the rolling mill. The mandrel is then displaced from its second position to its first position. The first rolling stage, the first displacement of the mandrel, the second rolling stage and the second displacement of the mandrel may be affected repeatedly as many times as necessary for completely rolling a blank 22. Also, it is obviously possible to invert the first and second rolling stages. In this way there is obtained at the output end of the pilgrim rolling mill a rolled tubular product comprising successive sections 24 whose inside diameter and wall thickness correspond to the inside diameter and wall thickness of the main part of a guide tube 25 to be produced, and whose inside diameter and wall thickness correspond to the diameter and wall thickness of the lower end parts of the guide tubes to be produced. Such a product obtained at the output end of the rolling mill is shown in FIG. 5 in which the wall thickness differences have been greatly exaggerated. In the case of the production of guide tubes for fuel assemblies of a pressurized water nuclear reactor, the main or body part 24 of the guide tubes has a thickness e1 which may be 0.5 mm. The reinforced lower end parts of the guide tubes have a thickness e2 of the order of 1.2 mm. The production process according to the invention on a pilgrim rolling mill permits obtaining a transition region between the main parts and the reinforced parts of the guide tubes of a length 1 of the order of 180 mm. In all cases, this length of the transition region exceeds 100 mm. As the guide tube itself has a diameter of the order of 12.5 mm, the result is that the change in the inside diameter of the guide tube between the main part and the reinforced part is very progressive. The transition region between the parts of different diameters of the internal surface of the tube is different from a chamfer, which constitutes the difference between the guide tubes according to the invention and guide tubes of the prior art. Further, the continuous tube-forming process permits obtaining transition regions in which the metal is faultless and which therefore do not constitute weak regions of the tube. As seen in FIG. 6, the tubular product 26 obtained at the output end of the rolling mill and comprising successive regions 24 and 25 of different wall thicknesses has a constant outside diameter. Further, the length of the regions 24 and 25 was chosen when rolling, in such manner as to provide, by a cutting or sectioning of the tube 26 in given regions, a plurality of guide tubes 27 each comprising a main or body part 27a and a reinforced lower end part 27b having the required length and wall thickness. Preferably, the regions 24 and 25 have a length which is roughly equal respectively to double the length of the main part and double the length of the reinforced part of the guide tube to be produced. The location of the position of the cutting lines 28 along which a tool 29 must effect in succession the cutting of the rolled tubular product 26, is obtained by the use of a device for precisely locating the transition regions 27c between the parts of the tubular product 26 of different thicknesses. The end of the regions 25 of the tubular product 26 connected to the transition regions 27c, of length 180 mm, along which the wall changes from the first thickness e1 to the second thickness e2 is very precisely located. The precise location of the end of the regions 25 and 27c may be obtained with the use of an air gauge 30 comprising a pipe 31 which is axially engaged inside the tubular product 26 and includes a nozzle 32 at its end. The flow characteristics of the air through the nozzle 32 which can be ascertained by the air gauge 30 permit very precisely determining the end of the regions 25 of thickness e2 and the transition regions 27c between the parts of the tubular product having different thicknesses. The cutting tool 29, formed by a cutting disc, is placed at a definite distance from the position which had been located for effecting the cutting of the tube along the line 28. The cutting tool 29 may be a tool of a flying cutting device which is displaced in synchronism with the tubular product 26 at the output end of the rolling mill. It is also possible to determine the position of the end of the regions 25 and of the transition regions 27 with the use of a coil 33 surrounding the tube and constituting an eddy current sensor. By locating the ends of the successive regions 25 and transition regions 27c of the rolled tubular product 26, it is possible to cut off guide tubes 27, 27xe2x80x2, 27xe2x80x3 formed by successive sections of the tubular product 26. It is possible to envisage blanks and pilgrim rolling operations which permit obtaining four to five guide tubes having a length of the order of 4m, from each of the blanks 22 rolled in the pilgrim rolling mill. It is also possible to employ a flying or mobile cutting device which is actuated by the advance or the retraction of the mandrel between the different rolling stages, with a certain time delay, or by devices for locating the ends of the transition regions such as those described hereinbefore, for cutting the rolled product in the form of the guide tube at the output end of the rolling mill and during the rolling operation. By achieving a precise location of the transition regions and effecting the cutting of the guide tubes by a flying cutting device at the output end of the rolling mill, it is possible to avoid undesired variations in the length of the successive regions of different wall thicknesses 24 and 25 of the rolled product and obtain guide tubes by a simple cutting. In the usual manner, the length of the lower end region of the tube whose wall thickness exceeds the wall thickness of the main part of the tube, represents 10 to 30% of the total,length of the guide tube. The invention therefore permits obtaining guide tubes in one piece, reinforced for example in their lower part, by means of a rolling process which may easily be rendered automatic and results in a very high productivity. It must be understood that the scope of the invention is not intended to be limited to the described embodiment. Thus the mandrel on which the pilgrim rolling is carried out may have a form different from that described. The process may be used for producing guide tubes composed of a material different from a zirconium alloy. Generally, the invention is applicable to the production of guide tubes of fuel assemblies of any type in which the motion of the control rods is slowed down by a dash-pot effect.
046860681	claims	1. A method of batchwise treating radioactive organic waste which is apt to melt and fuse to form large lumps, which comprises: introducing a first batch of radioactive organic waste into a bath of an aqueous reaction medium in a reactor, said reaction medium containing, as a fusion-preventing agent effective to prevent fusion of said radioactive waste, particles of one or more solid substances selected from the group consisting of silicon dioxide and the carbonates, hydroxides and oxides of calcium, barium, iron and zinc, the amount of said fusion-preventing agent being from 1.0 to 7.0% by weight, based on the weight of the radioactive organic waste to be treated, said reaction medium also containing a catalyst effective to catalyze oxidative decomposition of said radioactive organic waste; closing the reactor and heating the contents thereof until the internal temperature of the reactor is from 180.degree. to 250.degree. C.; supplying an oxygen-containing gas to the reactor so as to establish, in the reactor, an oxygen partial pressure of from 3 to 25 kg/cm.sup.2, and oxidatively decomposing the radioactive organic waste in the reactor, at a temperature of from 180.degree. to 250.degree. C., while maintaining the pH of the aqueous reaction medium in the range of from higher than 0.01 to less than 8; discharging gaseous effluents from the reactor which effluents are composed mainly of carbon dioxide, steam and non-condensable gases; and after said first batch of radioactive waste has been oxidatively decomposed, then supplying a second batch of radioactive organic waste and fusion-preventing agent to the aqueous reaction medium remaining in the reactor and repeating the oxidative decomposition under the same conditions as described above. 2. The method of batchwise treating radioactive organic waste as defined in claim 1, wherein solid matter is deposited in said reactor during repetitions of said batchwise treating method and wherein the method includes the step of discharging an excess amount of said solid matter prior to the subsequent supply of the radioactive organic waste and the fusion-preventing agent, when the amount of said solid matter remaining in the aqueous reaction medium exceeds a predetermined amount. 3. The method of batchwise treating radioactive organic wastes as defined in claim 1, wherein the fusion-preventing agent is added as a powder or in the form of an aqueous slurry into the reactor. 4. The method as defined in claim 1, wherein the catalyst is a compound of one or more of metals selected from the group consisting of copper, cobalt, iron, cerium, nickel, chromium, manganese and lead dissolved or deposited in the aqueous reaction medium, and the amount of said catalyst, calculated as the metal, is from 10 to 50,000 ppm by weight, based on the weight of the aqueous reaction medium in the reactor. 5. The method as defined in claim 1, wherein the catalyst is a supported catalyst comprising one or more of members selected from the group consisting of copper cobalt, palladium, platinum, ruthenium, and water-insoluble compounds thereof, supported at a ratio from 1 to 10% by weight on a support selected from the group consisting of alumina, silica-alumina and zeolite, and the amount of said supported catalyst in the reactor is from 10 to 200% by weight, based on the amount of radioactive organic wastes supplied batchwise into the reactor. 6. A method as defined in claim 1 in which the amount of said fusion-preventing agent in said reactor is from 2 to 4% by weight, the internal reaction temperature in the reactor is from 200.degree. to 230.degree. C., the oxygen partial pressure in the reactor is from 5 to 20 kg/cm.sup.3 and the pH of the aqueous reaction medium in the reactor is from 3 to 6. 7. A method as defined in claim 1 in which said aqueous reaction medium and said catalyst are maintained in the reactor when oxidative decomposition of said first batch of radioactive waste has been completed and said second batch of radioactive organic waste is added to the reactor. 8. The method of batchwise treating radioactive organic waste as defined in claim 1, which includes the step of repeatedly discharging amounts of inorganic substance from the aqueous reaction medium prior to the subsequent supply of radioactive organic waste and fusion-preventing agent, when the amount of said inorganic substance remaining in the aqueous reaction medium exceeds a predetermined amount.
043426204	claims	1. A box to be inserted into a stationary nuclear fuel storage pool frame having a multiplicity of vertically extending polygonal openings, the box adapted for receiving a nuclear fuel assembly, comprising: a plurality of vertically extending metal plates arranged as an open ended polygonal container having a smaller cross-sectional area than the opening in the frame; each plate having a flat portion forming the respective sides of the container and having an integral tab portion rigidly projecting outwardly from at least one longitudinal edge of the plate; connecting means joining each tab to a tab of an adjacent plate to form a rigid container having a plurality of outwardly projecting ribs; whereby the box may be slidingly inserted into the frame so that the ribs fit into the corners of the frame defining the opening. 2. The box insert of claim 1 wherein each plate has two tab portions extending over substantially the entire longitudinal length of the plate. 3. The box insert of claim 2 wherein the container is a square and each tab is angled at about 45 degrees to the flat portion of the plate. 4. The box insert of claims 2 or 3 wherein the adjacent tabs are connected at spaced intervals along their longitudinal dimension. 5. The box insert of claim 3 wherein each plate is made of stainless steel having a thickness in the range of about 0.050-0.065 inch. 6. The box insert of claims 3 or 5 wherein the flat portion of at least some plates has a layer of neutron absorbing poison material attached thereto. 7. The box insert of claim 6 wherein the thickness of the layer of poison material is less than about 0.090 inch. 8. In a rack for storing nuclear fuel in a pool area of a stationary facility including a frame having a plurality of perpendicular wall members defining a plurality of square openings and box inserts located within the openings for receiving assemblies to be stored, the improvement which comprises each box insert having a square, flat sided container portion for receiving the fuel assembly and having external ribs at the corners of the container portion, the ribs fitting slidingly into the inside corners of the openings whereby the container is maintained in predetermined, spaced relation from each wall defining the opening. 9. The improvement of claim 8 wherein the container is formed from four metal plates each having two tabs projecting at an angle from the flat surfaces thereof, the tabs of adjacent plates being connected to form the ribs. 10. The improvement of claim 9 wherein each tab is integral with and runs over substantially the entire longitudinal length of its respective plate. 11. The improvement of claim 10 wherein the plates are made of stainless steel having a thickness in the range of about 0.050-0.065 inches. 12. The improvement of claims 9 or 11 wherein the flat portion of at least some plates has a layer of neutron absorbing poison material attached thereto. 13. The improvement of claim 12 wherein the thickness of the layer of poison material is less than about 0.090 inch.
	description	This application is the National Stage filing under 35 U.S.C. 371 of International Application No. PCT/KR2016/004854, filed on May 10, 2016, which claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2015-0074212, filed on May 27, 2015, the contents of which are all hereby incorporated by reference herein in their entirety. The present invention relates to a passive natural circulation cooling system provided in a passive condensation tank and a cooling method using the same. Passive condensation tanks are used as heat sinks to remove heat of a reactor (sensible heat of the reactor and residual heat of a reactor core) upon an occurrence of accidents in various reactors including an integral reactor. The heat of the reactor is finally transferred to a passive condensation tank through a passive auxiliary feed water system. Accordingly, cooling water in the passive condensation tank evaporates and heat is discharged to the atmosphere. A heat exchanger in the passive auxiliary feed water system is a water-cooling type (SMART reactor in Korea, AP1000 of Westinghouse in USA), an air-cooling type (SCOR in France) or a hybrid-cooling (IMR in Japan) with the water-cooling and the air-cooling in a mixed manner. A cooling method of the heat exchanger is understood with reference to Reference Document 1. [Reference Document 1] IAEA-TECDOC-1624, Passive Safety Systems and Natural Circulation in Water Cooled Nuclear Power Plants, IAEA, 2009 Generally, the water-cooled heat exchanger is advantageous in reducing a capacity of the heat exchanger by virtue of its excellent cooling efficiency. However, cooling water inside the passive condensation tank which receives heat from the heat exchanger is gradually evaporated and eventually exhausted upon an occurrence of an accident. Therefore, the cooling water of the passive condensation tank should be periodically refilled for long-term cooling exceeding the cooling water storage capacity. On the other hand, the air-cooled heat exchanger is advantageous in that a periodic refill of the cooling water is not required because there is no passive condensation tank, but cooling efficiency of the air-cooled heat exchanger is lower than that of the water-cooled heat exchanger. The efficiency of the air-cooled heat exchanger depends on heat transfer efficiency of a wall surface of a tube with which air is brought into contact. Since heat transfer efficiency of the air-cooled heat exchanger is lowered while transferring heat to outside (external air) through the wall surface of the tube, size and number of the heat exchanger should increase. In addition, heat transfer performance of the hybrid-cooling type heat exchanger is drastically reduced at the time of operating in the air-cooling manner, as compared with that in the water-cooling manner, and thereby a relatively large heat exchanger must be used instead of the water-cooled heat exchanger. For cooling the inside of the heat exchanger of the passive auxiliary feed water system, a steam condensation type condensation heat exchanger having excellent heat transfer efficiency is widely employed. Since the heat exchanger of the passive auxiliary feed water system generally operates at high temperature and high pressure, design pressure is very high. Thus, stability must be further considered. When the size of the heat exchanger is increased, economical efficiency is drastically lowered. Heat transferred from the reactor upon an occurrence of an accident of the reactor is not always constant. Unlike general boilers, the nuclear reactor generates residual heat in a core for a considerable period of time after the reactor core is shut down. Accordingly, when the reactor is shut down due to an accident or the like, a large amount of residual heat is discharged from the core in the early stage of the accident, and the discharged residual heat is remarkably reduced according to a lapse of time. Therefore, the heat transferred from the reactor to the passive condensation tank is significantly reduced according to the lapse of the time after the accident. The related art passive condensation tanks are designed considering accidental characteristics of these reactors and generally an upper part of the passive condensation tank is open to atmospheric pressure. When heat is transferred to the passive condensation tank upon an occurrence of an accident, the cooling water in the passive condensation tank which has received the heat is evaporated after being heated up and then its phase is changed into steam. The steam is then discharged to outside through the open part of the passive condensation tank, so that a thermal load is reduced by heat of vaporization. However, the related art structure has a problem that the amount of cooling water in the passive condensation tank is gradually reduced due to a long-term operation of the passive condensation tank, and eventually exhausted. In addition, the cooling function may extend by periodically refilling the cooling water. However, if an access to the passive condensation tank is impossible due to a leakage of radioactive materials upon an occurrence of an accident, the refill of the passive condensation tank has actually a limit. An aspect of the present invention is to provide a passive natural circulation cooling system, capable of maintaining a cooling function for a long time by compensating for a disadvantage of a loss of cooling function due to a capacity limitation of a passive condensation tank, and a cooling method using the same. Another aspect of the present invention is to provide a passive natural circulation cooling system, capable of being operated merely by a natural driving force without a separate action of a driver (or operator) even when a station black out occurs or an access of the driver is impossible due to a leakage of a radioactive material, and a cooling method using the same. A passive natural circulation cooling system according to the present invention may include a passive condensation tank configured to accommodate cooling water therein, and a condensate water recirculation device provided in or above the passive condensation tank and configured to condense the cooling water so that the cooling water circulates inside the passive condensation tank. The condensate water recirculation device may include a duct extending upward from an upper portion of the passive condensation tank, and a plurality of separators provided in the passive condensation tank or the duct. The plurality of separators may include a first separator extending downward from one side of an inner wall of the passive condensation tank toward another side in an inclined manner, to partition lower and upper portions as first and second spaces, respectively. In one embodiment of the present invention, the plurality of separators may further include at least one of second and third separators extending along a lengthwise direction of the duct to minimize a leakage of steam rising along the duct. In an embodiment, the second and third separators may be spaced apart from each other. The second separator may extend upward from the first separator. The third separator may extend downward from an upper inner wall of the duct to generate a downward flow path of steam rising along the second separator. In an embodiment, the first separator may be provided with a steam collection guide pipe. The steam collection guide pipe may extend into a lower space of the first separator and an inner space of the duct partitioned by the second separator. In an embodiment, an inserted length of the steam collection guide pipe into the lower space of the first separator may be determined based on information related to a preset water level and pressure. In an exemplary embodiment, the duct may be provided therein with a heat exchanger to transfer heat of the cooling water inside the duct to external air, and the heat exchanger may include external air flow paths in a form of a bundle, formed in a manner of penetrating through the duct. In an embodiment, above the first separator may be provided an exhaust valve for filling water, and a safety valve for suppressing a pressure rise in a preset range or more within the passive condensation tank. In an embodiment, the duct may be provided with an external air outlet formed on an upper side thereof, and the external air outlet may be provided therein with a condensate water collecting structure for further collecting condensate water. The passive natural circulation cooling system according to another embodiment of the present invention may further include a heat exchanger installed below the first separator to receive heat from the cooling water within the first space. In an embodiment, the heat exchanger may include an inlet formed on the first separator to allow the cooling water in the second space to be introduced therethrough, an outlet formed on the first separator at a position spaced apart from the inlet to allow the cooling water introduced through the inlet to flow out therethrough, and a body portion connecting the inlet and the outlet on a rear surface of the first separator, and configured so that the introduced cooling water is evaporated by exchanging heat with the cooling water within the first space while passing through the body portion. Preferably, the outlet may be located higher than the inlet above the first separator. The body portion may be formed to be inclined upward from the inlet to the outlet. The body portion may include a plurality of tubes formed in a bundle to increase a heat exchange area. The inlet and the outlet may be provided in plurality, respectively. The body portion may include a plurality of first pipes each having one side connected to each of the plurality of inlets and another side extending downward, a plurality of second pipes each having one side connected to the another side of each of the plurality of first pipes, and another side formed in an inclined direction, and a plurality of third pipes each having one side connected to the another side of each of the plurality of second pipes, and another side extending upward to be connected to each of the plurality of outlets. The body portion may further include a first connection portion connecting the plurality of first pipes and the plurality of second pipes so that the cooling water introduced from each of the plurality of first pipes is joined and then dispersed again into the plurality of second pipes, and a second connection portion connecting the plurality of second pipes and the plurality of third pipes so that the cooling water introduced from each of the plurality of second pipes is joined and then dispersed again into the plurality of third pipes. The first exchanger may be provided in plurality, and heights of the inlet and the outlet of each of the first exchangers may be sequentially reduced on the first separator. The condensate water recirculation device may further include a second separator located above the first separator with being spaced apart from the first separator, to condense steam evaporated from the cooling water in the second space and steam generated in the heat exchanger. The second separator may extend downward from one side of the passive condensation tank toward another side in an inclined manner. The second separator may preferably be provided with a plurality of protrusions formed on one surface thereof in a protruding manner to increase heat exchange efficiency. A plurality of partitions may be formed on an inner wall of the duct to induce condensation of steam contained in air rising along the duct. An outer wall of the duct may be formed of a material having a low absorption rate by solar radiation, high reflectance, and high emissivity toward surrounding air, so as to suppress a temperature rise inside the duct. According to the present invention having the aforementioned structure, in the multi-stepped condensate water recirculation device, the steam evaporated in the passive condensation tank can be condensed after transferring heat to components of the condensate water recirculation device in each step, and a flow path can be formed such that the condensate water circulates within the passive condensation tank. This may result in condensing and recirculating the steam leaked out of the passive condensation tank. Therefore, even when the passive condensation tank can not be re-filled with the cooling water due to a leak of radiation upon an occurrence of a reactor accident, the passive condensation tank can be operated by natural driving force so as to passively collect condensed water and refill the cooling water therein, thereby constantly maintaining a cooling water level without an extension of a capacity of the passive condensation tank. Therefore, the cooling function of the passive condensation tank can be maintained even when power use is interrupted for a long time and various reactor accidents occur. Further, according to the present invention, sensible heat and residual heat emitted from the reactor can be removed for a long time by maintaining the function of the passive condensation tank for a long time. Hereinafter, description will be given in more detail of a passive natural circulation cooling system and a cooling method of the same according to the present invention, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components will be provided with the same reference numbers, and description thereof will not be repeated. A singular representation used herein may include a plural representation unless it represents a definitely different meaning from the context. In addition, cooling water refers to a liquid state, but may be used to refer to steam in some contexts. Prior to describing a passive natural circulation cooling system according to the present invention, a related passive auxiliary feed water system will be described first. FIG. 1 is a conceptual view of a passive auxiliary feed water system in accordance with the present invention. The passive auxiliary feed water system is configured to remove residual heat continuously generated in a reactor core (not illustrated) even after the reactor is shut down upon an occurrence of a reactor accident. Hereinafter, components of the passive auxiliary feed water system and their roles will be described in detail. The passive auxiliary feed water system includes a steam generator 10 connected to a main steam pipe 30 and a main feed water pipe 40, a condensation heat exchanger inlet connection pipe 31 connected to the main steam pipe 30, a condensation heat exchanger outlet connection pipe 41 connected to the main feed water pipe 40, and a condensation heat exchanger 20 connected to the condensation heat exchanger inlet connection pipe 31 and the condensation heat exchanger outlet connection pipe 41. The steam generator 10 is connected to a reactor (not illustrated) to generate steam by using heat transferred from the reactor. One side of an upper portion of the steam generator 10 is connected to the main steam pipe 30, and one side of a lower portion thereof is connected to the main feed water pipe 40. That is, the steam generator 10 receives water through the main feed water pipe 40, and supplies generated steam through the main steam pipe 30. The generated steam is supplied to a turbine (not illustrated) so as to produce electric power by a rotation of the turbine. However, since it is more important to lower temperatures of the reactor (not illustrated) and the steam generator 10 than to produce electric power upon an occurrence of a reactor accident, an inlet valve 32 and an outlet valve 42 are opened to activate the passive auxiliary feed water system. When the passive auxiliary feed water system is operated, a part of the steam supplied through the main steam pipe 30 is supplied to the condensation heat exchanger 20 through the condensation heat exchanger inlet connection pipe 31. The condensation heat exchanger 20 is provided within the passive condensation tank 100 accommodating the cooling water therein. Therefore, the steam passing through the condensation heat exchanger 20 transfers heat to the cooling water within the passive condensation tank 100, changes its phase into a liquid state, and then flows into the main feed water pipe 40 again through the condensation heat exchanger outlet connection pipe 41. On the other hand, although the cooling water in the passive condensation tank 100 is evaporated by receiving heat through the condensation heat exchanger 20, such that a thermal load is reduced by heat of vaporization. However, when the cooling water is fully evaporated and exhausted, the passive condensation tank 100 does not operate any more, thereby causing a limit of long-term cooling. Accordingly, the condensate water recirculation device 200 improves a heat exchange method of the passive condensation tank 100 to fundamentally eliminate the problem of exhaustion of the cooling water in the passive condensation tank 100. Since the cooling water in the passive condensation tank 100 can be circulated by the operation of the condensate water recirculation device 200, the passive condensation tank 100 can perform a heat dissipating function for a longer term of time. Hereinafter, with reference to FIGS. 2 and 3, the passive natural circulation cooling system will be described in more detail. FIG. 2 is a projected perspective view of a passive natural circulation cooling system including the condensate water recirculation system 200 in accordance with one embodiment of the present invention, and FIG. 3 is a projected perspective view of an enlarged portion of the passive natural circulation cooling system in accordance with one embodiment of the present invention. The passive natural circulation cooling system of the present invention includes a passive condensation tank 100, a condensation heat exchanger 20, and a condensate water recirculation device 200. The passive condensation tank 100 is formed to accommodate cooling water therein. The passive condensation tank 100 is preferably formed in a manner that a rear surface thereof is flat to correspond to the ground surface so as to stably accommodate the cooling water. In addition, although FIGS. 1 to 2 illustrate the passive condensation tank 100 in a substantially rectangular parallelepiped shape, the passive condensation tank 100 may be formed in various shapes such as a cylindrical shape. In addition, the passive condensation tank 100 may be located outside a containment building 50. The condensation heat exchanger 20 is provided in the passive condensation tank 100 so as to be in contact with the cooling water. Concretely, the condensation heat exchanger 20 is preferably located at a lower portion in an inner space of the passive condensation tank 100 to be sunk in the cooling water as much as possible even if a water level of the cooling water changes. As described above, the condensation heat exchanger 20 serves to transfer heat received from the steam generator 10 to the cooling water of the passive condensation tank 100. The condensate water recirculation device 200 is provided inside or above the passive condensation tank 100. The condensate water recirculation device 200 condenses the cooling water that evaporates from the passive condensation tank 100, so that the cooling water circulates inside the passive condensation tank 100. The condensate water recirculation device 200 includes a first separator 210. The first separator 210 extends downward from one side of an inner wall of the passive condensation tank 100 to another side of the passive condensation tank 100. One side of the first separator 210 may be integrally formed on the one side of the inner wall of the passive condensation tank 100. Alternatively, the first separator 210 and the passive condensation tank 100 may be separately formed and coupled to each other in a welding or bolting manner. Meanwhile, another side of the first separator 210 is not connected to the passive condensation tank 100. The first separator 210 may be formed in a plate shape having a predetermined thickness and a large surface of the plate may be positioned to face a lower and/or upper portion of the passive condensation tank 100. The first separator 210 may extend downward at a predetermined inclination angle. Alternatively, the first separator may extend with a curvature. In this instance, the first separator 210 is preferably convex upward. The inner space of the passive condensation tank 100 is partitioned into first and second spaces 110 and 120 with reference to the first separator 210. Specifically, the first space 110 is located at a lower portion and the second space 120 is located at an upper portion, with respect to the first separator 210. Since the another side of the first separator 210 is not connected to the passive condensation tank 100, the first and second spaces 110 and 120 are not completely separated from each other but have a portion therebetween to communicate with each other. Since the cooling water can freely move through this portion, overpressure of the passive condensation tank due to steam pressure generated in the first space is prevented. Since the first separator 210 is located at an upper portion of the first space 110, the cooling water evaporated in the first space 110 is sealed by the first separator 210. Steam pressure generated due to the steam collected in the first space 110 lowers a water level of the cooling water in the first space 110. This will be described in detail later. The condensate water recirculation device 200 may further include a heat exchanger 220 in addition to the first separator 210. The heat exchanger 220 is installed on a lower portion of the first separator 210 to receive heat from the cooling water in the first space 110. The heat exchanger 220 includes an inlet 226, a body portion 227, and an outlet 228. The inlet 226 is formed on the first separator 210, so that the cooling water in the second space 120 flows into the heat exchanger 220 therethrough. The outlet 228 is formed on the first separator 210 at a position spaced apart from the inlet 226, so that the cooling water introduced through the inlet 226 flows out therethrough. The body portion 227 connects the inlet 226 and the outlet 228 on the rear surface of the first separator 210. The inlet 226 and the outlet 228 are formed in a shape of a hole penetrating through the first separator 210, so that at least part of the body portion 227 can be inserted into the inlet 226 and the outlet 228. In addition, the body portion 227 may be formed in a hollow tube shape so that a fluid can flow therein. The cooling water introduced through the inlet 226 exchanges heat with the cooling water inside the first space 110 while flowing along the inside of the body portion 227. Specifically, since the condensation heat exchanger 20 is disposed in the first space 110, the cooling water in the first space 110 first receives heat from the condensation heat exchanger 20. Since the cooling water in the body portion 227 is relatively low in temperature compared to the cooling water in the first space 110, heat is transferred from the cooling water in the first space 110 to the cooling water in the body portion 227. The cooling water in the body portion 227 that has received the heat is heated up and/or evaporated, and discharged through the outlet 228 by a natural convection phenomenon. At this time, the outlet 228 is positioned higher than the inlet 226 on the first separator 210. In addition, an initial water level of the cooling water is located above the outlet 228. Details of this will be described later. In addition, the body portion 227 is inclined in a direction from the inlet 226 to the outlet 228, such that hot steam generated in the body portion 227 can be discharged only through the outlet 228 other than the inlet 226. This is because the cooling water in a liquid state and the steam in a gaseous state may coexist in the body portion 227 and the relatively high-temperature steam tends to rise by the convection phenomenon. That is, the cooling water in the second space 120 may move in a direction sequentially through the inlet 226, the body portion 227, and the outlet 228. FIGS. 4A and 4B illustrate the heat exchanger 220 in accordance with one embodiment of the present invention. Hereinafter, the structure of the heat exchanger 220 will be described with reference to FIGS. 4A and 4B. The inlet 226 and the outlet 228 of the heat exchanger 220 may be provided in plurality, respectively, and the body portion 227 may be provided with a plurality of tubes formed in a bundle so as to increase a heat exchange area. Specifically, the body portion 227 may include a plurality of first pipes 221, second pipes 222, and third pipes 223. One side of each of the plurality of first pipes 221 is connected to each of the plurality of inlets 226 and extends downward. One side of each of the plurality of second pipes 222 is connected to another side of each of the plurality of first pipes 221. One side of each of the plurality of third pipes 223 is connected to another side of each of the plurality of second pipes 222. In addition, another side of each of the plurality of third pipes 223 extends upward and is connected to each of the plurality of outlets 228. At this time, the second pipes 222 are formed to be inclined from the inlets 226 toward the outlets 228. The body portion 227 may further include first and second connection portions 224 and 225, in addition to the plurality of first pipes 221, second pipes 222 and third pipes 223. The first connection portion 224 connects the first pipes 221 and the second pipes 222 so that the cooling water in the plurality of first pipes 221 can be joined together and dispersed into the plurality of second pipes 222. That is, one side of the first connection portion 224 is connected to the plurality of first pipes 221, and another side thereof is connected to the plurality of second pipes 222. The second connection portion 225 connects the second pipes 222 and the third pipes 223 so that the cooling water in the second pipes 222 can be joined together and dispersed into the plurality of third pipes 223. That is, one side of the second connection portion 225 is connected to the plurality of second pipes 222, and another side thereof is connected to the plurality of third pipes 223. Referring to FIG. 4B, a plurality of pins 222a may be coupled along a periphery of each of the second pipes 222 of the heat exchanger 220 so as to increase the heat exchange area. Referring to FIGS. 2 and 3, the heat exchanger 220 is provided in plurality such that a water level in the first space (zone) can be maintained higher than that in the condensation heat exchanger 20. Specifically, a plurality of heat exchangers 220a, 220b and 220c are installed in a manner that heights of the inlet 226 and the outlet 228 of each heat exchanger 220 are sequentially reduced on the first separator 210. The heights of the inlet 226 and the outlet 228 of each of the heat exchangers 220 are sequentially reduced, so that at least one of the heat exchangers 220 can be operated even if the water level of the cooling water in the second space 120 changes. This will be described in more detail, with reference to FIG. 5. FIG. 5 illustrates the three heat exchangers 220a, 220b and 220c in order to explain the heat exchanger 220 operated according to a water level of cooling water. As illustrated in FIG. 5A, when a sufficiently large amount of cooling water is filled in the passive condensation tank 100, the water level of the cooling water in the second space 120 becomes sufficiently high. In this case, the cooling water in the second space 120 may be all introduced into the three heat exchangers 220a, 220b and 220c. That is, all of the three heat exchangers 220a, 220b and 220c are operated. However, as illustrated in FIG. 5B or 5C, when the amount of the cooling water is more reduced than its initial amount due to a part of the cooling water in the passive condensation tank 100 being evaporated to outside of the passive condensation tank 100, the water level of the cooling water of the second space 120 is lowered. In this case, the cooling water in the second space 120 may be introduced into two or one heat exchanger. Accordingly, only some of the plurality of heat exchangers 220a, 220b and 220c are operated. That is, installation heights of the plurality of heat exchangers 220a, 220b, and 220c may be set differently, so that the at least one heat exchanger 220 is operated regardless of the water level of the cooling water in the second space 120. This may result in improving performance of the condensate water recirculation device 200. The condensate water recirculation device 200 may further include a second separator 230, in addition to the first separator 210 and the heat exchanger 220. Hereinafter, the second separator 230 will be described, referring back to FIGS. 2 and 3. The second separator 230 is located above the first separator 210 in a spacing manner to condense steam evaporated from the cooling water in the second space 120 and steam generated in the heat exchanger 220. Specifically, the second separator 230 extends downward from one side of the inner wall of the duct 260 to another side in an inclined manner. One side of the second separator 230 may be integrally formed on the one side of the inner wall of the passive condensation tank 100. Alternatively, the second separator 230 and the passive condensation tank 100 may be separately formed and coupled to each other in a welding or bolting manner. On the other hand, another side of the second separator 230 is not connected to the passive condensation tank 100. Similar to the first separator 210, the second separator 230 may be formed in a plate shape having a predetermined thickness, and a large surface of the plate may be located to face the lower portion and/or the upper portion of the passive condensation tank 100. The second separator 230 may extend downward at a predetermined inclination angle. Alternatively, the second separator 230 may extend with a curvature. In this instance, the second separator 230 may also be formed to be convex upward. The second separator 230 takes heat away from surrounding hot steam so as to condense the steam. The condensed cooling water is moved down due to gravity and joined again to the cooling water in the second space 120. A phase change process will be described in detail later. The second separator 230 includes a plurality of protrusions 240 protruding from one surface of the second separator 230, to increase heat exchange efficiency. The plurality of protrusions 240 may be located on an upper surface or a lower surface of the second separator 230 so as to protrude upward or downward. The plurality of protrusions 240 serve to increase a contact area of the second separator 230 with external air having a relatively low temperature. Meanwhile, the plurality of protrusions 240 may also be formed as a structure in a form of a pin or a plate. In addition, the condensate water recirculation device 200 may further include an external air inlet 250 and a duct 260. The external air inlet 250 is formed at another side of the passive condensation tank 100 to induce an introduction of external air. The duct 260 is installed at the upper portion of the passive condensation tank 100 and extends upward so that air introduced through the external air inlet 250 is raised. Also, referring to FIG. 6, the duct 260 may be formed upward in a linear form, but alternatively formed to correspond to appearance of the containment building 50 so as to be attached to the containment building 50. That is, the duct 260 may have a predetermined curvature and be formed in an arcuate shape. Also, the duct 260 may be attached at a distance from the containment building (containment vessel). In addition, the duct 260 may have a rectangular or circular shape, but is not limited to a particular shape. The air introduced through the external air inlet 250 receives internal heat of the passive condensation tank 100 to be lowered in density, and flows upward along the duct 260 to be discharged to outside. In consideration of such convection, the external air inlet 250 is located at a position lower than the duct 260. Also, the second separator 230 is located on a path through which the air introduced through the external air inlet 250 flows. Temperature of the second separator 230 becomes lower than surrounding steam due to air cooling, so that the second separator 230 can perform heat exchange with the high temperature steam. A plurality of partitions 261 may be formed on the inner wall of the duct 260 in order to minimize an outflow and induce condensation of steam contained in the air flowing upward. One side of each of the partitions 261 is formed on one side of the inner wall of the duct 260. In addition, another side of each of the partitions 261 extends downward so that the cooling water stood on the partition 261 can be dropped into the second space 120. On the other hand, the plurality of partitions 261 are formed in a staggered shape to increase a flow path of steam, thereby effectively inducing condensation. An outer wall of the duct 260 is preferably formed of a material having a low water absorption rate, high reflectance and high emissivity so as to suppress a temperature rise inside the duct 260 due to solar heat and to radiate heat inside the duct 260 to the outside. Specifically, the outer wall of the duct 260 may be coated with a material having a white-based color. Referring to FIG. 6, a backflow preventing structure 270 may further be installed in the passive condensation tank 100. The backflow preventing structure 270 may extend inwardly from the another side of the passive condensation tank 100. The backflow preventing structure 270 prevents the cooling water in the passive condensation tank 100 from overflowing to outside. Hereinafter, a passive natural circulation cooling method will be described sequentially with reference to FIG. 7. Referring to FIG. 7A, when the passive auxiliary water supply system does not operate, the cooling water in the passive condensation tank 100 maintains a constant water level. At this time, an initial water level of the cooling water is located above the outlet 228. Referring to FIG. 7B, when the passive auxiliary feed water system starts to operate, the cooling water in the passive condensation tank 100 is heated up or evaporated by receiving heat from the condensation heat exchanger 20. The cooling water is subjected to evaporation in both of the first and second spaces 110 and 120. However, since the condensation heat exchanger 20 is disposed in the first space, the evaporation of the cooling water in the first space occurs more actively. At the same time, due to an influence of the first separator 210 located at the upper portion the first space 110, the steam generated in the first space 110 is collected below the first separator 210. Steam pressure higher than the atmospheric pressure is formed below the first separator 210 by the steam collected at the upper portion of the first space 110. The collected steam is used to push the cooling water downward so that the water level in the first space 110 is lower than the water level in the second space 120. As the steam works, the temperature of the steam can drop as internal energy decreases. Referring to FIG. 7C, when some of the cooling water evaporated from the first space 110 are bumped against the first separator 210, such cooling water transfers heat to cooling water above the first separator 210, and then is condensed to be collected back into the first space 110. Also, some of the cooling water evaporated in the first space 110 exchange heat with cooling water within the heat exchanger 220. Such cooling water is then condensed and collected back into the first space 110. That is, the steam in the first space 110 circulates to the cooling water while forming a cycle A by the first separator 210 and the heat exchanger 220. Referring to FIG. 7D, the cooling water in the second space 120 flows into the heat exchanger 220, as indicated with a flow c. The cooling water in the second space 120 is vaporized by receiving heat from the steam in the first space 110 while passing through the inside of the heat exchanger 220, as indicated with a flow d. The steam generated in the heat exchanger 220 is discharged to the upper portion of the first separator 210, as indicated with a flow e. The steam discharged to the outside of the heat exchanger 220 and the steam evaporated in the second space 120 flow upward to transfer heat to the second separator 230, are condensed and then circulate to the cooling water while forming a cycle B. Referring to FIG. 7E, external air introduced through the external air inlet 250 receives heat from the second separator 230, and thus the temperature thereof increases. The air is then discharged to the outside through the duct 260 by the convection phenomenon. At this time, the steam is condensed on the surface of the second separator 230 and flows downward along the second separator 230, as indicated with a cycle C. The condensed cooling water is collected back to the second space 120. When the steam rises up to an upper portion of the duct 260 without being condensed, temperature of the upper portion of the duct 260 is relatively lower than that of a lower portion of the passive condensation tank 100, and thus the steam may be condensed on the inner wall of the duct 260 so as to be collected back into the second space 120. Although the embodiment in which the heat exchanger 220 is installed below the first separator 210 has been described so far, the heat exchanger 220 may be omitted or installed above the duct. Hereinafter, another embodiment in which the heat exchanger 220 is omitted will be described in detail with reference to the drawings. FIG. 8 is a projected perspective view of a passive natural circulation cooling system in accordance with another embodiment of the present invention. FIGS. 9A to 9B are conceptual views sequentially illustrating a method of cooling a passive natural circulation cooling system in accordance with another embodiment of the present invention. Referring to FIG. 8, a passive natural circulation cooling system according to another embodiment of the present invention may include a passive condensation tank 100, a condensation heat exchanger 20, and a condensate water recirculation device. The condensate water recirculation device is a device for condensing steam evaporated from the cooling water in the upper portion of the passive condensation tank 100 and recirculating back to the passive condensation tank 100. The condensate water recirculation device may include first to third separators 310, 330 and 340, and a steam collection guide pipe 320. Detailed description of the first separator 310 is the same as or similar to that of the one embodiment of the present invention, and will not be described below. The second and third separators 330 and 340 may be installed inside the duct 350 and extend in a lengthwise direction of the duct 350 in order to increase a flow path of steam rising through the duct 350 and ultimately extend a heat transfer time. Here, the second and third separators 330 and 340 may be spaced apart from each other. The second separator 330 may extend upward from the first separator 310. More specifically, one side of the second separator 330 is formed on the first separator 310. The second separator is formed as a curved surface to correspond to the shape of the duct 350 as a whole and then extend with maintaining a predetermined interval from the inner wall of the duct 350 within the duct 350. The third separator 340 may extend downward from the upper inner wall of the duct 350 to generate a downward flow path of the steam which has been raised along the second separator 320. The steam collection guide pipe 320 is formed on the first separator 310 so that the steam generated in the first space 110 can be moved to the second space 120. At this time, the steam collection guide pipe 320 may extend into an inner space of the duct 350 defined by the second separator 330. A diameter or depth of the steam collection guide pipe 320 may be adjusted to meet a design pressure range of the passive condensation tank 100. In addition, a safety valve or the like may be provided inside the steam collection guide pipe 320. Meanwhile, referring to FIG. 8, a passive natural circulation cooling system according to another embodiment of the present invention may further include a backflow preventing structure 101, a condensate water guide plate 351, a condensate water collecting structure 352, and a pollution preventing structure 353. As described above with reference to FIG. 6, the backflow preventing structure 101 may extend from the another side of the passive condensation tank 100 toward the inside thereof. The backflow preventing structure 101 may prevent the cooling water inside the passive condensation tank 100 from overflowing to outside. The condensate water guide plate 351 is installed on the inner wall of the duct 350 to induce the condensed water condensed in the duct 350 to be re-circulated back to the second space 120. The condensate water collecting structure 352 is installed adjacent to an external air outlet formed on the upper portion of the duct 350, to ultimately condense steam discharged through the external air outlet. The pollution preventing structure 353 may be formed in an arcuate shape on the upper portion of the condensate water collecting structure 352. Hereinafter, a cooling method using the passive natural circulation cooling system according to another embodiment of the present invention will be described step by step with reference to FIGS. 9A and 9B. Referring to FIG. 9A, the condensation heat exchanger 20 transfers heat received from the steam generator 10 to the cooling water of the passive condensation tank 100. At this time, since the condensation heat exchanger 20 is disposed in the first space 110, boiling occurs in the cooling water in the first space 110. Referring to FIG. 9B, a cavity (zone) is formed below the first separator 310 due to the steam of the cooling water in the first space 110. Here, the cavity is formed only by a protruded depth of the steam collection guide pipe 320 to a lower portion of the first separator. The steam is transferred to the upper portion of the first separator 310 through the steam collection guide pipe 320. That is, the steam that has been discharged to the upper portion of the first separator 310 through the steam collection guide pipe 320 is directly re-condensed when the cooling water is present above the first separator 310, and a part of the steam flows into the duct 350 through a zone, in which the cooling water is present, due to steam pressure and buoyancy. At this time, pressure of the first space 110 is increased due to the formation of the cavity, but the diameter and depth of the steam collection guide pipe 320 may be adjusted or the safety valve may be provided, in consideration of the increased pressure. The steam raised through the steam collection guide pipe 320 is subjected to convective heat transfer by a flow of external air between the containment vessel 50 and the duct 350. Since the steam is continuously generated in the passive condensation tank 100, hot steam is located in the upper portion of the duct 350 due to a heat load. Since a flow path is blocked at the upper portion of the duct and the hot steam tends to flow upward due to the buoyancy, the steam slowly flows backward between the second and third separators 330 and 340. The steam is mixed (merged, joined) with external air which flows to the upper portion of the duct 350 through the external air inlet, and then flows upward again to the upper portion of the duct 350. At this time, the heat transfer is continuously caused due to a temperature difference between the duct 350 and the third separator 340. In addition, the heated steam is increased in speed due to the buoyancy and thus the heat transfer effect is enhanced. At this time, the entire outer wall of the duct 350 is constituted by a plate-type heat exchanger so as to increase a heat transfer area by several times or more, thereby improving heat removal ability due to convective heat transfer. By this multi-stage cooling method, a steam leakage speed in the passive condensation tank 100 is minimized, a heat exchange time is increased, and finally a total heat amount is increased. Accordingly, the steam is condensed as much as possible and then collected back into the passive condensation tank. As described above, in the passive natural circulation cooling system according to another embodiment of the present invention, as the number of separators inside the duct 350 increases, a time during which the steam stays in the duct 350 extends, thereby increasing a total heat transfer amount. So far, the embodiment in which the upper side of the duct 350 is opened has been described in detail. Hereinafter, another embodiment in which the upper side of the duct 350 is hermetically closed will be specifically described. Another embodiment in which the upper side of the duct is sealed may include first to third detailed embodiments. Referring to FIG. 10, a passive natural circulation cooling system according to a first embodiment may include a passive condensation tank 100, first and second separators 410 and 430, and a steam collection guide pipe 420. In this embodiment, one side of the second separator 430 may be spaced apart from the first separator 410. The second separator 430 may extend into a curved shape to correspond to a shape of the duct 440 within a duct 440. Another side of the second separator 430 may extend up to an upper side of the duct 440 and may be disposed with being spaced apart from an upper inner wall of the duct 440. Meanwhile, the steam collection guide pipe 420 may extend into an inner space of the duct 440 defined by the second separator 430. According to this structure, the steam in the first space 110 flows into a space between the duct and the second separator 430 along the steam collection guide pipe 420. The steam flows to the upper side of the duct 440 due to natural convection caused by a temperature difference from ambient temperature. In this embodiment, since the upper side of the duct 440 is closed, the steam that reaches the upper side of the duct 440 flows down along the second separator 430. A heat exchanger 450 may be installed in the duct 440 to increase heat exchange efficiency. FIGS. 11A and 11B are views of a passive natural circulation cooling system in accordance with a second detailed embodiment. In the second detailed embodiment, the components other than a heat exchanger 450 may be the same as or similar to those of the first detailed embodiment. Referring to FIG. 11A, the heat exchanger 450 may be installed in an upper side of the duct 440 of the passive natural circulation cooling system. The heat exchanger 450 is formed along a thickness direction of the duct 440 and may include external air flow paths. Referring to FIG. 11B, the heat exchanger 450 includes a plurality of external air flow paths 451 and 452 penetrating through the second separator 430. The plurality of external air flow paths 451 and 452 may be arranged in an alternating manner. More specifically, the external air flow paths 451 disposed along a first row of the duct 440 and the external air flow paths 452 disposed along a second row are arranged in an alternating manner. Afterwards, the arrangement of the external air flow paths along a third row is the same as that of the first row and the arrangement of the external air flow paths along a fourth row is the same as that of the third row, such that the same pattern is continuously repeated. The external air flow paths arranged along odd-numbered rows including the first and third rows may be configured so that external air flows therein along a first direction, and the external air flow paths arranged along even-numbered rows including the second and fourth rows may be configured so that external air flows therein along a second direction. As such, the steam can flow along the duct 440 between such external air flow paths. That is, the heat transfer between the steam in the duct 440 and external air can be further facilitated through the external air flow paths 451 and 452. FIGS. 12A and 12B are views of a passive natural circulation cooling system in accordance with a third detailed embodiment. In the third detailed embodiment, the components other than a heat exchanger may be the same as or similar to those of the first detailed embodiment. In the third detailed embodiment, a plurality of heat exchangers 450a, 450b, and 450c are installed within the duct 440. The plurality of heat exchangers 450a, 450b, and 450c may be spaced apart from each other by a predetermined distance. In other words, in the third detailed embodiment, hot steam may be collected in an uppermost end of the duct 440 due to the buoyancy effect. A flow path of external air of a containment vessel is formed by arranging a bundle of heat exchangers, which are perpendicular to an air flow, in the uppermost end in a penetrating manner (staggered arrangement). However, the flow path of the external air is isolated from the flow paths inside the duct 440. The external air flows upward through the bundle of staggered heat exchangers, so as to cool air within the uppermost end. Convective heat transfer can be expected to increase due to a chimney effect. A momentum due to the steam continuously generated in the passive condensation tank 100 can accelerate the steam leakage (outflow). Therefore, the heat exchangers can be arranged in multiple steps within the inner flow path to increase pressure drop, so as to minimize the steam leakage and simultaneously function as a heat exchanger so as to increase the heat transfer time and enhance the heat transfer performance. The aforementioned passive natural circulation cooling system and method are not limited to the configuration and the method of the embodiments described above, but the embodiments may be configured such that all or some of the embodiments are selectively combined so that various modifications can be made. The present invention can be used in a field of cooling systems provided in passive condensation tanks.
055815880	claims	1. A method for mitigating growth of a crack in a surface of a metal component adapted for use in high-temperature water, an uncoated surface of the metal component being susceptible to stress corrosion cracking in high-temperature water, comprising the step of applying a coating on the surface of the metal component, the coating comprising an electrically insulating material that is doped with a noble metal, the coating having restricted mass transport crevices which penetrate to the surface of the metal component and which restrict the flow of oxidants to the surface, the electrically insulating material doped to a concentration of the noble metal that is sufficiently small to avoid the establishment of conductive paths through the coating from the surface of the metal component to an outer surface of the coating, the crevices also exposing the noble metal to the oxidants thereby promoting reduction of the oxidants with available reductants, whereby the corrosion potential of the surface of the metal component is decreased by at least 0.050 V by application of the coating. 2. The method of claim 1, wherein the corrosion potential of the surface of the metal component is decreased by application of the coating below a critical potential at which stress corrosion cracking occurs. 3. The method of claim 1, wherein the electrically insulating material comprises zirconia and the noble metal comprises iridium, palladium, platinum, osmium, rhodium or ruthenium. 4. The method of claim 3, wherein the electrically insulating material further comprises yttria. 5. The method of claim 1, wherein the noble metal comprises .ltoreq.20 atomic percent of the insulating material. 6. The method of claim 1, wherein the electrically insulating material comprises alumina and the noble metal comprises iridium, palladium, platinum, osmium, rhodium or ruthenium. 7. The method of claim 1, wherein the noble metal comprises .ltoreq.20 atomic percent of the insulating material. 8. The method of claim 1, wherein the metal component is made of stainless steel or other reactor structural material. 9. The method of claim 1, wherein the electrically insulating material comprises particles sprayed onto the surface of the metal component. 10. The method of claim 1, wherein said step of applying comprises thermal spraying of the coating. 11. The method of claim 1, wherein hydrogen is added to the water of said reactor during reactor operation. 12. A component of a system adapted for use with high temperature water, such as a water-cooled nuclear reactor or related equipment, comprising: a metal substrate having a surface which has a corrosion potential and susceptible to stress corrosion cracking in high-temperature water when left untreated; and a coating on said surface of said metal substrate, said coating comprising an electrically insulating material that is doped with a noble metal, said coating having restricted mass transport crevices which penetrate to the surface of said metal substrate and which restrict the flow of oxidants to the surface, the electrically insulating material doped to a concentration of the noble metal that is sufficiently small to avoid the establishment of conductive paths through said coating from the surface of said metal component to an outer surface of the coating, whereby said coating decreases the corrosion potential of the surface of said metal substrate by at least 0.050 V in high temperature water as compared to an uncoated metal substrate. a metal substrate having a surface which has a corrosion potential and susceptible to stress corrosion cracking in high-temperature water when left untreated; and a coating on the surface of said metal substrate, said coating comprising an electrically insulating material that is doped with a noble metal, said coating having restricted mass transport crevices which penetrate to the surface of said metal substrate and which restrict the flow of oxidants to the surface, the electrically insulating material doped to a concentration of the noble metal that is sufficiently small to avoid the establishment of conductive paths through said coating from the surface of said metal component to an outer surface of the coating, whereby said coating decreases the corrosion potential of the surface of said metal substrate by at least 0.050 V in high temperature water as compared to an uncoated metal substrate. 13. The component of claim 12, wherein the electrically insulating material comprises zirconia and the noble metal comprises iridium, palladium, platinum, osmium, rhodium or ruthenium. 14. The component of claim 13, wherein the electrically insulating material further comprises yttria. 15. The component of claim 12, wherein the electrically insulating material comprises alumina and the noble metal comprises iridium, palladium, platinum, osmium, rhodium or ruthenium. 16. The component of claim 12, wherein the metal substrate comprises an iron-base, nickel-base, cobalt-base or zirconium-base alloy. 17. The component of claim 12, wherein the corrosion potential of the surface of said metal substrate is decreased by application of said coating below a critical potential at which stress corrosion cracking occurs. 18. The component of claim. 12, wherein the electrically insulating material comprises particles sprayed onto the surface of the metal substrate. 19. The component of claim 12, wherein the noble metal comprises .ltoreq.20 atomic percent of the insulating material. 20. A water-cooled nuclear reactor comprising metal components which are susceptible to stress corrosion cracking during reactor operation and which have been treated to mitigate said stress corrosion cracking, each of said metal components comprising: 21. The nuclear reactor of claim 20, wherein the electrically insulating material comprises zirconia and the noble metal comprises iridium, palladium, platinum, osmium, rhodium or ruthenium. 22. The nuclear reactor of claim 21, wherein the electrically insulating material further comprises yttria. 23. The nuclear reactor of claim 22, wherein the electrically insulating material comprises alumina and the noble metal comprises iridium, palladium, platinum, osmium, rhodium or ruthenium.
060699302	summary	FIELD OF THE INVENTION This invention relates generally to nuclear reactors and, more particularly, to passive containment cooling systems for such reactors. BACKGROUND OF THE INVENTION One known boiling water nuclear reactor includes a drywell, a wetwell, a Gravity Driven Cooling System (GDCS) and a passive containment cooling system (PCCS). The drywell is designed to contain pressure resulting from a Loss-Of-Coolant Accident (LOCA), and the PCCS is configured to remove core decay heat following a LOCA and to limit the pressure within the reactor containment to a pressure below a design pressure of the containment during a LOCA. The GDCS is substantially isolated from the drywell and is an emergency source of low pressure reactor coolant used following a loss of coolant event in at least one known boiling water reactor (BWR). A typical GDCS includes pools of coolant positioned so that when coolant from the pools must be supplied to the RPV, the coolant flows, under gravity forces, through the GDCS coolant delivery system into the RPV. Under normal reactor operating conditions, however, coolant from the GDCS does not flow into the RPV. A typical PCCS includes several condensers positioned in a PCCS pool, or pools, of water. Each condenser includes an upper drum, a lower drum, and several heat exchanger tubes extending between the upper and lower drums. The upper drums are coupled to the drywell via a steam inlet passage, and steam generated within the containment and noncondensible gases flow from the upper drums and to the lower drums through the exchanger tubes. The steam is condensed into water and the condensed steam is drained from the lower drums and to a condensate drain tank via a condensate drain line. The noncondensibles are purged from the lower drums utilizing vent lines. Particularly, a vent line extends from each lower drum and into the wetwell so that the noncondensibles collect in the wetwell. To condense any steam that might flow through the vent line and not through the condensate drain line, e.g., during a blowdown, one end of each vent line is submerged in the suppression pool. The wetwell is separated from the containment drywell by a wall having an opening therein. A vacuum breaker typically seals the opening and is movable between an open position and a closed position. The vacuum breaker is a check valve which allows fluid to pass from the wetwell to the drywell to substantially prevent a large differential pressure from developing between the wetwell and the drywell. Particularly, if pressure in the wetwell becomes sufficiently great compared to pressure in the drywell, the vacuum breaker opens and allows fluid to pass from the wetwell to the drywell and reduce the differential pressure. If the vacuum breaker becomes stuck in the open position, it is possible for the differential pressure between the wetwell and the drywell to reduce too much. Particularly, it is possible for the differential pressure to be insufficient to force noncondensibles to flow from the PCCS to the wetwell. The noncondensibles, accordingly, could build up in the PCCS and render the PCCS inoperable. It is known that one way to prevent a vacuum breaker from sticking in the open position, is to utilize an isolation valve. However, isolation valves sometimes fail, which causes the vacuum breaker to cease operating. In addition, the isolation valve must often be monitored to ascertain whether it is working properly. It would be desirable to provide a system facilitating the removal of noncondensibles from the PCCS even while the vacuum breaker is in the open position. It further would be desirable for such system to facilitate the maintenance of an acceptable drywell to wetwell pressure differential. SUMMARY OF THE INVENTION These and other objects may be attained by a passive containment cooling system (PCCS) which, in one form, includes a vent line coupled to the vacuum breaker. The vent line includes a first end, a second end, and a passage extending between the first and second ends for transporting noncondensibles and uncondensed steam between the first and second ends. The first end is coupled to a PCCS condenser, and the second end is submerged in a suppression pool. A branch extends from an intermediate portion of the vent line and is coupled to the vacuum breaker. The branch includes a first end, a second end, and a passage extending between the first and second ends. The first end of the branch is coupled to the intermediate portion of the vent line so that the branch passage is in communication with the vent line passage. The second end of the branch is coupled to the vacuum breaker so that the branch slopes substantially downwardly from its second end to its first end. The above described system facilitates removing noncondensibles from the PCCS even if the vacuum breaker is in the open position. Such system also facilitates maintaining an acceptable drywell to wetwell pressure differential.
	abstract	The present invention provides novel fuel assemblies for use with PWR nuclear reactors and power plants, and in particular, VVER nuclear reactors. The fuel assemblies offer enhanced structural stability, skeletal rigidity, and distortion (bow and twist) resistance to support high burn-up fuel management. Each fuel assembly may include a plurality of fuel rods, a plurality of control rods and guide thimbles, at least one instrumentation tube, and a plurality of grids. At least one fuel rod is replaced with a structural support replacement rod made from zirconium (Zr) alloy, stainless steel, or any other suitable material. The structural support replacement rod may be hollow or solid. The structural support replacement rods are preferably disposed at or about the periphery, and in some cases, the corners of the geometric array, which is preferably a hexagon or square.
	abstract	A writing error diagnosis method for a charged beam photolithography apparatus and a charged beam photolithography apparatus which can specify an error cause within a short period of time in occurrence of a pattern writing error are provided. The writing error diagnosis method for a charged beam photolithography apparatus is a writing error diagnosis method for a charged beam photolithography apparatus which irradiates a charged beam on a target object to write a desired pattern. Processing result data of a pattern writing circuit at a position where a pattern writing error occurs is collected after the pattern writing error occurs, and the collected processing result data of the pattern writing circuit is compared with correct data. The charged beam photolithography apparatus has means which realizes the diagnosis method.
	description	This application claims the benefit of Korean Patent Application No. 10-2016-0024706, filed on 20 Feb. 2017 in the Korean Intellectual Property Office. The entire disclosure of the application identified in this paragraph is incorporated herein by reference. The present invention relates to an aerosol generating and bending system operating at a high temperature and pressure. The present invention relates to a control system which allows handling an aerosol. The present invention aims to provide a control system which is able to control in a high temperature/high pressure state since there is not any aerosol control system which is able to control in a high temperature/high pressure state. In order to deal with a dangerous accident, for example, a Fukushima nuclear power plant's disaster, a technology development on a radioactive aerosol behavior inside a nuclear reactor building and a technology development on a containment building stability and a radioactive aerosol filtration and exhaust are underway. The conventional aerosol generating and mixing device is not equipped with any means to generate a high temperature/pressure aerosol, for example, like a dangerous accident at a nuclear power plant and to mix the aerosol with a transfer gas under a predetermined condition. Moreover, air or a nitrogen gas, in general, has been used as a transfer gas. A mixed gas condition, for example, vapor, air, nitrogen gas, etc. however exists under an environment wherein a high temperature/high pressure aerosol is present. An atomizer type, which is one of the conventional aerosol generating equipment, in general, has been used. A high pressure injection (higher than 8 bar) is available, but a normal temperature aerosol of a very low concentration might be generated. The generating device of a particle distribution type is able to generate an aerosol of a relatively high concentration and is configured to operate at a normal pressure/normal temperature condition. There, however, is not any system which is able to generate and mix an aerosol under the same condition of a high temperature/a high pressure. In particular, there is not any aerosol generating and mixing system which uses a mixed gas of vapor, air and a nitrogen gas as a transfer gas. In this connection, the Korea patent registration number 100145032 describes a tool engaging and aerosol generating device which is directed to a device for generating an aerosol at a normal temperature/a normal pressure. Any system which is able to generate/inject/mix a high temperature/high pressure aerosol, is not disclosed yet. Accordingly, it is an object of the present invention to provide an aerosol generating and mixing system operating at a high temperature and a high pressure. The present invention aims to satisfy the necessity of an aerosol generating and mixing equipment which can be adapted to a special condition, for example, a high temperature/a high pressure. To achieve the objects, there is provided an aerosol generating and mixing system operating at a high temperature and a high pressure, which may include, but is not limited to, an aerosol generating device and an aerosol mixing device. The aerosol generating device includes a mixing tank 11 and a pre-mixing tank 28. The mixing tank may include a wing 12 configured to rotate about a central shaft of the mixing tank so as to agitate the aerosol inside the mixing tank; a filling nozzle 13 configured to inject an aerosol particle in the mixing tank; a first air injector 22 configured to inject either a compressed air or a nitrogen gas so as to pressurize the tank; and a first sight glass 27 configured to confirm the mixing state inside the mixing tank. The agitation generates an aerosol particle aqueous solution. The air of a second air injector 23 configured to inject either a compressed air or a nitrogen gas inputted through a separate line and the aerosol particle aqueous solution are injected together in a second tank, thus generating an aerosol. The aerosol particle aqueous solution outputted from the mixing tank will pass through a gear pump 16 and will be inputted in a high pressure type and will be heated by a heater and will be inputted in a second tank. The air outputted from a second injector will pass through the heater and will be inputted in a heated state. The injection quantity can be controlled by a mass flow meter 29. The aerosol mixture is inputted through a binary fluid nozzle into which air and an aerosol are together injected when being injected in the second tank, so the aerosol mixture may form a previously set pattern. The generation of the aqueous aerosol may need an inside mixing binary fluid nozzle 18, and the generation of the non-aqueous aerosol may need an outside mixing binary fluid nozzle. The flow of the mixture may be carried out using a binary fluid nozzle when the flow is stabilized after it has been circulated through a bypass line 19 so as to stabilize the flow thereof before it is injected into the second tank through the binary fluid nozzle. Moreover, since the mixture passes through the bypass line while it is being heated by the heat, the temperature of the mixture can be set to a predetermined temperature. The aerosol of various pressures can be generated based on the pressure of the compressed air or the nitrogen gas inputted into the binary fluid nozzle and the pressure increase condition of the gear pump. At the initial stage of the aerosol generation, the pressure and temperature inside the mixing tank are the normal pressure and normal temperature conditions. If the compressed air or nitrogen gas is filled using a first air injector 22, the pressure of the mixing tank may be increased up to 6˜7 bar to the maximum, and if the difference pressure is set to 3˜4 bar using the gear pump, and the second air injector 23 supplies the compressed air or nitrogen gas of 9˜10 bar to the maximum, a high pressure aerosol corresponding to 9˜10 bar can be generated. The aerosol aqueous solution inside the mixing tank will be heated by a heater at the rear end of the gear pump, and at the initial state of generation, the aerosol aqueous solution is continuously heated while it is being circulated through the bypass line, so the generation of a high temperature aerosol is available. A ring-shaped mixing ring 21 is provided inside the second tank so as to supply a transfer gas which will be used to transfer the generated aerosol. The transfer gas is sprayed through a hole 26 formed at the mixing ring. A mixing ring blocking part 31 is provided to maintain a uniform flow speed distribution of the transfer gas at the upper and lower parts of the mixing ring. Vapor, a compressed air or a nitrogen gas may be used as the transfer gas based on the transfer condition. A mixture thereof may be used. The binary fluid nozzle is disposed in the center of the mixing ring, by which the generated aerosol can be injected into the second tank, and it will be mixed with the transfer gas transferred from the mixing ring. The aerosol gas inputted from the binary fluid nozzle may have a folding fan pattern or a circular pattern. The transfer gas may be sprayed from a portion spaced apart from a wall surface, not being attached to the wall surface of the second tank, so the phenomenon wherein the aerosol is attached to the wall surface, can be prevented. Moreover, the uniform mixing of the aerosol and the transfer can be made available. The aerosol inputted into the second tank will be mixed with a high temperature transfer gas, so the moisture can be completely removed, which makes it possible to prevent any flocculation phenomenon. The present invention provides an aerosol generating and mixing system operating at a high temperature/high pressure through the aforementioned configuration. The present invention will be described with reference to the accompanying drawings. FIG. 1 is a view illustrating an aerosol generating and injecting device according to the present invention. The pre-mixing tank 28 is configured to supply an aerosol solution to the mixing tank 11 through a pre-mixing procedure so as to supplement in real time an aerosol solution if it needs to uniformly mix the aerosol. The mixing tank is able to uniformly mix the aerosol solution inside the tank by rotating the wing 12 installed inside the tank and keep the mixed aerosol solution. The motor installed on the top of the tank is configured to rotate the wing 12 arranged along the central shaft of the tank. In order to generate a high temperature/high pressure aerosol, it is more advantageous that the gas and water are mixed uniform, and the mixture of the aerosol state is separately injected. According to the conventional method, the aerosol aqueous solution heated through a bypass line is bypassed, thus uniformly mixing the gas and liquid. In this case, it is easy to raise the temperature using the heater; there, however, is a problem in preparing a high pressure aerosol aqueous solution. The present invention is referred to a method wherein a pre-mixing tank is provided, by which water and gas can be uniformly mixed with the aerosol aqueous solution heated by the bypass line in an aerosol aqueous solution. More specifically, it is possible to more easily prepare a high temperature/high pressure aerosol in such a way to add the inputs which are made by the aerosol prepared through the pre-mixing tank. Here, the states of the bypassed aerosol aqueous solution and the aerosol aqueous solution inputted from the pre-mixing tank are different. When the state of the aerosol aqueous solution is a little stabilized through the mixing with the continued bypass, it will be transferred to the second tank. The aerosol aqueous solution and the aerosol particles may be inputted through a filling nozzle 13 installed at the top, and water can be inputted into the tank through the nizzle formed installed at the top. A level gauge 14 installed at the lateral side is connected to a drain 15 installed at the lower end, thus adjusting the water level inside the tank. The aerosol aqueous solution may be agitated and mixed while pressuring the inside of the tank up to the level required for the compressed air or nitrogen gas to be inputted into the tank so as to pressurize the tank. The aerosol aqueous solution discharged from the tank will be injected into a second tank 17 in a high pressure state through the gear pump 16 and will be mixed with the compressed air or nitrogen gas which is injected through another passage, and will be injected into the second tank 17. The aerosol aqueous solution may be recirculated to the mixing tank 17 through a bypass line 19 until a predetermined initial flow quality of the aerosol aqueous solution becomes stabilized. If the flow quantity of the aerosol aqueous solution is stabilized, the aerosol and the compressed air or the nitrogen gas is injected through the binary fluid nozzle 18. The binary fluid nozzle 18 will mix the aerosol and air and generate a uniform pattern of perfect fine spray sprays. The binary fluid nozzle is provided to generate a uniform pattern of fine particles. Alternatively, it may be implemented in another type in accordance with the speed and mixing of the inputted liquid and air. FIG. 2 is a view illustrating an embodiment of this fine spray. The fine spray provided at the top in FIG. 2 shows that it is formed in a folding fan due to a difference between the pressure of air and the pressure of aerosol, thus forming a different shape from each other. FIG. 3 is a view illustrating an embodiment of the binary fluid nozzle. The configuration of a nozzle may be changed based on the flow of liquid and gas and if the air and liquid are independently controlled. FIG. 4 is a view illustrating a configuration which allows mixing an aerosol and vapor sprayed from the binary fluid nozzle, a compressed air, a nitrogen gas or a mixture thereof. A fine spray can be formed as it is discharged from the binary fluid nozzle. A mixing ring 21 may be installed where the fine spray is formed. The mixing ring is configured in a ring shape, and a plurality of holes 26 are formed on the outer surface thereof. A mixture (a transfer gas) of steam and a nitrogen gas (or a compressed air) can be sprayed through the holes formed at the mixing ring. The aerosol and transfer gas which are present in a fine spray state, are mixed and discharged through the exit of the second tank. If the aerosol is generated in the aforementioned way, the high pressure condition can be satisfied by adjusting the initial pressure of the mixing tank 11, and the temperature of the aerosol can be raised in such a way to install a heater between the tanks. In particular, an aerosol satisfying the condition of the pressure which is higher than before can be obtained by installing the pre-mixing tank of the present invention. FIG. 5 is a view illustrating a mixing ring and a transfer gas spray hole which is formed at an outer circumferential surface of the mixing ring. The transfer gas sprat hole may allow uniformly spraying the vapor, compressed air, nitrogen gas or a mixture thereof which are supplied to the mixing ring. The binary fluid nozzle disposed in the center of the mixing ring may allow preventing the pattern of the aerosol from attaching to the wall surface. For this, the binary fluid nozzle sprays close to the wall surface of the second tank so as to prevent the pattern of the aerosol injected through the binary fluid nozzle disposed in the center of the mixing ring from being adsorbed to the wall surface while it is mixed covering the aerosol. Moreover, a mixing ring block part 31 is provided at the mixing ring. Since the agitation is not carried out by the wing in the second tank 17, a uniform mixing may not be available. If the mixed gas is sprayed with the aid of the mixing ring, since the opening through which the mixed gas comes in, positions at the top, the flow speed of the mixed gas may differ at the upper and lower parts of the mixing ring. If the mixing ring block part 31 is provided at a portion symmetrically matching with the opening, the flow speed of the mixed gas discharged from the transfer gas spray hole 26 around the mixing ring block part 31, may become fast, so the discharge speed of the mixed gas can become similar together. For this reason, even though there is not any agitating device, for example, a wing, it is possible to generate a more uniform aerosol. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described examples are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims. 11: Mixing tank12: Wing13: Filling nozzle14: Lever gauge15: Drain16: Gear pump17: Second tank18: Binary fluid nozzle19: Bypass line20: Transfer gas mixing tank21: Mixing ring22: First air injector23: Second air injector24: Agitating motor25: Cleaning water supply line26: Transfer gas spray hole27: First sight glass28: Pre-mixing tank29: Mass flow meter30: Second sight glass31: Mixing ring block part
	abstract	In a cooling structure and a cooling method for a control rod drive mechanism and in a nuclear reactor, a housing (59) in which magnetic jacks are housed is fixed to an upper portion of a reactor vessel (41), and an air intake unit (102) that takes cooling air into the housing (59), a first exhaust duct (104) that is arranged side by side with the air intake unit (102) in a circumferential direction of the housing (59), into which cooling air in the housing (59) is suctioned through a first inlet (109) at a lower portion thereof, and that guides the cooling air upward, a second exhaust duct (105) that is disposed below the air intake unit (102), into which cooling air in the housing (59) is suctioned through a second inlet (110), and that guides the cooling air to the first exhaust duct (104), and a discharging unit (111) that is formed at an upper portion of the housing (59) and discharges cooling air in the first exhaust duct (104) to the exterior are provided.
039986942	claims	1. In a power production system, a. a sensing device called an ion-chamber-electrometer-optical digitizer comprised of: b. said power production system being a nuclear reactor; c. said ion source being a chamber, and said chamber being so positioned as to be responsive to neutron flux level of said neuclear reactor; d. a control device for said nuclear reactor, comprised of: e. a linkage between said sensing device and said control device consisting of: f. said on line computer effecting control of said control device responsive to said time-intervals from said counter-timer apparatus of said sensing device. a. said on line computer incorporating a stored program. a. a sensing device called an ion-chamber-electrometer-optical digitizer comprised of: b. said power production system being a nuclear reactor; c. said ion source being a chamber, and said chamber being so positioned as to be responsive to neutron flux level of said nuclear reactor; d. a control device for said nuclear reactor, comprised of: e. a linkage between said sensing device and said control device consisting of: f. said stored program and said computer effecting control of said control device responsive to said time-intervals from said counter-timer apparatus of said sensing device. 2. In a power production system as described in claim 1, 3. In a power production system, in combination, 1. an on line computer interfaced to said counter-timer apparatus of said sensing device and also to said motorized control rod;
046848100	abstract	A cylindrical shield is affixed to the opposed marginal terminal end portions of a fluorescent light tube. The shields each include a layer of metallic substance which intersects X-rays emitted by the cathode of the tube to avoid the harmful effects that are brought about by the X-rays impinging upon people located nearby.
	summary
048511862	summary	FIELD OF THE INVENTION The invention relates to a core of a nuclear reactor and a process for charging said core. BACKGROUND OF THE INVENTION A core of a nuclear reactor, such as a fast neutron nuclear reactor cooled by liquid metal, comprises detachable assemblies disposed vertically and maintained in position by a support or bolster in which the lower parts or feet of the assemblies of the core are engaged, inside sleeves having a vertical axis disposed in a network corresponding to the network of the assemblies in the core. The vertical sleeves, termed pillars, join the upper part to the lower part of the bolster which is in the form of a hollow structure into which the coolant fluid of the reactor is injected, this fluid usually being constituted by liquid sodium. Each of the pillars comprises openings for the passage of the liquid sodium, corresponding openings in the foot of the assembly being aligned with the openings of the pillar. The liquid sodium can consequently travel to the assemblies in the upward direction for cooling said assemblies. The fuel assemblies comprise, above their foot of generally cylindrical shape which is engaged in the sleeve, a prismatic part usually having a hexagonal section and terminating in its upper part in a head permitting the seizure of the assembly for its handling and possibly ensuring the upper neutronic protection of the assembly. The assemblies constituting the core of a fast nuetron reactor are of several different types and have a predetermined position in the core. Some of these assemblies are fuel assemblies in which the power of the core is created, others of the assemblies being fertile and capable of ensuring a certain regeneration of the nuclear fuel, and still other assemblies being absorbent of various types for regulating the power or effecting urgent stoppages of the reactor. When effecting the first charging of the core of the reactor, it is necessary not only to place each of the assemblies in a defined position in the core, but also to correctly and precisely orient the assemblies relative to one another owing to their prismatic shape, the hexagonal sections of these assemblies being imbricated so as to constitute the cross-section of the core. It is also necessary to simultaneously place the opengings provided in the foot of the assembly into alignment with the openings provided in the pillars of the bolster to obtain satisfactory conditions for the circulation of the coolant fluid as it enters the core. In prior art designs of cores of fast neutron nuclear reactors, the feet of the assemblies are free to rotate about the axis of the pillar, all the corresponding foot and pillar sections bearing against one another being circular. When they are placed in position in the core, the assemblies are suspended from the grab of a handling machine so as to be substantially free to rotate about their vertical axis. The sole limit to the rotation of the assembly is provided by the friction of the bearing members for the suspension of the assembly from the grab under the effect of the weight of the assembly. In order to ensure correct orientation of the assemblies relative to one another, there are provided around the assembly, in the part of the foot connected with the hexagonal body, contact surfaces having the shape of cams or shoes adapted to cooperate with contact surfaces of corresponding shape on the neighboring assemblies. The constitution of the network of assemblies corresponding to the first core introduced in a new reactor is by a series of operations for achieving a perfect relative orientation of the assemblies of the network relative to one another. Before the filling of the vessel with liquid sodium, a complete network is constituted with false assemblies having the same geometry as the true assemblies. Each false assembly is placed in position manually, and then an in situ visual inspection permits checking that the sodium passage openings in the foot of the assembly are perfectly aligned in with the corresponding openings of the pillar. This positioning and this checking can easily be carried out, since the vessel of the reactor in which the core is constituted is at that time in a normal atmosphere of air. When all the false assemblies have been placed in position, there is available a complete network which acts as a reference for all the other handling operations which may be effected on the assemblies, and in particular for the charging of the first core after the vessel has been filled with liquid sodium. The false assemblies are replaced by the true assemblies by successive substitutions, each assembly taking the place of a false assembly having exactly the same geometry, and in particular identical contact and orientation surfaces. When an assembly is introduced in a cavity consituted by six adjacent assemblies, it is possible to correct a slight angular offset of this assembly by cooperation of the corresponding orientation surfaces. However, the risk of a progressive angular offset of the assemblies relative to one another is not completely eliminated. Such a progressive offset may result in difficulty in the introduction of an assembly or in a large disalignment between the openings of the pillars and the openings of the foot of the assembly. In this case, the passage of the coolant liquid sodium in the assembly may be considerably affected. In the course of the charging by progressive substitution of the assemblies of the first charge for the false assemblies, the position of each of the assemblies in the core is located in a precise manner by conventional primary handling means of the reactor. The charging operations of a fast neutron nuclear reactor are therefore long and difficult to carry out, and the adaptation of the assemblies requires the formation of orientation shoes whose profiles are very complex. Furthermore, the self-orienting shoes do not always perform their function, in particular when the assemblies are deformed after a certain irradiation time in the reactor. Difficulties are also related to the design of the seizing head of the assembly and its connection with the hexagonal case constituting the body of the assembly. Even in the case where they do not ensure the upper neutronic protection of the assembly, these seizing heads are massive and the design is delicate, bearing in mind the considerable thermal disturbances prevailing in the upper part of the assemblies. SUMMARY OF THE INVENTION An object of the invention is therefore to provide a core of a nuclear reactor constituted by detachable assemblies disposed vertically and a support or bolster receiving the lower part or foot of the assemblies, inside sleeves having vertical axes or pillars provided with openings for the passage of coolant fluid of the reactor located in alignment with openings provided in the foot of the assembly, said core comprising assemblies of simplified shape which are capable of being placed in position, with a perfect orientation around their vertical axes relative to the bolster and relative to the adjacent assemblies, by simple operations. For this purpose, each of the pillars comprises at least one means for orienting the assembly about the axis of the pillar, and each of the assemblies includes on its foot at least one orientation means adapted to cooperate with the corresponding means of the pillar, the engagement of the corresponding orientation means one on the other being effected at the moment of the introduction of the foot of the assembly in the bolster. The invention also relates to a simplified process for charging a nuclear reactor core.
062367102	description	DETAILED DESCRIPTION OF THE INVENTION An x-ray crystal device as shown in FIG. 1 consists of a thin doubly curved crystal lamella 10, a thick bonding layer 12, and a backing plate 14. In this device, the bonding layer 12 having a thickness typically 10 to 50 times the thickness of the crystal constrains and holds the crystal to a preselected geometry. The crystal can be one of a number of crystals used in x-ray diffraction, such as mica, silicon, germanium, quartz, etc. The bonding layer consists of a material that has a high viscosity in its initial state and can be transformed by polymerization, or by a temperature change to a solid. Suitable bonding materials are thermoplastic resins, various thermosetting resins, epoxy, low melting point glass, wax, etc. The most important property of the bonding layer is a viscosity of the order of 10.sup.8 -10.sup.8 Poise (c.g.s. units) before it reaches its final state. A particularly useful epoxy resin called "Torr Seal" is used in one preferred embodiment of the invention. This initially has a paste-like consistency, a viscosity of the order of 10.sup.3 Poise, and a pot life of 30-60 minutes. Furthermore, the low vapor pressure of this material in its cured state is desirable if the crystal device is used in a vacuum environment. Other paste types of epoxy that could be used include "plumber's epoxy" and "Milliput" epoxy putty which have physical properties similar to Torr Seal except for the low vapor pressure. A thin plastic separator sheet 16 between a portion of the surface of the crystal near its edges lies between the crystal 10 and the bonding layer 12. This plastic separator extends 1-3 mm beyond the crystal's edges in order to prevent the bonding material from sticking to the mold or flowing under the crystal during fabrication. Thin plastic strip with pressure sensitive adhesive coating such as "Scotch tape" or "transparent mending tape" which have a thickness of typically 0.05 mm have been successfully used for the said plastic sheet with the adhesive side facing the crystal. Somewhat thinner or thicker plastic sheets could also be used. The plastic separator sheet is omitted in an alternative form of the invention shown in FIG. 2. This form of the invention is simpler than the structure shown in FIG. 1 and is feasible if the epoxy has a sufficiently high viscosity that it cannot flow under the crystal lamella. In this case, the bonding layer 12' does not extend as far beyond the crystal lamella 10', in order to minimize it sticking on the mold. The backing plate 14 in FIG. 1 and 14' in FIG. 2 is selected of a material to which the bonding material adheres, which is dimensionally stable, and which has a coefficient of thermal expansion similar to the crystal. If the crystal to be used is transparent to light (e.g. quartz, alkali halides, etc.) it is desirable to use a transparent material for the backing plate and the bonding material so that optical interferometry can provide a means for quality control. The backing plate can be flat as indicated by reference no. 18 in FIG. 1, or it can have a concave surface as indicated by 19 in FIG. 2. The exact shape of the surface is usually not critical as will be seen in the fabrication method for a preferred embodiment that will be described. It will be noted generally, it is best to use a convex mold for bending the crystals as in U.S. Pat. No. 4,807,268. This allows for the mold to be reused and for the crystal to be conformed directly to the surface of the mold without any intervening layer, yielding high accuracy. In most cases, it is important that the crystal be properly located relative to the mold both in position and in angular orientation. This can be done by using a mold whose size matches the crystal size and using barriers at the exact boundaries of the crystal. This approach can be used for devices like the one in FIG. 2 but is inaccurate when used with ones like FIG. 1. FIG. 3 shows a preferred embodiment in the present invention wherein the crystal lamella 1 has half-circle indentations 2 and 2' accurately made on two opposing faces. This may be done with a special fixture or with an ultrasonic "cookie cutter" and an abrasive slurry. The two indentations engage dowel pins 3 and 3' which slide in cylindrical cavities made in the mold 4 by drilling and reaming. Helical springs such as 5 allow the dowel pins to slide into the mold when the crystal is bent, otherwise, they are essential flush with the top surface of the crystal. This approach to positioning the crystal relative to the mold is compatible with the use of a thick viscous agent for deformation according to the following method: The fabrication method for the crystal device is shown in FIGS. 4A-4D. A convex mold 20 having a surface of the desired shape is prepared by single point machining or by a numerically controlled milling machine. Single point machining (e.g. with a diamond tool) is particularly suited to toroidal surfaces, i.e. surfaces of revolution having one radius of curvature in a plane perpendicular to the axis and a second radius in the plane passing through the axis. The mold surface 22 is polished to a mirror finish; hence, materials such as stainless steel, glass, or hard aluminum alloys may be used. A glass or transparent mold would facilitate the use of interference fringes. After the mold is prepared (by steps that are not shown here), a crystal lamella is prepared. This lamella may be flat as shown by 11 and 13 in FIGS. 5A and 5B, or cylindrical as shown by 15 and 17 in FIGS. 5C and 5D. The thickness of the lamella is critical; it should be no more than .about.1/5,000of the smallest radius of curvature. For mica, the crystal surfaces as cleaved are satisfactory, but for brittle crystals without such pronounced cleavage planes (e.g. quartz and silicon), it is important that the surface be damage free. This may be accomplished by etching or by chemical polishing after cutting and mechanical polishing. After the crystal lamella is prepared, the thin plastic sheet 16 is attached around the edges of crystal 10 as shown in FIG. 4A, and the crystal with plastic sheet is positioned on the convex mold 20. At this stage, it is very important to avoid the presence of dust particles, particularly between the crystal and the mold. If epoxy is used for the bonding agent, a blob of epoxy 7 is placed on top of the crystal 10. The backing plate 14 is attached to a piston 28 by means of a screw 33 which threads into part of the piston and pulls the projecting surface 30 on the back side of the backing plate against a mating surface 31 on the piston. Due to of the slope of the surface 30, the backing plate's surface 40 is pulled snugly against surface 41 of the piston. The piston has a rectangular cross section matching the backing plate and these two components are placed on top of the epoxy as shown in FIG. 4A. The assembly is mounted in the pressing fixture 32 attached to the mold as shown in FIG. 4B. The pressing fixture has a rectangular cavity in which the piston 28 and backing plate 14 are free to slide. In this way, the backing plate is indexed in position relative to the mold via the backing plates's lateral surfaces (e.g. 38 and 40). The assembly is compressed lightly by turning the knob 36 attached to screw 34 to flatten the epoxy and bring the crystal in to better contact with the surface of the mold. As the epoxy begins to polymerize, the pressure on the backing plate 14 is gradually increased by further turning of the screw 34 so as to force the crystal 10 against the mold 20 as shown in FIG. 4B. During this process, if the backing plate and the crystal are transparent, contact between the crystal surface 24 and the mold surface 22 can be monitored by observing interference fringes with illumination by light through the surface 26 of the backing plate 14. Alternatively, such fringes can also be observed by light passing through the mold if it is transparent. Dust particles, or undesirable penetration of the bonding material between the crystal and the mold can be observed in this case, indicating that the plastic sheet 16 failed in its purpose of preventing this penetration. In addition it will be possible to observe cracking of brittle crystals if this happens to occur. However, it should be noted that as long as the pieces of the crystal remain in the proper position, cracking of the crystal will not affect the performance of the device significantly. When the epoxy completely fills the space between the backing plate and crystal with plastic strip as shown in FIG. 4C, the pressure on the backing plate is held constant until the epoxy is completely cured. Then, the device is removed from the mold, from the pressing fixture and from the piston, yielding the result shown in FIG. 4D. In this step, the plastic sheet 16 is important to prevent the bonding material 12 from sticking to the mold 20 so that removal can be accomplished without distorting the bonding material. In this connection, it should be noted that use of parting agents to prevent adhesion of the bonding material to the mold is not desirable because the presence of these agents will reduce the accuracy with which the crystal conforms to the desired shape. However, parting agents may be used to prevent the epoxy from sticking to the pressing fixture. This positioning is less critical and it is recognized that in most cases, the completed device must be aligned relative to the x-ray source after its fabrication is complete (one can only hope to get the least critical alignments correct--the others require in situ adjustments). One of the most important applications of this invention is that of focusing x-rays of a particular wavelength from a source to form an x-ray microprobe. This type of device with point-to-point focusing property is illustrated in FIG. 7A. The crystal in this device has a toroidal shape such that the crystal satisfies either the Johann or Johansson geometry in the plane of the Rowland circle 28 and also has axial symmetry about the line joining the source S and the image I. If a crystal lamella like the one shown in FIG. 5A is used, having crystal planes 21 parallel to the surface 11 and the mold has a radius of 2R.sub.1 in the plane of the focal circle having a radius R.sub.1, the result after bending will be as shown in FIG. 6A and the geometry in the plane of the focal circle after alignment will be the Johann geometry. In this case, the crystal device will be in the usual symmetric position A relative to the Source S and the Image I shown in FIG. 7B. On the other hand, if the crystal lamella of FIG. 5B is used with the crystal planes 23 making an angle with respect to the large surface 13 of the lamella, and the mold has a radius of 2R.sub.1 in the plane of the focal circle of radius R.sub.1, the result after bending will be as shown in FIG. 6B. Then, the geometry in the plane of the focal circle after alignment with respect to the source s and the image I will be similar to the Johann geometry but with the crystal device offset from the symmetric position as shown by position B in FIG. 7B. Two different Johansson geometries are obtained if the crystal slab is curved to a radius 2R.sub.1 as shown in FIG. 5C and FIG. 5D. Like their 2-dimensional analog, Johansson-based point-to-point focussing devices will provide greater solid angle of collection and also more exact focussing than Johann-based devices. They are particularly advantageous when used with crystals having a small rocking curve width. When the crystal planes 25 are parallel to the surface 15 of the crystal at its mid-line as shown in FIG. 5C, the result after bending to a mold with radius R.sub.1 is shown in FIG. 6C. This crystal device when aligned with respect to source s and image I will be in the symmetric position c shown in FIG. 7C. But if the crystal planes 27 make an angle with respect to the surface 17 as shown in FIG. 5D, the result after bending to a mold with radius R.sub.1 would be as shown in FIG. 6D. Then, when the crystal device is properly aligned, it will be asymmetric relative to S and I, as shown by position D in FIG. 7C. The alignment of the crystal devices relative to the Source S and Image I can be accomplished by a device similar to one described in U.S. patent application Ser. No. 09/149,690 (now U.S. Pat. No. . . . ) which is hereby incorporated by reference. For this purpose, it is important to have indexing features on the crystal device so that its position relative to the source and image can be roughly preset and also only adjustments that are absolutely necessary need to be accommodated. The initial positioning is facilitated by the mounting fixture 50 of FIG. 7A having a U shape with the space between the arms of the U configured to match the backing plate. The backing plate with crystal is attached to fixture 50 by screw 33 like it had been previously attached to the piston. A leaf spring 47 maintains contact of surface 38 of the backing plate with surface 39 of 50 before 33 is fully tightened and contact of surface 40 of the backing plate and 41' of 50 is maintained when 33 is fully tightened. Thus, the position of the crystal is now fixed relative to the fixture 50, as it was previously fixed relative to the mold 20. Details of the degrees of freedom for which adjustments might be provided as well as a simple mechanism for adjustment of the others are given in the reference cited. While the asymmetric cases shown in FIGS. 7B and 7D show the crystal device closer to the source than to the image, clearly the opposite situation case could be achieved (i.e. crystal device closer to the image than to the source). The asymmetric cases are sometimes useful to provide additional space in the x-ray source region or image region. DISCUSSION AND RAMIFICATIONS An x-ray crystal device according to this invention provides a doubly bent crystal that accurately conforms to a theoretically optimum shape and provides better performance than similar crystal devices made according to the prior art. Moreover, the methods of fabrication allow for the production of many identical crystal devices from the same mold, thus reducing the cost of the each device. The first monochromatic x-ray microprobe that had sufficient intensity for trace element determination in x-ray fluorescence analysis and was based on a laboratory source was developed using an x-ray crystal device similar to the one described herein (re: papers by Z. W. Chen and D. B. Wittry, "Monochromatic microprobe x-ray fluorescence-- . . . J. Appl. Phys. vol. 84, pp. 1064-73, 1998, and "Microprobe x-ray fluorescence . . . Appl. Phys. Lett. vol. 71, 1997, pp. 1884-6). The device used in the cited work was based on a Johann geometry with focal circle radius of about 125 mm with a mica crystal having an effective area of approximately 8 mm.times.28 mm and produced an x-ray spot size of about 50 .mu.m with an x-ray source of about 20 g .mu.m. An indication of the advantages of some of the features of the present invention can be obtained by comparing the theoretical performance of some examples of specific crystal devices with the Johann-based mica diffractor used by Chen and Wittry. If a silicon (111) crystal were used and the values of the rocking curve width of 8.7.times.10.sup.-5 radian (instead of 30.times.10.sup.-5) and peak reflectivity of 0.7 (instead of 0.2) are assumed, then, with the Johann-based geometry, the broadening of the focal spot due to the crystals rocking curve would be about 8.7 .mu.m instead of 30 .mu.m as it was for the mica crystal. The effective crystal width would be 8.times.(8.7/30).sup.0.5 =4.31 mm for the Johann-based geometry--but we must note that for copper K alpha radiation and Si crystal, the penetration of the rays into the crystal is sufficient that there would be little distinction between this geometry and the Johansson geometry. This distinction becomes more evident if we consider wider crystals, for example 16 mm. The peak reflectivity for the Si crystal is about 3.5 times higher than that of mica, so, if equal widths are considered, the total flux of the focused probe could be the same if the Gaussian image size were smaller by .about.(1/3.5).sup.0.5 =(1/1.87) yielding a spot size of (20/1.87)+8.7=19.4 .mu.m vs (20+30)=50 .mu.m. But, if a Johansson-based crystal were used having a width of 16 mm the corresponding Gaussian image would be 7.6 .mu.m, yielding a spot size of 7.6+8.7=16.3 .mu.m and then the number of photons/sec/cm.sup.2 would be greater than that which was obtained with mica by a factor of approximately (50/16).sup.2 =9.76. In order to make smaller spots, it is important to reduce the broadening due to the rocking curve width. But as this gets smaller, it is no longer possible to utilize all of the characteristic line's natural width. The intensity loss resulting from focusing only part of the characteristic line can be estimated as follows: Bragg's law is: n.lambda.=2d sin.theta. where .theta. is the Bragg angle. Differentiating Bragg's law on both sides and dividing by Bragg's law, we obtain: EQU (.DELTA..lambda./.theta.).sub.B =(1/tan.theta.).DELTA..theta. where .DELTA..THETA. is the rocking curve width. Assuming that the characteristic line has (.DELTA..lambda./.lambda.).sub.L =2.times.10.sup.-4 and assuming values for Cu K radiation and the (111) reflection from silicon, we obtain: EQU (.DELTA..lambda./.lambda.).sub.B /(.DELTA..lambda./.lambda.).sub.L =8.7.times.10.sup.-5 /(tan 14.21).times.2.times.10.sup.-4 =1/1.71 Thus the rocking curve width for the Si (111) crystal would appear to be reasonably well matched to focus nearly all the characteristic X-ray line. One can calculate similarly the results of using a crystal with even narrower rocking curve width e.g. .alpha. quartz (2243) with a rocking curve of about 5.times.10.sup.-6 radian. This would yield image broadening due to the rocking curve width of only about 0.5 .mu.m. Then, the loss of intensity due to not using all of the natural line width is more serious. For this case and copper K radiation we would obtain: EQU (.DELTA.2/.lambda./.lambda.).sub.s /(.DELTA..lambda./.lambda.).sub.L =5.times.10.sup.-6 /(tan 49.64).times.2.times.10.sup.-4 =1/46.8 In order to offset this effect, it is clearly desirable to use the Johansson-based geometry and wider crystals. Also one should use higher voltage for the x-ray source since the intensity of characteristic lines increases as the 1.63 power of the voltage above the critical excitation voltage (for copper K radiation this would be approximately 3.times. if 50 kV instead of 30 kV were used). For this case the total number of photons/sec in a 10 .mu.m spot formed by the quartz crystal would be lower than that obtained in a 16 .mu.m spot with a Si crystal by a factor of (9.5/7.6).sup.2.times.(3/46) 0.1. Thus, by using all available techniques, it should be possible to obtain focal spot sizes significantly less than 10 .mu.m with adequate intensity for x-ray fluorescence analysis, although the detection limits would be lower than those obtained for larger spot sizes. Note that in our calculations we have assumed for simplicity that the number of photons/sec in the Gaussian image is proportional to the square of its diameter, which would be the case for an aperture of fixed size in the electron beam forming the x-ray source. It is well known that if the aperture size is optimized, the current on a spot of diameter d is proportional to d.sup.8/3. We should also note that while it might appear that rocking curves as small as 5.times.10.sup.-6 would make it seem hopeless to align a doubly curved diffractor properly, the natural width of the characteristic x-ray line would in fact allow such an alignment to be done. In any case, it is important that it be possible to preset the position and orientation of the crystal device to as high a degree as possible--otherwise obtaining proper alignment not only requires a costly alignment fixture, but could be like looking for the proverbial "needle in a haystack". The features of the present invention including the possibility of fabricating Johansson-based doubly curved crystal devices and prepositioning them relative to a source and image position are vitally important for future developments in x-ray microprobe technology.
	summary
054266807	claims	1. A tool for indicating that a control rod drive is coupled to an associated control rod in a nuclear reactor, comprising: first detecting means for detecting the state of a first position switch inside a position indicator probe of said control rod drive during removal of said control rod drive from a control rod drive housing; and first indicating means for providing an indication in response to a signal from said first detecting means produced when said first position switch has a closed state. second detecting means for detecting the state of a second position switch inside said position indicator probe during removal of said control rod drive; and second indicating means for providing an indication in response to a signal from said second detecting means produced when said second position switch has a closed state. switching means for providing an output signal in response to signals from said first and second detecting means produced when said first and second position switches both have open states during control rod drive removal; and third indicating means for providing an indication in response to said output signal from said switching means. 2. The tool as defined in claim 1, further comprising a battery voltage source coupled to said first detecting means. 3. The tool as defined in claim 1, wherein said first indicating means is a light-emitting diode. 4. The tool as defined in claim 1, wherein said first position switch corresponds to an overtravel position of an index tube of said control rod drive, said overtravel position being attainable only if said control rod drive is uncoupled from said associated control rod. 5. The tool as defined in claim 5, further comprising: 6. The tool as defined in claim 5, wherein said second position switch corresponds to a "rod full out" position of said index tube, said "rod full out" position being attainable during control rod drive removal only if said control rod drive is coupled to said associated control rod. 7. The tool as defined in claim 5, wherein said first, and second indicating means are light-emitting diodes of different color. 8. The tool as defined in claim 5, further comprising a transparent housing enclosing said first and second indicating means. 9. The tool as defined in claim 5, further comprising:
	claims	1. A thermal-neutron reactor core comprising:a moderator extending to a lengthwise direction and formed in multiple concentric layers;a fuel in the moderator, parallel to the lengthwise direction of the moderator, the fuel containing a fissile material, a burnable poison, and formed in multiple concentric layers;a plurality of cooling tubes parallel to the lengthwise direction of the moderator, whereinthe multiple concentric layers of the moderator and the multiple concentric layers of the fuel alternate with each other, andthe plurality of cooling tubes are evenly distributed with circumferential intervals therebetween in at least one of the multiple concentric layers of the fuel. 2. The thermal-neutron reactor core according to claim 1, wherein the moderator contains a metal hydride. 3. The thermal-neutron reactor core according to claim 1, wherein the burnable poison is a burnable poison containing a concentration of one particular isotope of the burnable poison. 4. The thermal-neutron reactor core according to claim 1, wherein the burnable poison is cadmium-113 or europium-151. 5. The thermal-neutron reactor core according to claim 1, further comprising; a neutron multiplication material between the fuel and the moderator. 6. A design method for the thermal-neutron reactor core of claim 1 including a solid moderator, the method comprising:deciding a specification of the thermal-neutron reactor core which includes a kind of a fuel, a size of the thermal-neutron reactor core, a composition of the moderator, and a cooling system;determining a neutron energy spectrum based on the specification;selecting a plurality of kinds of burnable poison;examining a temperature dependence of an effective neutron multiplication factor in the thermal-neutron reactor core based on a proportion of the plurality of kinds of burnable poison; anddeciding whether the proportion is acceptable for an operation of the thermal-neutron reactor core or is not acceptable based on the temperature dependence of the effective neutron multiplication factor, wherein the effective neutron multiplication factor should decrease as temperature rises for the operation. 7. The design method for the thermal-neutron reactor core according to claim 6, further comprising:deciding a ratio of the plurality of kinds of burnable poison to the fuel if the proportion is proper for the operation of the thermal-neutron reactor core. 8. The design method for the thermal-neutron reactor core according to claim 6, wherein the plurality of kinds of the burnable poison include cadmium-113 and europium-151.
	summary
	claims	1. A multi-leaf collimator drive system, the multi-leaf collimator comprising a plurality of leaves and a plurality of motors configured to drive the plurality of leaves, the system comprising:a control module configured to program a movement profile of each leaf of the plurality of leaves according to parameters, for each leaf of the plurality of leaves, the parameters including at least one of leaf location information of the leaf, a time associated with the leaf location information of the leaf, a leaf location offset of the leaf, a distance that the leaf travels to reach the leaf target location, or a distance travelled by the leaf, wherein the leaf location information of the leaf includes at least one of an initial location of the leaf, a current location of the leaf, or a target location of the leaf;a driving module configured to drive the plurality of motors of the collimator to move the plurality of leaves according to the programed movement profile; anda position feedback module configured to provide the current locations of the leaves as a feedback to the control module;wherein, for each leaf of said plurality of leaves, the control module programs the movement profile of the leaf according to a pattern having a first stage, a second stage, and a third stage, according to the movement profile, the leaf moving from the initial location to the target location, and wherein the stages of the movement profile are updated based on the leaf current location and the time available for the leaf to reach its target location. 2. A collimator system comprising the drive system of claim 1, further comprising:a plurality of elongated flexible transmission units, each of the plurality of leaves being operably connected to one of the plurality of motors through one of the plurality of transmission units, wherein each of the plurality of transmission units includes a transmission line and an elastic piece operably connected to the transmission line, and the transmission line provides one leaf of the plurality of leaves a first force, and the elastic piece provides the leaf a second force. 3. The collimator system of claim 2, whereinthe first force includes a pulling force to the leaf; andthe second force is an elastic force to the leaf. 4. The system of claim 1, wherein for each of the plurality of leaves, the speed of the leaf movement decreases at a constant rate in the third stage. 5. The system of claim 1, wherein for each of the plurality of leaves, the control module controls the speed of the leaf movement to dynamically decrease the speed of the leaf movement at a variable rate in the third stage. 6. The system of claim 5, wherein for each of the plurality of leaves, the variable rate is determined based on a distance that the leaf moves in the third stage. 7. The system of claim 1, wherein for each of the plurality of leaves, the third stage occupies 10% to 30% of a time period of the movement of the leaf from the initial location to the leaf target location. 8. The system of claim 1, wherein for each of the plurality of leaves, a leaf location offset is determined based on a current location of the leaf and the target location of the leaf. 9. The system of claim 1, wherein for each leaf of the plurality of leaves, the position feedback module comprises a displacement transducer sensing the displacement of the leaf or an encoder installed on a motor of the plurality of motors. 10. The system of claim 1, wherein for each leaf of the plurality of leaves, the position feedback module comprises a first position feedback module corresponding to the leaf, a second position feedback module corresponding to a motor of the plurality of motors, and the control module is configured to assess whether the movement of the leaf is normal by determining if the position feedback of the leaf by the first position feedback module and the position feedback of the leaf by the second position feedback module fulfills a predetermined relationship. 11. The system of claim 10, wherein the first position feedback module comprises a displacement transducer sensing the displacement of the leaf and the second position feedback module comprises an encoder or a potentiometer installed on the motor. 12. The collimator system of claim 2, further comprising a protection module, wherein for each of the plurality of motors, the protection module is configured to monitor a working condition of the motor. 13. The collimator system of claim 12, wherein the protection module includes at least one of an inductive resistor, an isolation amplifier, an operational amplifier, an A/D converter, or a central processing unit (CPU). 14. The system of claim 1, wherein in the first stage, a speed of the leaf movement increases, in the second stage, the speed of the leaf movement is constant, and in the third stage, the speed of the leaf movement decreases. 15. A method for driving the leaves of a multi-leaf collimator using a multi-leaf collimator driving system, the collimator comprising a plurality of leaves and a plurality of motors configured to drive the plurality of leaves and the collimator driving system comprising a control module, a driving module, and a position feedback module;the method comprising:for each of the plurality of leaves:using the control module to receive a predetermined target location of the leaf;using the control module to:program a movement profile of the leaf based on parameters including at least one of leaf location information of the leaf, a time associated with the leaf location information of the leaf, a leaf location offset of the leaf, a distance that the leaf travels to reach the leaf target location, or a distance travelled by the leaf, wherein the leaf location information of the leaf includes at least one of an initial location of the leaf, a current location of the leaf, or a target location of the leaf, the leaf movement profile comprising a first stage, a second stage, and a third stage, according to the movement profile, the leaf moving from the initial location to the target location;using the driving module to move the leaf according to the leaf movement profile; andusing the control module to detect the current location of the leaf;wherein the stages of the movement profile are updated based on the current locations of each leaf and the time available for the leaf to reach its target location. 16. The method of claim 15, further comprising, for each leaf of the plurality of leaves:increasing the speed of the leaf movement during the first stage, keeping the speed of the leaf movement constant during the second stage, and decreasing the speed of the leaf movement during the third stage. 17. The method of claim 15, the collimator further comprising:a plurality of transmission units, each of the plurality of leaves being operably connected to one of the plurality of motors through one of the plurality of transmission units, wherein each of the plurality of transmission units includes a transmission line and an elastic piece operably connected to the transmission line, and the transmission line provides one leaf of the plurality of leaves a first force, and the elastic piece provides the leaf a second force, andthe method further comprising using the driving module to move the leaf according to the leaf movement profile by controlling the transmission unit and the motor. 18. The method of claim 15, further comprising:determining a first leaf displacement of the leaf;determining a second leaf displacement of the leaf; andassessing whether the movement of the leaf is normal based on the first leaf displacement and the second leaf displacement. 19. The method of claim 18, wherein the assessing whether the movement of the leaf is normal based on the first leaf displacement and the second leaf displacement includes:if a difference between the first leaf displacement and the second leaf displacement is less than a threshold, determining that the movement of the leaf is normal; orif a difference between the first leaf displacement and the second leaf displacement is greater than or equal to a threshold, determining that the movement of the leaf is abnormal. 20. The method of claim 17, whereinthe first force includes a pulling force to the leaf; andthe second force is an elastic force to the leaf.
	abstract	A technical installation, especially a nuclear power plant, has a number of system components that are respectively supported by a number of beams, and a number of pressurized conduits. The technical installation is designed in such a way that secondary damage occurring in the surroundings of pressurized conduits are kept particularly low even if the pressurized conduits rupture. This is achieved in that at least one of the beams is embodied in a segmented manner in an area that is expected to be affected if a pressurized conduit ruptures, adjacent segments preferably being connected to each other via screw connections.
	claims	1. A system, comprising:means for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy;bypass circuitry means operationally connected to the means for thermoelectrically converting heat for protecting the means for thermoelectrically converting heat; andmeans for supplying the electrical energy to at least one operation system of the gas cooled nuclear reactor system. 2. The system of claim 1, wherein the means for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 3. The system of claim 2, wherein the at least one thermoelectric device for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least one thermoelectric junction for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 4. The system of claim 2, wherein the at least one thermoelectric device for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least one thermoelectric device optimized for a specified range of operating characteristics for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 5. The system of claim 2, wherein the at least one thermoelectric device for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least one thermoelectric device optimized for a first range of operating characteristics and at least one additional thermoelectric device optimized for a second range of operating characteristics, the second range of operating characteristics different from the first range of operating characteristics, for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 6. The system of claim 2, wherein the at least one thermoelectric device for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device sized to meet at least one selected operational requirement of the gas cooled nuclear reactor system for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 7. The system of claim 6, wherein the at least one thermoelectric device sized to meet at least one selected operational requirement of the gas cooled nuclear reactor system for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device sized to at least partially match the heat rejection of the at least one thermoelectric device with at least a portion of the heat produced by the gas cooled nuclear reactor for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 8. The system of claim 6, wherein the at least one thermoelectric device sized to meet at least one selected operational requirement of the gas cooled nuclear reactor system for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least one thermoelectric device sized to at least partially match the power requirements of at least one selected operation system for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 9. The system of claim 1, wherein the means for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least two series coupled thermoelectric devices for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 10. The system of claim 1, wherein the means for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least two parallel coupled thermoelectric devices for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 11. The system of claim 1, wherein the means for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric module for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 12. The system of claim 2, wherein the at least one thermoelectric device for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device having at least a first portion in thermal communication with a first portion of the gas cooled nuclear reactor system and at least a second portion in thermal communication with a second portion of the gas cooled nuclear reactor system, for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 13. The system of claim 12, wherein the at least one thermoelectric device having at least a first portion in thermal communication with a first portion of the gas cooled nuclear reactor system and at least a second portion in thermal communication with a second portion of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device having at least a first portion in thermal communication with at least one heat source of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 14. The system of claim 13, wherein the at least one thermoelectric device having at least a first portion in thermal communication with at least one heat source of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device having at least a first portion in thermal communication with at least a portion of a nuclear reactor core, at least a portion of at least one pressure vessel, at least a portion of at least one containment vessel, at least a portion of at least one coolant loop, at least a portion of at least one coolant pipe, at least a portion of at least one heat exchanger, or at least a portion of a coolant of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 15. The system of claim 12, wherein the at least one thermoelectric device having at least a first portion in thermal communication with a first portion of the gas cooled nuclear reactor system and at least a second portion in thermal communication with a second portion of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device having at least a second portion in thermal communication with a second portion of the gas cooled nuclear reactor system, the second portion of the gas cooled nuclear reactor system at a lower temperature than the first portion of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 16. The system of claim 15, wherein the at least one thermoelectric device having at least a second portion in thermal communication with a second portion of the gas cooled nuclear reactor system, the second portion of the gas cooled nuclear reactor system at a lower temperature than the first portion of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device having at least a second portion in thermal communication with at least a portion of at least one coolant loop, at least a portion of at least one coolant pipe, at least a portion of at least one heat exchanger, at least a portion of a coolant of the gas cooled nuclear reactor system, or at least a portion of at least one environmental reservoir, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 17. The system of claim 1, further comprising:means for substantially increasing a thermal conduction between a portion of the gas cooled nuclear reactor system and a portion of at least one thermoelectric device. 18. The system of claim 1, wherein the means for supplying the electrical energy to at least one operation system of the gas cooled nuclear reactor system comprises:means for supplying the electrical energy to at least one control system of the gas cooled nuclear reactor system. 19. The system of claim 1, wherein the means for supplying the electrical energy to at least one operation system of the gas cooled nuclear reactor system comprises:means for supplying the electrical energy to at least one monitoring system of the gas cooled nuclear reactor system. 20. The system of claim 1, wherein the means for supplying the electrical energy to at least one operation system of the gas cooled nuclear reactor system comprises:means for supplying the electrical energy to at least one coolant system of the gas cooled nuclear reactor system. 21. The system of claim 20, wherein the means for supplying the electrical energy to at least one coolant system of the gas cooled nuclear reactor system comprises:means for supplying the electrical energy to at least one coolant pump of the gas cooled nuclear reactor system. 22. The system of claim 21, wherein the means for supplying the electrical energy to at least one coolant pump of the gas cooled nuclear reactor system comprises:means for supplying the electrical energy to at least one coolant pump coupled to a primary coolant loop of the gas cooled nuclear reactor system. 23. The system of claim 21, wherein the means for supplying the electrical energy to at least one coolant pump of the gas cooled nuclear reactor system comprises:means for supplying the electrical energy to at least one coolant pump coupled to a secondary coolant loop of the gas cooled nuclear reactor system. 24. The system of claim 21, wherein the means for supplying the electrical energy to at least one coolant pump of the gas cooled nuclear reactor system comprises:means for supplying the electrical energy to at least one coolant pump of the gas cooled nuclear reactor system, the at least one coolant pump circulating at least one pressurized gas coolant. 25. The system of claim 1, wherein the means for supplying the electrical energy to at least one operation system of the gas cooled nuclear reactor system comprises:means for supplying the electrical energy to at least one shutdown system of the gas cooled nuclear reactor system. 26. The system of claim 1, wherein the means for supplying the electrical energy to at least one operation system of the gas cooled nuclear reactor system comprises:means for supplying the electrical energy to at least one warning system of the gas cooled nuclear reactor system. 27. The system of claim 1, further comprising:means for at least partially driving at least one operation system of the gas cooled nuclear reactor system. 28. The system of claim 1, wherein the circuitry means for protecting at least one thermoelectric device comprises:regulation circuitry for protecting at least one thermoelectric device. 29. The system of claim 1, further comprising:means for selectively augmenting the at least one thermoelectric device. 30. The system of claim 1, wherein the circuitry means for selectively augmenting at least one thermoelectric device comprises:at least one reserve thermoelectric device and reserve actuation circuitry configured to selectively couple the at least one reserve thermoelectric device to the at least one thermoelectric device. 31. The system of claim 1, further comprising:means for modifying at least one thermoelectric device output. 32. An apparatus, comprising:at least one thermoelectric device for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy;regulation circuitry for protecting at least one thermoelectric device; andat least one electrical output of the at least one thermoelectric device electrically coupled to at least one operation system of the gas cooled nuclear reactor system for supplying the electrical energy to the at least one operation system of the gas cooled nuclear reactor system. 33. The apparatus of claim 32, wherein the at least one thermoelectric device for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least one thermoelectric junction for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 34. The apparatus of claim 33, wherein the at least one thermoelectric junction for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least one semiconductor-semiconductor junction for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 35. The apparatus of claim 34, wherein the at least one semiconductor-semiconductor junction for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least one p-type/n-type junction for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 36. The apparatus of claim 33, wherein the at least one thermoelectric junction for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least one metal-metal junction for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 37. The apparatus of claim 32, wherein the at least one thermoelectric device for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least one nanofabricated thermoelectric device for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 38. The apparatus of claim 32, wherein the at least one thermoelectric device for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least one thermoelectric device optimized for a specified range of operating characteristics for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 39. The apparatus of claim 32, wherein the at least one thermoelectric device for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least one thermoelectric device optimized for a first range of operating characteristics and at least one additional thermoelectric device optimized for a second range of operating characteristics, the second range of operating characteristics different from the first range of operating characteristics, for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 40. The apparatus of claim 32, wherein the at least one thermoelectric device for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device sized to meet at least one selected operational requirement of the gas cooled nuclear reactor system for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 41. The apparatus of claim 40, wherein the at least one thermoelectric device sized to meet at least one selected operational requirement of the gas cooled nuclear reactor system for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device sized to at least partially match the heat rejection of the at least one thermoelectric device with at least a portion of the heat produced by the gas cooled nuclear reactor for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 42. The apparatus of claim 40, wherein the at least one thermoelectric device sized to meet at least one selected operational requirement of the gas cooled nuclear reactor system for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least one thermoelectric device sized to at least partially match the power requirements of at least one selected operation system for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 43. The apparatus of claim 32, wherein the at least one thermoelectric device for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least two series coupled thermoelectric devices for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 44. The apparatus of claim 32, wherein the at least one thermoelectric device for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy comprises:at least two parallel coupled thermoelectric devices for thermoelectrically converting gas cooled nuclear reactor generated heat to electrical energy. 45. The apparatus of claim 32, wherein the at least one thermoelectric device for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric module for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 46. The apparatus of claim 32, wherein the at least one thermoelectric device for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device, the thermoelectric device having at least a first portion in thermal communication with a first portion of the gas cooled nuclear reactor system and at least a second portion in thermal communication with a second portion of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 47. The apparatus of claim 46, wherein the at least one thermoelectric device, the thermoelectric device having at least a first portion in thermal communication with a first portion of the gas cooled nuclear reactor system and at least a second portion in thermal communication with a second portion of the gas cooled nuclear reactor system, for converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device, the thermoelectric device having at least a first portion in thermal communication with at least one heat source of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 48. The apparatus of claim 47, wherein the at least one thermoelectric device, the thermoelectric device having at least a first portion in thermal communication with at least one heat source of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device, the thermoelectric device having at least a first portion in thermal communication with at least a portion of a nuclear reactor core, at least a portion of at least one pressure vessel, at least a portion of at least one containment vessel, at least a portion of at least one coolant loop, at least a portion of at least one coolant pipe, at least a portion of at least one heat exchanger, or at least a portion of a coolant of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 49. The apparatus of claim 46, wherein the at least one thermoelectric device, the thermoelectric device having at least a first portion in thermal communication with a first portion of the gas cooled nuclear reactor system and at least a second portion in thermal communication with a second portion of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device, the thermoelectric device having at least a second portion in thermal communication with a second portion of the gas cooled nuclear reactor system, the second portion of the gas cooled nuclear reactor system at a lower temperature than the first portion of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 50. The apparatus of claim 49, wherein the at least one thermoelectric device, the thermoelectric device having at least a second portion in thermal communication with a second portion of the gas cooled nuclear reactor system, the second portion of the gas cooled nuclear reactor system at a lower temperature than the first portion of the gas cooled nuclear reactor system, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy comprises:at least one thermoelectric device, the thermoelectric device having at least a second portion in thermal communication with at least a portion of at least one coolant loop, at least a portion of at least one coolant pipe, at least a portion of at least one heat exchanger, at least a portion of a coolant of the gas cooled nuclear reactor system, or at least a portion of at least one environmental reservoir, for thermoelectrically converting heat generated with a gas cooled nuclear reactor system to electrical energy. 51. The apparatus of claim 32, further comprising:at least one substance or at least one device for substantially increasing a thermal conduction between a portion of at least one gas cooled nuclear reactor system and a portion of at least one thermoelectric device. 52. The apparatus of claim 32, wherein the at least one operation system of the gas cooled nuclear reactor system comprises:at least one control system of the gas cooled nuclear reactor system. 53. The apparatus of claim 52, wherein the at least one control system of the gas cooled nuclear reactor system comprises:at least one rod control system of the gas cooled nuclear reactor system. 54. The apparatus of claim 52, wherein the at least one control system of the gas cooled nuclear reactor system comprises:at least one valve control system of the gas cooled nuclear reactor system. 55. The apparatus of claim 32, wherein the at least one operation system of the gas cooled nuclear reactor system comprises:at least one monitoring system of the gas cooled nuclear reactor system. 56. The apparatus of claim 32, wherein the at least one operation system of the gas cooled nuclear reactor system comprises:at least one coolant system of the gas cooled nuclear reactor system. 57. The apparatus of claim 56, wherein the at least one coolant system of the gas cooled nuclear reactor system comprises:at least one coolant pump of the gas cooled nuclear reactor system. 58. The apparatus of claim 56, wherein the at least one coolant system of the gas cooled nuclear reactor system comprises:at least one coolant pump coupled to a primary coolant loop of the gas cooled nuclear reactor system. 59. The apparatus of claim 56, wherein the at least one coolant system or the gas cooled nuclear reactor system comprises:at least one coolant pump coupled to a secondary coolant loop of the gas cooled nuclear reactor system. 60. The apparatus of claim 56, wherein the at least one coolant system of the gas cooled nuclear reactor system comprises:at least one coolant pump circulating at least one pressurized gas coolant of the gas cooled nuclear reactor system. 61. The apparatus of claim 32, wherein the at least one operation system of the gas cooled nuclear reactor system comprises:at least one shutdown system of the gas cooled nuclear reactor system. 62. The apparatus of claim 32, wherein the at least one operation system of the gas cooled nuclear reactor system comprises:at least one warning system of the gas cooled nuclear reactor system. 63. The apparatus of claim 32, wherein the regulation circuitry for protecting at least one thermoelectric device comprises:bypass circuitry for protecting at least one thermoelectric device. 64. The apparatus of claim 32, further comprising:at least one reserve thermoelectric device and reserve actuation circuitry configured to selectively couple the at least one reserve thermoelectric device to the at least one thermoelectric device for selectively augmenting at least one thermoelectric device. 65. The apparatus of claim 64, wherein the at least one reserve thermoelectric device and reserve actuation circuitry configured to selectively couple the at least one reserve thermoelectric device to the at least one thermoelectric device for selectively augmenting at least one thermoelectric device comprises:at least one relay system, at least one electromagnetic relay system, at least one solid state relay system, at least one transistor, at least one microprocessor controlled relay system, at least one microprocessor controlled relay system programmed to respond to at least one external parameter, or at least one microprocessor controlled relay system programmed to respond to at least one internal parameter of the at least one thermoelectric device. 66. The apparatus of claim 32, further comprising:power management circuitry for modifying at least one thermoelectric device output. 67. The apparatus of claim 66, wherein the power management circuitry for modifying at least one thermoelectric device output comprises:voltage regulation circuitry for modifying at least one thermoelectric device.
	claims	1. An apparatus comprising:a generally cylindrical pressure vessel defining a cylinder axis, the generally cylindrical pressure vessel comprising a sealing top portion, an upper vessel portion, and a lower vessel portion;a nuclear reactor core disposed in the lower vessel portion of the generally cylindrical pressure vessel;a steam annulus,a feedwater annulus,a central riser disposed coaxially inside the upper vessel portion of the generally cylindrical pressure vessel, the central riser being hollow and having an end proximate to the nuclear reactor core to receive primary coolant heated by the nuclear reactor core and an open end distal from the nuclear reactor core discharging the primary coolant;a once-through steam generator (OTSG) comprising a plurality of tubes arranged parallel with the central riser and disposed in an annular volume defined between the central riser and the upper vessel portion of the generally cylindrical pressure vessel, the primary coolant discharged from the open end of the central riser flowing through the OTSG and heating secondary coolant also flowing through the OTSG, the primary coolant and the secondary coolant being disposed in separate flow paths in the OTSG;neutron-absorbing control rods; andan internal control rod drive mechanism (CRDM) configured to controllably insert and withdraw the control rods into and out of the nuclear reactor core, the internal CRDM having all mechanical and electromagnetomotive components including at least a motor and a lead screw disposed inside the lower vessel portion of the pressure vessel. 2. The apparatus as set forth in claim 1, wherein the internal CRDM is non-integral with the generally cylindrical pressure vessel and disposed between the OTSG and the nuclear reactor core. 3. The apparatus as set forth in claim 1, wherein the generally cylindrical pressure vessel is vertical with its cylinder axis oriented vertically, and the internal CRDM is disposed below the OTSG in the vertical pressure vessel. 4. The apparatus as set forth in claim 3, further comprising:internal primary coolant pumps arranged to circulate primary coolant within the pressure vessel, the internal primary coolant pumps having all mechanical and electromagnetomotive components including at least a motor and at least one impeller disposed inside the lower vessel portion of the pressure vessel, the internal primary coolant pumps arranged below the OTSG to receive primary coolant discharged from the OTSG. 5. The apparatus as set forth in claim 4, wherein the internal primary coolant pumps are disposed peripherally around the internal CRDM. 6. The apparatus as set forth in claim 5, wherein a vertical height of the internal primary coolant pumps in the lower vessel portion of the vertical pressure vessel overlaps a vertical height range of the internal CRDM. 7. The apparatus as set forth in claim 3, wherein the internal CRDM comprises a plurality of CRDM units that are staggered at two or more different vertical heights such that no two neighboring CRDM units are at the same vertical height. 8. The apparatus as set forth in claim 1, wherein the internal CRDM comprises a plurality of CRDM units that are staggered at two or more different distances from the nuclear reactor core such that no two neighboring CRDM units are at the same distance from the nuclear reactor core. 9. The apparatus as set forth in claim 1, wherein a portion of the open end of the central riser extends vertically beyond the top elevation of the OTSG and further comprises a plurality of perforations. 10. The apparatus as set forth in claim 4, wherein the internal primary coolant pumps are arranged above the nuclear reactor core and wholly immersed in primary coolant. 11. The apparatus as set forth in claim 1, wherein a portion of the feedwater annulus has a larger diameter than the steam annulus. 12. The apparatus as set forth in claim 1, wherein the steam annulus is located above the feedwater annulus.
051805472	abstract	A natural circulation boiling water reactor system comprises a reactor vessel enclosing a reactor core, for generating steam to drive a turbine which can drive a generator to generate electricity. The vessel includes a chimney for guiding the recirculating water and steam vertically above the core and a dryer for helping to remove water from steam exiting the vessel toward the turbine. In contrast to prior reactor systems, the chimney is height-staggered so that its central sections are taller than its peripheral sections. Likewise, a dryer is elevation-staggered. This staggering minimizes carryover, water in the steam flow to the turbine, and carryunder, steam in the water recirculating through the core. In addition, the staggered chimney causes the fastest recirculation flow through the hottest portions of the core. The overall effect is a more efficient reactor system.
	abstract	A collimator incorporating shielding shaped according to the formula
	abstract	The present invention relates to a beam optical component including a charged particle lens for focusing a charged particle beam, the charged particle lens comprising a first element having a first opening for focusing the charged particle beam; a second element having a second opening for focusing the charged particle beam and first driving means connected with at least one of the first element and the second element for aligning the first opening with respect to the second opening. With the first driving means, the first opening and the second opening can be aligned with respect to each other during beam operation to provide a superior alignment of the beam optical component for a better beam focusing. The present invention also relates to a charged particle beam device that uses said beam optical component for focusing the charged particle beam, and a method to align first opening and second opening with respect to each other.
044951370	claims	1. A fast breeder reactor comprising: a reactor vessel; a guard vessel enclosing said reactor vessel, spaced a predetermined distance from said reactor vessel; and a liquid manometer structure, the space defined between said reactor vessel and said guard vessel communicating with the exterior of said guard vessel only through said liquid manometer structure, said manometer structure being filled with a liquid so as to liquid-seal said space between said reactor vessel and said guard vessel with respect to the exterior of said guard vessel said space between said reaction vessel and said guard vessel being charged with an inert gas so as to maintain said space at a pressure substantially greater than atmospheric pressure. an annular flange extending horizontally from the outer periphery of said guard vessel at the upper end thereof, said annular flange having a radially outer portion having spaced apart vertical sidewalls and a substantially U-shaped cross section; and an annular member extending horizontally from the outer periphery of said reactor vessel at a position above said flange and having an inverted L-shaped cross section; said annular flange and said annular member being combined with each other in such a manner that the lower end of said annular member is inserted between said sidewalls, said space communicating with the exterior of said guard vessel between said annular flange and said annular member. an annular flange extending horizontally from the outer periphery of said guard vessel at the upper end thereof, said annular flange having a radially outer portion having spaced apart vertical sidewalls and a substantially U-shaped cross section; and an annular member extending horizontally from the outer periphery of said reactor vessel at a position above said flange and having a sideways turned T-shaped cross section; said annular flange and said annular member being combined with each other in such a manner that the lower end of said annular member is inserted between said sidewalls, said space communicating with the exterior of said guard vessel between said annular flange and said annular member. an annular flange fitted to the inner peripheral surface of said guard vessel at the upper end thereof, and having an inverted L-shaped cross section; and an annular member fitted to the outer peripheral surface of said reactor vessel at the upper end thereof, and having an inverted L-shaped cross section; said annular flange and said annular member being combined with each other in such a manner that said space communicates with the exterior of said guard vessel between the lower end of said annular member and said annular flange. an annular flange fitted in the innner peripheral surface of said guard vesel at the upper end thereof, and having an inverted L-shaped cross section; and an annular member fitted to the outer peripheral surface of said reactor vessel at the upper end thereof, and having a sideways turned T-shaped cross section; said annular flange and said annular member being combined with each other in such a manner that said space communicates with the exterior of said guard vessel between the lower end of said annular member and said annular flange. 2. A fast breeder reactor according to claim 1, wherein said liquid manometer structure comprises a substantially U-shaped tube welded to a part of the outer circumferential surface of said guard vessel, said tube having an inner diameter sufficiently large enough to permit the passage of welders and welding tools therethrough. 3. The fast breeder reactor according to claim 1, wherein said liquid filling said liquid manometer structure is mercury. 4. The fast breeder reactor according to claim 1, wherein the pressure of said inert gas charged into said sealed space is about 1.5 to about 3 atms absoluted pressure. 5. A fast breeder reactor according to claim 1, wherein said liquid manometer structure comprises: 6. The fast breeder reactor according to claim 1, wherein said liquid manometer structure comprises: 7. The fast breeder according to claim 1, wherein said liquid manometer structure comprises: 8. The fast breeder reactor according to claim 1, wherein said liquid manometer structure comprises: 9. The fast breeder reactor according to claim 1, wherein said inert gas charged in said sealed space between said reactor vessel and said guard vessel comprises a tag gas, said reactor further including means for monitoring leakage of said tag gas from said sealed space. 10. The fast breeder reactor according to claim 9, wherein said means for monitoring leakage of said tag gas comprises means for detecting a pressure change inside said sealed space. 11. The fast breeder reactor according to claim 9, further comprising a cover gas space inside said reactor vessel, wherein said means for monitoring leakage of said tag gas comprises tag gas detection means, disposed in said cover gas space, for detecting leakage of said tag gas into said cover gas space. 12. The fast breeder reactor according to claim 9, wherein said means for monitoring leakage of said tag gas comprises tag gas detection means, disposed outside said guard vessel, for detecting leakage of said tag gas to ouside said guard vessel. 13. The fast breeder reactor according to claim 9, wherein said tag gas is helium. 14. The fast breeder reactor according to claim 9, wherein said tag gas is a gas containing therein a stable isotope of a rare gas. 15. The fast breeder reactor according to claim 11 or 12, wherein said tag gas detection means comprises a mass spectrometer and a gas sampling device cooperating therewith.
	summary
	claims	1. A method of determining a loss or gain of fluid from a first and second concentric container module, the method comprising:mounting a first gravity meter proximate to one of a vertical side and a top of the second concentric container module, the second concentric container module being external to the first concentric container module, the first concentric container module normally containing a mass of fluid, the first gravity meter being mounted above the mass of fluid normally contained in the first concentric container module, the first gravity meter for measuring a first time series of gravity signals, the first time series of gravity signals measuring a change in null of the mass of fluid normally contained in the first concentric container module,mounting a second gravity meter proximate to one of the vertical side and at the bottom of the second concentric container module, the second gravity meter mounted below the mass of fluid normally contained by the first concentric container module, the second gravity meter for measuring a second time series of gravity signals comprising a different change in pull of the mass of fluid normally contained in the first concentric container module responsive to a vertical distance between the first and second gravity meters,determining by a computer processor a change in gravimetric pull of the mass of fluid normally contained by the first concentric container module, the change in gravitational pull of the mass of fluid comprising:subtracting the second timer series of gravity signals from the first time series of gravity signals; result of the subtraction representing excludable changes in pull of the mass of fluid normally contained in the first concentric module measured over time due to expected changes in at least one of tides, atmosphere, a value of drift of one of the first gravity meter and the second gravity meter and groundwater levels, the subtraction eliminating noise effects of recurring events comprising at least one of the changes in tides, changes in atmosphere, changes in drift of one of the first gravity meter and the second gravity meter and changes in groundwater levels,calculating, responsive to the subtraction, a first center of mass of the fluid in a combination of the first and second concentric container modules at a first point in time via the gravity signals output by the first and second gravity meters and calculating a second center of mass of the fluid in the first and second concentric container modules at a second point in time later in time than the first point in time,responsive to a difference between calculations of the first center of mass and the later in time second center of mass, evaluating, responsive to the subtractions, the gravity signals over time measured by the first and second gravity meters to determine an occurrence of one of a leak from the first concentric container module to the second concentric container module and a leak to outside the second concentric container module via a value or center of mass over time falling below one or another of first and second predetermined values. 2. The method of determining a loss or gain of fluid from first and the second concentric container modules of claim 1 further comprising:low-pass filtering the first and second time series of gravity signals of the first and second gravity meters to remove high-frequency noise to aid in improving accuracy. 3. The method of determining a loss or gain of fluid from the first and the second concentric container modules as recited in claim 1 further comprising:mounting a third gravity meter proximate to one of the first concentric container module and the second concentric container module and horizontal to and at a predetermined distance from the first and second gravity meters, one of the first, second and third gravity meters for measuring a third time series of gravity signals, and eliminating noise effects of recurring events responsive to changes in groundwater levels by differentiating the first, second and third time series of gravity signals. 4. The method of determining a loss or gain of fluid from the first and the second concentric container modules as recited in claim 1, further comprising:defining m2 as a point mass of a source mass of fluid and integrating the equation E → 12 = Gm 2  r → 12  2 ⁢ r ^ 12 over a source fluid mass's entire geometry, calculating a gravity signal via at least one gravity meter due to a change in fluid levels using the equationdV=RdRdθdZ, andthe finite element mass (m2) being fluid density, ρ times the change in volume, dV: m2=ρdV. 5. The method of determining a loss or gain of fluid from the first and the second concentric container modules as recited in claim 1 further comprising:mounting a third gravity meter one of vertically and horizontally distant from the first and second gravity meters for removal of common-mode noise. 6. The method of determining a loss or gain of fluid from the first and the second concentric container modules as recited in claim 1 further comprising:differentiating among an internal loss of fluid from the first concentric container module, an external loss of fluid from the second concentric container module, and a normal or abnormal gain or loss of fluid occurring during normal regulation of fluid level of the first concentric contain module. 7. The method of determining a loss or gain of fluid from the first and the second concentric container modules of claim 1 further comprising:measuring one of fluid temperature of fluid normally contained in the first concentric container module, pressure, and in-flow rates and out-flow rates of fluid flow to or from thirst concentric container module via at least one sensor of at least one of the first and second gravity meters at a given point in time. 8. The method of determining a loss or gain of fluid from one of fluid from the first and the second concentric container modules as recited in claim 7 further comprising:calculating first and second gravity signal values by the first and second gravity meters at the given point in time responsive to measuring one of fluid temperature of fluid normally contained in the first concentric container module, pressure, and in-flow rates and out-flow rates of fluid flow to or from the first concentric container module. 9. The method of determining a loss or gain of fluid from the first and the second concentric container module as recited in claim 1 wherein the first concentric container module comprises a nuclear reactor container module containing fluid. 10. The method of determining a loss or gain of fluid from at first and the second concentric container modules as recited in claim 9 wherein the nuclear reactor container module comprises a nuclear reactor core at its bottom. 11. The method of determining a loss or gain of fluid from the first and the second concentric container modules as recited in claim 9 further comprising:detecting a variation from a predetermined expected range of fluid level of a pressurizer of a nuclear reactor comprising the nuclear reactor container module containing fluid. 12. The method of determining a loss or gain of fluid from the first and the second concentric container modules as recited in claim 9 further comprisingdetecting a difference between a rate of inflow of water to the nuclear reactor container module, the nuclear reactor container module comprising a containment pressure vessel of the nuclear reactor container module, anddetecting a rate of outflow of water to the containment pressure vessel, the flow of water regulated by a chemical volume and control system of the nuclear reactor container module within a level regulation band comprising an upper level and a lower level limit. 13. The method of determining a loss or gain of fluid from the first and the second concentric container modules as recited in claim 9 further comprising:comparing the location of the center of mass of the fluid in the nuclear reactor container module with an estimated location of a center of mass of the fluid in the nuclear reactor module as determined by the computer processor from gravity signal data received from sensors of the first and second gravity meters.
	description	The present application claims priority form Japanese application JP 2004-015049 filed on Jan. 23, 2004, the content of which is hereby incorporated by reference into this application. The present invention generally relates to a charged particle beam apparatus. More specifically, the present invention is directed to a charged particle beam apparatus capable of measuring actual image magnification of a material image and an image magnification shift of the apparatus in high precision, and also, capable of automatically calibrating image magnification of the apparatus. In charged particle beam apparatus which are typically known as scanning electron microscopes (SEMs), charged particle beams which have been focused in narrow beams are scanned over materials so as to acquire desirable information (for instance, material images) from the materials. Since such charged particle beam apparatus are employed in order to measure pattern widths and film thicknesses of semiconductor devices, it is very important to maintain image magnification of these apparatus in high precision. In order to measure an image magnification error, as indicated in FIG. 2A, while employing a reference material for image magnification which has a periodic structure whose pitch dimension (period) is already known as a nominal value, an enlarged image of this reference material is acquired. Then, a pitch dimension of a material is measured based upon the acquired enlarged image. Thereafter, a shift between this measurement value and the nominal pitch value is used as an image magnification error. In order to calibrate image magnification of an apparatus, an image magnification control parameter of this apparatus is adjusted in such a manner that this image magnification error becomes minimum. In a scanning beam microscope, this image magnification control parameter corresponds to a coefficient for determining a relationship between image magnification and a beam scanning width on a material. In general, a nominal pitch value of a reference material for image magnification represents an averaged pitch value of a repetition pattern of this reference material for image magnification. As a result, in order to perform an image magnification calibration in high precision, pitches are measured at at least 10 different positions on the reference material, and then, a pitch measurement value of an image must be determined from an average value of these measured pitch values. FIG. 3A and FIG. 3B indicate an example as to conventional pitch measuring methods. As indicated in FIG. 3A, in order to measure a pitch (Lm) of a reference material from a material image, a cursor is manually set to a position corresponding to the pitch on the material image which has been acquired as a digital image, and then, a total number of pixels (N) between the cursors is counted. Based upon this counted value (Nm) and a pixel size (Lp) of the material image, the pitch (Lm) is calculated by the following equation (1)Lm=NmLp (1) As other pitch measuring methods, as indicated in FIG. 3B, the following measuring method has been practically used. That is, while a pitch measuring area of a material image is designated, a pattern edge portion is detected from a line profile between these pitch measuring areas, and then, a pitch dimension is automatically measured. This line profile corresponds to a distribution of pixel values (brightness) along either a horizontal line or a vertical line. On the other hand, a relationship between the pixel size (Lp) and image magnification (M) is defined as follows:Lp=Kp/(NpM) (2) In this equation (2), symbol “Kp” indicates a display size of an image in order to correctly display image magnification, and symbol “Np” indicates a total number of pixels. For example, assuming now that a total pixel number of an acquired image is equal to 640×480 pixels and a display size of the image is equal to 128 mm×96 mm, the pixel size “Lp” in the image magnification of 10,000 power becomes 128 mm/(640×10,000)=20 nm. As a consequence, when the image magnification “M” contains an error, this error appears as an error of the pixel size “Lp” of the equation (2), so that an error may be produced in the pitch dimension (Lp) calculated in the equation (1). Based upon the pitch measurement value (Lm) and the nominal pitch value (Ls) of the reference material which have been measured by the above-described measuring method, a shift “ΔM” of image magnification of the apparatus may be calculated by the following equation (3):ΔM=(Lm/Ls)−1 (3)In a scanning beam microscope (SEM), the below-mentioned relationship (4) between image magnification (M) and a beam scanning width (Lb) on a material is established as follows:M=Km/Lb (4).An image magnification coefficient “Km” is employed so as to control image magnification (namely, to control beam scanning width) within a control program of an SEM apparatus. In such a case that the image magnification shift “ΔM” of the above-described equation (3) is present with respect to such an image magnification coefficient “Km” before being calibrated, if the below-mentioned equation (5) is established, then the image magnification of the SEM apparatus may be calibrated:M=Km(Lm/Ls)/Lb (5)In other words, such a process operation for converting the value of the image magnification coefficient used to control the SEM apparatus to “Km(Lm/Ls)” corresponds to an image magnification calibration. In a general-purpose scanning electron microscope (SEM) in which operating ranges as to accelerating voltages and WD are wide, it is technically difficult to control the image magnification in high precision over the entire operating area. As a consequence, the image magnification precision of this general-purpose SEM apparatus is set to ±10%. As a result, in order to perform observations and dimension measuring operations in higher precision while using such a general-purpose SEM apparatus, image magnification calibrations must be carried out with respect to each of apparatus use conditions such as accelerating voltages and WD. Also, for example, JP-A-2000-323081 discloses such a technical idea of a transmission type electron microscope (TEM). That is, two sheets of different images are compared with each other so as to measure an image magnification error of the TEM apparatus. Since higher precision (approximately ±1%) is necessarily required for measuring dimensions in semiconductor devices, in such a case that such a high precision dimension measuring operation is carried out in a general-purpose SEM, an image magnification calibration must be carried out with respect to each of use conditions such as accelerating voltages and WD. However, in the above-described conventional techniques, the pitches must be measured at the plural positions on the reference material so as to calibrate the image magnification. Furthermore, since these measuring works are manually performed, and occurrences of human errors and measuring mistakes cannot be avoided, the following problem may occur. That is, image magnification shifts cannot be simply measured in higher precision in user levels, and further, high-precision image magnification calibrations cannot be simply carried out by users. Also, in accordance with the conventional technical idea described in JP-A-2000-323081, images which constitute a reference image must be previously acquired by employing the same material, and also, under the same optical conditions. There is another problem that cumbersome operations are necessarily required, and further, high-precision measuring operations can be hardly carried out due to adverse influences caused by aging effects as to apparatus conditions. The present invention has been made to solve the above-described problems of the conventional techniques, and therefore has an object to provide both a method and an apparatus, which are capable of measuring an image magnification shift from an acquired image of a reference material for image magnification in higher precision, and also, capable of realizing a correction of the image magnification shift in higher precision. To achieve the above-described object, in accordance with the present invention, both a method and an apparatus are provided, by which a pitch of a periodic structure on a material is measured based upon periodic information as to a predetermined position of an image which is acquired by scanning a charged particle beam on the material, and, an image magnification error of the charged particle beam is measured based upon the measured pitch. It should be noted that concrete contents of the present invention, or other structures of the present invention and effects thereof will be explained in the below-mentioned embodiment modes of the present invention. In accordance with the present invention, the image magnification shift is detected from the acquired SEM image of the reference material for image magnification, and thus, the high-precision image magnification calibration can be automatically carried out. Also, the optimum image condition for the image magnification measuring operation can be automatically set in response to the nominal pitch value of the reference material, so that the image can be acquired. Since the auto-correlation function and the FFT method are employed in the image magnification measuring operation, the measured pitch information may become the averaged pitch value in the entire image, and thus, the result having the high reliability can be obtained which is mostly suitable for the nominal pitch value of the reference material. Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings. Now, in embodiments of the present invention, a description is made of technical ideas for measuring image magnification errors in such a manner that auto-correlation functions are acquired from digital images of reference materials for image magnification, which own periodic structures, so as to measure peaks of correlation values, and also, technical ideas for detecting spatial frequencies corresponding to periods by FFT-transforming images. Also, a description is made of such a technical idea that when a period (pitch) on an image is larger than a predetermined value, periodic information is detected by an auto-correlation method, whereas when a period (pitch) on an image is smaller than the predetermined value, periodic information is detected by an FFT transformation method. A further description is made of such a technical idea that when a periodic number (namely, total number of patterns) on an image is smaller than a preselected number, a plurality of material images within different visual fields of the material are acquired; an averaged value is calculated from respective periodic information detected from the plurality of acquired material images; and then, this calculated averaged value is employed as a representative value of the period. In addition, a description is made of both a technical idea capable of calculating an image magnification shift of an apparatus to display the image magnification shift, and a technical idea capable of calibrating the image magnification shift. That is, a nominal periodic value (known periodic value) of a reference material is entered to an apparatus; information as to image magnification and a pixel size of the apparatus is extracted from a control unit of the apparatus; and the image magnification shift of the apparatus is calculated based upon the information as to either the extracted image magnification or the extracted pixel size, the detected periodic information, and the nominal periodic value of the material; and then, the calculated image magnification shift is displayed and calibrated. Also, a description is made of such a technical idea that in order to detect as to whether or not an image is proper which has been acquired so as to measure, or calibrate image magnification, a direction (rotation) of a pattern is detected from the acquired image; and in such a case that the detected direction of the pattern cannot satisfy a predetermined condition, warning is issued. Further, a description is made of such a technical idea capable of controlling an apparatus in order that the direction of the rotated pattern is corrected so as to reacquire an image, namely, a control of a beam scanning direction, or a control of a rotation direction of a stage is carried out. In addition, a description is made of such a technical idea that both a total number of pixels and image magnification, which are proper for measuring, or calibrating image magnification, from both an image magnification range which constitutes a nominal pitch value and a measurement object of a reference material, and from a pixel number selecting range of an acquired image. Referring now to drawings, an embodiment mode of the present invention will be described. FIG. 1 is a diagram for schematically showing a structure of a scanning electron microscope according to one example of the present invention. In the scanning electron microscope, a voltage is applied between a cathode 1 and a first anode 2 by a high voltage controlling power supply 20 which is controlled by a computer 40, and primary electron beams 4 are derived from the cathode 1 by a predetermined emission current. An accelerating voltage is applied between the cathode 1 and a second anode 3 by the high voltage controlling power supply 20 under control of the computer 40, and the primary electron beams 4 emitted from the cathode 1 are accelerated, and the accelerated primary electron beams 4 are traveled to a lens system provided at a post stage. The primary electron beams 4 are focused by a first condenser lens 5 which is controlled by a first condenser lens controlling power supply 21, an unnecessary area of the primary electron beams 4 is removed by an aperture plate 8, and thereafter, the resulting primary electron beams 4 are focused as a very fine spot onto a material 10 by both a second condenser lens 6 controlled by a second condenser lens controlling power supply 22, and an objective lens 7 controlled by an objective lens controlling power supply 23. As the objective lens 7, various lens modes may be employed, for instance, an in-lens type, as out-lens type, a snorkel type and the like. Also, a retarding type objective lens may be employed, while a negative voltage is applied to a material so as to decelerate primary electron beams. Furthermore, the respective lenses may be arranged as an electrostatic type lens constituted by a plurality of electrodes. The primary electron beams 4 are scanned on the material 10 in a two-dimensional manner by a scanning coil 9 controlled by an image magnification controlling power supply 24. A secondary signal 12 such as secondary electrons which are produced by irradiating the primary electron beams on the material 10 is propagated to an upper portion of the objective lens 7, and thereafter, is separated from the primary electrons by a crossed electrostatic and magnetic field producing E cross B device 11 for separating a secondary signal, and then, the separated secondary signal is detected by a secondary signal detector 13. After the signal detected by the secondary signal detector 13 is amplified by a signal amplifier 14, the amplified signal is transferred to an image memory 25 so as to be displayed as a material image on an image display apparatus 26. While two stages of deflection coils (image shift coils) 51 controlled by a beam position controlling power supply 31 are arranged at the same position as the scanning coil 9, a scanning area (observation visual field) of the primary electron beams 4 can be moved in a two-dimensional manner. A stage 15 can move the material 10 along at least two directions (namely, X direction and Y direction) within a plane perpendicular to the primary electron beams. An input apparatus 42 may designate image acquiring conditions (scanning speed, accelerating voltage, magnification, pixel number etc.), and also, can designate outputs and storages of images. Then, the acquired image data, the designated observation condition, and the like are stored in a storage apparatus 41. Referring now to FIG. 4 and FIG. 5, a detailed description is made of such an embodiment 1 that an image magnification shift is measured by utilizing an auto-correlation function by operating the scanning electron microscope shown in FIG. 1. FIG. 4 is a flow chart for indicating process operations in which an image magnification error is measured by using the auto-correlation function. Step 1: Both a condition (accelerating voltage, WD, image magnification etc.) used to measures the image magnification error, and a total number of pixels (image resolution) used to acquire an image are set. Step 2: Information (nominal pitch value and direction for measuring image magnification error) as to a reference material for image magnification is set which is used so as to measure an image magnification error. For instance, in the case of a mesh reference material shown in FIG. 2A, since periodic structures are present along both an X direction and a Y direction, image magnification errors can be measured along both the X direction and the Y direction. However, in the case of such a reference material as a micro scale indicated in FIG. 2B, a measurement as to an image magnification error along such a direction perpendicular to a pattern direction is restricted. In such a case that either one piece or plural pieces of reference materials have been previously determined, material information may be alternatively set by displaying a list of the plural reference materials on an input screen so as to select a desirable reference material from this list. Step 3: An SEM (Scanning Electron Microscope) image of the reference material for image magnification is acquired. Step 4: An auto-correlation function of the acquired SEM image is calculated so as to detect a position (number of pixels) where a correlation value becomes a peak. FIG. 5 graphically represents an example of an auto-correlation function along the X direction with respect to the mesh reference material image shown in FIG. 2A. In this example, when the mesh image of FIG. 2A is shifted by 52 pixels along the X direction, a peak of a correlation value is detected. If a plurality of correlation values located before/after the peak of the correlation value are processed by way of a non-linear interpolation such as a secondary function, then the peak position can be detected in such a high precision smaller than, or equal to 1 pixel. It should be understood that although the auto-correlation function may be carried out over the entire image which has been acquired, the auto-correlation function may be performed by employing a portion (for instance, image center portion) of the image. Also, in the case that image magnification is low, and/or a scanning speed of beams is fast, there are some possibilities that image magnification of an image peripheral portion is slightly different from image magnification of an image center portion due to distortions of beam scanning operations. In such a case, it is proper to measure an image magnification error by employing data as to the image center portion. In the above-described case, the following measuring sequence may be alternatively established. That is, when image magnification is low, an image range for measuring an image magnification error is selected while the image peripheral portion is excluded, whereas when image magnification is high, either the entire image range or such a range larger than the image range for the low image magnification is selected to be an image range (predetermined area) used to measure an image magnification error. As a result, the image magnification errors can be measured in high precision irrespective of the image magnification. Step 5: In this embodiment 1, a total number of pixels when an image is acquired is equal to 640×480 pixels, and a pixel size in image magnification of 400 power (example of mesh image shown in FIG. 2A) becomes 0.5 μm based upon a relationship between the pixel size and control image magnification of the apparatus. As a result, pitch information which is measured by the auto-correlation function may be calculated as follows:52pixels×0.5 μm=26.0 μm. Step 6: An image magnification error is calculated based upon both the measured pitch value and the nominal pitch value of the step 5. In this embodiment 1 (mesh material of FIG. 2A), since the nominal pitch value is 25.4 μm, the image magnification error may be calculated as follows:(26.0−25.4)/25.4=0.024(2.4%) Step 7: The image magnification error calculated in the step 5 is displayed on the display apparatus. In such a case that the image magnification error is larger than a predetermined allowable value, such a warning message “image magnification error exceeds allowable value” may be alternatively displayed on this display apparatus. In accordance with the method of this embodiment 1 for acquiring the correlative relationship among the images within a predetermined area, while the pitch measuring operations at the plural positions are no longer required which have been executed in the conventional method, the image magnification error can be measured in the high precision without human errors as well as measuring mistakes, and furthermore, the image magnification error can be calibrated based upon the high-precision image magnification error measurement result. It should also be understood that the above-described effect achieved by this embodiment 1 does not exclude such a technical idea that a plurality of image magnification errors are measured by acquiring an auto-correlation function with respect to each of plural areas on an image from the technical scope of the present invention. For instance, in the case that a plurality of reference materials are present on a single screen, a predetermined area is set to each of these reference materials, an auto-correlation function as to each of these areas is calculated, so that a plurality of image magnification errors may be alternatively calculated. Referring now to FIG. 6 and FIG. 8, a detailed description is made of such an embodiment that an image magnification error is measured by utilizing an FFT transformation by operating the scanning electron microscope shown in FIG. 1. FIG. 6 is a flow chart for indicating process operations in which an image magnification error is measured by using the FFT transformation (Fast Fourier Transformation). Step 11 to Step 13: An SEM image as to a reference material for image magnification is acquired as a digital image in a similar sequential operation to that of the above-described embodiment 1. Step 14: The FFT transformation of the acquired SEM image is calculated, FIG. 7 shows an SEM image (total pixel number: 640×480 pixels) as to the reference material for image magnification employed in this embodiment 2. The embodiment 2 indicates such an example that while the micro scale material shown in FIG. 2B is employed, an image magnification error in relatively low image magnification (5000 power) is measured. While the FFT transformation can be carried out over the entire image, such an FFT transformation may be alternatively carried out by extracting only such an image portion from the image center portion by plural pixels whose number is power of 2. In the case of the FFT transformation, if a total number of pixels is selected to be power of 2, then calculation time may be shortened. FIG. 8 represents an FFT transformation result obtained by that 256×256 pixels of a center portion of the SEM image shown in FIG. 7 are extracted therefrom, and then, the FFT transformation is calculated. From this FFT transformation result of FIG. 8, peak frequencies (namely, both point “A” (frequency coordinate: −21, −39) and point “B” (frequency coordinate: 21, 39)) can be calculated. An absolute value of a spatial frequency is equal to 44.3 as to both the point A and the point B. Step 15: A pitch measurement value is calculated based upon both the peak frequencies and the pixel size. From the pitch frequency (namely, 44.3) obtained in the step 14, a pitch dimension (total number of pixels) may be calculated as 256/44.3=5.78 pixels. Also, a pixel size of an SEM image having the image magnification of 5000, which has been acquired based upon 640×480 pixels becomes equal to 0.04 μm. As a result, a pitch measurement value of this case may be calculated as 5.78×0.04 μm=0.231 μm. Step 16: An image magnification error is calculated based upon both the pitch measurement value and the nominal pitch value of the material. In this embodiment 2, since the nominal pitch value of the reference material (FIG. 7) is equal to 0.240 μm, the image magnification error may be calculated as follows:(0.231−0.240)/0.240=−0.038(−3.8%) Step 17: Similar to the embodiment 1, the calculated image magnification error is displayed. In an embodiment 3, the below-mentioned method will now be explained. That is, a one-dimensional averaged line profile is produced from a digital image as to a reference material for image magnification, and then, a pitch dimension is detected from this produced line profile by way of an auto-correlation function. In the case that such a reference material as the micro scale of FIG. 2B having a pattern structure made only in one direction is employed, line profiles along a direction perpendicular to the pattern are averaged along the direction of this pattern, so that one piece of line profile (namely, averaged line profile) can be produced. If this averaged line profile is shifted along a direction perpendicular to the pattern and an auto-correlation function is calculated, then such a position that a peak of a correlative value appears corresponds to a pitch dimension of the pattern. In this method, even when S/N (signal-to-noise ratio) of an image is deteriorated, a pitch dimension can be measured under high reproducibility, and also, calculation time can be largely shortened, as compared with that for an auto-correlation function of a two-dimensional image. In an embodiment 4, the following method will now be described with reference to FIG. 9. That is, periodic detecting methods are switched in the case that a period (converted into pixel number) of a reference material for image magnification is smaller than a predetermined value, and larger than this predetermined value with respect to a pixel size (converted into pixel number). FIG. 9 indicates a relationship between a total number of pixels which forms a period (pitch) constituting a measurement subject on an image, and maximum errors occurred when the period is detected by way of the auto-correlation function and the FFT transformation. As indicated in FIG. 9, in the case of the auto-correlation function, the larger a total number of pixels (pitch pixel number) corresponding to the pitch dimension is increased, the higher the measuring precision is improved. On the other hand, in the case of the FFT transformation, if a total number of pitch pixels is increased, then a total number of periods in the entire image is decreased, so that measuring precision is conversely lowered. Assuming now that a pitch pixel number under which the maximum measurement errors of both the auto-correlation function and the FFT transformation are made coincident with each other is equal to “Nc”, when a pitch dimension is larger than this pitch pixel number “Nc”, the auto-correlation function is employed, whereas when a pitch dimension is smaller than this pitch pixel number “Nc”, the FFT transformation is employed, so that pitch measuring errors can be suppressed to a minimum error. Maximum errors (namely, peak position detecting errors) occurred when peak positions are detected based upon the auto-correlation and the FFT transformation are different from each other, depending upon peak detecting methods. Assuming now that the peak detecting precision of both cases is made coincident with each other in the pixel conversions (for example, precision of ±0.5 pixels), the following fact could be found out: That is, the pitch pixel number “Nc” under which the maximum values of the measuring errors of both cases are made coincident with each other is given as follows:Nc=√{square root over (Np)} (6).In this equation (6), symbol “Np” denotes a total number of pixels of a measured image. A pitch pixel number on an acquired image may be predicted from a nominal pitch value of a reference material, image magnification of an apparatus, and also, a total pixel number of a measured image. As a consequence, since this predicted value is compared with the pitch pixel number “Nc” of the equation (6), a proper (namely, smaller measuring error) measuring method can be selected from the auto-correlation function and the FFT transformation. Alternatively, a pitch pixel number may be firstly measured by way of the auto-correlation function, and then, a final detecting method may be selected by comparing this measured pitch pixel number with the above-described pitch pixel number “Nc.” In an embodiment 5, an image magnification error measuring method will now be explained with reference to FIG. 10. That is, especially, such a measuring operation of the image magnification error in high image magnification is carried out in the case that a periodic number (pattern number) required for sufficiently securing reliability of this measuring operation is not present on an acquired image. As indicated in FIG. 10, in high image magnification (for instance, magnification of several hundreds and thousand), a very small pitch portion of a reference material is displayed as an image. At this time, if a pitch measuring operation is carried out only by using this information, then reliability of measurement values is lowered. In order to avoid lowering of the measurement reliability in the high image magnification, in such a case that a ratio of pitch pixel numbers exceeds a predetermined value (for example, 20%), as indicated by a dotted line of FIG. 10, a plurality of images may be acquired in different scanning areas (visual fields). Normally, movement of a visual field is carried out by controlling a beam irradiation position (namely, image shift). When a move amount is large, a sample stage may be moved so as to move a visual field. Then, pitches are measured by using the auto-correlation function from the plurality of these images acquired in the above-described manner respectively, an average value is calculated from these measured pitches, and thus, this calculated averaged pitch value may be defined as a pitch measurement value of the reference material. In this embodiment 5, even in such a case that the image contains a small amount of pitch information, the reliability of the pitch measurement value which can be finally acquired can be increased. An embodiment 6 corresponds to such an example. That is, in the case that in an image whose pitch is tried to be measured, a direction of a pattern is not proper, a pitch measuring operation is not executed. FIG. 11A shows an SEM image formed under such a condition that a pattern of an acquired reference material is shifted along a rotation direction (clockwise direction). Under this condition, for example, when pitch information along the X direction is detected, a pitch measurement value is shifted by such a value that the rotation is shifted. To avoid this value shift, the following means is provided. This means detects edge information (edge line) of a pattern from an image, and also detects an angle defined between this detected edge line and either a horizontal line or a vertical line. As the method of detecting the edge line, for instance, there is a method for differentially processing an image so as to obtain a binary image. FIG. 11B illustratively indicates an example of a processed image in which the edge line has been extracted. If a straight line is extracted from this edge line, then a shift angle “θ” of the pattern along the rotation direction is obtained from an inclination of the straight line. In this embodiment 6, when the shift angle “θ” of the pattern along the rotation angle which is detected from the edge line is larger than, or equal to a predetermined angle (for example, ±5 degrees, or more), such an information “pitch measuring operation is invalid” is displayed and may be notified to an operator. Furthermore, this shift angle “θ” is fed back to a beam scanning function (raster rotation function), so that an SEM image which does not produce a rotation shift may be newly acquired. Alternatively, in order that an image magnification error in a specific scanning direction is measured, when the raster rotation is moved at an angle which is larger than, or equal to a predetermined angle, since an image magnification error along the X direction is mixed with an image magnification error along the Y direction, in such a case that the shift angle “θ” becomes larger than, or equal to a preselected value (for example, larger than, or equal to 20°), this shift angle “θ” is not fed back to the raster rotation, but is fed back to a mechanical rotation operation of a stage, so that an SEM image which does not produce a rotation shift may be newly acquired. It should also be noted that such a “raster rotation” technique implies a technical idea capable of rotating a scanning direction of beams by utilizing either an electric field or a magnetic field. In an embodiment 7, a description is made of a concrete example as to a means (process operation) for determining an optimum image acquisition condition (image magnification and total number of pixels) when both an image magnification control range for measuring a nominal pitch value and an image magnification error of a reference material, and a selection range for a total pixel number of an image. Since a range for image magnification of an SEM is defined from several tens of magnification to several hundreds and thousand of magnification, or more, an amplitude of a scanning signal supplied to a scanning coil requires a wide dynamic range. It is technically difficult to cover all of such a wide dynamic range only by a gain of a circuit. As a result, normally, as indicated in FIG. 12, while a circuit is arranged in such a manner that after a scanning signal is processed by an attenuator, the attenuated scanning signal is supplied to the scanning coil, attenuation ratios of the attenuator are switched with respect to each of image magnification ranges. At this time, due to errors contained in the attenuation ratios, different image magnification errors are produced every time an attenuation ratio (image magnification range) is switched. In order to correct this image magnification error, an image magnification calibration must be carried out every time an image magnification range is switched. An object of this embodiment 7 is to determine such an image acquisition condition under which the highest precision can be achieved in an image magnification error measuring operation within each of the image magnification ranges. Assuming now that a pitch pixel number is “Npitch”, and a peak detection error (converted into pixel) for measuring a pitch is “P”, a maximum value “ε (ACF)” of pitch measurement errors which are calculated based upon the auto-correlation function method is given by the following equation (7):ε(ACF)=P/Npitch (7). In this equation (7), symbol “ACF” is abbreviated from Auto Colleration Function. Also, since the pitch pixel number “Npitch” is directly proportional to both image magnification “M” and a pixel number “Np” along a pitch measuring direction, the above-explained equation (7) may be rewritten by the below-mentioned equation (8):ε(ACF)=K×P/(M×Np) (8).In this equation (8), symbol “K” indicates a conversion coefficient. In this embodiment 7, the pixel number “Np” may be selected from 640, 1280, 2560, and 5120. When an image magnification range is determined under such a condition that both an accelerating voltage and WD are given, an image magnification control range (M1, M2) within this image magnification range may be exclusively determined from the values of the attenuator shown in FIG. 12. As a consequence, assuming now that a target value of the pitch measuring error is equal to “ε0”, a combination between the image magnification “M” and the pixel number “Np” may be determined which may satisfy the following equation (9):ε(ACF)=K×P/(M×Np)<ε0 (9).In this embodiment 7, when the image magnification owns a top priority, such a pixel number “Np” capable of satisfying the above-described equation (9) in the lowest image magnification (M1) within the image magnification range is fined out from the selection tree. On the other hand, when the pixel number “Np” has a top priority, such an image magnification capable of satisfying the above-described equation (9) is determined from the range defined from “M1” up to “M2.” It should be understood that when any of the above-described selecting operations cannot satisfy the above-described equation (9), such a condition (M·Np) that the pitch measuring error of this equation (9) can be approximated to the target value “ε0” in the highest degree. On the other hand, a maximum error “ε(FFT)” in the case that a pitch measurement is carried out by employing the FFT transformation is given by the following equation (10):ε(FFT)=(Npitch/Np)×P (10).Similar to the above-explained condition of the auto-correlation function, since the pitch pixel number “Npitch” is directly proportional to both the image magnification “M” and the pixel number “Np” of the pitch measuring direction, the above-explained equation (7) may be rewritten as follows:ε(FFT)=K×M×P (11). As a consequence, in the case that the pitch is measured by employing the FFT transformation, the lowest image magnification (M1) within the range is selected. It should also be noted that if a value as to the pitch pixel number “Npitch” is smaller than, or equal to 2 pixels, then periodic information is lost from an image. Therefore, a specific care should be taken in a process operation when an image magnification selection is carried out in such a manner that a value as to the pitch pixel number may become larger than, or equal to at least 3 pixels. An embodiment 8 describes such an example that an image magnification calibration is automatically carried out. That is, a pitch measurement value of a reference material which has been detected by executing the methods described in the previous embodiment, or similar methods is fed back to an image magnification control in order that an image magnification calibration is automatically carried out. A scanning signal flows through a scanning coil of an SEM, while this scanning signal is used so as to scan primary beams on a material. At this time, assuming now that an amplitude of the scanning signal is “Id”, and image magnification of the SEM is “M”, an image magnification control circuit controls this amplitude “Id” in such a manner that the below-mentioned relationship (12) can be satisfied:Id=K1×K2×(1/M) (12). In this equation (12), symbol “K1” corresponds to an image magnification controlling coefficient which is obtained by a control CPU in accordance with a calculation of an electo-optical system in connection with an accelerating voltage, WD, an image magnification range, and so on. Further, symbol “K2” represents an image magnification correcting coefficient which is used to increase the image magnification control precision by correcting a control error of the image magnification controlling coefficient. If the image magnification control is performed in an ideal manner, then “K2” may be made equal to 1. However, an image magnification error is produced due to an image magnification control error is an actual apparatus. A decision of a value as to the image magnification correcting coefficient “K2” used for correcting this image magnification error corresponds to an image magnification calibration. When a pitch dimension “Lm” of a reference material for image magnification is measured by executing the methods which have been indicated in the embodiment 1 to the embodiment 7, or similar methods thereto, a relationship between the control image magnification “M” and image magnification “M0” (true value) defined by the pitch dimension of the reference material for image magnification may be calculated from a nominal pitch value “Ls” of the reference material as follows:M/M0=Lm/Ls (13). For example, assuming now that the pitch measurement value (Lm) is measured to be such a value larger than the nominal value (Ls), this assumed measurement result implies that the control image magnification “M” causes an image magnification error along a plus direction with respect to the correct image magnification “M0.” In order to correct this image magnification error (calibration of image magnification), the image magnification correcting coefficient (K2) defined in the above-explained equation (12) may be substituted by the below-mentioned formula (14): K 2 ⇒ K 2 · L m L ⁢ ⁢ s ( 14 ) In other words, when the control image magnification “M” is shifted along the plus direction (namely, amplitude of scanning signal is shifted along small amplitude direction), the correcting coefficient “K2” may be corrected (calibrated) along such a direction that the amplitude of the scanning direction is increased. In this embodiment 8, the formula (14) is automatically calculated from both the pitch measurement value (Lm) obtained in the measurement for the image magnification error, and the set nominal pitch value (Ls), so that the control image magnification is carried out. Since the image magnification correcting coefficient “K2” can be independently set for that of the X scanning operation and that of the Y scanning operation, in this embodiment 8, a selection may be made as to such a case that the coefficient correction of the formula (14) is executed in the pitch measuring direction (namely, any one of X direction and Y direction), and such a method for reflecting the measurement result to both the correction coefficients along the X direction and the Y direction at the same time. An embodiment 9 describes such an example that a dimension of an application image is measured in high precision. That is, while an image as to the acquired reference material for image magnification and an actual application image are acquired under the same apparatus observation condition (accelerating voltage and WD), a dimension of the application image is measured from these acquired images in the high precision. In accordance with the embodiments which have been so far described, the pitch (Lm) of the reference material can be measured from the image of the reference material for image magnification can be measured in the high precision. If this pitch value (Lm) and the nominal pitch value (Ls) are employed, then the below-mentioned conversion is carried out with respect to the dimension (L) which has been measured in the actual application, so that such a dimension (L′) can be obtained in high precision: L ′ ⇒ L · L ⁢ ⁢ s L m ( 15 ) It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims.
	abstract	Apparatus for generating thermal neutrons includes an electron accelerator for generating an electron beam and a converter for converting the electron beam into photons. A receiving device is provided for receiving the photons and includes a material which provides a photoneutron target for the photons, for producing high energy neutrons in a photonuclear reaction between the photons and the photoneutron target, and for moderating the high energy neutrons to generate the thermal neutrons. The electron beam has an energy level high enough to produce photons of sufficient energy to exceed the photodissociation threshold of the selected target material, but that is sufficiently low as to enable the material to moderate the high energy neutrons resulting from the photonuclear reaction.
040452891	summary	BACKGROUND OF THE INVENTION This invention relates to a nuclear reactor containment structure. In more detail, the invention relates to a reactor containment building having excellent resistance to wind and seismic forces. In still more detail, the invention relates to a reactor containment building for a Safety Research Experiment Facility which is designed to be used to investigate the performance and safety characteristics of fuels and fuel assemblies for large fast breeder reactors. Many nuclear reactors are enclosed within containment structures which conventionally are free standing steel or reinforced-concrete steel-plate-lined cylindrical shells with a top dome. The entire structure generally rests on a thick reinforced-concrete base slab. This structure is the final barrier preventing release of radioactive material to the atmosphere as a result of accidental occurrences within the containment. It is a passive element of the safety system -- a static fission product barrier which must perform its safety function under all postulated operating and accident conditions. The depth of embedment of a nuclear reactor containment structure -- i.e., the depth below grade of the main foundation slab -- can range from very shallow embedment to virtually full embedment. The degree of embedment can have a profound effect on the forces for which the structure must resist, and can affect overall cost. For example, conventional containment structures which are primarily above grade must resist very high shear forces and overturning moments due to wind and seismic loads. While a structure can be designed and constructed to serve the intended purpose, the cost is probably greater than for a structure with a greater degree of embedment. Likewise, a containment structure which is fully embedded having its top at or slightly below grade would probably be substantially more expensive than a partially embedded structure due to increased excavation costs. A partially embedded reactor containment building accordingly has potential cost advantages over either shallow embedment or full embedment. Generally, such advantages depend upon the nature of the soil environment, and can be realized only if significant reductions in the shear forces and overturning moments from lateral loads can be accomplished. SUMMARY OF THE INVENTION The reactor containment building of a safety research experiment facility is constructed of reinforced concrete partially embedded in competent rock with the concrete poured in contact with the competent rock and includes a continuous, hollow, circular, reinforced-concrete ring tunnel surrounding the shell of the reactor containment building with its top at grade and having one wall integral with the containment building shell and at least its base poured in contact with the competent rock.
044341300	description	DETAILED DESCRIPTION General FIG. 1 illustrates production of nuclear fusion reactions between two accelerated beams of ions in a suitable high density mode to produce heat energy from a reaction such as the combination of deuterium and helium-3 or protons and boron. A very high density sheath of electrons rotates in a coaxial system under cylindrical electrostatic focusing. The electron sheath or beam is introduced in cylindrical form through a magnetic field and then is constrained to rotate in a radially compressing electric field so that the centrifugal force of the rotating electrons is balanced against the inward radial force of an electric field. The electron beam is thus directed down a compression ramp where the electric field becomes continually more intense so that the beam is forced to travel in smaller and smaller radii. The charge density that can be contained by this system is inversely proportioned to the fourth power of the radius. Therefore, a very dense and thin electron sheath is produced in a small annulus in a coaxial system. The electron sheath has a negative space charge which is most dense on the inside of the sheath. This defines a channel to confine positively charged ions. The amount of positive charge and its mass is such that the mass and charge in the electron channel is not overcome. Thus, the electron sheath rotates around a central conductor to balance the electron centrifugal force against the inward radial electric field. The space charge of a cylindrical ion beam of positive ions is brought in through a grid for travel along the zone of negative potential minimum created by the electron sheath. This confines the positive ions to a very much smaller cylindrical volume inside the electron sheath than the sheath itself occupies. From the opposite end of the electron sheath channel, a second ion beam is introduced traveling in the opposite direction and likewise confined. The two ion beams are thus brought together in thin, powerfully confined, shell-like channel under influence of the space charge of the confined electrons. There is provided a long and extremely dense collision space for ions traveling in cylindrical beams in opposite directions. For example, a cylindrical beam of deuterium ions may travel through one end of the electron negative space charge channel and a similar beam of helium-3 ions may travel from the opposite direction. The two beams meet all along the channel. The channel may be so thin and so confining that the cross section for nuclear reaction is extremely high compared to the particle density in the beams multiplied by the area of the hollow cylinder beams. Thus, the probability of a useful nuclear collision approaches unity, meaning that most of the ions in the two ion beams react to produce the energetic particles resulting from such an interaction. The energy of the electrons and the energy of the ions are independent. The two ion beams can be accelerated so that they meet in their center of mass system with the energy difference which is optimum for a maximum cross section to produce the desired nuclear reaction. The nuclear reaction may be chosen to produce only charged particles which can be collected on the surfaces of the coaxial confining system for the electrons and the heat thereby converted to useful energy. The particles resulting from the nuclear reaction will have so much energy that they easily escape from the coaxial sheath. They are collected by the walls of the coaxial confining system. The electrons exit up a decompression ramp and are collected or put through an inverse magnetic field and collected against a decelerating electric field so as to return their energy to the original electron power supply. Thus, the power necessary to maintain the electron space charged compression region can be extremely small and, in fact, negligible compared to that released by the nuclear reaction. FIG. 1 Referring to FIG. 1, a source 16 of electrons is mounted at the left end of a reactor unit which is provided with a central conductive mandrel 35 from which there are supported two sets of deflecting electrodes. The first set of deflecting electrodes comprises the electrodes 40, 41 and 42. The second set comprises electrodes 43, 44 and 45. An outer housing has a left-hand conical section housing 31, a central cylindrical section housing 32 and a right-hand conical section housing 33. Potential sources 50, 51 and 52 maintain the electrodes 40, 41 and 42, respectively, at positive potentials relative to the housing 31-33. Similarly, sources of potential 53, 54 and 55 maintain the electrodes 43, 44 and 45, respectively, at potentials positive relative to housing 31-33. A source 56 maintains the central mandrel 35 at a predetermined positive potential relative to housing 31-33. It will be noted that electrodes 40-42 and 45 have been partially broken away. A magnet, now shown, is provided to produce a magnetic field H at the output of the electron source 16. Ion sources 18 and 19 are provided at opposite ends of the central mandrel 35. Ion sources 18 and 19 are ring shaped and preferably continuous to provide cylindrical beams 20 and 21 of oppositely directed ions. The ions from source 18 may comprise deuterium ions. The ions from source 19 may comprise helium-3 ions. The cylindrical beams 20 and 21 pass through grids 22 and 23 that are located at the confronting portions of electrodes 42 and 45. Grids 22 and 23 provide passageways through which beams 20 and 21 may enter into an elongated cylindrical reaction zone 29. Electrons from source 16 are first forced into a spiral orbit. The stream of electrons is then compressed in the compression zone for entry into and travel through the reaction zone and then out from the system through the expansion zone and exit port 17. The ions in beams 20 and 21 pass through grids 22 and 23 and then travel towards each other in the reaction zone 29. They are forced by reason of the potential gradient in the spiraling electron sheath to occupy the same cylindrical paths. The ions in beams 20 and 21 travel straight line paths, but because the sources 18 and 19 are continuous ring sources, the ions in paths 20 and 21 form essentially cylindrical beams. Collisions between ions from the paths 20 and 21 in the reaction zone 29 bring about the release of energy from the fusion reaction. If the ions from source 18 are deuterium ions and ions from the source 19 are helium-3 ions, then the following well known reaction takes place: EQU .sup.2 D+.sup.3 He.fwdarw..sup.4 He+p+18.3 MeV (1) Two particles result, i.e., a helium atom and a proton, plus 18.3 MeV of energy. The particles at such energy no longer are confined by the field and, thus, may escape to impinge the chamber wall. The energy is then absorbed by carbon liners in reaction chamber 29. Heat may then be extracted through use of heat exchangers encasing the walls of reaction chamber 29. The electric fields applied in the compression and expansion zones, FIG. 1, are such as to force the electrons into a very thin, highly compressed, dense sheath which spirals at a very low pitch or grade. FIG. 2 Referring now to FIG. 2, a highly enlarged view of the reaction zone 29 has been shown. A portion of the wall of the housing 32 has been shown in its relation to the inner wall of the mandrel 35. The potential gradient in the reaction zone 29 is represented by the curve 29a having a minimum at point 29b. Because of this minimum, the ion beams 20 and 21 are forced to occupy a very thin cylindrical zone to enhance the likelihood of ion collisions. It is to be understood that the entire system in which the electrons are generated, compressed and expanded is evacuated and that the fields in the compression zone and the expansion zone are so tailored as to cause the electrons to follow uniform spiral paths through the reaction zone 29. The electron paths shown in FIG. 1 have been shown as having a very coarse pitch. It is to be understood that this is solely for the purpose of illustration. In actual practice the pitch would be low so that in the reaction chamber 29 there would be a high concentration of electrons at any one time. A high incidence of head-on ion collisions is thus promoted. The electric fields between the outer shell housing 31, 32, 33 and the various electrodes are tailored in the compression zone and the expansion zone to provide a gradual decrease and increase, respectively, in the diameter of the spiral path as the electrons travel from source 16 to exit port 17. More or fewer discrete compression fields may be imposed on the ion beam, the specific configuration depending upon particular design. An alternate embodiment shown in FIG. 3 employs two electron beams, one from each end of the system occupying slightly different radii so that a space charge potential minimum is created between the two beams. This provides a very strong focusing region for the positive ions to produce a nuclear reaction which is essentially free from electrons and is advantageous in reducing scattering and energy losses between the ion beams and the confining electrons. The electron beams travel in opposite directions in the sense that electrons from source 16 travel from left to right whereas electrons from source 16a travel from right to left. As they so travel they follow spiral paths as the beams are comprised and then follow helical paths through the reaction zone 29. Thus, as the term spiral paths is used herein it is to be taken to include the truly helical portions of the paths in reaction zone 29. Where the radial magnetic fields in gaps 11 and 13 are the same (i.e., both directed radially inward from north to south poles) the direction in which the electrons from source 16 follow the spiral paths will be opposite the direction the electrons from source 16a follow their paths. In such case, if the radii of the two beams were the same, then the electrons would travel such as to experience head-on collisions. However, if the magnetic field 11 is opposite in sense from the magnetic field 13, then electrons from sources 16 and 16a would travel spiral paths in the same general direction, as the electron moves from left to right from source 16 and from right to left from source 16a. The following paths through reaction zone 29 at slightly different radii, the space charge potential is minimum between the two beams. It is at this location of minimum space charge potential that the ions then tend to settle into paths at the common radius, and thus in paths that tend to promote head-on collisions. The dual electron beam system or the single electron beam system in which the ions and the electrons occupy the same space may serve in carrying out this invention. FIGS. 3-5 A dual electron-dual ion beam reactor is illustrated in FIGS. 3-5. A hollow annular magnetic ring 10 of rectangular cross section has circumferential gap in one face thereof. Similarly, a second hollow annular ring 12 is provided with gap 13. Rings 10 and 12 are spaced apart on a common axis with the gaps 11 and 13 facing each other. Ring 10 is provided with an electrical winding 14. Ring 12 is provided with an electrical winding 15. Controllable currents in windings 14 and 15 produce magnetic fields across gaps 11 and 13 to force the electrons to follow spiral paths for introduction into the electric field confinement space with desired angular momentum. Electron generator-accelerator source 16 is provided inside ring 10. Electron generator-accelerator source 16a is provided inside ring 12. Source 16 may comprise a plurality of electron beam sources at angularly spaced positions around the circumference of ring 10. A like number of sources angularly spaced around the interior of ring 12 may be used. In such case, many individual beams are accelerated through gaps 11 and 13, respectively. Magnetic fields across gaps 11 and 13 will cause the electrons to be deflected and forced into spiral paths as they move away from gaps 11 and 13. As above explained, electric fields are imposed on each electron to force the spiraling electron sheaths to follow paths of progressively decreasing diameter. As the diameter decreases, the electron density increases. The two oppositely traveling high density beams of electrons will have slightly different velocities as to pass through a cylindrical reaction zone at slightly different radii. The structure between rings 10 and 12 forms compression zone adjacent ring 10, compression zone adjacent ring 12, and central reaction zone. An outer housing is provided with cylindrical section housing 30, a conical section housing 31, a cylindrical section housing 32, a conical section housing 33, and cylindrical section housing 34. Housings 30-34 as shown are integral one with another with the central section housing 32 being cylindrical. Mandrel 35 extends coaxially of the compression zones and the reaction zone. A closure plate 36 is secured between ring 10 and the end of mandrel 35. Similarly, an end closure plate 37 is secured between ring 12 and the end of mandrel 35. With such closure plates, the space inside the housing 30-34 and outside the central cylinder 35 can be evacuated as by vacuum pumps 38. Electrodes 40-45 are symmetrical to the axis 35a of the system. Electrode 40 is generally cylindrical in shape. The end of electrode 40 opposite ring 10 is slightly conical. Electrode 41 is of conical shape with an internal angle less than the angle of the conical section housing 31. Electrode 42 in the form of a truncated cone is connected to mandrel 35 at the entrance to the cylindrical housing 32 and extends toward ring 10 with the end thereof inside the small end of electrode 41. Electrode 41 extends toward ring 10 with the end thereof inside the end of electrode 40. In a similar manner, electrodes 43, 44 and 45 are mounted in the compression zone. Ion sources 18 and 19 are mounted at opposite ends of mandrel 35 inside the evacuated zone for providing oppositely traveling ion beams 20 and 21. The inner wall of the cylindrical housing 32 is provided with a lining 100 of carbon, preferably pyrolitic carbon. The outer surface of the cylindrical housing 35 is provided with a like lining 101 of pyrolitic carbon. A cylindrical heat exchange jacket 102 surrounds the cylindrical housing 32 and is provided with a fluid inlet 103 and a fluid outlet 104. A heat exchange jacket 105 inside the mandrel 35 spans its reaction zone and is provided with an inlet channel 106 and an outlet channel 107. Jackets 102 and 105 are flow connected to a utilization unit 108. As shown in FIG. 3, the electrode 40 is positioned near the end of ring 10 adjacent gap 11 and is supported by electrically conductive rods 40a and 40b, which extend through closure plate 36 by way of insulators 36a. Four supporting rods are employed for electrode 40, only two, rods 40a and 40b, being shown in FIG. 3. Similarly, electrode 41 is supported by rods 41a, 41b which also pass through insulators in plate 36. The end of mandrel 35 is secured to plate 36 by way of insulators 36c. In FIG. 4, the ring 10 is shown in sectional view. Plate 36 is of disc or washer shape and with the electrodes 40a-40d, 41a-41d, and the end of mandrel 35 extending therethrough. While only one flow channel has been illustrated leading to the vacuum pump 38 of FIG. 2 it will be apparent that a manifold may be provided leading from several passages through closure plate 36 to facilitate evacuation. The supporting rods 40a-40d and 41a-41d, as well as the central mandrel 35, provide for the application of DC voltages to the electrodes 40, 41 and 42 in order to force electrons from source 16 to follow a spiral path of progressively decreasing radius until they enter the cylindrical reaction zone 29. FIG. 5 is an enlarged sectional view of the reaction zone 29. The inner mandrel 35 supports the internal heat exchange jacket 105 around which a flow of suitable heat exchange fluid is established during operation of the system. The outer wall of mandrel 35 is coated with the pyrolitic carbon lining 101 for absorbing the energy of the particles produced in connection with fusion reactions in the reaction zone 29. Similarly, the housing 32 extending through the reaction zone has the internal coat of pyrolitic carbon lining 100 for absorption of energy of the reaction products. Heat exchange jacket 102 encircles housing 32 in coaxial spaced relation for flow therethrough of suitable cooling fluid. FIG. 6 FIG. 6 illustrates cross sections for several fusion reactions. Particle energy, in electron volts, is plotted on the ordinates. The reaction cross section, in barns, is plotted along the abscissa where each barn is 10.sup.-24 cm.sup.2. FIG. 6 indicates that fusion of deuterium and tritium (DT) is probably the easiest reaction to manage. More particularly, nuclei at 20 KeV of deuterium and tritium have, from FIG. 6, curve A, a fusion cross section of about 0.1 barn. Particles having relative energy of 115 KeV have a fusion cross section up to 5 barns. The DT reaction produces a neutron of relatively low energy, i.e., 3.2 MeV. Neutron production may or may not be desirable, as will be discussed later. The reaction represented by curve B where helium-3 and deuterium are employed is preferred. In that reaction a helium atom and a proton are produced plus 18.3 MeV of energy per reaction. The cross section for the reaction between lithium and deuterium to produce two helium atoms is only partially shown and is not further available. However, it appears to be attractive, the reaction being: EQU .sup.2 D+.sup.6 Li.fwdarw.2.sup.4 He+22.4 MeV (2) Other modes of operation may prove to be equally or perhaps more desirable. For example, note the reaction between boron ions and protons from the curve H of FIG. 6. It should be understood that the data shown in FIG. 6 comprises the cross sections for various reactions in a thermonuclear case, i.e., where particle velocity is randomly directed. It is to be understood in the present case where the motion is not random, but wherein particle velocities are in head-on collision courses, the cross section is significantly greater by an amount approximately equal to the square root of 6. From the foregoing it is shown that nuclear particles are directed and controlled to produce head-on collisions in opposing beams of suitable positive ions. This is in contrast with the usual concept of plasma which is thermal, i.e., random, and includes undesirable electrons which radiate profusely, but are necessary for plasma neutralization. Thermal plasma which is hard to contain and which is inefficient for energy release is avoided. Such inefficiency exists because only a small fraction of positive ions in the thermal plasma have the right conditions for fusion, namely, that part of Maxwellian distribution which has the right kinetic energy and relative direction. In accordance with the present invention, two beams of selected positive ions move in a cylindrical path, traveling at the same radii and in opposite directions, hence optimal for head-on collisions. A most important property of the focusing employed is that electron beam radii are stable. That is, any electron deviating from the sheath is automatically pulled back into the sheath. Thus, the electrons are forced into a thin sheet. The energy conversion efficiency from heat to electricity or to mechanical energy can be as high as 45% to 50%. Thus, the ratio of reaction output to beam input energy may be the order of 61 to 1. The reaction: EQU .sup.3 He+.sup.2 D.fwdarw..sup.4 He+.sup.1 p+18.34 (3) gives this ratio. In such case, about 40% to 45% of total fusion energy is recoverable. It is known and can be shown that the stability condition for focusing a particle is given by the equation: ##EQU1## where: r.sub.0 =the stable radius v.sub.0 =particle velocity PA1 r=the instantaneous radius PA1 .phi. is the magnetic flux which originally guides the electrons into the circular Harris orbit; PA1 M is the mass of the electron; and PA1 r is the radius of the orbit. If a particle deviates in either direction from the stable radius r.sub.0 for velocity v.sub.0, the particle is pulled back to the stable orbit r.sub.0. The small oscillations die down by means of dissipative currents at the walls and in the pyrolytic carbon coating. Thus, stable and extremely dense beams of particles are produced. As above noted, the electron beams thickness can be very small and particle density can be made very large by means of independently controlling the electron sources. It is to be noted that space charge does not lead to beam spreading because as focused the wall develops a charge density: EQU q=-e.phi..sup.2.epsilon..sub.0 /2.sup..pi. r.sub.a.sup.2 (5) and, thus, overall beam spread due to space charge is prevented. The space charge effect is compensated by q. The only remaining particle deviations from the beam are due to the coulomb scattering of individual particles due to the granular nature of the charges. Under these conditions the charge density .rho. for negative electrons is given by the equation: ##EQU2## where: Z is the charge-number of the negative electrons; Charge density, and thus electron density, depend upon the inverse of r.sup.4. This density increases by a large factor by starting with a large radius and then compressing the beam to a small radius. The compression is achieved by bending the ion beam, which is originally obtained via a steady electric field. The radial magnetic field is the term .phi. in equation (6). The beam is fed into the small stable radius in zone 29, FIG. 1, as controlled by electrostatic focusing. Since e.phi..sup.2 /Mr.sup.4 can be very large, the electron density can be made very large. The ratio of the total number of electrons forming the sheath to the total number of ions in the sheath is at least equal to the ratio of the average ion mass to the mass of the electron whereby said ions respond to the electric fields in the sheath to settle into paths at a radius in the sheath at which the potential gradient is minimum. In obtaining beams of high density electrons an operation related to what is known as Harris focusing is employed. Harris focusing is of the type described in W. W. Harmon, Fundamentals of Electronic Motion, McGraw-Hill Book Company, Inc., 1953, pages 161 and 162. Having described the invention in connection with certain specific embodiments thereof, it is to be understood that further modifications may now suggest themselves to those skilled in the art and it is intended to cover such modifications as fall within the scope of the appended claims.
	description	The United States Government has certain rights in this invention pursuant to Contract No. DE-AC07-05ID14517 between the United States Department of Energy and Battelle Energy Alliance, LLC. The present invention relates to radiation shielding materials for nuclear criticality control, and more specifically to a neutron absorbing material which may be applied to storage containers for use in spent nuclear fuel applications requiring long term storage and corrosion resistance. The reliance on nuclear power as a method for power generation has increased in recent years due to a corresponding increase in the demand for electrical power throughout the world. Accordingly, the amount of spent nuclear fuel has increased along with the need for safe methods for long term storage and disposal of these radioactive waste materials. Ideal containers for storage and transport of radioactive waste should have the capability of safe containment for as many years as possible. There are however, significant safety issues involved in the safe long-term storage of spent nuclear fuel due to the high levels of uranium enrichment. Various approaches have been developed for the containment of spent nuclear fuel. Prior art references such as U.S. Pat. No. 6,125,912 to Branagan disclose advanced neutron absorber materials and a method of utilizing rare earth metals such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials having a combination of superior neutron capture cross sections along with enhanced resistance to corrosion and oxidative leaching. Still further, U.S. Pat. No. 6,730,180 discloses advanced neutron absorbing structural material for use in spent nuclear applications requiring structural strength, weldability and long term corrosion resistance. This particular reference is directed to a austenitic stainless steel alloy containing gadolinium and less than 5% of a ferrite content. Other nickel-based alloys are also disclosed. In addition to the foregoing, U.S. Pat. No. 6,919,576 and which issued on Jul. 19, 2005 is directed to a composite neutron absorbing coating material applied to a substrate surface, and which includes neutron absorbing layers overlying at least a portion of the substrate surface, and a corrosion resistant top coat layer overlying at least a portion of the neutron absorbing layer. Optional bond coat layers can be formed on the substrate prior to forming the neutron absorbing layer. In this particular patent, the neutron absorbing layer can include neutron absorbing materials such as a gadolinium oxide, gadolinium phosphate, or gadolium in the form of a gadolinide dispersed in a metal allow mixture. The coating layers may be formed by a plasma spray process or a high velocity oxygen fuel process. While the prior art patents have operated with some degree of success, the inventors have endeavored to try and identify a new neutron absorbing nuclear criticality control material which may, in powder form, be applied to structural internals of spent nuclear fuel packaging components by a thermal spray process and which operates with a greater degree of success. A neutron absorbing coating for nuclear criticality control therefore, is the subject matter of the present invention. A first aspect of the present invention relates to a neutron absorbing coating for use on a substrate and which includes a nickel, chromium, molybdenum, and gadolinium alloy having less than about 5% boron, by weight. Still another aspect of the present invention relates to a neutron absorbing coating and which includes about 0.1% to about 10%, by weight of gadolinium; about 20% to about 24%, by weight of chromium; about 14% to about 16%, by weight of molybdenum; about 0.01% to about 6%, by weight of iron; less than about 5% of boron, by weight; residual amounts of manganese, phosphorous, sulfur, silicon, carbon and nitrogen; and a balance of material substantially comprising nickel, and wherein the nickel is greater than about 40%, by weight. Still another aspect of the present invention relates to a neutron absorbing coating which may be formed into a powder and is applied over a surface of a container, canister, tube, block, squares, baskets, and/or grid arrays which are used to store and support spent nuclear fuel. These and other aspects of the present invention will be described in greater detail hereinafter. This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8). The present invention is directed to a thermal neutron absorbing coating material which provides nuclear criticality control and which is useful when applied as a coating material to spent nuclear fuel storage containers or other radioactive waste storage systems such as storage containers and structures within storage containers and more specifically containers, canisters, tubes, blocks, squares, baskets, and/or grid arrays which are used to store and support spent nuclear fuel for storage. A related prior art thermal neutron absorbing coating is described and claimed in U.S. Pat. No. 6,919,576, the teachings of which are incorporated by reference herein. The coating material as provided by the present invention is distinguishable from that shown in U.S. Pat. No. 6,919,576 and has shown sufficient neutron absorbing or neutron poisoning capability and long term corrosion resistance to provide for criticality control and spent nuclear fuel storage systems. The term, “neutron absorbing or neutron poisoning” with reference to the present application refers to the ability of a material or element to interact with neutrons emitted from a radioactive material, such as by attenuating, and/or absorbing such neutrons. A storage container coated with the neutron absorbing material of the present invention is suitable for use in the safe transport, storage, and disposal of radioactive waste and is expected to retain neutron absorbing and radioactive shielding properties for extremely long periods of time. Referring now to the drawing, wherein a very simplified storage container 10 is shown, it will be seen that the sectional view of FIG. 1 shows a coating 11 applied to an inside substrate surface 12. As seen, the substrate surface can be the interior surface of a spent nuclear fuel storage container 10 such as a Department of Energy standardized canister, or other suitable object. Further, it should be understood that the substrate surface can also be a surface of an internal structural member within a storage container such as tubes, blocks or squares, baskets an array of grids and the like, not shown. FIG. 1 is merely illustrative of one structure that the present invention can be employed with. The neutron absorbing layer 11 contains a mixture of various metallic materials that include neutron absorbing materials. Preferred neutron absorbing materials include gadolinium, and compounds of gadolinium such as gadolinium oxide and gadolinium phosphate as well as various mixtures thereof. Gadolinium is advantageous as a neutron absorbing material since it has the highest thermal neutron absorbing cross-section of any known material. For example, gadolinium has a neutron absorption capability four times as great of boron. Other properties of gadolinium include good malleability and ductility which are extremely favorable characteristics for use in storage containers. Additionally, gadolinium has a relatively low cost (about a factor of five times less expensive then boron) and is available as a metal or an oxide. When gadolinium oxide is used as the neutron absorbing material, the gadolinium oxide can be synthesized using conventional chemical precipitation processes or can be obtained from various commercial sources. When gadolinium phosphate is used as the neutron absorbing material, either anhydrous or hydrated crystalline phases of gadolinium phosphate can be employed. Anhydrous and hydrated gadolinium phosphates are insoluble in water, which makes these materials favorable in providing a resistance to corrosion and long-term life for a coated storage container 10 and the like. Gadolinium phosphate does not exist in pure form in nature, but can be fabricated by chemical processes commencing with gadolinium containing chemicals. The gadolinide will be incorporated into the metallic powder matrix during the initial powder solidification process during powder manufacturing. Another suitable neutron absorbing material that can be utilized in the present invention includes boron. In the present invention, the amount of boron is less than about 5% by weight. Other metallic materials that can be utilized in combination with the neutron absorbing material to form the neutron absorbing coating as provided for in the present invention may include nickel-based alloys. In the present invention, the nickel or nickel-based alloy is greater than about 40% by weight. One suitable nickel-based alloy is UNS NO. 6022 (Alloy 22) available from Anvil, Inc. Alloy 22 exhibits extreme resistance to corrosion even at elevated temperatures. Other suitable metallic materials that can be utilized in combination with the neutron absorbing material, as described above, include but is not limited to UNS NO. 06625; UNS NO. 86276; UNS NO. S30403; and UNS NO. S31603. In the present invention, the preferred neutron absorbing composition comprises a metal alloy comprising nickel, molybdenum, gadolinium, chromium, iron and boron. As should be understood, a plurality of the neutron absorbing particles comprising gadolinium are dispersed in the metal alloy matrix. In the present invention, a first broad aspect of the present invention relates to a neutron absorbing coating 11 for use on a substrate 12 which comprises a nickel, chromium, molybdenum, and gadolinium alloy having less than about 5% boron, by weight. In the present invention, the neutron absorbing coating 11 forms an alloy matrix which is applied to the supporting surface or substrate 12. In the present invention, the neutron absorbing coating includes gadolinium in an amount equal to about 0.1 to about 10%, by weight. Still further, the neutron absorbing coating 11 of the present invention includes molybdenum in an amount of about 1.5 to about 16%, by weight. Moreover, the neutron absorbing coating 11 further includes chromium in an amount of about 13% to about 24%, by weight. In the present alloy, the amount of nickel is greater than about 50%, by weight. In the neutron absorbing coating 11 as discussed herein, the neutron absorbing coating further includes about 0.1 to about 6%, by weight, of iron; and residual amounts of manganese, phosphorous, sulfur, silicon, carbon, and nitrogen. In the arrangement as shown in FIG. 1, the neutron absorbing coating is applied to a container 10 or an internal or the like to a thickness of about 0.1 to about 2 mm. As earlier discussed, the substrate 12 may be incorporated, at least in part, into an object 10 which is selected from the group comprising storage containers, canisters, tubes, blocks, squares, baskets and grid arrays which are used to store or support spent nuclear fuel. More specifically, the present invention relates to a neutron absorbing coating 11 which includes about 0.1% to about 10%, by weight of gadolinium; about 20% to about 24%, by weight of chromium; about 14% to about 16%, by weight of molybdenum; about 0.01% to about 6%, by weight of iron; less than about 5% of boron, by weight; residual amounts of manganese, phosphorous, sulfur, silicon, carbon and nitrogen; and a balance of material substantially comprising nickel, and wherein the nickel is greater than about 40%, by weight. In the present invention, the coating is formed into a powder and is applied over a surface of a container 10, canister, tube, blocks, squares, baskets, and/or grid arrays which are used to store or support spent nuclear fuel. The coating of the present invention has a thickness of less than about 2 mm. In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.
039473201	abstract	A fuel element comprises highly a enriched uranium bodies coated with a nonfissionable, corrosion resistant material. A plurality of these bodies are disposed in layers, with sodium filling the interstices therebetween. The entire assembly is enclosed in a fluid-tight container of nickel.
	claims	1. A jet pump measurement pipe repair method for repairing a breakage part of a measurement pipe which is horizontally fixed to a lower part of a jet pump provided in reactor water in a reactor pressure vessel, the method comprising:cutting the measurement pipe including the breakage part;cutting a support member supporting the measurement pipe to a diffuser of the jet pump;removing part of the measurement pipe and part of the support member;fixing, by a clamp, a spool piece having a tubular shape directly to part of the support member remaining after the removing, both ends of the spool piece being connected to connection pipes, for supplementing the measurement pipe having been cut and removed;deforming the spool piece having the tubular shape to match a shape of the breakage part; andconnecting ends of the remaining measurement pipe to the connection pipes. 2. The jet pump measurement pipe repair method according to claim 1, whereinthe connection pipe used in the connecting is made of shape-memory alloy. 3. The jet pump measurement pipe repair method according to claim 1, whereinthe connection pipe used in the connecting is a biting joint including a joint body, union nuts, and sleeves. 4. The jet pump measurement pipe repair method according to claim 1, whereinin the connecting, the ends of the remaining measurement pipe and the connection pipes are connected by welding.
	summary
049838482	description	DETAILED DESCRIPTION OF THE INVENTION Referring now specifically to FIG. 1, 1 is a typical support conventionally used in the manufacture of X-ray intensifying screen elements. Typical X-ray screen supports include paper or cardboard suitably sized or coated with baryta, for example, films such as polyethylene terephthalate (preferred), cellulose acetate, cellulose propionate, cellulose acetate propionate, cellulose acetate butyrate, poly(vinyl chloride or vinyl acetate), and polyamides, among others, as well as thin metals or foils, etc. For use as an X-ray screen, the support must be permeable to X-rays. A thickness of about 0.00025 inch (0.00064 cm) to about 0.30 inch (0.76 cm) is adequate for these supports, with a thickness of about 0.01 inch (0.025 cm) being preferred. These supports may contain reflecting agents such as TiO.sub.2 dispersed therein, for example. Alternatively, the reflecting material may be applied on the support as a separate layer. Likewise, other adjuvants such as absorbing dyes, etc., may be useful within the support of the screen element of this invention. Preferably the support is a thin yet strong, dimensionally stable polyethylene terephtahalate of about 0.004-0.12 inch (0.1-0.3 mm) in thickness, although other thicknesses are also satisfactory. The phosphor containing layer 2 conventionally contains the phosphor particles dispersed in an appropriate binder. The phosphor materials are usually mixed in the desired amount in an appropriate solvent, e.g., a mixture of n-butyl acetate and n-propanol, etc., and the resulting solution is mixed with a suitable binder, e.g., polyvinyl butyral, etc., to form a suspension. This suspension is coated on any of the aforementioned supports or alternatively on the polyamide film protective layer. Dispersion of the phosphor in any one of a legion of conventional binders can be accomplished by ball-milling and by other procedures well known to those skilled in the art, for example, U.S. Pat. Nos. 2,648,013; 2,819,183, 2,907,882; 3,043,710; and 3,895,157, the disclosures of which are incorporated herein by reference. Useful phosphors are also legion in number and include, for example, the tungstates of calcium and magnesium, including those activated by lead; terbium activated rare earth metal oxysulfide type phosphors such as Y.sub.2 O.sub.2 S:Tb, also those of lanthanum and those activated by Tm, and Gd.sub.2 O.sub.2 S type phosphors; terbium activated rare earth phosphate phosphors such as YPO.sub.4 :Tb and those of gadolinium and lanthanum; rare earth oxyhalide type phosphors such as LaOBr:Tb and those activated with thulium; barium sulfate type phosphors such as BaSO4:Pb and those activated with europium and also containing strontium; also to be mentioned are the europium activated alkaline earth metal phosphor type phosphors and the divalent europium activated alkaline earth metal fluorohalide type phosphors; iodide type phosphors and sulfide type are also known. Still other phosphor compositions include the mixed CaWO.sub.4 rare earth tantalate phosphors of Patten, U.S Pat. No. 4,387,141 as well as the tantalate phosphors of Brixner, U.S. Pat. No. 4,225,653, the disclosures of which are incorporated herein by reference. The protective layer 3 is the improvement of this invention. Although it is known to use laminated films as protective layers in X-ray screen elements, it is not known to use thin, clear, transparent, flexible, tough, dimensionally stable (stretched and annealed) polyamide films having a low dynamic coefficient of friction and low static bonded to the phosphor-containing layer. These polyamide films are conventionally synthesized and have a thickness of about 2.5 .mu.m to 15.2 .mu.m, and preferably about 2.5 .mu.m to 12.7 .mu.m. Illustrations of polyamide films include: crystalline types, e.g., nylon 6,6, --HN--(CH.sub.2).sub.6 --NH--OC--(CH.sub.2).sub.4 --CO--].sub.n ; nylon 6, --CH.sub.2 --).sub.5 --CO--NH--].sub.n ; nylon 12, 12, etc.; amorphous types, e.g., Selar.RTM. 3426. E. I. du Pont de Nemours & Co., etc.; and blends thereof. The polyamide films may be bonded to the phosphor-binder layer 2 with or without an adhesive material. For example, the phosphor-binder layer can be coated on a surface of the polyamide film or the polyamide film may be extruded onto the surface of the phosphor-binder layer. It may be useful, however, to also use an adhesive material in the above bondings. The adhesive material, when used, may be applied directly on the surface of phosphor-containing layer 2 or, alternatively, may be applied directly or indirectly to the polyamide topcoat 3 prior to lamination of the structures to achieve the X-ray intensifying screen element of this invention as shown in FIG. 1. Conventionally used adhesives may be used within the metes and bounds of this invention. Useful adhesives include: water soluble acrylic adhesives, solvent soluble acrylic adhesives produced under the tradename Carboset.RTM. of B. F. Goodrich, Co., Specialty Polymers & Chemicals Division, Cleveland, Ohio, solvent soluble polyester adhesives such as produced by Whittaker Corp., Dayton Chemicals Div., W. Alexandria, Ohio, solvent soluble polyester polyurethane, water soluble vinyl chloride copolymer, etc. Examples of solvents are methylene chloride, ethyl acetate, butyl acetate methanol, isopropanol, etc. I prefer using Carboset.RTM. XPD-1294, a high molecular weight carboxylated polymer in ethyl acetate, made by the aforesaid B. F. Goodrich Co. and applying same directly or ndirectly to the polyamide film prior to lamination of the phosphor layer of this invention thereto. Care must be taken to minimize the effect of adhesive thickness and light absorption on subsequent image quality. A useful dry adhesive thickness range is about 1-8 .mu.m when measured on the surface of the polyamide film. In the practice of this invention, the X-ray screen element produced containing the polyamide protective layer must perform well within, for example, book cassettes, automatic changers and other automatic systems used within the hospital environs. Examples of such automatic changers include but are not limited to Canon Film Changer Model CFC-U1, Schonander AOT Model DST-893R, Du Pont CDS Compact Daylight System Model WH-29, and Du Pont MDS Modular Daylight System Model C-345. If the COF of the screen is too high, the screens show increased wear when used in association with the aforementioned automatic changers. In addition, the screen must have a low propensity for the buildup of static in order that photographic films associated therewith are not needlessly exposed and are easily removed from within the aforementioned automatic changer in order to process same to the requisite image. Thus, there is a pressing need to balance the toughness of the protective surface of the screen and to insure that no static is built up during the handling process. The polyamide film topcoats of this invention, surprisingly of all the known topcoat films, will produce this delicate balance of reduced COF, toughness to resist gouging and abrasion, and low propensity to produce static. FIG. 2, illustrates a device for the measurement of COF within this medical X-ray invention, wherein 4 is a continuous web of film (E. I. du Pont de Nemours and Company, Wilmington, Del. Cronex.RTM. medical X-ray film, 4 inches (10.16 cm) in width), traveling in the direction shown and pulled by rollers 5 and 6 under a pressure plate 7. Film speed is set, for the test of this invention, at ca. 130 inches (330.2 cm)/minute. The screen to be tested (not shown in FIG. 2) is placed on Load Scale 8 which can be adjusted from 0-21 pounds of pressure (0-9.34.times.10.sup.6 dynes) by adjusting device 9. The screen is placed on table 10 at 11 said table borne by a pair of rollers shown as 12 and 13. A Friction Scale 14 is attached thereto by means of a wire 15. As the film 4 is passed over the screen surface at 11 the testing pressure expressed in pounds (dynes) is applied and the friction force vs load and slip speed measured at 14. Thus, for any particular screen, the COF can be calculated from various friction forces and loads and a determination made of the amount of damage occurring to the surface thereof. Polyamide films of this invention with average COF limits of from about 0.15 to 0.25 and preferably from about 0.15 to 0.22 produce adequate surfaces for the protection of the screens of this invention. Propensity to generate static can be measured using a Monroe Static Charge Analyzer, Model 276A (Monroe Electronics, Inc., Lyndonville, N.Y.), for example. This instrument is used to measure the time to reach 1/2 of the initial charge to the surface for screen samples equilibrated at 70.degree. F. and 60% RH (relative humidity). Each screen sample surface is cleaned by wiping with isopropanol or other appropriate cleaner, drying well, equilibrating and then testing. Surfaces are also tested after wiping with an antistatic solution (e.g., Du Pont Cronex.RTM. Screen Cleaner) followed by drying and equilibrating. Samples are charged to a maximum of 2000 volts for 10 seconds and the charge decay with time is recorded. Isopropanol cleaned surfaces which have an average static decay 1/2 time less than 6.0 at 60% R.H. are preferred and surfaces which have an average decay 1/2 time less than 3.0 seconds at 60% R.H. are most preferred. Thus, it should be apparent, only thin, clear, tough, transparent and flexible polyamide films as defined will function within this invention. Other film elements, when compared to those of this invention, fail for a number of reasons. Most do not possess the required COF and toughness to provide protection against wear, or static protection. Other topcoat films cannot be applied as a thin layer, are not transparent or are colored and thus are not satisfactory as X-ray intensifying screen protective layers. This will be illustrated in the Examples set out below, of which Example 4 is considered to be a preferred mode of this invention. EXAMPLES The following examples illustrate but do not limit the invention. EXAMPLE 1 Sixteen (16) screens were made with a structure as shown in FIG. 1 except for the topcoat films. In each case, a topcoat film was applied according to Table 1 below using various currently available surface materials. The phosphor layer comprises YTaO.sub.4 :Nb phosphor dispersed in a polyacrylate binder. Various tests were run on each sample to test for the average COF using the equipment described above, and for susceptibility to static as described above. In these samples, the various surfaces comprise materials with formulations and manufacturers as shown in Table 2 below. Other unusual observations such as static, thickness and transparency were also made with the results set out in Table 1 below: TABLE 1 ______________________________________ Average Topcoat Film COF Remarks ______________________________________ Polyamide, Nylon 6,6 0.20 Low Static, High Transparency Polyamide, Nylon 6 0.20 Same as Above Polyethylene 0.15 High Static Terephthalate Film Polyimide Film 0.17 Yellow Color PVDC-PP-PVDC Film.sup.1 0.25 Too Thick, Low Transparency Polycarbonate.sup.2 0.28 Too Thick, COF Too High PVDC/PVC 0.33 COF Too High Teflon .RTM. PFA 0.28 COF Too High Teflon .RTM. FEP 0.31 COF Too High Tedlar .RTM. PVF 0.31 COF Too High Polypropylene 0.33 COF Too High Tyril .RTM. Extruded 0.33 COF Too High Polyethylene 0.34 COF Too High Polyurethane 0.66 COF Too High Spray Coated Teflon .RTM. 0.63 COF Too High Solution Coated Tyril .RTM. 0.35 COF Too High ______________________________________ .sup.1 thickness 19.1 .mu.m .sup.2 thickness 25.4 .mu.m As can be seen from the above results, only the topcoat film made from polyamides having the requisite limitations of this invention provided high quality X-ray intensifying screen elements with good COF, high transparency, low static and no physical deficiencies noted. All of the remainder had severe problems of at least one type. TABLE 2 __________________________________________________________________________ Film Samples Tested General Structure Manufacturer __________________________________________________________________________ Polyamide Crystalline, Amorphous, Blends Du Pont, Allied PET [OCH.sub.2CH.sub.2OOCC.sub.6 H.sub.4CO].sub.n Du Pont, Toray Polyimide ##STR1## Du Pont PVDC-PP-PVDC Film [CH.sub.2CCl.sub.2].sub.n for the outer layer Hercules Polycarbonate [ROCOO].sub.n where R = aromatic General Electric PVDC/PVC [CH.sub.2CCl.sub.2]/[CH.sub.2CHCl] copolymer Dow Chemical Teflon .RTM. PFA ]CF.sub.2CF.sub.2]/[CF.sub.2CF(OR)] copolymer Du Pont Teflon .RTM. FEP [CF.sub.2CF.sub.2]/[CF.sub.2CF(CF.sub.3)] copolymer Du Pont Tedlar .RTM. PVF [CF.sub.2CF.sub.2].sub.n Du Pont Polypropylene [CH.sub.2CH(CH.sub.3)].sub.n ICI, Hercules, Mobil, Toray Polyethylene [CH.sub.2CH.sub.2].sub.n Du Pont Polyurethane Polyester type J. P. Stevens, Polyether type Deerfield, Dow Chemicals Spray-Coated -- Du Pont Polyimide Solution Coated [CH.sub.2CH(C.sub.6 H.sub.5)]/[CH.sub.2CH(CN)] Dow Chemical or Extruded Tyril .RTM. copolymer __________________________________________________________________________ EXAMPLE 2 In this example, polyamide topcoat films which meet the general definition of this invention were applied over phosphor layers made as described in Example 1. Nylon 6 and nylon 6,6 films of varying thickness were used. Only those with thicknesses of 15.2 .mu.m or less functioned within the ambit of this invention. The remainder were too thick and thus produced poor results with photographic elements exposed therewith. TABLE 3 ______________________________________ Film Thickness Sample (.mu.m) Remarks ______________________________________ Nylon 6,6 7.8 Best Image Resolution Nylon 6,6 12.2 Good Image Resolution Nylon 6,6 15.2 Marginal Image Resolution Nylon 6,6 25.4 Inadequate Image Resolution Nylon 6 12.2 Good Image Resolution ______________________________________ EXAMPLE 3 Various adhesive materials were tried successfully in this experiment. These were tried either on top of the phosphor layer (see Example 1) or applied directly to the polyamide layer which was a 7.8 .mu.m thick film of Nylon 6,6. The results for application to the polyamide layer are shown in Table 4, below: TABLE 4 ______________________________________ Sample Adhesive Used Adhesion ______________________________________ 1 Robond .RTM. LEC-58.sup.1 Good 2 Robond .RTM. PS-60.sup.2 Good 3 Carboset .RTM. XPD-1117.sup.3 Very good 4 Carboset .RTM. XPD-1246.sup.4 Very good 5 Carboset .RTM. XPD-1294.sup.5 Excellent 6 Carboset .RTM. 531.sup.6 Good 7 Whittaker 46960.sup.7 Very good 8 Whittaker 56065.sup.8 Very good 9 Rhoplex .RTM. AC201.sup.9 Poor 10 Adhesive E-2067.sup.10 Very good 11 Tycel .RTM. 7909/7283.sup.11 Very good 12 Geon .RTM. 57612.sup.12 Poor ______________________________________ .sup.1 acrylic, water soluble, pressure sensitive, Rohm & Haas, Philadelphia, PA .sup.2 acrylic, water soluble, pressure sensitive, Rohm & Haas, Philadelphia, PA .sup.3 acrylic, solvent soluble, B. F. Goodrich, Cleveland, OH .sup.4 acrylic, solvent soluble, thermoset, B. F. Goodrich, Cleveland, OH .sup.5 acrylic, solvent soluble, B. F. Goodrich, Cleveland, OH .sup.6 acrylic, water soluble, thermoset, B. F. Goodrich, Cleveland, OH .sup.7 polyester, solvent soluble, Whittaker Corp., W. Alexandria, OH .sup.8 polyester, solvent soluble, Whittaker Corp., W. Alexandria, OH .sup.9 acrylic, water soluble, thermoplastic, Rohm & Haas, Philadelphia, .sup.10 acrylic, waterborne, pressure sensitive, Rohm & Haas, Philadelphia, PA .sup.11 modified aliphatic polyester polyurethane, Lord Corp., Erie, PA .sup.12 plasticized vinyl chloride copolymer, B. F. Goodrich, Cleveland, OH EXAMPLE 4 A commercial grade, dimensionally stable, polyethylene terephthalate film of ca. 0.010 inch (0.25 mm) thickness and filled with TiO.sub.2 to provide reflection, was used as support 1 to prepare the screen of this example. YTaO.sub.4 :Nb phosphor dispersed in an acrylic polymer binder was applied thereon as layer 2, 0.006 inch (0.15 mm) thick. A 7.8 .mu.m thick Nylon 6,6 film was used as the topcoat 3 of this invention. This topcoat was first treated with Carboset.RTM.XPD-1294 adhesive described in Example 3 and then applied over phosphor layer 2 by lamination (Riston.RTM.HRL-24 laminator at 135.degree. C. and 0.4 m/minute with air assist.) This screen element, representing the invention, was tested first using the device shown in FIG. 2 and also used to expose a standard medical X-ray photographic film element to test for sensitometry. The average COF was 0.20, the static decay 1/2 time at 60% R.H. was 2.0 seconds and the speed and resolution of the film exposed therewith were equivalent to the control, indicating that the topcoat would provide superior protection with no loss of sensitometry. EXAMPLE 5 A commercial grade, dimensionally stable, polyethylene terephthalate film of ca. 0.010 inch (0.25 mm) thickness and filled with TiO.sub.2 to provide reflection, was used as support to prepare the screens of this example. YTaO.sub.4 :Nb phosphor dispersed in an acrylic polymer binder was applied thereon as a layer, 0.006 inch (0.15 mm) thick. The nylon films listed in Table 5 below were used as the topcoat film of this invention. These topcoat films were first treated with Carboset.RTM.XPD-1294 adhesive as described in Example 3 and then applied over the phosphor layer by lamination (Riston.RTM.HRL-24 laminator at 135.degree. C. and 0.4 m/minute with air assist). Each screen element was tested using the device shown in FIG. 2. The average COF and remarks concerning the screen elements are set out in Table 5 below. TABLE 5 ______________________________________ Film Gouge and Thickness Average Abrasion (.mu.m) COF Resistance ______________________________________ Polyamide Film None (control) -- 0.40 Poor Nylon 6,6 Dartek .RTM..sup.1 7.8 0.19 Excellent Nylon 6,6-extruded 15.2 0.20 Very good Nylon 6,12-extruded 15.2 0.23 Good Nylon 12,12-extruded 15.2 0.24 Satisfactory Nylon-amorphous and blends Selar .RTM. PA 3426.sup.2 Nylon 6 20% 80% 25.4* 0.22 Excellent 30% 70% 25.4* 0.24 Excellent 50% 50% 25.4* 0.23 Excellent 80% 20% 25.4* 0.25 Excellent 100% 0% 12.7 0.21 Excellent 100% 0% 25.4* 0.20 Excellent Nylon 6 12.7 0.21 Excellent Capran Emblem .RTM. 1200.sup.3 Nylon 6,6 7.8 0.18 Excellent Dartek .RTM..sup.1 ______________________________________ .sup.1 oriented nylon film manufactured by Du Pont Canada Inc., Mississauga, Canada .sup.2 amorphous nylon manufactured by E. I. du Pont de Nemours and Company, Wilmington, Delaware .sup.3 biaxially oriented nylon film manufactured by Allied Signal, Inc., Morristown, NJ *Film thickness does not adversely affect determination of COF. While films of amorphous nylon and blends of amorphous nylon with crystalline nylon are useful in the invention, the thickness should be no greater tha about 15.2 .mu.m to provide proper transparency to maintain image quality EXAMPLE 6 Example 4 was repeated with the following exceptions: the YTaO.sub.4 :Nb phosphor acrylic polymer binder layer was coated on the polyamide film and then laminated to the TiO.sub.2 filled support which was treated with Carboset.RTM. XPD-1294 adhesive. This screen element was tested as described in Example 4 and gave equivalent results.
059237163	description	DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the various figures of the drawing wherein like reference characters refer to like parts, there is shown in FIG. 1 a schematic cross-sectional side view of a plasma extrusion dynamo 2 of the present invention showing the applied and current loop fields separately. In the present invention, the continuous extrusion of plasma through a converging magnetic nozzle forms a stationary, steady-state current loop 15 within the moving plasma stream 14 as hereinafter described. In an exemplary embodiment, the plasma extrusion dynamo 2 of the present invention includes a plurality of nozzle coils 12 that are configured to produce the converging field lines 11. While two coils are illustrated, this is not a limitation. It is with the skill of those knowledgeable in the art to adjust the strength, size and number (i.e., at least one) of the coils to provide the desired magnetic field so as to create the desired annular current flow path 15 in the moving plasma flow 14. For example, the nozzle coils can be arranged alone or in combination with ferromagnetic structures to produce the converging magnetic fields. Also, the nozzle coils can be arranged to generate funnel like converging magnetic fields that present any of a number of cross sections, including circular, elliptical, oval and polygonal cross sections, that will produce a closed current loop 15 responsive to the flowing conductive plasma. Preferably, the magnetic field being generated by the nozzle coils 12 is a converging conical magnetic field so as to form a nozzle or inlet region that receives the plasma flow 14. In the illustrated embodiment, the nozzle coils 12 are direct current electromagnetic coils. Alternatively, the nozzle coils can be superconducting coils or permanent magnets. Further, ferromagnetic structures such as iron, disposed outside the plasma, can be used to concentrate or guide the magnetic fields being generated by the nozzle coils 12 to produce a magnetic field have the desired cross section and strength. As described in specific fusion reactor embodiments below (see FIGS. 3-4), a neutral fuel 32 is converted into a conductive plasma using any one of a number of techniques known in the art, as well as using the heat and radiation from continuous fusion reactions. The conductive plasma being presented to the converging magnetic field is a pressurized conductive plasma flow so as to form a high pressure region 10 upstream of the nozzle region. The conductive plasma flows towards the converging field lines 11 formed by the set of direct current carrying nozzle coils 12 to a lower pressure exhaust region 13. The nozzle or inlet region is formed by the converging magnetic field lines 11 such as those near the center of a circular current loop 15. The plasma flow 14 intersects the converging field lines 11 and crosses the radial components of the field. The crossing of the magnetic field lines 11 by a conductive fluid such as the plasma flow 14 is resisted if the field and plasma geometry is such that a sustained current is free to flow in the fluid in a direction perpendicular to the plane defined by the magnetic field lines and the plasma pressure gradient. More particularly, the crossing of the field lines by the plasma flow 14 generates a circularly polarized voltage and current loop 15 surrounding or about the axis 16 of the nozzle and plasma extrusion dynamo 2. Because the plasma current loop 15 interacts with the radial nozzle field components to retard the flow, a pressure gradient between the upstream and downstream side of the nozzle is required to maintain the flow of plasma. The current loop 15 in the plasma also interacts with the axial components of the magnetic field lines 11 in the nozzle region to generate radially inward forces 18 that tend to squeeze the plasma current loop to a smaller diameter. The squeezing forces 18 are resisted by plasma pressure as well as by the mutual magnetic repulsion of the opposite sides of the plasma current loop 15. The resistive plasma continues to flow and cross the nozzle field lines. The new plasma entering behind it interacts in turn with the magnetic field in the nozzle region and renews the plasma current loop. The result is a steady plasma extrusion flow through the nozzle that generates a steady-state, stationary current loop 15 for an indefinite period of time. The flow energy sustains the current against resistive losses. At higher plasma temperatures the lower plasma resistivity reduces the losses and consequently reduces the required flow rate. In sum, the conditions are such that the plasma flow is retarded by the field lines 11 and a current loop 15 is formed in the nozzle region of the magnetic field. The current loop 15 interaction with the radial components of the field lines 11 produces axial retarding forces 17, and the interaction with the axial field lines produces radial squeeze forces 18. The retarding forces 17 and the radial squeeze forces 18 act to retard the plasma flow 14 and compress the plasma to a smaller diameter. This occurs because the plasma particles are the charge carriers that form the current and experience the electromagnetic field forces. The current loop 15 generates a poloidal magnetic field 19, i.e., a set of closed poloidal magnetic flux loops, that extends along the circumferential length of the current loop 15. This poloidal magnetic field 19 has three effects. First, it encloses a toroidal plasma volume with closed field lines 20 (FIG. 2) which tend to contain the plasma particles. Second, the plasma current loop charge carriers interact with the poloidal field and are compressed toward the center of the current path cross-section through a pinch effect. This pinched center forms the fusion reaction zone. Third, the current loop interacts with itself through the poloidal field to expand the loop and resist the radial squeeze forces 18. The pinched plasma also is contained so it is far from any physical walls so as to sustain nuclear fusion reaction conditions. Under steady-state conditions the current loop 15 will reach an equilibrium size and current level that depends on the applied pressure gradient for the plasma flow and the strength and geometry of the magnetic nozzle field 11. Plasma particles, acting as current charge carriers, will loose momentum in the current carrying direction through collisions (the normal electrical resistance effect), and flow toward the exhaust under the influence of the pressure gradient. The motion across the field lines 11 will cause the plasma particles to again become current loop charge carriers, but in a path closer to the exhaust. The net result of this process is a pressure driven flow through the magnetic nozzle which maintains a steady-state current flow through dynamo action which balances resistive losses. It should be noted that while there is a plasma flow through the magnetic nozzle under steady-state conditions, the current loop is stationary with respect to the nozzle coils 12 and the axis 16. This flow-through effect provides an automatic means of adding fresh fuel to the reaction zone and removing reaction products. Second order interactions such as flux relaxation may convert some of the poloidal flux 19 to toroidal flux parallel to the current loop 15. This will result in a more stable flux configuration. The form of the plasma toroid depends on the design of the magnetic nozzle. If radial field lines dominate, a relatively force-free toroid resembling a spheromak will result. If axial flux lines dominate, a tightly squeezed structure will be formed which resembles a theta pinch toroid. Referring now to FIG. 2, there is shown a schematic cross-sectional side view of the plasma extrusion dynamo 2 of FIG. 1 showing the resultant of the nozzle field 11 and the current loop poloidal field 19. As shown, the closed field lines 20 of the poloidal field 19 encloses the current loop 15 and forms a toroidal volume 21. As indicated above, the interaction of the plasma current loop 15 with its own poloidal magnetic field 19 compresses the plasma in the toroidal volume 21 toward the toroid section axis through the pinch effect. The closed field lines 20 forming the toroidal volume 21 retard the plasma in the high pressure region 10 from flowing directly to the lower pressure exhaust region 13. As such, the toroidal volume 21 acts in effect acts as a flow retarding device. The closed field lines 20 also present a converging field region 24 to the high pressure region 10 which is similar to converging field generated by the nozzle coils 12, but which is smaller and of opposite polarity. The converging region 24 tends to retard flow through the center of the toroidal volume 21 thereby enhancing the flow retarding performance of the toroidal volume 21. The border between the closed poloidal field lines 20 of the current loop 15 and the surrounding open field lines 23 generated by the nozzle coils 12, is typically referred to as the separatrix 22. The relative position of the separatrix 22 with respect to the axis 16 is a function of both the velocity of the plasma flow 14 and the strength of the nozzle coil generated magnetic field. For example, the diameter of the current loop 15 can be increased by increasing the velocity of the plasma flow 14 and, correspondingly, the diameter can be decreased by increasing the strength of the nozzle coil generated magnetic field. Now referring to FIG. 3, there is shown a schematic cross-sectional side view of one embodiment of a fusion reactor 100 with a plasma extrusion dynamo 2 of the present invention. The fusion reactor 100 includes a plasma extrusion dynamo 2 of the present invention, a means 102 for providing the pressurized plasma, an housing 104 and a vacuum pump 106. In terms of a fusion reactor, the conductive plasma is deuterium, tritium or any other element known in the art, or any combination of elements thereof, that can release energy as a result of a nuclear fusion reaction. The reactor also includes means (not shown) for capturing the energy generated by the fusion reactions so useable energy (e.g., electricity) can be provided to consumers. Reference also should be made to the foregoing for any item not specifically described hereinafter. The means 102 for providing the pressurized plasma 102 includes a plasma jet 31 that forms and accelerates the high velocity plasma 30 towards the nozzle region of the converging magnetic field lines 11 set up by the nozzle coils 12. The plasma jet 31 using known principles or techniques, e.g., arc discharge, converts neutral fuel 32 (e.g., deuterium) into a high velocity plasma stream using electric power 33 as an energy source. The plasma jet 31, the nozzle coils 12, the stagnation pressure zone 34, and the exhaust region 13 are enclosed in an impermeable vessel or housing 104. A vacuum pump 106 and associated exhaust piping is fluidically interconnected to the interior of this impermeable vessel or housing 104 so as to remove the exhaust gas and fusion reaction by-products as well as maintaining the low pressure conditions required for reactor operation. The impermeable vessel or housing may be manufactured from any of a number for materials, or combination of materials, as is known in the art that are adequate for the intended use and environmental conditions, e.g., a gas impermeable metallic shell with a ceramic or graphite lining. The vacuum pump 106 may be any of a number of known vacuum pumps or vacuum pumping systems that can maintain the required low pressure conditions within the housing 104 and capable of removing fusion reaction by-products and/or exhaust gases. For example, a system including a mechanical type of vacuum pump and a diffusion type of vacuum pump can be used to evacuate the housing interior and maintain a continuing exhaust process. The high velocity plasma jet 30 interacts with the converging nozzle field lines 11 and is decelerated, forming a high pressure stagnation region 34 upstream of the nozzle. The high pressure of the stagnation pressure zone 34 causes plasma to flow towards the lower pressure exhaust region 13. This flow of plasma, as previously described above, as it crosses the magnetic field lines 11 generates a current loop 15 for fusion reaction containment. The stagnation zone 34 and the continuous replenishment of conductive plasma from the high velocity plasma jet 30 assures a constant source of flowing plasma to maintain the current loop 15 as well as to create the conditions conducive to fusion reactions. Now referring to FIG. 4, there is shown a schematic cross-sectional side view of another embodiment of a fusion reactor 200 that is configured with two plasma extrusion dynamos 2,2' of the present invention having a common supply chamber 202. Reference should also be made to the foregoing for any item or feature not specifically described hereinafter. Also, in the following certain reference numerals have been provided with and without a "'" (e.g., 2 and 2') to distinguish the corresponding components of, and the two plasma extrusion dynamos 2,2'. Unless otherwise indicated in the following, the above described characteristics and features apply equally to the corresponding components and/or the dynamos. In operation, neutral fuel 32 is injected into the central volume of the common supply chamber 202, wherein it is converted to a relatively high pressure, relatively low temperature plasma 40. Microwaves 203, neutral beams or other known means of heating neutral material to form plasma can be supplied from an outside source to start or sustain the process. Preferably, the radiation 44 from fusion reactions supplies most or all of the plasma formation energy in steady-state operation. Each pair of direct current carrying nozzle coils 12,12' of the respective plasma extrusion dynamos 2,2' are placed back-to-back on a common axis 205. Both nozzle coils 12,12' are energized with a current in the same rotational direction so the converging nozzle fields 11,11' join and surround the central volume of the common supply chamber 202 with a common field 206. A separator coil 207 is placed midway between the nozzle coils, and centered on their common axis 205. The separator coil 207 is energized with a current in the same rotational direction as is used to energize the nozzle coils 12,12'. The separator coil 207 contributes to the common field 206 and has other functions that are described below. As with the first fusion reactor embodiment described above, the fusion reactor 200 also includes a housing 104 and a vacuum pump 106. The impermeable vessel or housing 104 surrounds both of the extrusion dynamos 2,2' including both sets of nozzle coils 12,12', the common supply chamber 202, and separator coil 207. The vacuum pump 106 and the associated exhaust piping 209 or ducts are fluidically interconnected to the interior of the impermeable vessel or housing 104 so as to remove the exhaust gas and fusion reaction byproducts as well as to maintain the low pressure conditions required for reactor operation. The plasma 40 in the common supply chamber 202 is at relatively high pressure, and flows to the lower pressure exhaust regions 13,13' defined for the respective extrusion dynamos. As described in the foregoing, the plasma flow crosses the field lines 11,11' and generates current loops 15,15' for fusion reaction containment in each of the plasma extrusion dynamos. Because the plasma current loops 15,15' have parallel currents, the magnetic fields of each will have a tendency to attract each other creating the potential for merging the two current loops. Such a merger would disrupt the dynamo process in at least one of the two magnetic nozzles. The separator coil 207, preferably carries current anti-parallel to that in the plasma current loops 15,15' to repel the current loops thereby preventing merger. The separator coil 207 also clamps the plasma current loops 15,15' between anti-parallel coils to reduce their tendency to rotate about an axis perpendicular to the axis 205 common to the extrusion dynamos 2,2'. Although a preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.
	abstract	A movable carriage for moving an article support member in a lithographic apparatus is provided. The article support member is constructed and arranged to move and support an article to be placed in a beam path of the lithographic apparatus. The carriage includes a compartmented composite structure.
043137938	abstract	A machine for smoothly and controllably winding or unwinding a stiff in-core-instrument tube onto and off of a reel during ythe refueling of a nuclear reactor. The machine includes a frame (33) and a circular reel (32) having a substantially continuous helical groove (44) extending around the circumference of the reel. The groove is adapted to receive the tube (14). A plurality of cam rollers (52) are carried by the frame and closely spaced around the circumference of the reel. The rollers keep the tube in the groove whereby the tube may be more easily wound onto or off of the reel. In the preferred embodiment, the reel carries a disposable cartridge (46) in which the grooves are formed.
	description	Throughout the following detailed description, similar reference characters refer to similar elements in all figures of the drawings. Tiling, in the present context, means the assembly of a plurality of tiles, each a replicate of the prototile by arraying the tiles contiguously side by side to form a large area comprising a plurality of tiles. As explained in xe2x80x9cA series of books in the mathematical sciencesxe2x80x9d edited by Victor Klee, Copyright 1987, page 20, basic notions, paragraph 1.2 xe2x80x9cTilings with tiles of a few shapesxe2x80x9d, monohedral tiling is the process of assembling a plurality of same size and shape tiles. Each of these tiles is replicated from a prototile. In the present description, when we refer to tiling we imply monohedral tiling, and when we refer to xe2x80x9cprototile,xe2x80x9d consistent with accepted terminology, we refer to an individual tile of a group of same size and shape tiles. Such prototiles may be virtual, that is exist only as a mathematical expression or may take physical form such as a displayed soft or hard image. When the prototiles contain a design within the prototile, referred to herein as a xe2x80x9cmotifxe2x80x9d the combined motifs of all the tiled prototiles forms a pattern. There are an infinite number of related prototiles that can be used to generate a particular grid. Any repeating unit of a grid can be said to be generated from a prototile of that repeat pattern. The prototile outline can be translated in the X or Y directions to select an equivalent prototile. Ordinarily, the motif exhibiting the greatest symmetry is preferred, however this is not required. Preference for the highest symmetry motif originates in that the relationship between the motif structure and function is more easily apparent visually. Referring now to FIG. 1, there is shown a portion of a radiation detection panel 10 useful for radiographic imaging applications. The portion of a panel 10 comprises a plurality of sensors 12 arrayed in a regular pattern. Each sensor comprises a switching transistor 14 and a radiation detection electrode 16, which defines the sensor radiation detection area. Each radiation detection area has a width xe2x80x9cWsxe2x80x9d and a length xe2x80x9cLs,xe2x80x9d and is separated from an adjacent radiation detection area by an interstitial space xe2x80x9cS.xe2x80x9d The interstitial spaces are substantially incapable of detecting incident radiation. Associated with the sensors, there is also a sensor pitch along the sensor length, xe2x80x9cPLxe2x80x9d and a sensor pitch along the sensor width,xe2x80x9cPwxe2x80x9d. FIG. 2 shows a schematic section elevation of a smaller portion of the panel 10 viewed along arrows 2xe2x80x942 in FIG. 1. The sensor used for illustrating this invention is of the type described in U.S. Pat. No. 5,319,206 issued to Lee et al. and assigned to the assignee of this application, and in U.S. Pat. No. 6,025,599 issued to Lee et al., also assigned to the assignee of this application. A sensor of this type comprises a dielectric supporting base 20. On this base 20 there is constructed a switching transistor 22, usually a FET built using thin film technology. The FET includes a semiconductor material 25, a gate 24, a source 26 and a drain 28. Adjacent the FET there is built a first electrode 30. A dielectric layer 32 is placed over the FET and the first electrode 30. A collector electrode 34 is next placed over the first electrode 30 and the FET 22. Over the collector electrode there is placed an barrier or insulating layer 36 and over the insulating layer 36 a radiation detection layer 38 which is preferably a layer of amorphous selenium. A second dielectric layer 40 is deposited over the radiation detection layer, and a top electrode 42 is deposited over the top dielectric layer. The barrier or insulating layer 36, the radiation detection layer 38, the second dielectric layer 40 and the top electrode layer 42 are continuous layers extending over all the FETs and collector electrodes. In operation, a static field is applied to the sensors by the application of a DC voltage between the top electrode and the first electrodes. Upon exposure to X-ray radiation, electrons and holes are created in the radiation detection layer which travel under the influence of the static field toward the top electrode and the collector electrodes. Each collector electrode collects charges from the area directly above it, as well as some fringe charges outside the direct electrode area. There is thus an effective radiation sensitive area xe2x80x9cWxe2x80x9d associated with this type of sensor which is somewhat larger that the physical area of the collector electrode. The sensitive areas are separated by a dead space D. In the case where the effective sensitive area is equal to the electrode area, D becomes the interstitial S space. In an embodiment where the radiation detection layer is columnized, that is where the radiation detection layer extends upward from the collector electrode in an isolated column, the radiation sensitive area will be the same as the physical area of the collector electrode. This is particularly true in the type of sensor that employs a photodiode together with a radiation conversion phosphor layer. In such cases the phosphor layer is usually structured as discreet columns rising above the photodiode. In describing this invention we will use the term xe2x80x9cradiation sensitive areaxe2x80x9d to designate the actual area which is radiation sensitive, whether it is the same as the physical area of the sensor or not, and the term xe2x80x9copaquexe2x80x9d will designate radiation absorption material. In addition, because in practical use an anti-scatter grid is (a) three dimensional and (b) occasionally positioned spaced away from the surface of the radiation detection layer, the terms prototile width and prototile length refer to the width and length of a prototile such that its projected image on the sensitive surface satisfies the required relationships between prototile dimensions and sensitive surface dimensions, when the prototile is in the grid plane. For design purposes, this can be any plane through the grid, parallel to the width and length of the grid. Preferably, this plane is the plane closest to the sensitive surface. Finally, while the grid is usually described as having a height perpendicular to its width and length, it is to be understood that this height can also be inclined with respect to the perpendicular to produce a grid having opaque elements aligned with the incident radiation path which may be a path that diverges radially from the radiation source. This type of grid element orientation is also well known in the art and grids having such inclined walls are described in U.S. Pat. No. 4,951,305 issued to Moore et al. (Particularly Moore, FIG. 8). Grids having such oriented elements are still to considered as being included when there is reference to a grid height. In practice, particularly where the grid is placed in contact with, or close to the sensitive surface, the projected and actual dimensions will be substantially the same, in which case the actual dimensions will be convenient to use. The relationship between the projected grid and the sensitive area is described herein in terms of percent mismatch between the elements of the grid and the corresponding elements of the sensor. FIG. 3 shows a portion of a radiation detection panel of the type described above with a portion of a scattered radiation shielding grid 44 placed over the panel. As shown in the figure, the grid comprises a pattern of a plurality of opaque strips 46 and 48 aligned along the width and length of the panel. This type of anti-scatter grid, is a common type of anti-scatter grid available, and may be manufactured easily. See for instance U.S. Pat. No. 5,606,589 issued to Pellegrino et al., which discloses such a cross grid and a method for its manufacture and use in medical radiography. However, use of this type of grid with a radiation detection panel of the type disclosed above is prone to the production of Moirxc3xa9 patterns, unless as taught by Tsukamoto et al. in U.S. Pat. No. 5,666,395, the grid is fixed in relationship to the underlying array of radiation sensors, the grid pitch is the same as the array pitch, and the grid bars are aligned with the centerlines of the interstitial spaces. Such a relationship requires zero percent mismatch between the detection panel and the grid. The present invention employs a grid having a pattern of absorbing material that does not produce Moirxc3xa9 patterns without requiring the exact placement of the grids of the prior art. As clearly shown in FIG. 3, the absorbing material pattern of grid 44 is not aligned with the interstitial or dead spaces of the underlying array of sensitive areas 11. Unlike the Tsukamoto grid, grid 44 may be placed anywhere and still function effectively, within the limits of alignment to the radial radiation. Further more the grid may be moved during the radiation exposure. Each of the tiles tiled to form the grid are replicates of a prototile that includes a motif 52 which will be used to design the opaque pattern of the grid. In FIG. 3A this motif is a cross. The motif of the prototile is selected such that when the tiles are tiled, the pattern of the plurality of the tiled tiles combined form the grid pattern shown in FIG. 3. As better shown in FIG. 3A, the prototile 50 has a width Wp and a length Lp. The width of the prototile Wp equals the width Ws of the radiation sensitive area 11 of the sensor of the panel divided by an integer I. Thus Wp=Ws/I. In most instances I=1. The same is applicable to the length Lp of the prototile relative to the length Ls of the sensitive area; again Lp=Ls/B, where B is an integer, and again, preferably B=1. Referring now to FIG. 11, grid 94 has been designed in accordance with this invention by tiling a plurality of tiles, replicated from prototile 90, shown in dotted lines in FIG. 11 to generate the pattern for the absorbing material. The radiation absorbing material in the figures are shown as thick black segments. The prototile 90 and the grid 94 are not shown to scale in the figures. The prototile is enlarged relative to the grid to provide detail. As better shown in FIG. 11A, the prototile 90 also has a width Wp and a length Lp. The width of the prototile Wp equals the width Ws of the radiation sensitive area 11 of the sensor of the panel divided by an integer I. Thus Wp=Ws/I. In most instances I=1. The same is applicable to the length Lp of the prototile relative to the length Ls of the sensitive area; again Lp=Ls/B, where B is an integer, and again, preferably B=1. The prototile includes a motif 92 which represents radiation absorbing material. In FIG. 11A this motif is a xe2x80x9cpinwheel.xe2x80x9d The motif is selected such that when the tiles derived from the prototile 90 are tiled, the motifs of the plurality of the tiles combine upon tiling of the tiles to form the pattern shown in FIG. 11. This is the pattern for the opaque material in the grid. The pinwheel motif shown in the protiles 69, 78 of FIGS. 4A and 7A respectively is a preferred motif. Unlike the cross motif shown in FIG. 3A and the diamond motif shown in a comparative example in FIG. 8A, the pinwheel motif has no xe2x80x9ccrossover regionxe2x80x9d at the center of the motif. The crossover region of the cross motif is the location where the two diagonal linear segments of the cross overlay, such as the lines of an xe2x80x9cXxe2x80x9d. Since the linear segments overlap in the crossover region, even if only conceptually, the area of radiation absorbing material, along the width or length of the tile is less at the cross-region than at any other position. A pinwheel motif avoids any such crossover region in the tile. The elimination of the crossover region achieved by the pinwheel motif, eliminates a Moirxc3xa9 xe2x80x9chot spotxe2x80x9d caused by the reduced area of radiation absorbing material in the crossover region. By eliminating the crossover region, the modulation and overall perception of the Moirxc3xa9 pattern is reduced. An exemplary reduction in Moirxc3xa9 pattern perception is shown in comparing the resulting Moirxc3xa9 patterns in FIGS. 4C and 8C. The pinwheel motif 69 of FIG. 4A forms the patterned grid 71 shown in FIG. 4B when assembled into a grid. This grid 71 produces the Moirxc3xa9 pattern 73 shown in FIG. 4C. In FIGS. 4A, B, and C; 7A, B, and C; and 8A, B, and C the prototiles, grids and resulting Moirxc3xa9 patterns are not shown to scale. The prototile is enlarged relative to the grid, and the grid is enlarged relative to the corresponding Moirxc3xa9 pattern to better illustrate the features of interest. In computer simulations, this grid 71 of FIG. 4B produced a Moirxc3xa9 pattern modulation of 1.0%, whereas a grid 86 (FIG. 8B) assembled from the diamond motif 84 of FIG. 8A produced a Moirxc3xa9 pattern 88, shown in FIG. 8C, with a modulation of 11.2% in simulations. Moirxc3xa9 pattern modulation is the difference between the highest amplitude and lowest amplitude areas of the pattern, divided by the highest amplitude of the overall Moirxc3xa9 pattern, multiplied by 100. The modulation percentage of the Moirxc3xa9 pattern is an indication of the perception of the Moirxc3xa9 pattern as the greater the differences between the high and low amplitude regions, the greater the perception of the Moirxc3xa9 pattern. Similar to FIGS. 4A, B and C, FIG. 7B shows a grid 80 assembled from of a plurality of tiles replicated from the prototile 78 shown in FIG. 7A. The radiation absorbing material of prototile 78 occupies a higher percentage of the prototile area than does the radiation absorbing area of prototile 69. FIG. 7C shows a Moirxc3xa9 pattern 82 resulting from the grid shown in FIG. 7B when mismatched 5% with a radiation detection panel. The pinwheel motif is also less sensitive to mismatching between the anti-scatter grid and detection panel than other prototile motifs. As shown in FIGS. 5 and 6, the Moirxc3xa9 pattern modulation resulting from a grid comprising tiles with a pinwheel motif increases modestly with an increase in mismatch between grid and detector elements. The Moirxc3xa9 pattern 75 in FIG. 5 was simulated with a 10% mismatch between the tiles of the grid and the sensors of the detection panel. This arrangement exhibits a modulation of 4.7%, and a radiation transmission value of 70.5% in simulation. The Moirxc3xa9 pattern 76 of FIG. 6 was simulated with a 20% mismatch, and showed a modulation of 10.0%, and a radiation transmission value of 72.1% in simulation. FIG. 9 is a graph showing the calculated Moirxc3xa9 pattern amplitude as a function of percent mismatch between the detection panel and the anti-scatter grid for three prototile motifs: the pinwheel motif according to the present invention FIG. 4A; the cross motif FIG. 3A, as discussed above; and a diamond motif FIG. 8A, shown in U.S. Pat. No. 5,606,589 Pellegrino et al. to ThermoTrex (now held by Hologic). The graph in FIG. 9 shows that the cross motif (triangle symbol) shown in FIG. 3A is highly sensitive to any mismatch between the anti-scatter grid and the detection panel. However, the diamond (square symbol) (FIG. 8A) and the pinwheel (square-on-point symbol) (FIGS. 4A and 7A) motifs are considerably less sensitive, with the pinwheel motif being the least sensitive to mismatch between the anti-scatter grid and the detector panel. The amplitude of the Moirxc3xa9 pattern remains small for a grid using the pinwheel even as the projected size of the elements or tiles of the grid varies. This occurs when the X-ray source to grid or the grid to detector distance varies, for example. Further, manufacturing variances in grid construction will be less detrimental in producing Moirxc3xa9 patterns when the pinwheel motif is used. A number of different grid designs can be produced using the technology disclosed in U.S. Pat. No. 5,259,016 issued to Dickerson et al. The use of photographic techniques to produce radiation absorption grids having shapes other than straight lines is shown in that reference and can be used to produce grids designed using the present invention wherein the opaque grid strips are other than straight lines. The aforementioned U.S. Pat. No. 4,951,305 issued to Moore et al. also teaches methods for producing complex grid shapes. Although the above discussion has been limited to the grid design in the x-y plane, it is understood that the grid has a third dimension along the z axis, or in other words the grid walls have a height. The wall height ranges from about 2 to 16 times the thickness of the wall. A preferred height ratio is about 6 to 12. The ratio of wall thickness to the prototype width ranges from about {fraction (1/10)} to xc2xd with a preferred ratio of about ⅙. Because the radiation impinges on the panel at different angles rather than perpendicular, i.e. along the z axis, the projection of the grid on the panel will be both magnified and distorted depending on the distance of the grid from the radiation sensitive surface, and to some extent depending on the distance and nature of the radiation source. A collimated radiation source, for instance, will produce no magnification or distortion effect, while a point source will produce both. These effects are well understood in the art and proper compensation to the grid design will be made, by designing a grid using a prototile such that its projection on the panel will satisfy the above developed criteria. These effects are minimized by placing the grid in close proximity and preferably intimate contact with the sensitive area, and by minimizing the grid wall height. In summary, a grid is designed as follows in accordance with this invention. First, the effective radiation detection area of the panel sensors is determined to identify the radiation sensitive area and the prototile size is then determined according to the relationships given above. Next, a desired motif is created in the prototile. The prototile is then duplicated and a plurality of tiles assembled to create the pattern of the grid which results from the combined motifs of the tiles. Mirror images of the prototile may also be used with the original prototile to create a pattern. This pattern is then used for the radiation absorption material which forms the anti-scatter grid. This material may be lead. The grid may be constructed according to the teachings of the aforementioned U.S. patents to Dickerson et al., Pellegrino et al. or Moore et al. If the grid is not to be in contact with the sensors and the radiation source is a point source, the prototile design is based on the projection of the grid onto the sensitive area, as discussed above. As may be surmised by the above discussion, it is very difficult to obtain grids with the exact requisite absorbing material spacing and thickness completely free from manufacturing imperfections. Furthermore, thermal expansion may alter somewhat the grid element spacing, and a shift during installation may change the originally calculated distance between the grid elements and the detection panel so that the relationship W(p)=W/I no longer holds absolutely true. Surprisingly, it has been observed that some deviation of the theoretically optimum grid pattern for a particular detection panel and grid positioning is acceptable when the detection panel includes, as is almost always the case, an associated gain control circuit. Gain control circuits are used to compensate for different output levels of different individual sensors in an array of such sensors by correcting the individual output of each sensor or pixel such that when a detection panel is illuminated by uniform intensity radiation, the output of each sensor becomes the same. In a typical digital gain correction system, this involves a calibration step whereby prior to using a detection panel in an image detection system, the panel is exposed to radiation at a predetermined level of intensity. Each of the individual sensors output is recorded and for each individual sensor there is generated and stored a correction factor usually in a Look-Up-Table (LUT). When an image is obtained the raw output of each sensor is corrected by the corresponding correction factor from the LUT. According to this invention, if the calibration step is undertaken with the grid in place, whereby instead of a substantially uniform illumination level the grid image is projected on the panel variations in the grid absorbing material pattern of as much as + or xe2x88x9210% from the calculated dimensions are compensated for by the gain correction system. Thus a manufactured grid whose pattern corresponds to a prototile width W(p)=W/(Ixc2x10.11) and W(p) different (xe2x89xa0) from W+D still results in a grid that presents no objectionable Moirxc3xa9 patterns. FIG. 10 illustrates the use of this grid in a system to obtain a radiogram. The system includes a radiation source 60, which is typically an X-ray source emitting a beam of radiation 62. A target or patient 64 is placed in the beam path. On the other side of the patient there is placed a combination of a grid 66 and detection panel 68. The grid is a grid created in accordance with the present invention and has a pattern of absorbing material, such as, for instance, shown in FIG. 11 discussed earlier. Behind the grid 66 at a fixed distance therefrom is positioned a radiation detection panel 68 such as the panel described earlier in conjunction with FIGS. 1 and 2. The panel is connected over wire 70 to a control console 72 which may include a display screen 74 and/or a hard copy output device (not shown) for producing a hard copy of the radiogram. Typically the control console will also include a plurality of image processing circuits, all of which are well known in the art. Preferably, a gain control circuit is included, either as a part of the detection panel itself or as part of the control console. Preferably, the grid was originally designed such that W(p)=W/I. However even if due to manufacturing imperfections, thermal change, actual spacing between the installed grid and detection panel or whatever other reason such relationship is not satisfied exactly, as long as the actual grid pattern satisfies the relationship W(p)=W/(Ixc2x10.10I) discussed above, such grid is acceptable. In obtaining the radiogram, first the system is calibrated by obtaining a blank exposure of the detection panel, that is one without the target present, and using the gain control circuit to generate a flat field output image, i.e. one that has a uniform density throughout the image area. The target is then placed in position and exposed to radiation. The radiation becomes imagewise modulated as it traverses the target and impinges on the detection panel after transiting the grid. The resulting image has been found substantially free of Moirxc3xa9 interference patterns. The same result was obtained whether the grid was stationary during exposure or whether the grid is mounted on a moving support that moves the grid during exposure in a plane substantially parallel to the plane of the detection panel. Those having the benefit of the above disclosure, which teaches a grid for limiting scattered radiation from impinging on a radiation detection panel having an array of sensitive areas separated by non radiation sensitive interstitial spaces by designing a grid of radiation opaque areas such that regardless of the placement of the grid relative to the sensitive area array the opaque areas always cover the same amount of area of the sensitive area, may modify this invention in numerous ways to achieve this result. These modifications are to be construed as being encompassed within the scope of the present invention as set forth in the appended claims.
054065968	abstract	The device includes a removable supporting end piece (26) which comes to rest on the top end part of a support assembly (21) fixed to the end of a port adapter of the head of the vessel of a nuclear reactor, and a pressure plate (28) including an odd number of lifting screws (31), so as to move the instrumentation column (22) upward and to clamp it against a support surface (24). A tightening assembly (35) for the lifting screws includes a tightening spindle (42a) having an end part (45) shaped to receive a tool (40) for rotating the spindle, and in turn rotates tightening spindles mounted so as to idle in the mounting plate (38) of the tightening assembly (35). The tightening spindles comprise shaped end parts (46a) coming into engagement with drive parts (31b) of the lifting screws (31) of the pressure plate (28), so as to tighten all the lifting screws simultaneously.
	summary
	summary
	description	This application claims the benefit under 35 U.S.C. § 119(e) of the priority of the following U.S. Provisional Applications filed on Apr. 3, 2013, the entire disclosures of which are hereby incorporated by reference: U.S. Provisional Application No. 61/808,136, entitled “MAGNETIC FIELD PLASMA CONFINEMENT FOR COMPACT FUSION POWER”; U.S. Provisional Application No. 61/808,122, entitled “MAGNETIC FIELD PLASMA CONFINEMENT FOR COMPACT FUSION POWER”; U.S. Provisional Application No. 61/808,131, entitled “ENCAPSULATION AS A METHOD TO ENHANCE MAGNETIC FIELD PLASMA CONFINEMENT”; U.S. Provisional Application No. 61/807,932, entitled “SUPPORTS FOR STRUCTURES IMMERSED IN PLASMA”; U.S. Provisional Application No. 61/808,110, entitled “RESONANT HEATING OF PLASMA WITH HELICON ANTENNAS”; U.S. Provisional Application No. 61/808,066, entitled “PLASMA HEATING WITH RADIO FREQUENCY WAVES”; U.S. Provisional Application No. 61/808,093, entitled “PLASMA HEATING WITH NEUTRAL BEAMS”; U.S. Provisional Application No. 61/808,089, entitled “ACTIVE COOLING OF STRUCTURES IMMERSED IN PLASMA”; U.S. Provisional Application No. 61/808,101, entitled “PLASMA HEATING VIA FIELD OSCILLATIONS”; and U.S. Provisional Application No. 61/808,154, entitled “DIRECT ENERGY CONVERSION OF FUSION PLASMA ENERGY VIA CYCLED ADIABATIC COMPRESSION AND EXPANSION”. This disclosure generally relates to fusion reactors and more specifically to heating plasma for compact fusion power using neutral beam injection. Fusion power is power that is generated by a nuclear fusion process in which two or more atomic nuclei collide at very high speed and join to form a new type of atomic nucleus. A fusion reactor is a device that produces fusion power by confining and controlling plasma. Typical fusion reactors are large, complex, and cannot be mounted on a vehicle. According to one embodiment, a fusion reactor includes two internal magnetic coils suspended within an enclosure, a center magnetic coil coaxial with the two internal magnetic coils and located proximate to a midpoint of the enclosure, a plurality of encapsulating magnetic coils coaxial with the internal magnetic coils, and two mirror magnetic coil coaxial with the internal magnetic coils. The fusion reactor further includes one or more heat injectors operable to inject a beam of neutral particles toward the center of the enclosure. Technical advantages of certain embodiments may include providing a compact fusion reactor that is less complex and less expensive to build than typical fusion reactors. Some embodiments may provide a fusion reactor that is compact enough to be mounted on or in a vehicle such as a truck, aircraft, ship, train, spacecraft, or submarine. Some embodiments may provide a fusion reactor that may be utilized in desalination plants or electrical power plants. Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions, and claims. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some, or none of the enumerated advantages. Fusion reactors generate power by confining and controlling plasma that is used in a nuclear fusion process. Typically, fusion reactors are extremely large and complex devices. Because of their prohibitively large sizes, it is not feasible to mount typical fusion reactors on vehicles. As a result, the usefulness of typical fusion reactors is limited. The teachings of the disclosure recognize that it is desirable to provide a compact fusion reactor that is small enough to mount on or in vehicles such as trucks, trains, aircraft, ships, submarines, spacecraft, and the like. For example, it may be desirable to provide truck-mounted compact fusion reactors that may provide a decentralized power system. As another example, it may be desirable to provide a compact fusion reactor for an aircraft that greatly expands the range and operating time of the aircraft. In addition, it may desirable to provide a fusion reactor that may be utilized in power plants and desalination plants. The following describes an encapsulated linear ring cusp fusion reactor for providing these and other desired benefits associated with compact fusion reactors. FIG. 1 illustrates applications of a fusion reactor 110, according to certain embodiments. As one example, one or more embodiments of fusion reactor 110 are utilized by aircraft 101 to supply heat to one or more engines (e.g., turbines) of aircraft 101. A specific example of utilizing one or more fusion reactors 110 in an aircraft is discussed in more detail below in reference to FIG. 2. In another example, one or more embodiments of fusion reactor 110 are utilized by ship 102 to supply electricity and propulsion power. While an aircraft carrier is illustrated for ship 102 in FIG. 1, any type of ship (e.g., a cargo ship, a cruise ship, etc.) may utilize one or more embodiments of fusion reactor 110. As another example, one or more embodiments of fusion reactor 110 may be mounted to a flat-bed truck 103 in order to provide decentralized power or for supplying power to remote areas in need of electricity. As another example, one or more embodiments of fusion reactor 110 may be utilized by an electrical power plant 104 in order to provide electricity to a power grid. While specific applications for fusion reactor 110 are illustrated in FIG. 1, the disclosure is not limited to the illustrated applications. For example, fusion reactor 110 may be utilized in other applications such as trains, desalination plants, spacecraft, submarines, and the like. In general, fusion reactor 110 is a device that generates power by confining and controlling plasma that is used in a nuclear fusion process. Fusion reactor 110 generates a large amount of heat from the nuclear fusion process that may be converted into various forms of power. For example, the heat generated by fusion reactor 110 may be utilized to produce steam for driving a turbine and an electrical generator, thereby producing electricity. As another example, as discussed further below in reference to FIG. 2, the heat generated by fusion reactor 110 may be utilized directly by a turbine of a turbofan or fanjet engine of an aircraft instead of a combustor. Fusion reactor 110 may be scaled to have any desired output for any desired application. For example, one embodiment of fusion reactor 110 may be approximately 10 m×7 m and may have a gross heat output of approximately 100 MW. In other embodiments, fusion reactor 110 may be larger or smaller depending on the application and may have a greater or smaller heat output. For example, fusion reactor 110 may be scaled in size in order to have a gross heat output of over 200 MW. FIG. 2 illustrates an example aircraft system 200 that utilizes one or more fusion reactors 110, according to certain embodiments. Aircraft system 200 includes one or more fusion reactors 110, a fuel processor 210, one or more auxiliary power units (APUs) 220, and one or more turbofans 230. Fusion reactors 110 supply hot coolant 240 to turbofans 230 (e.g., either directly or via fuel processor 210) using one or more heat transfer lines. In some embodiments, hot coolant 240 is FLiBe (i.e., a mixture of lithium fluoride (LiF) and beryllium fluoride (BeF2)) or LiPb. In some embodiments, hot coolant 240 is additionally supplied to APUs 220. Once used by turbofans 240, return coolant 250 is fed back to fusion reactors 110 to be heated and used again. In some embodiments, return coolant 250 is fed directly to fusion reactors 110. In some embodiments, return coolant 250 may additionally be supplied to fusion reactors 110 from APUs 220. In general, aircraft system 200 utilizes one or more fusion reactors 110 in order to provide heat via hot coolant 240 to turbofans 230. Typically, a turbofan utilizes a combustor that burns jet fuel in order to heat intake air, thereby producing thrust. In aircraft system 200, however, the combustors of turbofans 230 have been replaced by heat exchangers that utilize hot coolant 240 provided by one or more fusion reactors 110 in order to heat the intake air. This may provide numerous advantages over typical turbofans. For example, by allowing turbofans 230 to operate without combustors that burn jet fuel, the range of aircraft 101 may be greatly extended. In addition, by greatly reducing or eliminating the need for jet fuel, the operating cost of aircraft 101 may be significantly reduced. FIGS. 3A and 3B illustrate a fusion reactor 110 that may be utilized in the example applications of FIG. 1, according to certain embodiments. In general, fusion reactor 110 is an encapsulated linear ring cusp fusion reactor in which encapsulating magnetic coils 150 are used to prevent plasma that is generated using internal cusp magnetic coils from expanding. In some embodiments, fusion reactor 110 includes an enclosure 120 with a center line 115 running down the center of enclosure 120 as shown. In some embodiments, enclosure 120 includes a vacuum chamber and has a cross-section as discussed below in reference to FIG. 7. Fusion reactor 100 includes internal coils 140 (e.g., internal coils 140a and 140, also known as “cusp” coils), encapsulating coils 150, and mirror coils 160 (e.g., mirror coils 160a and 160b). Internal coils 140 are suspended within enclosure 120 by any appropriate means and are centered on center line 115. Encapsulating coils 150 are also centered on center line 115 and may be either internal or external to enclosure 120. For example, encapsulating coils 150 may be suspended within enclosure 120 in some embodiments. In other embodiments, encapsulating coils 150 may be external to enclosure 120 as illustrated in FIGS. 3A and 3B. In general, fusion reactor 100 provides power by controlling and confining plasma 310 within enclosure 120 for a nuclear fusion process. Internal coils 140, encapsulating coils 150, and mirror coils 160 are energized to form magnetic fields which confine plasma 310 into a shape such as the shape shown in FIGS. 3B and 5. Certain gases, such as deuterium and tritium gases, may then be reacted to make energetic particles which heat plasma 310 and the walls of enclosure 120. The generated heat may then be used, for example, to power vehicles. For example, a liquid metal coolant such as FLiBe or LiPb may carry heat from the walls of fusion reactor 110 out to engines of an aircraft. In some embodiments, combustors in gas turbine engines may be replaced with heat exchangers that utilize the generated heat from fusion reactor 110. In some embodiments, electrical power may also be extracted from fusion reactor 110 via magnetohydrodynamic (MHD) processes. Fusion reactor 110 is an encapsulated linear ring cusp fusion device. The main plasma confinement is accomplished in some embodiments by a central linear ring cusp (e.g., center coil 130) with two spindle cusps located axially on either side (e.g., internal coils 140). These confinement regions are then encapsulated (e.g., with encapsulating coils 150) within a coaxial mirror field provided by mirror coils 160. The magnetic fields of fusion reactor 110 are provided by coaxially located magnetic field coils of varying sizes and currents. The ring cusp losses of the central region are mitigated by recirculation into the spindle cusps. This recirculating flow is made stable and compact by the encapsulating fields provided by encapsulating coils 150. The outward diffusion losses and axial losses from the main confinement zones are mitigated by the strong mirror fields of the encapsulating field provided by encapsulating coils 150. To function as a fusion energy producing device, heat is added to the confined plasma 310, causing it to undergo fusion reactions and produce heat. This heat can then be harvested to produce useful heat, work, and/or electrical power. Fusion reactor 110 is an improvement over existing systems in part because global MHD stability can be preserved and the losses through successive confinement zones are more isolated due to the scattering of particles moving along the null lines. This feature means that particles moving along the center line are not likely to pass immediately out of the system, but will take many scattering events to leave the system. This increases their lifetime in the device, increasing the ability of the reactor to produce useful fusion power. Fusion reactor 110 has novel magnetic field configurations that exhibit global MHD stability, has a minimum of particle losses via open field lines, uses all of the available magnetic field energy, and has a greatly simplified engineering design. The efficient use of magnetic fields means the disclosed embodiments may be an order of magnitude smaller than typical systems, which greatly reduces capital costs for power plants. In addition, the reduced costs allow the concept to be developed faster as each design cycle may be completed much quicker than typical system. In general, the disclosed embodiments have a simpler, more stable design with far less physics risk than existing systems. Enclosure 120 is any appropriate chamber or device for containing a fusion reaction. In some embodiments, enclosure 120 is a vacuum chamber that is generally cylindrical in shape. In other embodiments, enclosure 120 may be a shape other than cylindrical. In some embodiments, enclosure 120 has a centerline 115 running down a center axis of enclosure 120 as illustrated. In some embodiments, enclosure 120 has a first end 320 and a second end 330 that is opposite from first end 320. In some embodiments, enclosure 120 has a midpoint 340 that is substantially equidistant between first end 320 and second end 330. A cross-section of a particular embodiment of enclosure 120 is discussed below in reference to FIG. 8. Some embodiments of fusion reactor 110 may include a center coil 130. Center coil 130 is generally located proximate to midpoint 340 of enclosure 120. In some embodiments, center coil 130 is centered on center line 115 and is coaxial with internal coils 140. Center coil 130 may be either internal or external to enclosure 120, may be located at any appropriate axial position with respect to midpoint 340, may have any appropriate radius, may carry any appropriate current, and may have any appropriate ampturns. Internal coils 140 are any appropriate magnetic coils that are suspended or otherwise positioned within enclosure 120. In some embodiments, internal coils 140 are superconducting magnetic coils. In some embodiments, internal coils 140 are toroidal in shape as shown in FIG. 3B. In some embodiments, internal coils 140 are centered on centerline 115. In some embodiments, internal coils 140 include two coils: a first internal coil 140a that is located between midpoint 340 and first end 320 of enclosure 120, and a second internal coil 140b that is located between midpoint 340 and second end 330 of enclosure 120. Internal coils 140 may be located at any appropriate axial position with respect to midpoint 340, may have any appropriate radius, may carry any appropriate current, and may have any appropriate ampturns. A particular embodiment of an internal coil 140 is discussed in more detail below in reference to FIG. 7. Encapsulating coils 150 are any appropriate magnetic coils and generally have larger diameters than internal coils 140. In some embodiments, encapsulating coils 150 are centered on centerline 115 and are coaxial with internal coils 140. In general, encapsulating coils 150 encapsulate internal coils 140 and operate to close the original magnetic lines of internal coils 140 inside a magnetosphere. Closing these lines may reduce the extent of open field lines and reduce losses via recirculation. Encapsulating coils 150 also preserve the MHD stability of fusion reactor 110 by maintaining a magnetic wall that prevents plasma 310 from expanding. Encapsulating coils 150 have any appropriate cross-section, such as square or round. In some embodiments, encapsulating coils 150 are suspended within enclosure 120. In other embodiments, encapsulating coils 150 may be external to enclosure 120 as illustrated in FIGS. 3A and 3B. Encapsulating coils 150 may be located at any appropriate axial position with respect to midpoint 340, may have any appropriate radius, may carry any appropriate current, and may have any appropriate ampturns. Fusion reactor 110 may include any number and arrangement of encapsulating coils 150. In some embodiments, encapsulating coils 150 include at least one encapsulating coil 150 positioned on each side of midpoint 340 of enclosure 120. For example, fusion reactor 110 may include two encapsulating coils 150: a first encapsulating coil 150 located between midpoint 340 and first end 320 of enclosure 120, and a second encapsulating coil 150 located between midpoint 340 and second end 330 of enclosure 120. In some embodiments, fusion reactor 110 includes a total of two, four, six, eight, or any other even number of encapsulating coils 150. In certain embodiments, fusion reactor 110 includes a first set of two encapsulating coils 150 located between internal coil 140a and first end 320 of enclosure 120, and a second set of two encapsulating coils 150 located between internal coil 140b and second end 330 of enclosure 120. While particular numbers and arrangements of encapsulating coils 150 have been disclosed, any appropriate number and arrangement of encapsulating coils 150 may be utilized by fusion reactor 110. Mirror coils 160 are magnetic coils that are generally located close to the ends of enclosure 120 (i.e., first end 320 and second end 330). In some embodiments, mirror coils 160 are centered on center line 115 and are coaxial with internal coils 140. In general, mirror coils 160 serve to decrease the axial cusp losses and make all the recirculating field lines satisfy an average minimum-β, a condition that is not satisfied by other existing recirculating schemes. In some embodiments, mirror coils 160 include two mirror coils 160: a first mirror coil 160a located proximate to first end 320 of enclosure 120, and a second mirror coil 160b located proximate to second end 330 of enclosure 120. Mirror coils 160 may be either internal or external to enclosure 120, may be located at any appropriate axial position with respect to midpoint 340, may have any appropriate radius, may carry any appropriate current, and may have any appropriate ampturns. In some embodiments, coils 130, 140, 150, and 160 are designed or chosen according to certain constraints. For example, coils 130, 140, 150, and 160 may be designed according to constraints including: high required currents (maximum in some embodiments of approx. 10 MegaAmp-turns); steady-state continuous operation; vacuum design (protected from plasma impingement), toroidal shape, limit outgassing; materials compatible with 150C bakeout; thermal build-up; and cooling between shots. Fusion reactor 110 may include one or more heat injectors 170. In order to create the hot plasma condition needed for fusion energy release, energy (e.g., heat) is added to plasma 310. Heat injectors 170 are generally operable to allow any appropriate heat to be added to fusion reactor 110 in order to heat plasma 310 and create the necessary hot plasma condition for fusion reactions. In some embodiments, for example, heat injectors 170 may be utilized to add neutral beams in order to heat plasma 310 within fusion reactor 110. In such embodiments, the neutral beams become fast ions or ionized gas in fusion reactor 110, with the fast ions then coupling kinetic energy into “cold” electrons and plasma ions via collisions. Neutral beams may also provide a way to add fuel ions into the center of fusion reactor 110, where new fuel for fusion reactions is desired. The location of fuel and energy deposition may be determined in some embodiments by the energy of the beam and the density of the target plasma. Typically, gaseous fuel may be added to the edge of the plasma. However, this is less ideal than injecting fuel to the center of the reactor as the edge-added fuel must diffuse inward with much of it being lost in the process. In addition, the distribution of edge-added fuel cannot be controlled as precisely as injected beams of fuel. In addition to heating plasma 310, neutral beams may also add fuel to fusion reactor 110 by injecting neutral particles that may be used in fusion reactions. For instance, neutral beams can be injected through heat injectors 170 so that fast ions are created in the center of fusion reactor 110, where they are well-confined and have time to fuse before they leak out of the device. The neutralized particle beams may be injected in any suitable location of fusion reactor 110. The particles may be any suitable material for use in neutral beam injection such as deuterium or tritium. For example, neutral deuterium particles may be used for injection through heat injectors 170 in some embodiments. In other embodiments, the injected neutral particles may be tritium particles injected through heat injectors 170. The neutral particles may be injected into fusion reactor 110 through any suitable mode of operation. For example, neutral deuterium particles may be injected to form neutral deuterium gas (D2 gas). As another example, neutral deuterium particles may be injected to form fully ionized plasma (including electrons and positively charged deuterium ions). As yet another example, neutral deuterium particles may be injected to form partially ionized deuterium and deuterium gas. The locations of heat injectors 170 may be chosen such that the injected ion beams propagate past internal structures unique to the fusion reactor 110. The locations of heat injectors 170 may be either on-axis (i.e., in-line with center line 115) and/or off-axis (i.e., off-line with center line 115). For example, embodiments using encapsulated linear ring cusp field configurations (such as fusion reactor 110 of FIGS. 3A and 3B) may include heat injectors 170 in off-axis locations as shown in FIG. 3B. Such a location may allow the injected ion beams to propagate to the center of fusion reactor 110 without contacting center coil 130, internal coils 140, or encapsulating coils 150. Although not shown in FIG. 3B, particular embodiments using encapsulated linear ring cusp field configurations (such as fusion reactor 110 of FIGS. 3A and 3B) may include heat injectors 170 in on-axis locations in addition to off-axis heat injectors 170. Furthermore, some embodiments using encapsulated linear ring cusp field configurations (such as fusion reactor 110 of FIGS. 3A and 3B) may include heat injectors 170 solely in on-axis locations. For efficient injection, the beams may be shaped such that the beams can propagate ideally through the internal structures. The beam may be shaped in certain embodiments to maximize the cross section of the beam as it propagates through fusion reactor 110. For example, in embodiments incorporating on-axis heat injectors 170, a circular beam may be designed in order to fit within the internal coil (e.g., internal coil 140 of FIG. 3B) as it propagates. As another example, in embodiments incorporating off-axis heat injectors 170 (such as shown in FIG. 3B), an elliptical beam may be designed in order to fit between the center coil and internal coil (e.g., center coil 130 and internal coil 140 of FIG. 3B) as it propagates. In certain embodiments, the beam may be focused in a particular way (e.g., the beam of neutral particles is focused toward a focal point within the enclosure) and/or injected at a particular divergence angle (e.g., the beam of neutral particles diverges as it propagates in the enclosure). The particular focus and/or divergence angle may be chosen such that when the neutral ions are transformed into fast ion via collisions in fusion reactor 110, the fast ions will be in zones of good confinement. Zones of good confinement may refer to an area within fusion reactor 110 that minimize the loss of fast ions. For example, the use of an annular (i.e., ring-shaped) neutral beam in on-axis injection may allow for less loss of fast ions since the center part of the beam may have unfavorable confinement properties. As another example, for off-axis injection locations, the shape may be elongated and directed at the device center or on an angle such that the converted fast ions are created in the center of fusion reactor 110 which is well-confined. In particular embodiments, the injected neutral beams may be aimed slightly off-center to facilitate better trapping of fast ions into stronger magnetic fields near the coils. In operation, fusion reactor 110 generates fusion power by controlling the shape of plasma 310 for a nuclear fusion process using at least internal coils 140, encapsulating coils 150, and mirror coils 160. Internal coils 140 and encapsulating coils 150 are energized to form magnetic fields which confine plasma 310 into a shape such as the shape shown in FIGS. 3B and 5. Gases such as deuterium and tritium may then be reacted to make energetic particles which heat plasma 310 and the walls of enclosure 120. The generated heat may then be used for power. For example, a liquid metal coolant may carry heat from the walls of the reactor out to engines of an aircraft. In some embodiments, electrical power may also be extracted from fusion reactor 110 via MHD. In order to expand the volume of plasma 310 and create a more favorable minimum-β geometry, the number of internal coils can be increased to make a cusp. In some embodiments of fusion reactor 110, the sum of internal coils 140, center coil 130, and mirror coils 160 is an odd number in order to obtain the encapsulation by the outer ‘solenoid’ field (i.e., the magnetic field provided by encapsulating coils 150). This avoids making a ring cusp field and therefor ruining the encapsulating separatrix. Two internal coils 140 and center coil 130 with alternating polarizations give a magnetic well with minimum-β characteristics within the cusp and a quasi-spherical core plasma volume. The addition of two axial ‘mirror’ coils (i.e., mirror coils 160) serves to decrease the axial cusp losses and more importantly makes the recirculating field lines satisfy average minimum-β, a condition not satisfied by other existing recirculating schemes. In some embodiments, additional pairs of internal coils 140 could be added to create more plasma volume in the well. However, such additions may increase the cost and complexity of fusion reactor 110 and may require additional supports for coils internal to plasma 310. In the illustrated embodiments of fusion reactor 110, only internal coils 140 are within plasma 310. In some embodiments, internal coils 140 are suspending within enclosure 120 by one or more supports, such as support 750 illustrated in FIG. 7. While the supports sit outside the central core plasma well, they may still experience high plasma fluxes. Alternatively, internal coils 140 of some embodiments may be amenable to levitation, which would remove the risk and complexity of having support structures within plasma 310. FIG. 4 illustrates a simplified view of the coils of fusion reactor 110 and example systems for energizing the coils. In this embodiment, the field geometry is sized to be the minimum size necessary to achieve adequate ion magnetization with fields that can be produced by simple magnet technology. Adequate ion magnetization was considered to be ˜5 ion gyro radii at design average ion energy with respect to the width of the recirculation zone. At the design energy of 100 eV plasma temperature there are 13 ion diffusion jumps and at full 20 KeV plasma energy there are 6.5 ion jumps. This is the lowest to maintain a reasonable magnetic field of 2.2 T in the cusps and keep a modest device size. As illustrated in FIG. 4, certain embodiments of fusion reactor 110 include two mirror coils 160: a first mirror coil 160a located proximate to first end 320 of the enclosure and a second magnetic coil 160b located proximate to second end 330 of enclosure 120. Certain embodiments of fusion reactor 110 also include a center coil 130 that is located proximate to midpoint 340 of enclosure 120. Certain embodiments of fusion reactor 110 also include two internal coils 140: a first internal coil 140a located between center coil 130 and first end 320 of enclosure 120, and a second internal coil 140b located between center coil 130 and second end 330 of enclosure 120. In addition, certain embodiments of fusion reactor 110 may include two or more encapsulating coils 150. For example, fusion reactor 110 may include a first set of two encapsulating coils 150 located between first internal coil 140a and first end 320 of enclosure 120, and a second set of two encapsulating coils 150 located between second internal coil 140b and second end 330 of enclosure 120. In some embodiments, fusion reactor 110 may include any even number of encapsulating coils 150. In some embodiments, encapsulating coils 150 may be located at any appropriate position along center line 115 other than what is illustrated in FIG. 4. In general, encapsulating coils 150, as well as internal coils 140 and mirror coils 160, may be located at any appropriate position along center line 115 in order to maintain magnetic fields in the correct shape to achieve the desired shape of plasma 310. In some embodiments, electrical currents are supplied to coils 130, 140, 150, and 160 as illustrated in FIG. 4. In this figure, each coil has been split along center line 115 and is represented by a rectangle with either an “X” or an “◯” at each end. An “X” represents electrical current that is flowing into the plane of the paper, and an “◯” represents electrical current that is flowing out the plane of the paper. Using this nomenclature, FIG. 4 illustrates how in this embodiment of fusion reactor 110, electrical currents flow in the same direction through encapsulating coils 150, center coil 130, and mirror coils 160 (i.e., into the plane of the paper at the top of the coils), but flow in the opposite direction through internal coils 140 (i.e., into the plane of the paper at the bottom of the coils). In some embodiments, the field geometry of fusion reactor 110 may be sensitive to the relative currents in the coils, but the problem can be adequately decoupled to allow for control. First, the currents to opposing pairs of coils can be driven in series to guarantee that no asymmetries exist in the axial direction. The field in some embodiments is most sensitive to the center three coils (e.g., internal coils 140 and center coil 130). With the currents of internal coil 140 fixed, the current in center coil 130 can be adjusted to tweak the shape of the central magnetic well. This region can be altered into an axial-oriented ‘bar-bell’ shape by increasing the current on center coil 130 as the increase in flux ‘squeezes’ the sphere into the axial shape. Alternatively, the current on center coil 130 can be reduced, resulting in a ring-shaped magnetic well at midpoint 340. The radius of center coil 130 also sets how close the ring cusp null-line comes to internal coils 140 and may be chosen in order to have this null line close to the middle of the gap between center coil 130 and internal coils 140 to improve confinement. The radius of internal coils 140 serves to set the balance of the relative field strength between the point cusps and the ring cusps for the central well. The baseline sizes may be chosen such that these field values are roughly equal. While it would be favorable to reduce the ring cusp losses by increasing the relative flux in this area, a balanced approach may be more desirable. In some embodiments, the magnetic field is not as sensitive to mirror coils 160 and encapsulating coils 150, but their dimensions should be chosen to achieve the desired shape of plasma 310. In some embodiments, mirror coils 160 may be chosen to be as strong as possible without requiring more complex magnets, and the radius of mirror coils 160 may be chosen to maintain good diagnostic access to the device center. Some embodiments may benefit from shrinking mirror coils 160, thereby achieving higher mirror ratios for less current but at the price of reduced axial diagnostic access. In general, encapsulating coils 150 have weaker magnetic fields than the other coils within fusion reactor 110. Thus, the positioning of encapsulating coils 150 is less critical than the other coils. In some embodiments, the positions of encapsulating coils 150 are defined such that un-interrupted access to the device core is maintained for diagnostics. In some embodiments, an even number of encapsulating coils 150 may be chosen to accommodate supports for internal coils 140. The diameters of encapsulating coils 150 are generally greater than those of internal coils 140, and may be all equal for ease of manufacture and common mounting on or in a cylindrical enclosure 120. In some embodiments, encapsulating coils 150 may be moved inward to the plasma boundary, but this may impact manufacturability and heat transfer characteristics of fusion reactor 110. In some embodiments, fusion reactor 110 includes various systems for energizing center coil 130, internal coils 140, encapsulating coils 150, and mirror coils 160. For example, a center coil system 410, an encapsulating coil system 420, a mirror coil system 430, and an internal coil system 440 may be utilized in some embodiments. Coil systems 410-440 and coils 130-160 may be coupled as illustrated in FIG. 4. Coil systems 410-440 may be any appropriate systems for driving any appropriate amount of electrical currents through coils 130-160. Center coil system 410 may be utilized to drive center coil 130, encapsulating coil system 420 may be utilized to drive encapsulating coils 150, mirror coil system 430 may be utilized to drive mirror coils 160, and internal coil system 440 may be utilized to drive internal coils 140. In other embodiments, more or fewer coil systems may be utilized than those illustrated in FIG. 4. In general, coil systems 410-440 may include any appropriate power sources such as battery banks. FIG. 5 illustrates plasma 310 within enclosure 120 that is shaped and confined by center coil 130, internal coils 140, encapsulating coils 150, and mirror coils 160. As illustrated, an external mirror field is provided by mirror coils 160. The ring cusp flow is contained inside the mirror. A trapped magnetized sheath 510 that is provided by encapsulating coils 150 prevents detachment of plasma 310. Trapped magnetized sheath 510 is a magnetic wall that causes plasma 310 to recirculate and prevents plasma 310 from expanding outward. The recirculating flow is thus forced to stay in a stronger magnetic field. This provides complete stability in a compact and efficient cylindrical geometry. Furthermore, the only losses from plasma exiting fusion reactor 110 are at two small point cusps at the ends of fusion reactor 110 along center line 115. This is an improvement over typical designs in which plasma detaches and exits at other locations. The losses of certain embodiments of fusion reactor 110 are also illustrated in FIG. 5. As mentioned above, the only losses from plasma exiting fusion reactor 110 are at two small point cusps at the ends of fusion reactor 110 along center line 115. Other losses may include diffusion losses due to internal coils 140 and axial cusp losses. In addition, in embodiments in which internal coils 140 are suspended within enclosure 120 with one or more supports (e.g., “stalks”), fusion reactor 110 may include ring cusp losses due to the supports. In some embodiments, internal coils 140 may be designed in such a way as to reduce diffusion losses. For example, certain embodiments of fusion reactor 110 may include internal coils 140 that are configured to conform to the shape of the magnetic field. This may allow plasma 310, which follows the magnetic field lines, to avoid touching internal coils 140, thereby reducing or eliminating losses. An example embodiment of internal coils 140 illustrating a conformal shape is discussed below in reference to FIG. 7. FIG. 6 illustrates a magnetic field of certain embodiments of fusion reactor 110. In general, fusion reactor 110 is designed to have a central magnetic well that is desired for high beta operation and to achieve higher plasma densities. As illustrated in FIG. 6, the magnetic field may include three magnetic wells. The central magnetic well can expand with high Beta, and fusion occurs in all three magnetic wells. Another desired feature is the suppression of ring cusp losses. As illustrated in FIG. 6, the ring cusps connect to each other and recirculate. In addition, good MHD stability is desired in all regions. As illustrated in FIG. 6, only two field penetrations are needed and MHD interchange is satisfied everywhere. In some embodiments, the magnetic fields can be altered without any relocation of the coils by reducing the currents, creating for example weaker cusps and changing the balance between the ring and point cusps. The polarity of the currents could also be reversed to make a mirror-type field and even an encapsulated mirror. In addition, the physical locations of the coils could be altered. FIG. 7 illustrates an example embodiment of an internal coil 140 of fusion reactor 110. In this embodiment, internal coil 140 includes coil windings 710, inner shield 720, layer 730, and outer shield 740. In some embodiments, internal coil 140 may be suspending within enclosure 120 with one or more supports 750. Coil windings 710 may have a width 715 and may be covered in whole or in part by inner shield 720. Inner shield 720 may have a thickness 725 and may be covered in whole or in part by layer 730. Layer 730 may have a thickness 735 and may be covered in whole or in part by outer shield 740. Outer shield may have a thickness 745 and may have a shape that is conformal to the magnetic field within enclosure 120. In some embodiments, internal coil 140 may have an overall diameter of approximately 1.04 m. Coil windings 710 form a superconducting coil and carry an electric current that is typically in an opposite direction from encapsulating coils 150, center coil 130, and mirror coils 160. In some embodiments, width 715 of coils winding is approximately 20 cm. Coil windings 710 may be surrounded by inner shield 720. Inner shield 720 provides structural support, reduces residual neutron flux, and shields against gamma rays due to impurities. Inner shield 720 may be made of Tungsten or any other material that is capable of stopping neutrons and gamma rays. In some embodiments, thickness 725 of inner shield 720 is approximately 11.5 cm. In some embodiments, inner shield 720 is surrounded by layer 730. Layer 730 may be made of lithium (e.g., lithium-6) and may have thickness 735 of approximately 5 mm. Layer 730 may be surrounded by outer shield 740. Outer shield 740 may be made of FLiBe and may have thickness 745 of approximately 30 cm. In some embodiments, outer shield may be conformal to magnetic fields within enclosure 120 in order to reduce losses. For example, outer shield 740 may form a toroid. FIG. 8 illustrates a cut-away view of enclosure 120 of certain embodiments of fusion reactor 110. In some embodiments, enclosure 120 includes one or more inner blanket portions 810, an outer blanket 820, and one or more layers 730 described above. In the illustrated embodiment, enclosure 120 includes three inner blanket portions 810 that are separated by three layers 730. Other embodiments may have any number or configuration of inner blanket portions 810, layers 730, and outer blanket 820. In some embodiments, enclosure 120 may have a total thickness 125 of approximately 80 cm in many locations. In other embodiments, enclosure 120 may have a total thickness 125 of approximately 1.50 m in many locations. However, thickness 125 may vary over the length of enclosure 120 depending on the shape of the magnetic field within enclosure 120 (i.e., the internal shape of enclosure 120 may conform to the magnetic field as illustrated in FIG. 3b and thus many not be a uniform thickness 125). In some embodiments, inner blanket portions 810 have a combined thickness 815 of approximately 70 cm. In other embodiments, inner blanket portions 810 have a combined thickness 815 of approximately 126 cm. In some embodiments, inner blanket portions are made of materials such as Be, FLiBe, and the like. Outer blanket 820 is any low activation material that does not tend to become radioactive under irradiation. For example, outer blanket 820 may be iron or steel. In some embodiments, outer blanket 820 may have a thickness 825 of approximately 10 cm. FIG. 9 illustrates an example computer system 900. In particular embodiments, one or more computer systems 900 are utilized by fusion reactor 110 for any aspects requiring computerized control. Particular embodiments include one or more portions of one or more computer systems 900. Herein, reference to a computer system may encompass a computing device, and vice versa, where appropriate. Moreover, reference to a computer system may encompass one or more computer systems, where appropriate. This disclosure contemplates any suitable number of computer systems 900. This disclosure contemplates computer system 900 taking any suitable physical form. As example and not by way of limitation, computer system 900 may be an embedded computer system, a system-on-chip (SOC), a single-board computer system (SBC) (such as, for example, a computer-on-module (COM) or system-on-module (SOM)), a desktop computer system, a laptop or notebook computer system, an interactive kiosk, a mainframe, a mesh of computer systems, a mobile telephone, a personal digital assistant (PDA), a server, a tablet computer system, or a combination of two or more of these. Where appropriate, computer system 900 may include one or more computer systems 900; be unitary or distributed; span multiple locations; span multiple machines; span multiple data centers; or reside in a cloud, which may include one or more cloud components in one or more networks. Where appropriate, one or more computer systems 900 may perform without substantial spatial or temporal limitation one or more steps of one or more methods described or illustrated herein. As an example and not by way of limitation, one or more computer systems 900 may perform in real time or in batch mode one or more steps of one or more methods described or illustrated herein. One or more computer systems 900 may perform at different times or at different locations one or more steps of one or more methods described or illustrated herein, where appropriate. In particular embodiments, computer system 900 includes a processor 902, memory 904, storage 906, an input/output (I/O) interface 908, a communication interface 910, and a bus 912. Although this disclosure describes and illustrates a particular computer system having a particular number of particular components in a particular arrangement, this disclosure contemplates any suitable computer system having any suitable number of any suitable components in any suitable arrangement. In particular embodiments, processor 902 includes hardware for executing instructions, such as those making up a computer program. As an example and not by way of limitation, to execute instructions, processor 902 may retrieve (or fetch) the instructions from an internal register, an internal cache, memory 904, or storage 906; decode and execute them; and then write one or more results to an internal register, an internal cache, memory 904, or storage 906. In particular embodiments, processor 902 may include one or more internal caches for data, instructions, or addresses. This disclosure contemplates processor 902 including any suitable number of any suitable internal caches, where appropriate. As an example and not by way of limitation, processor 902 may include one or more instruction caches, one or more data caches, and one or more translation lookaside buffers (TLBs). Instructions in the instruction caches may be copies of instructions in memory 904 or storage 906, and the instruction caches may speed up retrieval of those instructions by processor 902. Data in the data caches may be copies of data in memory 904 or storage 906 for instructions executing at processor 902 to operate on; the results of previous instructions executed at processor 902 for access by subsequent instructions executing at processor 902 or for writing to memory 904 or storage 906; or other suitable data. The data caches may speed up read or write operations by processor 902. The TLBs may speed up virtual-address translation for processor 902. In particular embodiments, processor 902 may include one or more internal registers for data, instructions, or addresses. This disclosure contemplates processor 902 including any suitable number of any suitable internal registers, where appropriate. Where appropriate, processor 902 may include one or more arithmetic logic units (ALUs); be a multi-core processor; or include one or more processors 902. Although this disclosure describes and illustrates a particular processor, this disclosure contemplates any suitable processor. In particular embodiments, memory 904 includes main memory for storing instructions for processor 902 to execute or data for processor 902 to operate on. As an example and not by way of limitation, computer system 900 may load instructions from storage 906 or another source (such as, for example, another computer system 900) to memory 904. Processor 902 may then load the instructions from memory 904 to an internal register or internal cache. To execute the instructions, processor 902 may retrieve the instructions from the internal register or internal cache and decode them. During or after execution of the instructions, processor 902 may write one or more results (which may be intermediate or final results) to the internal register or internal cache. Processor 902 may then write one or more of those results to memory 904. In particular embodiments, processor 902 executes only instructions in one or more internal registers or internal caches or in memory 904 (as opposed to storage 906 or elsewhere) and operates only on data in one or more internal registers or internal caches or in memory 904 (as opposed to storage 906 or elsewhere). One or more memory buses (which may each include an address bus and a data bus) may couple processor 902 to memory 904. Bus 912 may include one or more memory buses, as described below. In particular embodiments, one or more memory management units (MMUs) reside between processor 902 and memory 904 and facilitate accesses to memory 904 requested by processor 902. In particular embodiments, memory 904 includes random access memory (RAM). This RAM may be volatile memory, where appropriate. Where appropriate, this RAM may be dynamic RAM (DRAM) or static RAM (SRAM). Moreover, where appropriate, this RAM may be single-ported or multi-ported RAM. This disclosure contemplates any suitable RAM. Memory 904 may include one or more memories 904, where appropriate. Although this disclosure describes and illustrates particular memory, this disclosure contemplates any suitable memory. In particular embodiments, storage 906 includes mass storage for data or instructions. As an example and not by way of limitation, storage 906 may include a hard disk drive (HDD), a floppy disk drive, flash memory, an optical disc, a magneto-optical disc, magnetic tape, or a Universal Serial Bus (USB) drive or a combination of two or more of these. Storage 906 may include removable or non-removable (or fixed) media, where appropriate. Storage 906 may be internal or external to computer system 900, where appropriate. In particular embodiments, storage 906 is non-volatile, solid-state memory. In particular embodiments, storage 906 includes read-only memory (ROM). Where appropriate, this ROM may be mask-programmed ROM, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), electrically alterable ROM (EPROM), or flash memory or a combination of two or more of these. This disclosure contemplates mass storage 906 taking any suitable physical form. Storage 906 may include one or more storage control units facilitating communication between processor 902 and storage 906, where appropriate. Where appropriate, storage 906 may include one or more storages 906. Although this disclosure describes and illustrates particular storage, this disclosure contemplates any suitable storage. In particular embodiments, I/O interface 908 includes hardware, software, or both, providing one or more interfaces for communication between computer system 900 and one or more I/O devices. Computer system 900 may include one or more of these I/O devices, where appropriate. One or more of these I/O devices may enable communication between a person and computer system 900. As an example and not by way of limitation, an I/O device may include a keyboard, keypad, microphone, monitor, mouse, printer, scanner, speaker, still camera, stylus, tablet, touch screen, trackball, video camera, another suitable I/O device or a combination of two or more of these. An I/O device may include one or more sensors. This disclosure contemplates any suitable I/O devices and any suitable I/O interfaces 908 for them. Where appropriate, I/O interface 908 may include one or more device or software drivers enabling processor 902 to drive one or more of these I/O devices. I/O interface 908 may include one or more I/O interfaces 908, where appropriate. Although this disclosure describes and illustrates a particular I/O interface, this disclosure contemplates any suitable I/O interface. In particular embodiments, communication interface 910 includes hardware, software, or both providing one or more interfaces for communication (such as, for example, packet-based communication) between computer system 900 and one or more other computer systems 900 or one or more networks. As an example and not by way of limitation, communication interface 910 may include a network interface controller (NIC) or network adapter for communicating with an Ethernet or other wire-based network or a wireless NIC (WNIC) or wireless adapter for communicating with a wireless network, such as a WI-FI network. This disclosure contemplates any suitable network and any suitable communication interface 910 for it. As an example and not by way of limitation, computer system 900 may communicate with an ad hoc network, a personal area network (PAN), a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), or one or more portions of the Internet or a combination of two or more of these. One or more portions of one or more of these networks may be wired or wireless. As an example, computer system 900 may communicate with a wireless PAN (WPAN) (such as, for example, a BLUETOOTH WPAN), a WI-FI network, a WI-MAX network, a cellular telephone network (such as, for example, a Global System for Mobile Communications (GSM) network), or other suitable wireless network or a combination of two or more of these. Computer system 900 may include any suitable communication interface 910 for any of these networks, where appropriate. Communication interface 910 may include one or more communication interfaces 910, where appropriate. Although this disclosure describes and illustrates a particular communication interface, this disclosure contemplates any suitable communication interface. In particular embodiments, bus 912 includes hardware, software, or both coupling components of computer system 900 to each other. As an example and not by way of limitation, bus 912 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a front-side bus (FSB), a HYPERTRANSPORT (HT) interconnect, an Industry Standard Architecture (ISA) bus, an INFINIBAND interconnect, a low-pin-count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCIe) bus, a serial advanced technology attachment (SATA) bus, a Video Electronics Standards Association local (VLB) bus, or another suitable bus or a combination of two or more of these. Bus 912 may include one or more buses 912, where appropriate. Although this disclosure describes and illustrates a particular bus, this disclosure contemplates any suitable bus or interconnect. Herein, a computer-readable non-transitory storage medium or media may include one or more semiconductor-based or other integrated circuits (ICs) (such, as for example, field-programmable gate arrays (FPGAs) or application-specific ICs (ASICs)), hard disk drives (HDDs), hybrid hard drives (HHDs), optical discs, optical disc drives (ODDs), magneto-optical discs, magneto-optical drives, floppy diskettes, floppy disk drives (FDDs), magnetic tapes, solid-state drives (SSDs), RAM-drives, SECURE DIGITAL cards or drives, any other suitable computer-readable non-transitory storage media, or any suitable combination of two or more of these, where appropriate. A computer-readable non-transitory storage medium may be volatile, non-volatile, or a combination of volatile and non-volatile, where appropriate. Herein, “or” is inclusive and not exclusive, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A or B” means “A, B, or both,” unless expressly indicated otherwise or indicated otherwise by context. Moreover, “and” is both joint and several, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A and B” means “A and B, jointly or severally,” unless expressly indicated otherwise or indicated otherwise by context. The scope of this disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments described or illustrated herein that a person having ordinary skill in the art would comprehend. The scope of this disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although this disclosure describes and illustrates respective embodiments herein as including particular components, elements, functions, operations, or steps, any of these embodiments may include any combination or permutation of any of the components, elements, functions, operations, or steps described or illustrated anywhere herein that a person having ordinary skill in the art would comprehend. Furthermore, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative.
	abstract	The invention relates to a method for generating a focused charged-particle beam, comprising at least the steps of: a) generating a charged-particle beam (10); b) emitting a laser pulse (40); c) generating a focusing magnetic field structure in a target (50) by means of an interaction between the laser pulse and the target; and d) making the charged-particle beam penetrate the focusing magnetic field structure at least partially.
	description	This application is a continuation in part of U.S. application Ser. No. 11/400,730 file on Apr. 7, 2006 now abandoned entitled “Probes, Methods of Making Probes and Applications of Probes”, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application Nos. 60/669,029 filed on Apr. 7, 2005 entitled “DNA Sequencing Method and System” and 60/699,619 filed on Jul. 15, 2005 entitled “Molecular Analysis Probe, Systems and Methods, including DNA Sequencing”, and is a Continuation in Part of U.S. Non-provisional application Ser. No. 10/775,999 filed on Feb. 10, 2004 now abandoned entitled “Micro-Nozzle, Nano-Nozzle, Manufacturing Methods Therefor, applications Therefore, Including Nanolithography and Ultra Fast Real Time DNA Sequencing”; Ser. No. 09/950,909, filed Sep. 12, 2001 now U.S. Pat. No. 7,045,878 entitled “Thin films and Production Methods Thereof”; Ser. No. 10/222,439, filed Aug. 15, 2002 now U.S. Pat. No. 6,956,268 entitled “MEMs And Method Of Manufacturing MEMs”; Ser. No. 10/017,186 filed Dec. 7, 2001 now abandoned entitled “Device And Method For Handling Fragile Objects, And Manufacturing Method Thereof”; U.S. Non-provisional application Ser. No. 10/717,220 filed on Nov. 19, 2003 now U.S. Pat. No. 7,033,910 entitled “Method of Fabricating Multi Layer Mems and Microfluidic Devices”; Ser. No. 10/719,666 filed on Nov. 20, 2003 now U.S. Pat. No. 7,056,751 entitled “Method and System for Increasing Yield of Vertically Integrated Devices”; Ser. No. 10/719,663 filed on Nov. 20, 2003 now U.S. Pat. No. 7,163,826 entitled “Method of Fabricating Multi Layer Devices on Buried Oxide Layer Substrates”; all of which are incorporated by reference herein. The present invention relates to methods and apparatuses for analyzing molecules, particularly polymers, and molecular complexes with extended conformations. In particular, the methods and apparatuses are used to identify sequence information in molecules or molecular ensembles, which is subsequently used to determine structural information about the molecules. Further, the present invention relates to forming probes and films for making such probes. Twenty-first century science and technology endeavors, research and development innovations that solve problems for man-kind will increasingly be dominated by the ability to make structures and objects that have sizes with length scales approaching those of atoms and molecules having dimensions of a nano-meter or less. Nano-scale matter and objects exhibit unique behaviors, some of which have yet to be unraveled in addition to the known remarkable optical, thermal, electrical and mechanical properties. These open new vistas for many beneficial applications making them suitable for many applications. For example, sequencing, imaging, nano-lithography, manipulation, nano-scale self assembly, nanometer scale chemistry, and infinite other applications with benefit from nano-scale technology development. It is envisioned and believed that being involved in the nano-size frontier of science, technology and innovation is a sure path to regional and national economic well being, and competitiveness. This is evidenced by the extraordinary investment activities by big and small countries, large and small private sector enterprises and nearly unparalleled entrepreneurial activities. To advance in the nano-scale frontier science and technology requires access to and mastering the following: Tools to produce nano-objects Tools to measure sizes with sub-Angstrom precision Substrates that have atomic smoothness with minimum contamination Tools to see (image) nano-objects and manipulate them, grabbing, moving, gluing, etc. Nano funnels/nozzles/probes for dispensing substances and stimuli Tools to accurately measure all physical properties, thermal, electrical, optical, Key parameters become smaller by 10 to 20 orders of magnitude of quantities accustomed to in the macro-world. In the last 5 years the collective achievements of the best and brightest people around the world related to the above tools have grown at astonishing rates, delivering numerous discoveries, innovations, methods, products and tools. One area that could tremendously benefit from nanotechnology is the -development of high-throughput DNA sequencers in the 1990's have helped launched the genomic revolution of the 21st century. Almost on a monthly basis, one research group or another is announcing the complete sequencing of a biologically important organism. This has allowed researchers to cross reference species, finding shared and/or similar genes, and allowing the knowledge of molecular biologists in all the various fields to come together in a meaningful way. However, current techniques in DNA sequencing are far too tedious, tying up the valuable time of researchers. Even the fastest, most advanced DNA sequencers can at most process a few hundred thousand base pairs a day. The Human Genome Project took over 10 years to complete, indicating that current DNA sequencing technology still has a long way to go before it can be used as a diagnostic tool. Considering that there are about 3 billion DNA base pairs in the mammalian genome, and current sequencing technology is capable of sequencing about 2 million DNA base pairs per day, it would still take over 4 years to sequence the human genome. Known nucleic acid sequencing methods are generally based on chemical reactions that yield multiple length DNA strands cleaved at specific bases. Alternatively, other known nucleic acid sequencing methods are based on enzymatic reactions that yield multiple length DNA strands terminated at specific bases. In either of these methods, the resulting DNA strands of differing length are then separated from each other and identified in strand length order. The chemical or enzymatic reactions, and the methods for separating and identifying the different length strands, usually involve repetitive procedures. Thus, there remains significant limitations on the speed of DNA sequencing using conventional technology. Despite these limitations, an incredible collaborative heroic effort was undertaken for the Human Genome Project. It took many years and billions of dollars to obtain the sequence to the human genome. It would be highly desirable to provide a method and system that reduces the time and effort required would represent a highly significant advance in biotechnology. Indeed, frontier advances are required to increase the efficiency and speed of DNA sequencing if we are to expand the genome databases that presently exist to include a genome library including flora and fauna. Certain flowering plants have 100 times more base pairs than the human genome, so existing sequencing technology must be leaped for a new frontier of sequencing systems. One particular type of sequencing method relies on passing strands of DNA through pores. For example, U.S. Pat. Nos. 5,795,782, 6,015,714, 6,267,872, 6,362,002 6,428,959 6,465,193 6,617,113, 6,627,067, 6,673,615, 6,746,594 6,870,361 describe various sequencing techniques and apparatus based on pores and flow of DNA fragments through pores. In general the prior art pores have thickness that cannot directly resolve with high spatial resolution without some other indirect deconvolution of the date resulting from changes in ionic conductivities. It further cannot be used for large DNA fragments. Further, it is very time consuming. In general, for an ultra fast DNA sequencing system, there are many limitations with pore based systems. Therefore, it would be desirable to provide an improved system and method of analyzing extended objects such as linear polymers (including proteins, DNA and other biopolymers). The present invention teaches new methods, devices and tools that advances the nanotechnology art listed above. Probes and methods of making probes are provided, particularly probes or nano-tools having tip active areas of extremely small dimensions, e.g., on the order of one angstrom to a few nanometers. One method of making a nano-tool includes forming a composite including a tool layer less than 10 nm thick on a substrate layer, subtracting a region of the substrate layer at least partially through the thickness of the substrate layer, thereby exposing a well surface, and folding the composite so that portions of the tool layer surface diverge and portions of the well surface converge, wherein an outer crease of the folded tool layer is a nanotool active area. Another method of making a nano-tool includes forming a composite including a tool layer less than 10 nm thick on a substrate, subtracting a region of the substrate layer at least partially through the thickness of the substrate layer, thereby exposing a well surface, and folding the composite so that portions of the tool layer surface diverge and portions of the well surface converge, wherein an outer crease of the folded tool layer is a nanotool active area, whereby the tip may be cut mechanically or altered to expose two probe active areas. The herein probes may be very useful in systems and methods that benefit from probes having resolution capabilities less than the dimensions of the objects to be analyzed. General Described herein is a novel system and method for analyzing extended object specimens. The system includes analytical probes configured and dimensioned such that the edge of the probe has a thickness direction that is spatially smaller than the desired resolution. Further, in certain embodiments, the analytical probe has a width dimension that is much larger than the thickness of the extended object. In other embodiments, the analytical probe has a path in the width direction that is much larger than the thickness of the extended object. Definitions Extended Object The “extended object” to be analyzed using the probes described herein may be a complex macromolecule, including complex monomers, polymers, oligomers, dentimers, or other molecules. Examples of such complex macromolecules include, but are not limited to, proteins, polypeptides, peptide-nucleic acids (PNA), having a polypeptide-like backbone, based on the monomer 2-aminoethyleneglycin carrying any of the four nucleobases: A, T, G, or C. In certain embodiments, the polymers are homogeneous in backbone composition and are, e.g., nucleic acids or polypeptides. A nucleic acid as used herein is a biopolymer comprised of nucleotides, such as deoxyribose nucleic acid (DNA) or ribose nucleic acid (RNA). In certain embodiments, the extended object is a single stranded (denatured) DNA molecule with a rigid structure. Other organic or inorganic molecular structures may also be extended objects for the purpose of the present invention whereby these extended objects may be analyzed, manipulated, physically altered or chemically altered. Further, double stranded structures may be analyzed according to certain embodiments herein, such as double stranded helical DNA strands. It will be appreciated by one skilled in the art that the system described herein for monomer level resolution may be used for other molecular level detection, e.g., for single small molecules, single monomers, oligomers, or other nano-scale structures. Probe Further, as used herein, the term “probe” refers generally to any device used to interact with individual portions of the extended object including, for example, individual nucleotides of a RNA or DNA strand, atomic groups an extended object, atomic and molecular bonds and bond interactions, groups of atoms or molecules within the extended objects, and other interactive forces such as covalent bonds, hydrogen bonds, ionic bonds, and other know interactions. Probes may be formed of various configurations and materials to be described further herein. Detectable Interaction Further, as used herein, the term “detectable interaction” refers generally to an interaction between the probe and a portion of the extended object. The portion of the extended object with which a detectable interaction occurs may include individual atoms, molecules, or groups of atoms or molecules, and their bonds. The detectable interaction may be in the form of electric field, magnetic field, optical variations, vibration forces, gravitational forces, or other measurable events. Probe Configurations The probes used herein may be formed of various materials and configurations. For example, probes may be in the form of wells, nozzles or funnels (herein after “hollow probes”) having a tip for dispensing or holding materials (including solids, liquids, gases and transition phases) to facilitate analysis of the specimen. Alternatively, the wells or nozzles may be provided in a system and configuration for suction or application of fluid pressure. The nozzles configured for dispensing materials may include conductive inner walls, or a conductive element disposed within a material holding region, in order to facilitate measurement and other voltage applications across the probe. In other examples, the dispensing materials are within a conductive medium to facilitate measurement and other voltage applications across the probe. Continuous Edge Probe Referring now to FIG. 1A, a continuous edge probe 102 is depicted, for example, in the form of a continuous knife edge. Probe 102 is particularly well suited for analyzing extended object specimens such as biopolymers. Probe 102 is characterized by a tip 104 thickness t, a tip 104 width w, and a height (not identified in the Figure). Importantly, the tip thickness t is dimensioned to obtain the desired resolution of the system. For example, when information regarding individual monomers of a DNA strand is desired, the thickness t should be less than the nucleotide spacing on the strand (about 0.5 nm). Still further, probe 102 has a width dimension w that is preferably much greater than the tip dimension and also much greater than the width of the specimen. In certain embodiments, this width dimension that is much greater than the tip dimension minimizes or eliminates landing error associated with typical probe analysis systems as the probe passes over the specimen. The ratio of w to t may be, for example, on the order of about 5:1. 10:1, 10 s to 1, 100 to 1, 100 s to 1, 000 to 1, 10,000 to 1, or greater depending on the desired application. These continuous edge probes may be hollow, solid or partly solid and partly hollow. As shown, in certain preferred embodiments, the probe has a shape that provides a larger end 106 opposite the tip 104. This can, for example, reduce electrical resistance of the probe when end 106 serves as a contact region. Further, the larger end 106 serves to facilitate introduction and dispensation of materials from the probe when the probe is in the form of a nozzle filled with suitable material, as described further herein. Discontinuous Edge Probe Referring now to FIGS. 1B and 1C, discontinuous probes 122, 142 are provided. Probes 122, 142 have an elongated width structure with desirably sized tip with, e.g., cutouts or discontinues edge portions. The generalized probes, 122, 142 made according to the present invention can be made in a configurations that several probe sections, 130, 150, which can be accessed independently or together as shown in FIGS. 1B and 1C. In certain embodiments, the probe sections 130, 150 serve identical functionality, for example, for redundancy, or to examine plural specimens in parallel. In further embodiments the probe sections 130, 150 serve different functionalities. For example, some applications may require that sub-probe 130a be used for analyzing or sequencing the specimen, adjacent section, 130b used for dispensing substances or stimuli, and section 130c used for imaging or reading alignment marks. In another example, probe section 150a is in the form of an edge with an elongated width as shown, while probe section 150b may be point like probe, as represented in FIG. 1C with dotted lines. The probe sections may be functionalized differently to recognize parts of a specimen under test with high degrees of specificity. These discontinuous edge probes may be hollow, solid or partly solid and partly hollow. Scanning Probe Referring now to FIG. 1D, a probe 162 is depicted. Probe 162 is particularly well suited for analyzing extended object specimens such as biopolymers. Probe 162 is characterized by a tip thickness t, a tip width w, and a height (not identified in the Figure). Further, probe 162 is positioned within a suitable sub-system 168 to impart motion to the probe generally in the direction of the width w along a path pw. Similar to probe 102, the tip thickness t is dimensioned to obtain the desired resolution of the system. The width dimension w of probe 162 is not critical. However, the path width pw is preferably much greater than the width of the specimen. This ensure that as the probe passes over the specimen, landing error associated with typical probe analysis systems is eliminated. Probe Shape The probes described herein may take on various shapes and functionalities. In certain embodiments, the probes herein have a continuous edge that is closed. In certain embodiments, the probes herein have a discontinuous edge that is closed. In certain embodiments, the probes herein have a continuous edge that is open. In certain embodiments, the probes herein have a discontinuous edge that is open. In certain embodiments, the probes herein have a continuous edge that has some portions along the width w of the probe that are closed and some portions along the width w of the probe that are open. In certain embodiments, the probes herein have a discontinuous edge that has some portions along the width w of the probe that are closed and some portions along the width w of the probe that are open. Note that the probes herein may have a constant cross section along the width w of the probe, or in certain embodiments, it may be desirable to provide a cross section along the width w of the probe that is different therealong, for example, with a broader or narrower central portion. Further, the probes herein may have a constant tip opening or tip active area dimension along the width w of the probe. Alternatively, in certain embodiments, it may be desirable to provide a tip opening or tip active area dimension along the width w of the probe that is different therealong, for example, with a smaller and larger sections of tip opening or tip active area dimension for different applications. Additionally, the probes may be formed of a generally inactive body portion, and an active area that forms the tip opening, such as a conductor in the case of closed tip probes, or a tip opening. Alternatively, the body portion may incorporate some other functionality, such as thermal and electrical shielding, precise metrology spacing, or other elements such as micro- or nano-fluidic or micro- or nano-electromechanical devices. Further embodiments will be described herein. Closed Tip The probes described herein may be formed many different shapes that will provide the desired tip characteristics and dimensions. FIGS. 2A-2L show various shapes of certain embodiments of probes herein, generally having a closed tip configuration. However, it should be understood that these shapes may also be suitable of any tip configuration and may be incorporated in any continuous edge or discontinuous edge probe described herein. FIG. 2A shows a prismatic shaped probe having a cross section in the form of an elongated tip integral with a triangular region and an elongated rectangular portion at an end opposite the probe tip. FIG. 2B shows a prismatic shaped probe having a cross section in the form of a right triangle, e.g., with the tip flattened. FIG. 2C shows a prismatic shaped probe having a cross section in the form of a trapezoid. FIG. 2D shows a prismatic shaped probe having a cross section in the form of a rectangle. FIG. 2E shows a prismatic shaped probe having a cross section in the form of a triangle, with the tip at the adjoining end of the long sides of the triangle forming the tip for probing or other applications as described herein. FIG. 2F shows a prismatic shaped probe having a cross section in the form of a rectangle with a triangle at the probe tip end, with the tip at the adjoining end of the long sides of the triangle forming the tip for probing or other applications as described herein. FIG. 2G shows a prismatic shaped probe having a cross section in the form of an irregular polygon, e.g., symmetrical about the height axis, with a flat end and with a tip at the adjoining end of sides of the polygon with an acute angle as shown. FIG. 2H shows a probe having a cross section generally in the form of an inverted tear drop, with a tip t at the point of the tear drop shape. FIG. 2I shows a probe having a cross section generally in an elongated irregular form, with a tip t at an elongated end thereof. FIG. 2J shows a probe having a cross section generally in the form of an ellipse, with a tip t at a tangential point elliptical shape at an elongated end thereof. FIG. 2K shows a probe having a cross section generally in the form of a nozzle, such as a “flattened” end of an elliptical or circular cross sectioned tube, with a tip t at the “flattened” end thereof. FIG. 2L shows a probe having a cross section generally in the form of a V-shape, with a tip t at the point of the V-shape. Open Tip Referring now to FIGS. 3A-3E, probes are shown in various configurations having tip openings to, suitable for dispensing and/or holding materials according to the various embodiments herein. FIG. 3A shows a probe having a cross section in the form of an elongated hollow tip integral open to a triangular well region and an elongated rectangular well portion at an end opposite the probe tip with an opening to, having a channel therein for holding and facilitating dispensing of materials. FIG. 3B shows a probe having an asymmetrical cross section in the form a rectangle and a truncated triangle forming a probe tip with an opening to, having a channel therein for holding and facilitating dispensing of materials. FIG. 3C shows a probe having a symmetrical cross section in the form a truncated triangles forming a probe tip with an opening to, having a channel therein for holding and facilitating dispensing of materials. FIG. 3D shows a probe having a symmetrical cross section in the form a angled members forming a probe tip with an opening to, having a funneling channel therein for holding and facilitating dispensing of materials. FIG. 3E shows a probe having a symmetrical cross section forming a probe tip with an opening to, having a shaped well and a channel therein for holding and facilitating dispensing of materials. Extended Tip Referring now to generally to FIGS. 4A-5B, probes having tips, for example, conductive tips, with tip active area dimensions of t, are shown, whereby tips 410, 510, extend beyond the bodies 420, 520, of the structures. As shown, in FIGS. 4A-4B, a symmetrical probe is provided, and in FIGS. 5A-5B, a symmetrical probe is provided. Generally, the dimensions a FIG. 4A and the dimensions a and b in FIG. 5A are greater than the tip dimension t, preferably multiples of the tip dimension t. These embodiments advantageously provide for tips that extend sufficiently far away, for example, to minimize interaction between the probe body, for example, with the specimen or a substrate depending on the application of the probe. This avoids negative effects of substrate material such as accumulation of electrostatic charge and other interfering effects. Referring to FIG. 15, an example of an array of probes according to the embodiment of FIG. 5A-5B is shown. In systems herein where metal contacts or probes are used to measure currents and voltages from small structures such as the monomers of the specimen, four probe tunneling devices as are known in the art (e.g., shown in FIG. 109, are preferred to minimize contact and lead resistance. Irregular Inner Channel Referring now to FIGS. 6A-6C, views of an open tip probe according to certain embodiments of the present invention is shown, showing an irregular inner channel surface. FIG. 6B shows an array of such probes. FIG. 6C shows a probe generally as in FIG. 6A, wherein only a portion of the inside surface has electrodes 642 therethrough, which may be advantageously in certain applications. Referring now to FIGS. 7A-7B, views of an open tip probe according to certain embodiments of the present invention is shown, showing an irregular inner channel surface with differing sub-sections therein. For example, referring to FIG. 7A, a probe is shown having sub-sections that are divided generally along the height dimension of the channel, including sub-sections 712, 714, 716, 718 and 720. For example, sub-sections 712, 714, and 720 may be formed of insulating materials, sub-section 716 formed of conductive materials, and sub-section 718 formed of semiconductor materials. In a further example, and referring to FIG. 7B, a probe is shown having sub-sections that are divided generally along the height dimension of the channel, including sub-sections 732, 734, 736, 738 and 730. For example, sub-sections 732 and 736 may be formed of conductive materials, sub-sections 738 and 740 formed of insulating materials, and sub-section 734 formed as an open channel perpendicular to the channel of the probe tip, for example, for providing micro-fluidic operations or other suitable functionality. Variable Opening Probe In general, variable opening probes may be provided. In certain preferred embodiments, the opening tip dimension is controllable with sub-angstrom precision. Referring now to FIG. 8A a sectional view of a variable tip probe 810 according to certain embodiments of the present invention is shown, showing an irregular inner channel surface having a fixed section 814 and a complementary movable section 816. The movable section 816 preferably are actuated with angstrom or sub-angstrom precision to define the probe opening 812. FIGS. 8B1 and 8B2 shows views looking into the probe opening according to one embodiment, and FIGS. 8B1 and 8B2 shows views looking into the probe opening according to another embodiment. Referring now to FIG. 9, another embodiment of a variable gap probe 910 is shown. An actuator 924 imparts motion to section 916 of the probe, thereby changing the opening dimension of the tip opening 912. Probe Set FIGS. 10A and 10B show an enlarged isometric view and side view, respectively, of a probe set 1030 including probes 1042, 1044, 1046, and 1048, and a specimen extended object 1050 upon a platform 1028. In certain preferred embodiments, polymer strand 1050 is a biopolymer such as a nucleic acid (e.g., DNA). FIG. 10C shows an enlarged sectional view through any one of probes 1042, 1044, 1046, or 1048. FIG. 10D shows a top view of the base platform 1028, showing an exemplary channel 1052. As shown in FIGS. 10C and 10D, in certain embodiments, a measuring voltage is applied across each probe 1042, 1044, 1046, 1048, and platform 1028, denoted by reference numerals 1054a and 1054b, respectively. As the polymer strand 1050 passes under an activated probe (e.g., a probe with a measuring voltage applied thereto), detectable interactions occur as described in further detail herein. FIGS. 11A-11D show a probe set 1130 formed according to embodiments of the present invention. The probe set includes, e.g., a 1×4 array (although it is understood that this may be scaled to any size n×m nozzles) of probes 1142, 1144, 1146, 1148. In certain embodiments, these probes 1142, 1144, 1146, 1148 are in the form of nozzles, e.g., having tips 1154 associated with wells 1156, as shown in FIGS. 11B and 11C. Generally, the wells having widths in the y direction greater than the widths of the nozzle tips. FIG. 11D shows a sectional view of the nozzle array. The probe set 1130 may be embedded in a body 1158. The material for the probes or nozzles, and the body, may be the same or different materials, and may include materials including, but not limited to, plastic (e.g., polycarbonate), metal, semiconductor, insulator, monocrystalline, amorphous, noncrystalline, biological (e.g., nucleic acids or polypeptides based materials or films) or a combination comprising at least one of the foregoing types of materials. For example, specific types of materials include silicon (e.g., monocrystalline, polycrystalline, noncrystalline, polysilicon, and derivatives such as Si3N4, SiC, SiO2), GaAs, InP, CdSe, CdTe, SiGe, GaAsP, GaN, SiC, GaAlAs, InAs, AlGaSb, InGaAs, ZnS, AlN, TiN, other group IIIA-VA materials, group IIB materials, group VIA materials, sapphire, quartz (crystal or glass), diamond, silica and/or silicate based material, or any combination comprising at least one of the foregoing materials. Of course, processing of other types of materials may benefit from the process described herein to provide probes and bodies of desired composition. Specimen/Probe Orientation Referring now to FIGS. 12A and 12B, all probes and probe sets described herein may be configured with respect to the specimen at various angles. For example, referring to FIG. 12A, a probe set 1230 may be oriented generally perpendicular (in the length direction) to a specimen 1250. Further, referring to FIG. 12B, a probe set 1230 may be oriented (in the length direction) generally at an angle θ with respect to a specimen 1250. Referring to FIG. 12C, a system 1260 is presented whereby the orientation of plural probe sets 1230 relative a specimen 1250 varies. Because the objects of the specimen 1250 (e.g., bases within a DNA strand) may have different orientations, it may be desirable to sequence with a plurality of probe sets 1230. The plurality of probe sets 1230 may have different angles θ1, θ2, θ3, θ4, θ5, . . . θn (e.g., 20° to 160° in suitable increments, arranged sequentially, randomly or in another desirable arrangement. During measurement as described further herein, a controller may determine which orientation of the probe set yields the best signal for a particular base at its inherent orientation. This allows one to measure the data from the probe sets of the array, and determine the optimum signal for certain bases or groups of bases. In another embodiment, and referring to FIGS. 12D-12F, the angles of orientation in the height direction may also be varied. For example, referring to FIG. 12D, probe set 1230 may be oriented in the height direction generally perpendicular (90°) with respect to the specimen 1250. Further, as shown in FIG. 12E, probe set 1230 may be oriented in the height direction generally at an angle ω with respect to the specimen 1250. Referring to FIG. 12F, a system 1270 is presented whereby the orientation in a height direction of plural probe sets 1230 relative a specimen 1250 varies. Because the objects of the specimen 1250 (e.g., bases within a DNA strand) may have different orientations, it may be desirable to sequence with a plurality of probe sets 1230. The plurality of probe sets 1230 may have different angles ω1, ω2, ω3, . . . ωn (e.g., 20° to 160° in suitable increments, arranged sequentially, randomly or in another desirable arrangement. Extended Opening Channel In another embodiment, and referring now to FIGS. 13A-13B, the probes according to the present invention may be configured about more than one portion of the specimen to be analyzed, for example, in the form of an extended opening channel which interrogates from more than one side of the specimen. Presently, it is known to coax DNA fragments through a pore for the purpose of measuring a change in ionic conductivity. Challenges are posed in the consistency of motion through the holes, the resolution, and other interference. The pore is often part of a system of ionic fluids, whereby ionic conductivity change is measured across regions of ionic fluids separated by a membrane and/or layer having one or more pores. For example, as described in the background of the invention, U.S. Pat. Nos. 6,870,361, 5,795,782, 6,267,872, 6,362,002, 6,627,067 describe such pores. However, according to the extended opening channel system 1300 of the present invention, a specimen 1350 is passed through an extended opening channel 1301. Each extended channel opening includes several probes formed according to any one or more of the various embodiments herein. The probes may be configured on one side of the opening, or multiple sides of the opening. In certain embodiments, using an extended opening channel which interrogates from more than one side of the specimen, accuracy may be enhanced, and signal is increased. As discussed below with respect to FIGS. 14A-14C, these extended opening channels may be configured in arrays in a 2 dimensional or 3 dimension configuration, which presently known pore based sequencing systems cannot achieve. Probe Arrays Referring now to FIG. 14A, a serial probe array 1477 is shown. The probe array includes Q serial probe sets 1430. In general, extended objects to be analyzed may be passed through the Q serial probe sets 1430. The Q serial probe sets may be homogeneous or heterogeneous. For example, using homogeneous probe sets 1430, each probe set may include various individual probes optimized for adenine, cytosine, guanine, and thymine. Further, referring to FIG. 14B, an array 1480 of probe sets may comprise heterogeneous probes. For example, one probe set may be optimized for adenine (A), a second optimized for cytosine (C), a third for guanine (G) and a fourth for thymine (T). These serial arrays would not be possible using conventional known techniques, for example, based on pores as described in the background of the invention. Importantly, redundancy is readily achievable in a serial configuration of the present invention, whether the system is formed of serial heterogeneous probe sets, serial homogeneous probe sets, or combinations thereof. Referring now to FIG. 14C, a parallel and serial probe array 1478 is shown. The probe array includes M×N channels of Q serial probe sets 1430. This probe array 1478 may be very useful for high speed parallel processing of extended objects to be analyzed. The probe sets 1430 within the array 1478 may be homogeneous or heterogeneous. The extended objects may be the same or different. In general, extended objects to be analyzed may be passed through the Q serial probe sets. An M×N array of extended objects, which may be the same or different, are passed through the M×N arrays of Q serial probe sets 1430. Probe Type for Various Detectable Interactions The above described probes may be used in various configurations. Certain probes may be in the form of open tip probes. The various open tip probes described herein may be used for dispending materials, for example, as a nano-nozzle or nano-funnel. Further, various open tip probes described herein may be used to expose a specimen or a workpiece to photonic energy or stimuli, serve as a as a nano-nozzle or nano-funnel for ion or particle beam operations, or the like. Further, various open tip probes described herein may be used to expose materials to a specimen or a workpiece, whereby a) forces are applied within the body of the probe, within the well of the probe, or by another element within the probe to keep the material from dispensing; b) operate at suitable temperature the reduces the likelihood of or prevents the material from dispensing; or c) operate at suitable pressure the reduces the likelihood of or prevents the material from dispensing). Certain probes may be in the form of nano-electrodes for measuring detectable interactions. Certain probes may be in the form of materials that result in detectable interactions such as a system of correlating biological materials that create hybridization events with the extended object to be analyzed. Nucleotide Filled Well In certain embodiments, and referring now to FIGS. 16A and 16B, the basic principle is described, wherein a DNA chain (or other protein or extended object to be analyzed) 1650 upon a base 1628 is passed underneath four open tip probes 1642, 1644, 1646 and 1648 (or arrays of nozzles, e.g., as shown in FIG. 16B). The four funnels or nozzles 1642, 1644, 1646 and 1648 are filled with adenine, cytosine, guanine, and thymine molecules respectively. Due to the complementary structures of adenine and thymine, and of guanine and cytosine, a hybridization event between nucleotides on the DNA chain and the nucleotides in the nozzle will occur when the correct pairs come into contact. This hybridization results in a lower energy state and charge transfer, which can be detected via an ammeter. This is because the conductivity between the nozzles and the electrode ground plate will be affected, thereby altering the current between the nozzle and the ground plate. FIG. 16B shows an exemplary array setup, e.g., that may average out noise and increase SNR. These features will help in assuring an excellent SNR. Note that the above described probes may also be formed with one or more conductors therein for increase signal detection capabilities. For example, the conductor may be layered within or upon an inner wall of the probe or nozzle well and tip. Solid State Nucleotide Referring to FIG. 17A, an embodiment of a system 1700 having probes formed of solid state nucleotide materials is shown. A probe set 1730 is depicted wherein each probe 1742, 1744, 1746, 1748 is formed of a solid state nucleotide, e.g., adenine, cytosine, guanine, and thymine molecules respectively. A solid state nucleotide may be manufactured on thin films, and formed as probes using the various manufacturing methods described herein or other thin film manufacturing techniques. Preferably, these SSN have a single molecule thickness at the probe tip, so that a desirable monomer scale resolution is maintained. These films may be formed in the nozzle wells, e.g., by layering during the manufacturing process prior to slicing. In preferred embodiments of a DNA sequencing system herein, the nozzles are formed with a tip dimension of less than about 0.5 nanometers to resolve corresponding monomers. It is known that DNA strands may be condensed on substrates. In the herein probes, single species nucleotide strands may be condensed in the form of lines or films. Referring to FIG. 17B, these may be formed on a substrate (M), such as a conductive substrate, Referring to FIG. 17C, condensed single species nucleotide strands may be sandwiched between substrates (M). The films resulting from FIG. 17B or 17C may be used directly as the probes. Alternatively, these films may be slices and attached to metallic “knife blades”. In a further alternatively, they may be folded, whereby exposed condensed single species nucleotides serve as the probe. Metal Conductor Referring now to FIG. 18, a system 1800 is shown using metal conductors as probes 1831. The probe may be formed of a suitable conductor material. Further, probes in the form of nozzles may be filled or layered with metal conductor material. The metal may be platinum, gold, or other suitable metal or non metal conductor. In preferred embodiments of a DNA sequencing system herein, the conductor probes formed to a tip dimension of less than about 0.5 nanometers to resolve corresponding monomers. In one method of using a probe 1831, stimuli (e.g., a voltage) is applied across the subject nucleotide within the subject strand, and a characteristic I vs. V curve may be obtained. For example, FIG. 19 shows an exemplary representation of characteristic curves for various monomers adenine, cytosine, guanine, and thymine (A, C, G and T). In certain embodiments, a single probe 1831 may be used as described in FIG. 18. In other embodiments, a probe set may be used, whereby bias waveforms across different electrodes may be varied to adjust sensitivity for expected specimen portions or monomers. For example, a four-probe probe set may be used for identifying A, C, T, G components of biopolymers such as DNA strands. Further, identical waveforms may be applied whereby multiple probes are used for redundancy. These may be gated or un-gated, depending on the application. Probe with Attached Functionalized Group Referring now to FIG. 20, a functionalized group 2050 (FG) is mounted onto probe 2010. The 2050 may include known nucleotide strands, oligomers, peptides, single molecules, or other known species. The 2050 is selected to have a known specific sensing capability, for example, electrostatic, magneto-static, chemical, and other interactions with a specimen under analysis. Referring now to FIG. 21, a functionalized group 2150 may be attached to cylinders of micrometer diameters which may then be attached to a larger structures. The cylinders may be coated glass, metal, or organic or inorganic. Referring now to FIG. 22, plural functionalized groups 2252, 2254, 2256 are mounted onto a probe 2210. In this embodiment, stepping operations, either of the probe or the specimen, is in two directions. By stepping in a direction substantially normal to the width w of the probe 2210 and in a direction substantially parallel to the width w of the probe 2210, analysis may be simplified. For example, functionalized group 2252 interacts with the specimen, the observation is recorded, then the probe is stepped so that functionalized group 2254 interacts with the specimen, the observation is recorded, and then the probe is stepped so that functionalized group 2256 interacts with the specimen, the observation is recorded. Then, the entire probe may be stepped in a direction substantially normal to the width w of the probe 2210 to continue analyzing the specimen. Metal Plus Known Nucleotide Stand, Preferably Same Species Referring now to FIG. 23A, an embodiment of a system 2300 having probes formed of a conductor with a known material strand attached to the edge of the probe, particularly the “knife edge” probe, e.g., described above with respect to FIGS. 2 and 3. For example, a probe set 2330 is depicted wherein each probe 2342, 2344, 2346, 2348 has a known nucleotide strand, e.g., adenine strand, cytosine strand, guanine strand, and thymine strand respectively. In a preferred embodiment, a single strand/single species nucleotide strand is provided. It is stretched and attached to the tip of a conductor probe. The known nucleotide strand may be attached to the tip if the conductor probe by various nano- or micro-manipulation means. In one embodiment, magnetically attractive molecules, referred to as “magnetic beads”, may be attached at opposing ends of the known strand to facilitate manipulation. A nano-manipulator magnet system may be used to stretch the strands for attachment to the probe set. For example, this is shown with respect to FIG. 23B. Further, this configuration ensure that as the probe passes over the specimen, landing error associated with typical probe analysis systems is eliminated. With a single-strand, single-species chain attached at the probe tip, when the tip encounters a specimen portion or monomer that is capable of forming a hybrid pair with the probe species, bond energies associated with the hybridization event enhances the resonance activity being measuring. Open Well or Funnel Referring to FIG. 24, an embodiment of a system 2400 having probes formed as open wells or funnels is shown. A probe set 2430 is depicted wherein each probe 2442, 2444, 2446, 2448 is formed as an open well or funnel. This open well or funnel may be used as a path for various probe activities, for example, generated by sources 2482, 2484, 2486, 2488. Particle Beam Particle beam emitters can be made directly into nano probes or indirectly through the funnel described herein. They include ion beam and electron beam emitters. Photon Beam Photon beam emitters such as x-ray emitters, ultraviolet emitters, IR emitters, visible emitters, and terahertz emitters can be formed with the herein probes or trough funnels as described herein. In the event that the excitation photon beams have wavelengths large than the probe diameter, the use of evanescent fields that extend only to the width scale of the beam (probe) will be utilized. Electron Beam Emission In another embodiment, an electron beam emitter is focused and shaped to provide a nano-scale resolution beam. They can be tuned in energy. This tunability can give one selectivity in directly interacting with the specimen to be analyzed. Electron beams may be used as the probe for the systems of the present invention. It is known in the electron optics art that atomic scale resolution may be achieved with SEM, TEM, and STEM since the beams themselves can be made nano-scale as the probing beams. In preferred embodiments of a DNA sequencing system herein, the electron beams are focused to a sectional dimension of less than about 0.5 nanometers to resolve corresponding monomers. The electron beam may be a line beam (analogous the probe of FIG. 1A), or electron beam scanning may be employed (analogous the probe of FIG. 1B, although it is to be understood that the funnel need not be moved, only the beam). Referring to FIG. 24, the electron beam may be inserted through the funnel. This minimized the need for nano-scale resolution electron optics required for direct electron beam formation at the atomic scale. It should be appreciated that the funnel walls for x-ray, electron beams and ion beams will be constructed appropriately to be able to propagate from the funnel opening to the funnel end to achieve nano-scale resolution. In the case of electron beams, electric fields appropriately placed may cause these beams to bend toward the funnel tip. Alternately, secondary electron emission may be created from inner funnel wall surfaces which lead to the creation of a beam that exits the funnel tip. Ion Beam In another embodiment, a focused ion beam emitter with nano-scale resolution known in the art may be used as the probe to interact with the specimen. They can be tuned in energy. This tunability can give one selectivity in directly interacting with the specimen to be analyzed. Further, the ion beams may be based on H+, He+, Ge+, Ga+, or other suitable ions of substances that may be formed into beams that have specific selective interaction with the specimen to be resolved. Referring to FIG. 24, the ion beam may be inserted through the funnel. This minimized the need for nano-scale resolution electron optics required for direct electron beam formation at the atomic scale. It should be appreciated that the funnel walls for x-ray, electron beams and ion beams will be constructed appropriately to be able to propagate from the funnel opening to the funnel end to achieve nano-scale resolution. In the case of electron beams, electric fields appropriately placed may cause these beams to bend toward the funnel tip. Alternately, secondary electron emission may be created from inner funnel wall surfaces which lead to the creation of a beam that exits the funnel tip. X-Rays X-ray beams, such as an x-ray laser beam, may be used as the probe for the systems of the present invention. In preferred embodiments of a DNA sequencing system herein, the x-ray beams are focused to a sectional dimension of less than about 0.5 nanometers to resolve corresponding monomers. For example, the electron beam system described above may be used to generate nano-scale x-ray beams in a manner known in the art. Further, referring to FIG. 24, an x-ray beam (directly or indirectly) may be inserted through the funnel. This minimized the need for nano-scale resolution x-ray and electron optics required for direct electron beam formation at the atomic scale. It should be appreciated that the funnel walls for x-ray, electron beams and ion beams will be constructed appropriately to be able to propagate from the funnel opening to the funnel end to achieve nano-scale resolution. In the case of x-ray, the inner surfaces of the funnel may be made of multi-surface to achieve interference reflection, or may be of single crystal using Bragg reflection properties, or may be grazing incidence angle rejection until the rays reach the funnel end. To avoid stray x-rays that may interfere with excitation and/or measurement and increase noise, the inner and outers surfaces of the funnel as appropriate may be coated with x-ray absorbers. Scanning Tunneling Microscopy (STM) and Atomic Force Microscopy (AFM) Scanning tunneling microscopy (STM) or atomic force microscopy (AFM) probe tips may be arranged into arrays and utilized according to the teachings of the present invention. Probe Type for Other Applications The above described probes may be used in various configurations. Certain probes may be in the form of wells with dispending tips. Certain probes may be in the form of nano-nozzles. Certain probes may be in the form of nano-funnels. Certain probes may be in the form of electrodes for lithography. Variable Gap Probe—Manipulator and Other Applications As described herein, for example, with respect to FIGS. 8 and 9, probes may be provided herein with variable dimensioned or actuate-able tip openings. This type of variable gap probe may be very useful for many applications, including but not limited to controlled dispensation of materials, controlled vacuum or fluid pressure, manipulation of nanometer sized structures, and other applications. Hollow Probe for Suction/Fluid Pressure Various configurations of the open tip probes herein may be useful for vacuum or fluid pressure. For example, certain embodiments of the open tip probes described herein may be used to impart vacuum or fluid pressure. In another embodiment, and referring now to FIG. 25, a probe 2510 is provided having a plurality of openings 2512 along the length of the extended width probe tip, with other regions 2514 plugged with suitable plug material. The vacuum or fluid source may further be divided, or alternatively, the plural openings 2512 may share a common vacuum or fluid source. Methods of Making the Probes Herein disclosed are probes, nano-probes and methods of manufacturing probes and nano-probes. With the disclosed methods, it is possible to create probes with tip active area dimension, such as opening dimensions in the cases where the probe has an open tip, on the order of about 0.1 nanometers to about 10 nanometers, 10 nanometers to about 100 nanometers, or 100 nanometers to 1000 nanometers. Further, it is possible to make such probes in arrays with exact spacing therebetween, and with additional supporting functionality such as stimuli providing structures, metrology structures, micro- and nano-fluidic structures or devices, micro- and nano-electromechanical structures, or other supporting features. Such features enable molecular level dispersion, precise material deposition, molecular level detection, and other nano-scale processes. Furthermore, the herein described analytical systems including sequencing of extended objects such as DNA or RNA strands or fragments is enabled by creating a probe having tip dimensions on the order of about 5 Angstroms, for example, utilizing the herein referenced and described probe and nozzle manufacturing methods. There are various methods of making the probes, probe sets and probe arrays described herein. Co-pending U.S. Non-provisional application Ser. No. 10/775,999 filed on Feb. 10, 2004 (and corresponding PCT Application PCT/US04/03770) entitled “Micro-Nozzle, Nano Nozzle and Manufacturing Methods Therefor”, incorporated herein by reference, describe various techniques for manufacturing probes in the form of nozzles or funnels are described. These techniques may be modified to provide other probe configurations and probe types described herein. Further, in certain embodiments, it may be desirable to conduct various fabrication, handling and assembly steps in clean room environments. In other embodiments, it may be desirable to conduct various fabrication, handling and assembly steps in a negative pressure environment and/or in ultra-pure inert gas environments. In general, in certain embodiments of the herein described methods of making the films, the probe tip active area has relevant tip dimensions (e.g., tip width t as shown in the above FIG. 1A) that is a function of a very thin film that is layered, deposited, or otherwise formed either on a portion of a probe body or on intermediate structures between plural probes. Making Film Prior art teaches how sub-micron objects and features can be produced by means of conventional optical, UV, e-beam, X-ray and lithography. These tools are being extended to produce sizes below 30 nanometers. As they are stretched to produce even smaller sizes, their limitations become more and more apparent, in terms of cost, foot-print, etc. Indeed, at high electron and ion beam accelerating voltages >100 KV features smaller that 10 nm have been demonstrated. The preparation steps and the cost of the equipment and ancillary components make these prior art methods cumbersome and slow. The present invention shows ways to produce similar or better results faster, and more convenient by departing from using lithography based photon, ion and e-beams to produce the smallest features. Instead, ultra-thin films are used for this purpose. There are many known methods of producing films with atomic precision. These include, deposition by sputtering, electron beam, ion beam, molecular beam epitaxy, CVD, MOCVD, plasma, laser deposition, pyrolitic deposition, electrochemical, thermal evaporation, sputtering, electro-deposition, molecular beam epitaxy, adsorption from solution, Langmuir-Blodgett (LB) technique, self-assembly and many other related methods collectively referred to as Thin Film Deposition Methods. Accurate metrology enables the production and control of thicknesses with Angstrom precision. Producing free standing films by peeling is possible as taught in copending U.S. patent application Ser. No. 09/950,909 filed on Sep. 12, 2001 and U.S. patent application Ser. No. 10/970,814 filed on Oct. 21, 2004 and manipulation taught in applicant's co-pending U.S. Non-provisional application Ser. No. 10/717,220 filed on Nov. 19, 2003 entitled “Method of Fabricating Multi Layer Mems and Microfluidic Devices” and other related applications. The films produced by the conventional deposition methods need atomically flat substrates. The advent of scanning tunneling microscopy (STM), atomic force microscopy, AFM, scanning probe microscopy, SPM, and related tools have enabled the imaging of surfaces and structures with atomic resolution. This opened new vistas to advance our understanding of many physical and chemical phenomena that are being exploited in numerous practical applications in the fields of medicine, nanotechnology, nano-electronics, genomics, proteomics, nano-electrochemistry, and destined to make even more contributions in other fields in the futures. To achieve nano-scale resolution and nanofabrication accuracy and to properly interpret physical and chemical phenomena, it necessary to use atomically flat, atomically smooth substrates over a large area preferably in the range of several square microns to several square centimeters. To produce such substrates, prior art relies of unsophisticated and inaccurate techniques of attaching an adhesive tape to the surface of mica or graphite to peel the top most atomic layers to reveal a fresh atomically smooth surface of a piece of mica or graphite of size and tetchiness. In almost all situations the atomic surface is the desired result while the lateral shape or size or thickness is of little importance. Prior art techniques could not teach methods of producing, handling and manipulating samples having a single layer graphite (also called graphene) or mica of a predetermined desired number of mono-atomic of mica or graphite. Graphites are well known and are widely used materials. For example U.S. Pat. No. 6,538,892 exploits its good mechanical and anisotropic thermal properties for the construction of heat sinks. Graphites according to the description in U.S. Pat. No. 6,538,892, are made up of layer planes of hexagonal arrays or networks of carbon atoms. These layer planes of hexagonally arranged carbon atoms are substantially flat and are oriented or ordered so as to be substantially parallel and equidistant to one another, as shown in FIG. 26. The substantially flat, parallel equidistant sheets or layers of carbon atoms, 2610, usually referred to as graphene layers or basal planes, are linked or bonded together and groups thereof are arranged in crystallites. Highly ordered graphites consist of crystallites of considerable size: the crystallites being highly aligned or oriented with respect to each other and having well ordered carbon layers. In other words, highly ordered graphites have a high degree of preferred crystallite orientation. It should be noted that graphites possess anisotropic structures and thus exhibit or possess many properties that are highly directional e.g. thermal and electrical conductivity and fluid diffusion. Briefly, graphites may be characterized as laminated structures of carbon, that is, structures consisting of superposed layers of carbon atoms joined together by weak van der Waals forces 2612. In considering the graphite structure, two axes or directions are usually noted, to wit, the “c” axis or direction and the “a” axes or directions. For simplicity, the “c” axis or direction may be considered as the direction perpendicular to the carbon layers. The “a” axes or directions may be considered as the directions parallel to the carbon layers or the directions perpendicular to the “c” direction. The graphites suitable for manufacturing flexible graphite sheets possess a very high degree of orientation. The bonding forces holding the parallel layers of carbon atoms together are only weak van der Waals forces. In a process referred to as exfoliation of graphite, natural graphites can be treated so that the spacing 2612, d, in FIG. 26A between the superposed carbon layers 2610 can be appreciably opened up so as to provide a marked expansion of Nd, as in FIG. 26B, the direction perpendicular to the layers, that is, in the “c” direction, and thus forms an expanded graphite structure in which the laminar character of the carbon layers is substantially retained. It has been shown that N can be in the range of 100 to 1000 according to the treatment process. The graphite layers are referred to as graphene layers possess very high electrical and thermal conductivities exceeding those of copper, while retain high temperatures and exceedingly Young modulus. Recently, Andrei Geim and colleagues of the University of Manchester isolated a single sheet of graphene and measured its remarkable properties which include conductivity 100 higher than copper and astonishing Quantum Hall Effect behavior. These and other results are described in January, 2006, Physics Today. These results could be made possible only after successful isolation of a single 1 Angstrom graphene layer, a feat that was not previously possible. Geim's team succeeded in isolating a single graphene layer by random and tedious and unpredictable method. According to the Physics Today Article: “Their method is astonishingly simple: Use adhesive tape to peel off weakly bound layers from a graphite crystal and then gently rub those fresh layers against an oxidized silicon surface. The trick was to find the relatively rare monolayer flakes among the macroscopic shavings. Although the flakes are transparent under an optical microscope, the different thicknesses leave telltale interference patterns on the SiO2, much like colored fringes on an oily puddle. The patterns told the researchers where to hunt for single monolayers using atomic force microscopy. The work confirmed that graphene is remarkable-stable, chemically inert, and crystalline under ambient conditions.” From the above and other recent investigations on graphene as well as from commercial supplier of graphite substrate, one concludes that there is a need for inventing convenient, low cost, and fast methods for isolating single layers of graphene and predictable stacks of selected number of graphene layers. There is further the need for general methods for isolating single layer or predictable number of layers from lamellar or multilayer materials which include but not limited to mica, Super lattices MoS2, NbSe2, Bi2Sr2CaCu2Ox, graphite, mica, Boron nitride, dichalcogenides, trichalcogenides, tetrachalcogenides, pentachalcogenides and Hydrotalcite-like materials. Therefore, many aspects of the present invention involve production of single and multiple layers of lamellar material. Many of the inventive features and certain embodiments of the present invention rely on the ability to make ultra-thin, nano-scale films. In further embodiments, it is desirable that these films are atomically flat films. These enable the fabrication of all the probe configurations that perform a variety of functions necessary to advance the frontier of nano-science and technology including but not limited to imaging, analysis, sequencing, nano-lithography, and nano-manipulation as well a variety of other applications. Thin film deposition methods describe above may be used to produce thing films with Angstrom precision. Alternatively, even more precisely define thickness can be produced the controlled peeling of one or more predetermined number of layers from lamellar material as taught herein. These embodiments described herein apply to graphite to produce graphene layers, to producing layers of mica, MoS2 and lamellar materials. One embodiment to selectively peel off a single layer from a lamellar material, 2710, is illustrated in FIG. 27A. The material is cut along the line 2712, at an angle of, for example, 20 degrees or more relative the “c” axis. The goal is the have access to the top most layer 2722, as each layer is sequentially removed according to FIG. 27B. Two knife edge probes, as described herein, having tip opening dimensions small enough to access individual layers or groups of layers that are revealed due to the angular cut, are use to facilitate the peeling process. Knife edge probe 2718 pushes down on the second layer against the first substrate 2714 while knife edge probe 2720, pushes up the first layer against a second substrate 2716, attached to the desirable first layer. FIG. 27C shows the complete separation of the first layer that is attached to the substrate 2716 which is being pulled vertically to facilitate the separation process. In another embodiment, knife edges 2718, 2720, are applied in the horizontal directions pushing on both sides pry loose the first layer while the substrate 2716 is pulling upward. This method illustrated in FIGS. 27A-B, is facilitated with the knowledge of the exact separation between layers by known imaging techniques such as AFM and STM. This information, along with well know tools to move the knife edges with sub-angstrom precision, allows for reliable separation of the layers. FIG. 28A-C illustrates yet another embodiment to reliably separate single layers. It exploits etching the peripheral regions of the first layer to expose the second layer by known etching techniques including electrochemical etching as shown in FIG. 28A. Here, a voltage source 2818 is applied across electrodes 2815, that are contacting the peripheral regions 2810, of the first layer 2822. The exposed second layer 2812 is pushed as in FIG. 28B. After the etching is complete, the electrodes 2815 push down on the second layer against the substrate 2814 while the top substrate 2816 is pulling upward the selected first layer 2822. Thus a single layer is conveniently and inexpensively removed and transferred to a third substrate, optionally. The substrate 2816 is removably bonded to the first layer 2822 by many bonding techniques including but not limited to adhesives, waxes, vacuum, etc. The final result in 28C is repeated for all the other layers of the lamellar material until all layers are removed with minimum of waste. This method can also be combined with method described in FIG. 27A-F above to allow for the selection and the removal of more than a single layer. For instance, in the graphene case, it may be desirable to have a single layer of 1 Ang, 2 layers of 2 Ang, N layers of multiple Ang, depending on how the graphite is exfoliated to swell the interlayer spacing by factors of 10-1,000. (See exfoliated graphite description presented above with respect to FIGS. 26A and 26B). Another embodiment that takes advantage of the unique properties of graphene and metallically coated other lamellar materials is described in FIG. 29A-B. A special substrate 2916 is provided and is removable attached to the first layer 2922 we intend to peel. Current source 2912 is applied to the first graphene layer 2922 and electrode 2924 deposited on top of substrate 2916. The current 2928 flowing in electrode 2924 and flowing out (in the opposite direction) of single layer 2922 result in a magnetic force 2920 that selectively pulls upward in the upward direction 2918, only the first layer 2922. By further applying a mechanical force upward to substrate 2916, the combination of magnetic and mechanical forces allows peeling with ease 2922. Since no such forces are influencing second and third layers, they are left intact. Separation process is illustrated in 29A-B. Instead of exploiting the magnetic force in the aforementioned embodiment, it is possible to use instead electrostatic force as illustrated in 30A-B. In this case a voltage source 3016 is applied to electrode 3024, deposited on substrate 3012 and a revealed portion of the first layer 3022. The electric field 3020 is applied and causes an electrostatic force in the upward direction 3018, and along with a mechanical force applied to a substrate upward in a pulling selection, the first layer is selectively removed from the entire multi layer structure 3010. Another embodiment of peeling layers of lamellar material is shown in FIGS. 31A-C. Here the multilayer lamellar structure 3110 is attached to a substrate 3114 to the bottom while at the top implement substrate 3112 is removably attached to the top of the specimen. Said substrate 3112 may be a vacuum handler, adhesive tapes or other films with removable adhesives. The first step is to lift substrate 3112 which will pull or peel a random number of layers 3116, shown in FIG. 31A. This process is repeated as necessary until the last few layers remain as in FIG. 31B. In FIG. 31C the second to last layer is finally removed, leaving the last layer 3122 bonded to substrate 3114. Note that the shavings, or the peelings of random number of layers are in turn attached to substrate 3114 and the process is repeated until the desired number of single layers are removed and utilized. The above embodiments of methods to selectively remove single layers, or predetermined number of layers from lamellar could be combined as appropriate to achieve most advantageous, practical and economical way to produce the desired results. Probe Thickness Defined By Thickness of a Layer As discussed herein, in certain embodiments of the herein described methods of making the films, the probe tip active area has relevant tip dimensions (e.g., tip width t as shown in the above FIG. 1A) that is a function of a very thin film that is layered, deposited, or otherwise formed either on a portion of a probe body or on intermediate structures between plural probes. Probe Thickness Defined By Thickness of a Layer As discussed herein, in certain embodiments of the herein described methods of making the films, the probe tip active area has relevant tip dimensions (e.g., tip width t as shown in the above FIG. 1A) that is a function of a very thin film that is layered, deposited, or otherwise formed either on a portion of a probe body or on intermediate structures between plural probes. Using various film processing techniques invented by the inventor hereof and incorporated by reference herein above and below, ultra thin layers of materials are deposited to form a stack of layers. The probes areas may be formed as openings, whereby a series of probes may be readily formed by creating a stack of layers alternating between insulator or semiconductor materials and selectively removable materials, whereby the geometry and dimensions of the selectively removable materials defines the opening geometry and dimensions. Note the selectively removable materials may also be placed adjacent a conductor, or between a pair of conductors, to, e.g., allow for controllable dispensing or other functionality. In other embodiments, the probes areas may be a suitable conductors, whereby a series of probes may be readily formed by creating a stack of layers alternating between insulator or semiconductor materials and conductive material, whereby the geometry and dimensions of the conductive material defines the probe or electrode geometry and dimensions. MFT Certain methods to make the probes, probe sets, and probe arrays may utilize the processing techniques and various tools invented by applicants hereof suitable for processing thin layers and forming vertically integrated devices. Various probes and configurations thereof may be manufactured with the use of Applicant's multi-layered manufacturing methods, as described in U.S. Non-provisional application Ser. No. 09/950,909, filed Sep. 12, 2001 entitled “Thin films and Production Methods Thereof”; Ser. No. 10/222,439, filed Aug. 15, 2002 entitled “MEMs And Method Of Manufacturing MEMs”; Ser. No. 10/017,186 filed Dec. 7, 2001 entitled “Device And Method For Handling Fragile Objects, And Manufacturing Method Thereof”; PCT Application Serial No. PCT/JUS03/37304 filed Nov. 20, 2003 and entitled “Three Dimensional Device Assembly and Production Methods Thereof”; U.S. Pat. No. 6,857,671 granted on Apr. 5, 2005 entitled “Method of Fabricating Vertical Integrated Circuits”; U.S. Non-provisional application Ser. No. 10/717,220 filed on Nov. 19, 2003 entitled “Method of Fabricating Multi Layer MEMs and Microfluidic Devices”; Ser. No. 10/719,666 filed on Nov. 20, 2003 entitled “Method and System for Increasing Yield of Vertically Integrated Devices”; Ser. No. 10/719,663 filed on Nov. 20, 2003 entitled “Method of Fabricating Multi Layer Devices on Buried Oxide Layer Substrates”; all of which are incorporated by reference herein. However, other types of semiconductor and/or thin film processing may be employed. MFT—Formation of MFT Layer Referring now generally to FIGS. 32A-32F, a method and system for making a thin device layer 3220 that may be used as a probe or probe precursor, or may be used as a substrate for a probe, probe precursor, probe set, or probe array thereon or therein (generally referred to herein as “probe elements”) according to various embodiments of the present invention. FIG. 32A shows a bulk substrate 3202 as a starting material for the methods and structures of the present invention. Referring to FIG. 32B, a release inducing layer 3218 is created at a top surface of the bulk substrate 3202. This release inducing layer 3218 may include a porous layer or plural porous layers. The release inducing layer 3218 may be formed by treating a major surface of the bulk substrate 3202 to form one or more porous layers 3218. Alternatively, the release inducing layer 3218 in the form of a porous layer or plural porous layers may be derived from transfer of a strained layer to the bulk substrate 3202. Further, the release inducing layer 3218 may include a strained layer with a suitable lattice mismatch that is close enough to allow growth yet adds strain at the interface. For example, for a single crystalline silicon substrate 3202, the release inducing layer in the form of a strained layer may include silicon germanium1, other group III-V compounds, InGaAs, InAl, indium phosphides, or other lattice mismatched material that provides for a lattice mismatch that is close enough to allow growth, in embodiments where single crystalline material such as silicon is grown as the device layer 3220, and also provide for enough of a mismatch to facilitate release while minimizing or eliminating damage to probes or probe precursors formed in or upon the device layer 3220. The release inducing layer 3218 may be formed by treating (e.g., chemical vapor deposition, physical vapor deposition, molecular beam epitaxy plating, and other techniques, which include any combination of these) a major surface of the bulk substrate 3202 with suitable materials to form a strained layer 3218 with a lattice mismatch to the device layer 3220 (e.g., silicon germanium when the device layer 3220 and the substrate 3202 are formed of single crystalline Si). One key feature of the release layer, particularly in the form of the strained layer, is that at least a portion of the release layer comprises a crystalline structure that is lattice mismatched compared to the bulk substrate and the device layer to be formed or stacked atop the release layer. Alternatively, the release inducing layer 3218 in the form of a strained layer may be derived from transfer of a strained layer to the bulk substrate 3202. 1For example, U.S. Pat. No. 6,790,747 to Silicon Genesis Corporation, incorporated by reference herein, teaches using a silicon alloy such as silicon germanium or silicon germanium carbon, in the context of forming SOI; S.O.I.Tec Silicon on Insulator Technologies S.A. U.S. U.S. Pat. No. 6,953,736, incorporated by reference herein, discloses using a lattice mismatch to form a strained silicon-on-insulator structure with weak bonds at intended cleave sites. In other preferred embodiments, the release inducing layer comprises a layer having regions of weak bonding and strong bonding (as described in detail in Applicant's copending U.S. patent application Ser. No. 09/950,909 filed on Sep. 12, 2001 and U.S. patent application Ser. No. 10/970,814 filed on Oct. 21, 2004, both entitled “Thin films and Production Methods Thereof” incorporated by reference herein, and further referenced herein as “the '909 and '814 applications”). Still further, the release inducing layer may include a layer having resonant absorbing material (i.e., that absorbs certain exciting frequencies) integrated therein. For example, when certain exciting frequencies are impinged on the material such as during debonding operations, resonant forces cause localized controllable debonding by heating and melting of that material Referring to FIG. 32C, a device layer 3220 is formed on top of or within the release layer 3218. In certain preferred embodiments, the device layer 3220 is epitaxially grown, e.g., as an epitaxial single crystal silicon layer. In still further alternative embodiments, the device layer may be attached to the release layer and placed atop the substrate layer or bulk substrate 3202. For example, a suitable vacuum handler (such as one formed as described in 10/017,186 filed Dec. 7, 2001 entitled “Device And Method For Handling Fragile Objects, And Manufacturing Method Thereof”, incorporated by reference herein, or other vacuum handlers) may be used to hold and transfer a thin layer as mentioned above. A buried oxide layer may optionally be provided below the device layer 3220. For example, after the step described with respect to FIG. 32B, a portion of the release layer 3218 may be formed into an oxide layer or region. Alternatively, portions of the release layer 3218 may be treated to form buried oxide regions. Further, in another example, after the step described with respect to FIG. 32C, a portion of the release layer 3218 may be formed into an oxide layer or region, e.g., with suitable implantation treatment, or treated to form buried oxide regions. In a further alternative, where the device layer is attached to the release layer, the surface of the device layer intermediate the release layer may be treated to form an oxide layer, or an oxide layer may be deposited on the surface of the device layer intermediate the release layer. Referring to FIG. 32D, one or more probes and/or probe precursors 3222 may be formed in or upon the device layer. In certain embodiments, the device layer has wafer scale dimensions, whereby plural probes and/or probe precursors are formed on the wafer. The release layer 3218 allows the device layer 3220 to be sufficiently bonded to the bulk substrate 3202 such that during processing of the probes and/or probe precursors 3222, overall structural stability remains. Referring now to FIG. 32F, the device layer 3220 having probes and/or probe precursors 3222 thereon or therein may easily be separated from the bulk substrate 3202. As shown in FIG. 32G, the device layer may optionally include a portion 3218′ of the release layer. This may be kept with the device layer, or removed by conventional methods such as selective etching or grinding. This allows one to have a very thin device layer that may be used alone, e.g., for probes according to certain embodiments hereof. Alternatively, the thin device layer may be stacked to form a probe (e.g., in the case where the probe precursor is a portion of a probe that is stacked with another probe precursor, for example, stacked halves of a probe), or to form an array of probes. Further, the remaining substrate 3202 (which may have a portion 3218″ of the release layer) remains behind, which may be recycled and reused in the same or similar process after any necessary polishing. Accordingly, a method to make thin device layer utilizing the release layer described above with respect to FIGS. 32A-32F includes providing a structure A with 3 layers 1A, 2A, 3A, wherein layer 1A is a device layer, layer 2A is a release layer, and layer 3A is a support layer. In this manner, layer 1A is releasable from layer 3A. One or more probes and/or probe precursors are fabricated on the device layer 1A. Then, device layer 1A may be released from support layer 3A. The support layer 3A may be reused for subsequent processes, e.g., as a support layer or as a device layer. As shown in FIGS. 32A-32F, release layer 3218 may comprise a layer of porous material, such as porous Si. In a further alternative embodiment, and referring now generally to FIGS. 33A-33G, a method and system for making a thin layer with a useful device thereon or therein is provided, wherein the release layer comprises a sub-layer 3318 of first porosity P1 and a sub-layer 3326 of second porosity P2. Thus, the release layer comprises a porous release layer having a sub-layer region of relatively large pores P1 proximate the substrate and a sub-layer region of relatively small pores P2 proximate the device layer. In certain embodiments, sub-layer region P1 is formed directly on said substrate. In other embodiments, sub-layer region P2 is grown on said sub-layer region P1. Note that although these representations show distinct sub-layers 3318 of first porosity P1 and sub-layers 3326 of second porosity P2, other porosity gradients across the thickness of the overall release layer may be used. FIG. 33A shows a bulk substrate 3302 as a starting material for the methods and structures of the present invention. Referring to FIG. 33B, a porous layer P1 (3318) is created at a top surface of the bulk substrate 3302. Referring to FIG. 33C, a second porous layer P2 (3326) may be formed on the first porous layer P1 (3318). In certain embodiments, a layer 3326 may be stacked and bonded to layer 3318. In certain other embodiments, a layer 3326 may be grown or deposited upon layer 3318. Referring to FIG. 33D, a device layer 3320 is formed on top of the porous layer P2 (3326). In certain embodiments, the device layer 3320 is epitaxially grown, e.g., as a single crystal silicon layer. In still further alternative embodiments, the device layer may be attached to the release layer, e.g., transferred to the release layer. A buried oxide layer may optionally be provided below the device layer 3320. For example, after the step described with respect to FIG. 33B or 33C, a portion of the layer 3318 or 3326 may be formed into an oxide layer or region. Alternatively, portions of the layer 3318 or 3326 may be treated for form buried oxide regions. Further, in another example, after the step described with respect to FIG. 33D, a portion of the layer 3318 or 3326 may be formed into an oxide layer or region, e.g., with suitable implantation treatment, or portions of the layer 3318 or 3326 may be treated to form buried oxide regions. Alternatively, where the device layer is attached to the layer 3326, the surface of the device layer intermediate the release layer may be treated to form an oxide layer, or an oxide layer may be deposited on the surface of the device layer intermediate the release layer. Referring to FIG. 33E, one or more probes and/or probe precursors 3322 may be formed on the device layer. In certain embodiments, the device layer has wafer scale dimensions, whereby plural probes and/or probe precursors are formed on the wafer. The layer 3318 or 3326 allows the device layer 3320 to be sufficiently bonded to the bulk substrate 3302 such that during processing of the probes and/or probe precursors 3322, overall structural stability remains. Referring now to FIG. 33F, the device layer 3320 having probes and/or probe precursors 3322 thereon or therein may easily be separated from the bulk substrate 3302. As shown in FIG. 33G, the device layer may optionally include a portion 3326 of the porous layer P2. This may be kept with the device layer 3320, or removed by conventional methods such as selective etching or grinding. As shown in FIGS. 32A-32F and 33A-33G, release layer 3218 may comprise a layer of strained material, such as a layer of silicon-germanium (SiGe). For example, a layer of SiGe may be grown on a the substrate layer. Since germanium has a larger lattice constant than Si, the SiGe layer is compressively strained as it grows. Referring now to FIGS. 34A-34F, another method of making a thin layer including one or more probes and/or probe precursors therein or thereon is provided. A bulk substrate 3402 is provided (FIG. 34A). Referring to FIG. 34B, all or a portion of a surface 3404 of the bulk substrate 3402′ is treated to form a region 3406. In this embodiment, as described below, region 3406 is formed of a material and/or having material characteristics to allow growth of a layer on top thereof, and also serve as a portion of the release layer, wherein portion 3406 represents a weak bond region as described above and described in further detail in Applicant's copending the '909 and '814 applications incorporated by reference herein. In the embodiment shown with respect to FIGS. 34A-34F, a portion of the surface 3404 of the bulk substrate 3402′ is treated, whereby portions 3408 of the surface 3404 remain as the original bulk substrate which (shown in FIGS. 34B-34F as the periphery, but it is to be understood that other patterns may be created as described in Applicant's copending the '909 and '814 applications incorporated by reference herein). These portions represent strong bond regions as described in the '909 and '814 applications. Referring now to FIG. 34C, a single crystalline material layer 3410 such as single crystalline silicon is epitaxially grown on top of the weak and strong regions 3406, 3408. FIG. 34D shows probes and/or probe precursors fabricated upon or within the single crystalline material layer 3410. Referring to FIG. 34E, portions of the single crystalline material layer 3410 are removed corresponding to the regions of the portions 3408, and the portions 3408 are removed, for example by chemical etching, mechanical removal, hydrogen or helium implantation and heating of the portions 3408, or providing a material containing a resonant absorber at the portions 3408 for subsequent heating and melting of that material. Accordingly, a modified single crystalline material layer 3410′ on the portion 3406 remains. FIG. 34F shows the portion 3406 removed, thereby leaving single crystalline material layer 3410′ with probe elements 3412 thereon or therein. Alternatively, single crystalline material layer 3410′ with probe elements 3412 thereon or therein may be removed from the portion 3406, for example, by mechanical cleavage (parallel to the plane of the layers), peeling, or other suitable mechanical removal, whereby some residue of the portion 3406 may remain on the back of the single crystalline material layer 3410′ with probe elements 3412 thereon or therein and some residue of the portion 3406 may remain on the top of the bulk substrate 3402″ left behind. In this manner, the bulk substrate 3402″ may be recycled and reused with minimal polishing and/or grinding, thereby minimizing waste of the single crystalline material of the bulk substrate 3402. The single crystalline material layer 3410′ with probe elements 3412 thereon or therein may be used as is, diced into individual devices or structures, or aligned and stacked (on a probe or probe array scale, or on a wafer scale) to form a probe, probe array, or plurality of probes and/or probe arrays. In certain embodiments, the strong bond portions 3408 may be formed by starting with a uniform layer. For example, the surface 3404 may comprise a strained material, such as silicon germanium. Utilizing zone melting and sweeping techniques, the germanium swept away from the desired strong bond regions 3408. When a layer 3410 is grown or formed on the layer having portions 3406, 3408, layer 3410 will be strongly bonded at the regions of portions 3408 and relatively weakly bonded at the regions of portions 3406. Referring now to FIGS. 35A-35F, another method of making a thin layer including one or more useful devices or structures therein or thereon is provided. A bulk substrate 3502 is provided (FIG. 35A). Referring to FIG. 35B, all or a portion of a surface 3504 of the bulk substrate 3502′ is treated to form porous sub-regions 3505 and 3506. In this embodiment, as described below, region 3506 is formed of a material and/or having material characteristics to allow growth of a layer on top thereof, and also serve as a portion of the release layer, wherein porous sub-regions 3506/3505 represent a weak bond region as described above and described in further detail in the '909 and '814 applications incorporated by reference herein. In the embodiment shown with respect to FIGS. 35A-35F, a portion of the surface 3504 of the bulk substrate 3502′ is treated (forming sub-regions 3505/3506), whereby portions 3508 of the surface 3504 remain as the original bulk substrate which (shown in FIGS. 35B-35F as the periphery, but it is to be understood that other patterns may be created as described in Applicant's copending the '909 and '814 applications incorporated by reference herein). These portions represent strong bond regions as described in the '909 and '814 applications. Thus, the release layer comprises sub-regions 3505/3506 and portions 3508. Sub-region 3505 has relatively large pores P1 proximate the substrate and sub-region 3506 has of relatively small pores P2 proximate the device layer to be described below. In certain embodiments, sub-region 3505 is formed directly on said substrate, and sub-region 3506 is grown on said sub-region 3505. In certain embodiments, sub-region 3506 may be stacked and bonded to sub-region 3505. In certain other embodiments, sub-region 3506 may be grown or deposited upon sub-region 3505. Referring now to FIG. 35C, a single crystalline material layer 3510 such as single crystalline silicon is epitaxially grown on top of the weak and strong regions 3506, 3508. FIG. 35D shows devices or structures fabricated upon or within the single crystalline material layer 3510. Referring to FIG. 35E, portions of the single crystalline material layer 3510 are removed corresponding to the regions of the portions 3508, and the portions 3508 are removed, for example by chemical etching, mechanical removal, hydrogen or helium implantation and heating of the portions 3508, or providing a material containing a resonant absorber at the portions 3508 for subsequent heating and melting of that material. Accordingly, we are left with a modified single crystalline material layer 3510′ on the portion 3506. FIG. 35E shows an exemplary cleaving device, for example a knife edge device, water jet, or other device, used to cut between the sub-regions 3505 and 3506. FIG. 35F shows the bottom portion of sub-region 3506 removed (with a portion of sub-region 3506 remaining on the bottom of the single crystalline material layer 3510), and the top portion of sub-region 3505 removed (with a portion of sub-region 3505 remaining on the bulk substrate 3502″). Accordingly, the single crystalline material layer 3510′ is left with devices or structures 3512 thereon or therein. In this manner, the bulk substrate 3502″ may be recycled and reused with minimal polishing and/or grinding, thereby minimizing waste of the single crystalline material of the bulk substrate 3502. The single crystalline material layer 3510′ with devices or structures 3512 thereon or therein may be used as is, diced into individual devices or structures, or aligned and stacked (on a device or structure scale, or on a wafer scale) to form a vertically integrated device. Referring to FIG. 36, a starting multiple layered substrate 3600 is shown. The substrate 3600 may be, in certain preferred embodiments, a wafer for processing thousands or even millions of probe elements, or be used to derive a very thin layers for use as probes and/or probe precursors. The multiple layered substrate 3600 includes a first device layer 3610 selectively bonded to a second substrate layer 3620, having strongly bonded regions 3603 and weakly bonded regions 3604. Using the techniques described in the above-mentioned patent applications, or other suitable wafer processing and handling techniques, the first layer 3610, intended for having one or more probe elements therein or therein, or used as a probe or probe precursor as a very thin layer, may readily be removed from the second substrate layer 3620 (which serves as mechanical support during device processing) with little or no damage to the structure(s) formed (including material deposited or otherwise incorporated, or wells or other subtractions to the layer 3610) in or on the device layer 3610. Accordingly, according to the methods of FIGS. 32 and 33, a layered structure is formed generally includes a first layer suitable for having a useful element formed therein or thereon releasably attached or bonded to a second layer, e.g., a substrate. A method to form a layered structure generally comprises releasably adhering a first layer to a second layer. Further, according to the methods of FIGS. 34A-35F, a layered structure is formed generally includes a first layer suitable for having a useful element formed therein or thereon selectively attached or bonded to a second layer, e.g., a substrate, with regions of weak bonding and regions of strong bonding. The layered structure may be used for production of various devices including probes and/or probe precursors as provided for herein. Alternatively, a layered structure may be used as a source of one or more probes and/or probe precursors, for example, when the device layer is used as the probe, whereby the capability to produce and remove with little or no damage allows for ultra thin layers that may be used for ultra high resolution probes. The separation, for example, shown at steps of FIGS. 32E, 33F, 34E and 35E, may comprise various separation techniques. These separation techniques includes those described in further detail in Applicant's copending the '909 and '814 applications, incorporated by reference herein. The separation may be multi-step, for example, chemical etching parallel to the layers followed by knife edge separation. The separation step or steps may include mechanical separation techniques such as peeling, cleavage propagation; knife edge separation, water jet separation, ultrasound separation or other suitable mechanical separation techniques. Further, the separation step or steps may be by chemical techniques, such as chemical etching parallel to the layers; chemical etching normal to the layers; or other suitable chemical techniques. Still further, the separation step or steps may include ion implantation and expansion to cause layer separation. The material for the layers used herein, as the device layer, the release layer and the substrate layer, may be the same or different materials, and may include materials including, but not limited to, any of the lamellar materials described above, plastic (e.g., polycarbonate), metal, semiconductor, insulator, monocrystalline, amorphous, noncrystalline, biological (e.g., DNA based films) or a combination comprising at least one of the foregoing types of materials. Further, the release layer may comprise a material layer having certain amounts of dopants that excite at known resonances. When the resonance is excited, the material may locally be heated thereby melting the areas surrounding the dopants. This type of release layer may be used when processing a variety of materials, including organic materials and inorganic materials. The device layer and the substrate layer may be derived from various sources, including thin films described herein, wafers or fluid material deposited to form films and/or substrate structures. Where the starting material is in the form of a wafer, any conventional process may be used to derive the device layer and/or the substrate layer. For example, the substrate layer may consist of a wafer, and the device layer may comprise a portion of the same or different wafer. The portion of the wafer constituting the device layer may be derived from mechanical thinning (e.g., mechanical grinding, cutting, polishing; chemical-mechanical polishing; polish-stop; or combinations including at least one of the foregoing), cleavage propagation, ion implantation followed by mechanical separation (e.g., cleavage propagation, normal to the plane of the layers, parallel to the plane of the layers, in a peeling direction, or a combination thereof), ion implantation followed by heat, light, and/or pressure induced layer splitting), chemical etching, or the like. Further, either or both the device layer and the substrate layer may be deposited or grown, for example by chemical vapor deposition, epitaxial growth methods, or the like. The dimensions of the device layers may also vary in thickness and surface area. For example, fabrication of probes having ultra high resolution may benefit from the methods and embodiments herein, whereby probes may be formed on layers that are a few tenths of a nanometer to a few nanometers. The surface areas for the methods and embodiments of the present invention may be die-scale, wafer scale, or in larger sheets; accordingly, surface areas may be on the order of nanometer(s) squared to a few microns squared for die-scale; on the order of a centimeters squared for wafer-scale; and on the order of centimeters squared to a meters squared for sheet scale. MFT—Probe as Device on Device Layer Referring now to FIGS. 37A and 37B, top isometric and sectional views, respectively, are provided of a selectively bonded substrate 3700 having a plurality of wells 3730 formed in the weakly bonded regions of the selectively bonded substrate 3700. The wells may be formed by etching, mechanical subtraction methods, ion or particle beam etching, or other suitable methods. Note that the pattern of weak bond regions and strong bond regions may vary, as described in the '909 and '814 applications. However, in certain preferred embodiments, all of the wells 3730 are formed at the weak bond regions of the device layer 3710 and supported during processing by the support layer 3720. FIGS. 37C and 37D show plan and sectional views, respectively, of a single well 3730 formed in the device layer 3710 described above. Referring to FIG. 37C, the intersecting region between the dashed lines and the walls 3732 of the wells 3730 shows regions wherein probe elements may be processed in certain embodiments, as described hereinafter. In other embodiments, there may be only one intended region for processing nozzles (e.g., on the left or right sides as shown in FIGS. 37C and 37D). In further embodiments, the wells may be formed only at the intended probe element region, e.g., resembling grooves having the thickness shown by the dashed lines. Referring also to FIG. 38, the well 3730 generally has angular walls 3732, the function of which will be readily apparent. Further, the center recessed portion 3734 of the well will become part of a reservoir of the probes. At the top surface of the device layer 3710 adjacent the outer ends of the angular walls 3732 are plateau regions, which ultimately may be part of the inside wall of the probes as described herein. Referring now to FIG. 38, a layer 3710 (e.g., having thickness on the order of about 0.1 nanometers to about 10 nanometers, 10 nanometers to about 100 nanometers, or 100 nanometers to 1000 nanometers) is selectively bonded to a support layer 3720 as described with respect to FIGS. 32-36 and in the '909 and '814 applications. A region of reservoir 3730 is etched away or otherwise removed from a region of the device layer in the weak bond region 3703. Suitable nano-scale material subtraction methods may be used. Referring now to FIG. 39A, a layer 3738 (e.g., having thickness on the order of about 0.1 nanometers to about 10 nanometers, 10 nanometers to about 100 nanometers, or 100 nanometers to 1000 nanometers) of material, preferably material that is easily removable by etching or other subtractive methods, is deposited on the wafer. This material may be conductive, such as copper, silicon oxide, aluminum, or other suitable materials. This space will later become the opening for the nozzle. Referring to FIG. 39B, a fill material 3740 may optionally be incorporated, also of easily removable material in certain embodiments. The material optionally used to fill the wells during processing and stacking may be the same or different from the material used at the plateaus (that will form nozzle walls). In certain embodiments, since the device layer including the etched well having suitable material deposited thereon is generally positioned over the weak bond region 3703 of the multiple layered substrate 3700, the device layer 3710 may readily be removed from the support layer 3720. For example, the strong bond regions 3704 may be etched away by through etching (e.g., normal to the surface through the thickness of the device layer in the vicinity of the strong bond region), edge etching (parallel to the surface of the layers), ion implantation (preferably with suitable masking of the etched well and deposited material to form the nozzle, or by selective ion implantation), or other known techniques. Since the above techniques are generally performed at the strong bond regions 3704 only, the etched well and material deposited in the weak bond regions 3703 are easily released form the substrate, as schematically shown in FIG. 40, for example with a handler 3750. Referring now to FIG. 41, several layers 3710 including etched wells 3730 having material deposited 3738 thereon (and optionally fill 3740) may be stacked to form a structure 3760. The structure 3760 may further include a solid layer 3762, e.g., to form a wall for the top-most nozzle as shown in FIG. 41. Although in certain embodiments precise alignment may be desired at this point, certain embodiments may use relaxed alignment standards at this point, as will be apparent from the further described steps. As shown in FIG. 42, the wafer stack 3760 can now be sliced along a cut line 3764, creating two portions with exposed reservoirs. From the opposing side, these devices can also be sliced along the line 3766. The end may be grinded and polished until it is very close to the etched away reservoir, but no less than the desired nozzle length. Referring now to FIGS. 43 and 44, the deposited material 3738 may be etched away, exposing an etched channel 3768 (e.g., 5 nm opening when the material deposition layer is 5 nm). A material reservoir 3770 (or region 3770 for other purposes, depending on the desired use of the nozzle structure) remains behind the opening 3768. Each etched channel 3768 is generally spaced apart by approximately the thickness of the device layer 3710. Thus, a nozzle device 10 having plural openings 3768 each associated with regions 3770 is provided. Accordingly, when the thickness of the material to be removed is extremely small, e.g., on the order of about 0.1 nanometers to about 10 nanometers, 10 nanometers to about 100 nanometers, or 100 nanometers to 1000 nanometers, the extended edge probe tip as described above is created at the openings 3768. Alternatively, and referring to FIG. 45, to form an opening less than the width of the entire edge, the outside portions may be masked 3772 prior to etching the deposited material 3738 to form openings 3768′. Thus, a nozzle device 3710′ having plural openings 3768′ is provided. Accordingly, the width (i.e., the y direction as shown in FIGS. 43-45) of the probes may be the same or different from the width of the wells. In certain embodiments, it may be desirable to provide wells having widths larger than that of the nozzle to increase the material capacity of the well while maintaining the nozzle dimensions as small as possible. In a further embodiment, and referring now to FIGS. 46 and 47, a nozzle device 3780 (e.g., as describe herein), of a single layer, may be rotated approximately 90° with respect to the stack of layers 3760 having layers 3738 deposited therein at the locations of the nozzles. Etchant may be filled in the reservoir of the rotated nozzle structure 3780, and the openings 3782 of the nozzles may be formed. Using this technique, it is possible to create nozzles having approximately the same width and height with extremely small dimensions as provided for herein. Thus, a nozzle device 3710″ having plural openings 3768″ is provided. Referring now to FIGS. 48 and 49, another embodiment of a method of forming very small width nozzle diameters. As described with reference to FIGS. 43 and 44, the deposited material between layers may be etched away, exposing an etched channel spaced apart by approximately the thickness of the device layer. These etched channels 3768 may then be filled with an etchable material. For example, a nozzle device 3780 as describe herein, of a single layer, may be rotated approximately 90° with respect to the stack of layers having material etched away at the locations of the nozzles. An etchable material may be filled in the reservoir of the rotated nozzle structure, which is filled at the regions where the nozzles on the stack of layers are to be formed. The surrounding areas between the layers are then filled with a plug material. Then the etchable material in the nozzle region is etched away, exposing the nozzles 3768′″. Using this technique, it is possible to create nozzles having approximately the same width and height of extremely small dimensions. Thus, a nozzle device 3710′″ having plural openings 3768′″ is provided. Note this etchable material should be selectively removable by an etchant (e.g., not removing the bulk material). Referring now to FIGS. 50A and 50B, a nozzle array 5000 of the present invention is shown. Therein, one or more spacer layers 5002 may be positioned between a desired number of to-be-formed channels, e.g., during stacking of the well structures. Referring to FIG. 51, an enlarged cross section of stacked layers used to form the probes such as nano-probes having wells and tip portions with tip active area dimensions equal or less than the sub-objects being analyzed by the specimen, or of a nanometer or sub-nanometer scale for other applications as described herein. These tip portions are also formed to desired tip length, is shown. As described above, the layers 3738 have been processed to form the wells 3730 and nozzle tip regions generally by deposition of a layer 3738 of material capable of being selectively removed (e.g., etched) therein (the well) and thereon (the shelf at the top of the well), as described herein. The materials capable of being selectively removed for the plateau and and/or the well may be the same or different. The wells and plateaus have various dimensions that will characterize the nozzle array ultimately formed. The nozzle has a tip length NL, a tip opening height NO, and a period P. Note that the dimensions of such nozzles may be on the order of a less than a nanometer (e.g., less than 0.1 nm) to 10 or 10 s of nanometers, on the order of 10 or 10 s of nanometers to 100 or 100 s of nanometers, or on the order of a tenth of a microns or tenths of a micron to a micron or a few microns, depending on the desired application. Further, the arrays may be spaced apart by a few nanometers to several micros apart. Referring to FIG. 52, an enlarged cross section of stacked layers used to form the micro and nano nozzles herein is shown, detailing grind stops 5286 provided to enhance the ability to control the nozzle length NL. In certain embodiments, it is desirable to minimize the nozzle length. A grind stop 5286 is provided proximate the desired nozzle length. The grind stop may be provided during processing of the wells on the device layer. Further, the grind stops may further serve as alignment marks, e.g., as described in aforementioned U.S. patent application Ser. No. 10/717,220, incorporated by reference herein. Referring to FIGS. 53A and 53B, an enlarged cross section of stacked layers used to form the micro and nano probes, and a front view of the open tip of the prove, respectively, are shown. Note that in certain embodiments, the well 5370 has a width (y direction) greater than that of the nozzle tip 5368. Note that in any of the herein described probe elements, associated structures may be provided. For example, in certain embodiments, one or more electrodes may be provided to facilitate material discharge, detection capabilities, etc. Further, one or more processors, micro or nano fluidic devices, micro or nano electromechanical devices, or any combination including the foregoing devices may be incorporated in a nozzle device. In certain preferred embodiments, electrodes are provided at the nozzle openings and/or wells, and an electrode controller and/or a microfluidic device (e.g., to feed or remove material from the nozzles) is associated with an array of nozzles. Further, and referring now to FIGS. 54A-54D, an exemplary method of making probes with open tips and having various conductors (e.g., serving as electrodes) within an open region in the body of the probe is depicted. FIG. 54A shows a starting section of a multiple layer substrate with layers 5410 and 5420 as described hereinabove. An well 5430 generally has angular walls 5432 and a center recessed portion 5434, although other shapes may be provided. Plateau regions 5436 form the opening walls or supports. A layer 5438 of conductive material is deposited on the wafer. A removable fill material 5440 may be provided in the well to facilitate layering. Referring to FIG. 54B, a removable fill layer 5442 is provided on the surface having the conductive layer 5438 and the optionally fill material 5440. In this embodiment, the opening of the probe will be formed at the fill layer 5442. Further, a conductive layer 5444 is deposited or layered on the fill layer 5442, forming a nozzle sub-structure 5450. Referring now to FIG. 54C, a plurality of nozzle sub-structures 5450 are aligned and stacked (e.g., as described above with respect to FIG. 41). Referring to FIG. 54D, nozzle openings 5460 may be formed, e.g., according to one of the methods described above with respect to FIGS. 43-49, or other lithography or oxidation methods. Note that the plug material may be conductive or insulating, depending on the desired properties of the probe. Referring now to FIG. 55, an enlarged view of a nozzle structure 5500 is provided, viewing a nozzle opening 5502. Nozzle opening 5502 is generally positioned on a nozzle layer “N” between a top portion “A” and a bottom portion “B” (although top and bottom are considered to be relevant for the purpose of description herein only). To describe various embodiments of possible configurations, sections N, A and B have been divided into descriptive sections. These descriptive sections may be actual discrete regions of different material, or in certain embodiments multiple descriptive sections may be of the same material and thus actually a uniform region, as will be apparent from the various embodiments herein. AA and BB may be the same or different materials, such as insulator or semiconductor materials to provide the structure of the nozzle 200, electrically insulate the nozzle openings from one another, fluidly seal the openings from one another, or other functionality. In certain embodiments, the descriptive sections AL, AC, AR, NL, NR, BL, BC and BR are all of the same materials as AA and BB. Any combination of AL, AC, AR, NL, NR, BL, BC and/or BR may be provided in the form of conductors. For example, referring back to FIG. 45, upon removal of the mask after etching the nozzle opening, a structure may be provided having AL, AC, AR, BL, BC and BR of the same materials as AA and BB, and NL, NR of conductive material. Further, one or more conductors (e.g., electrodes) may be included inside within the probes, thereby enabling creation of fields across the nozzle opening. For example, NL and NR, AC and BC, AL and BR, AR and BL, AL, AR and BL, BR may all be electrode pairs to provide any desired functionality. Additionally, one or more conductive electrodes may be within the well regions, e.g., to provide electromotive forces to move materials. Referring now to FIGS. 56A-56C, an example of a method of manufacturing the herein described nozzles is shown whereby a plurality of sub-layers 5602 form each layer 5610. Wells 5630 are processed through the layer 5610 as shown in FIG. 56B. FIG. 56C shows nozzle openings 5660 having plural sub-layers 5602 therearound. These sub-layers may be very useful, for example, where precise metrology is desired. For example, in certain embodiments, the sub-layers 5602 are formed to very precise tolerances, e.g., having thicknesses on the order of 0.1 to about 5 nanometers. When these sub-layers 5602 are formed of differing materials (e.g., alternating between insulator and semiconductor, semiconductor and conductor, or conductor and insulator), precise step motion may be enabled in the nozzle structures based on known dimensions of the nozzle sub-layers. Traditional Lithography Methods to Make Micro and Nanostructures, Photon Beam, Ion Beam, Electron Beam, Other Particle Beams While it is possible to use conventional lithographic tools such as electron beams, particle beams, UV, X-ray, etc., to define certain features herein, extending them to the nano-scale becomes very cumbersome and expensive. In the present invention, certain embodiments may benefit from the use of applicants nanolithography tools described in applicants U.S. patent application Ser. No. 11/077,542 filed on Mar. 10, 2005 and entitled “Nanolithography and Microlithography Devices and Method of Manufacturing Such Devices” incorporated by reference herein. This is advantageous in that a compact, easy to use and inexpensive tool may be provided. Further, use of applicants nanolithography tools described in above referenced U.S. patent application Ser. No. 11/077,542 may advantageously provide extremely small future sizes down to angstrom scale. Various probes and configurations thereof may be manufactured with the use of Applicant's microlithography and nanolithography tools and methods, as described in U.S. Non-provisional application Ser. No. 11/077,542 filed on Mar. 10, 2005 entitled “Nanolithography and Microlithography Devices and Method of Manufacturing Such Devices”. Folding In certain embodiments herein, a probe or nano-tool may be formed by folding a very thin layer to expose a point at the outside of the fold angle, thereby creating a probe tip with a very small active area suitable for the various applications provided for herein including ultra high resolution analyses of the specimen at the sub-object level (e.g., nucleotide level of a DNA or RNA strand or fragment). Furthermore, in certain embodiments herein, a probe or nano-tool device may be formed with multiple probe tips that may be useful in various applications. One benefit of the methods of making probe or nano-tool device may be formed with multiple probe tips of nano-scale dimensions as described herein related to folding of various composite structures is that the probes are at angles relative one another, such that the back end (opposite the tip active areas) are spaced apart at distances greater than the spacing of the tip active areas. This allows for molecular scale active areas at the probe tips, while maintaining greater distances at the back end, e.g., to facilitate interconnection or other form of interface to various energy sources, detection circuitry, other interconnecting or integrated functionality. For example, and referring now to FIGS. 57-59, a method of manufacturing a probe 5702 is shown. FIG. 57A shows an ultra thin layer 5704 bonded to a first surface 5708 of a base layer 5706. The base layer 5706 may comprise any suitable material, for example, that will form a portion of the probe body, or that may be further processed for additional features and/or functionality. The ultra-thin layer 5704 may comprise any suitable material that may be deposited, laminated or otherwise formed on the surface 5708 of base layer 5706. For example, to form a conductive probe, a conductive material may be deposited, laminated or otherwise formed on the surface 5708. Referring now to FIG. 57B, a well 5712 of suitable geometry is etched or otherwise created on surface 5710 of base layer 5706. In certain embodiments, it may be desirable to configure the well such that the deepest portion is very close (e.g., on the order of about 0.1 to about 1 nanometer, or about 1 to about 10 nanometers, or on the order of 10 s of nanometers) to the thin layer 5704. In other embodiments, it may be desirable to configure the well such that the deepest portion exposes the back surface (i.e., the surface attached to surface 5708 of base layer 5706) of the thin layer 5704. Referring now to FIG. 57C, surface 5710 may optionally be coated with a bending layer 5714 formed of a material that has flexible characteristics, including but not limited to polyvinyl alcohol, silicone, or other suitable flexible and stretchable polymeric or other materials. Referring now to FIG. 57D, the composite of layer 5704 and base layer 5706 is folded to diverge opposing angled portions of the well 5712. Folding is completed to provide a probe precursor structure 5702′, shown in FIGS. 58A and 58B. As shown, the probe precursor structure 5702′ has a cross section in a substantially pentagonal shape resembling a triangle adjacent a rectilinear polygon. Of course, one may alter this shape by changing the shape of the well 5712. Further, the shape may be symmetrical as shown, or asymmetrical. One of the benefits of the present folding techniques is that certain alignment requirements may be relaxed. The bending layer 5714 may be removed. Further, to expose the probe tip active area 5720, the tip edge 5716 of the structure 5702′ may be mechanically altered, e.g., cut, grinded, polished, subject to water or other fluid jet, or otherwise removed to expose the folded thin layer of material. Alternatively, the tip may be exposed by chemical etching, e.g., to remove a portion of the substrate material. Mechanical or chemical removal may also be used to provide a tip that extends beyond the substrate material, for example, as shown in FIGS. 4A-5B. Notably, the dimension of the probe tip active area 5720 is defined by a multiple of the thickness of the layer 5704, in this case 2t. With the methods of making and manipulating thin films as described above, extremely small tip dimensions for the probe tip active area are possible. For example, if the layer 5704 is a single two dimensional layer of graphene, then the tip dimension 2t as shown in FIG. 59 may be on the order of 2 angstroms, and is highly conductive. Alternatively, the layer 5704 may be formed of a material that can be selectively removed (either completely or partially) to open a channel or path. Nonetheless, in either embodiment, the tip dimensions for the tip active area 5720 are a multiple of the thickness of the layer 5704 deposited, layered, or otherwise formed on the base layer 5706. In another embodiment, and referring now to FIGS. 60A-60J, methods of manufacturing a probe 6002, 6002′ or 6002″ are shown. FIGS. 60A and 60B show a base layer 6006 having a well 6012 of suitable geometry is etched or otherwise created on surface 6010 of base layer 6006. In certain embodiments, it may be desirable to configure the well such that the deepest portion is very close to the thin layer described below. In other embodiments, it may be desirable to configure the well such that the deepest portion exposes the back surface (i.e., the surface attached to surface 6008 of base layer 6006) of the thin layer described below. The base layer 6006 may comprise any suitable material, for example, that will form a portion of the probe body, or that may be further processed for additional features and/or functionality. Referring now to FIG. 60C, portions 6024 are removed from the base layer 6006, generally from the side of surface 6008. Referring now to FIG. 60D, portions 6024 are filled with a suitable material 6026. This material 6026 may be an insulating or conducting plug material (if a probe in the configuration of FIG. 60H or 601 is desired), or the material 6026 may comprise a removable substance (if a probe in the configuration of FIG. 60J is desired). Referring now to FIG. 60E, an ultra thin layer 6004 bonded to the surface 6008 of base layer 6006 having material portions 6026 to form a flat surface. Known techniques may be applied to smooth the surface formed by both the surface 6008 of base layer 6006 having material portions 6026. Alternatively, the methods for forming atomically smooth surfaces described herein may be employed. The ultra-thin layer 5704 may comprise any suitable material that may be deposited, laminated or otherwise formed on the surface 5708 of base layer 5706. In certain preferred embodiments, thin films formed according to the embodiments herein are used, such as one or more layers of graphene, thereby allowing for extremely small (e.g., 0.1 nanometers to 10 nanometers) tip dimensions. Notably, with the methods of making and manipulating thin films as described above, extremely small tip dimensions for the probe tip active area are possible. For example, if the layer 6004 is a single two dimensional layer of graphene, then the tip dimension 2t as shown above in FIG. 59 is on the order of about 0.2 nanometers. Alternatively, the layer 6004 may be formed of a material that can be selectively removed (either completely or partially) to open a channel or path. Nonetheless, in either embodiment, the tip dimensions for the tip active area 6020 are a function of the thickness of the layer 6004 deposited, layered, or otherwise formed on the base layer 6006. Referring now to FIG. 60F, surface 6010 may optionally be coated with a bending layer 6014 formed of a material that has flexible characteristics, including but not limited to polyvinyl alcohol or other suitable polymeric or flexible metallic material. The composite of layer 6004 and base layer 6006 having material portions 6026 is folded to diverge opposing angled portions of the well as described above with respect to FIG. 57. A probe or probe precursor structure 6002 is provided as shown in FIG. 60H (after the material of the optional bending layer 6014 is removed as shown in FIG. 60G). If a probe 6002′ is desired, the selectively removable material is used as the material for layer 6004, and may be removed at this stage, whereby a gap 6028. Further, if probe 6002″ is desired, the selectively removable material is used as material 6026 and may be removed at this stage, whereby a cavity 6040 is created. Referring to FIGS. 61A-61B, note that cavities of various configurations and dimensions 6140′, 6140″ may readily be created by varying the configurations and dimensions of portions 6024 described above with reference to FIGS. 60A-60J. Referring now to FIG. 62A-62D, another alternative method of making various probes with additional versatility and functionality according to the present invention is provided. In this case, the structure having a thin layer 6204 on a base layer 6206 with a well 6212 at the surface opposite the thin layer 6204 is folded so that angled portions of the well 6212 converge as shown. The bending layer or material 6214 may be removed, resulting in probe 6202 having a tip 6240. The tip 6240 includes portions of thin 6204 on both sides of the structure. In a further embodiment, and referring now to FIG. 62E, a probe 6203 is shown, which includes isolated dual probe elements including tips 6242, 6244. Such a probe may be useful in various applications, such as “real time” imaging (e.g., STN, AFM, stereoscopic imaging), for applying plural energy sources, or, e.g., using one probe for applying stimuli and another for detecting variations. For example, and referring now to FIG. 63A through FIG. 63, a method of manufacturing a probe 6302 is shown. FIG. 63A shows an ultra thin layer 6304 of thickness t bonded to a first surface 6308 of a base layer 6306. The base layer 6306 may comprise any suitable material, for example, that will form a portion of the probe body, or that may be further processed for additional features and/or functionality. The ultra-thin layer 6304 may comprise any suitable material that may be deposited, laminated or otherwise formed on the surface 6308 of base layer 6306. For example, to form a conductive probe, a conductive material may be deposited, laminated or otherwise formed on the surface 6308. Referring now to FIG. 63B, a well 6312 of suitable geometry is etched or otherwise created on surface 6310 of base layer 6306. In certain embodiments, it may be desirable to configure the well such that the deepest portion is very close (e.g., on the order of about 0.1 to about 1 nanometer, or about 1 to about 10 nanometers, or on the order of 10 s of nanometers) to the thin layer 6304. In other embodiments, it may be desirable to configure the well such that the deepest portion exposes the back surface (i.e., the surface attached to surface 6308 of base layer 6306) of the thin layer 6304. Alternatively, the layer 6304 may be formed of a material that can be selectively removed (either completely or partially) to open a channel or path. Referring now to FIG. 63C, another ultra-thin layer 6305 of thickness t′ may be deposited, laminated, or otherwise formed on surface 5710. Note that this layer may be the same or different material as the material of layer 6304. Furthermore, layer 6305 may be formed of plural sections, or a layer that is cut or notched, for example, along an intended fold line as described herein, or at the deepest portion of the well 6312. Now referring to FIG. 63D, the layer 6305 may optionally be coated with a bending layer 6314 formed of a material that has flexible characteristics, including but not limited to polyvinyl alcohol, silicone, or other suitable flexible and stretchable polymeric or other materials. Referring now to FIG. 63E, the composite of layer 6304, base layer 5706 and layer 6305 is folded to diverge opposing angled portions of the well 6312. Folding is completed to provide a probe precursor structure, e.g., similar to that described above with respect to FIGS. 58A and 58B, and further including the layer 6305 folded about the structure. The bending layer 6314 may be removed. As shown in FIG. 63F, the tip region of the folded structure may be cut, grinded, polished, or otherwise removed to expose the probe tip active area 6320 of probe 6319 (derived from folded layer 6304) and probe tip active areas 6322, 6324 of probes 6321, 6323 (derived from layer 6305). The dimension of the probe tip active area 6320 is defined by a multiple of the thickness of the layer 6304, in this case 2t, and the dimensions of probe tip active area 6322, 6324 are defined by the thickness of the layer 6305, in this case t′. Notably, with the methods of making and manipulating thin films as described above, extremely small tip dimensions for the probe tip active area are possible. For example, if the layer 6304 is a single two dimensional layer of graphene, then the probe tip active area 6320 may be on the order of 2 angstroms, and the dimensions of probe tip active area 6322, 6324 may be on the order of 1 angstrom. Furthermore, when a material such as graphene is used, the probes may be extremely conductive. Furthermore, the spacing between tip active areas 6320, 6322 and between tip active areas 6320, 6324 may be controlled by, e.g., the thickness of the layer 6306, the angle of the walls of well 6312 and the degree of folding (i.e., at step 63E). Additionally, the angle allows for greater distances between the conductors at the end opposite the tip regions as compared to the distances between the conductors at the tip regions. This allows for molecular scale active areas at the probe tips, while maintaining greater distances at the back end, e.g., to facilitate interconnection or other form of interface to various energy sources, detection circuitry, other interconnecting or integrated functionality. Referring now to FIG. 64A-64E, another alternative method of making various probes with additional versatility and functionality according to the present invention is provided. A structure is provided having a thin layer 6404 having a thickness t on a base layer 6406 with a well 6412 at the surface opposite the thin layer 6404. Referring now to FIG. 64B, another ultra-thin layer 6405 of thickness t′ may be deposited, laminated, or otherwise formed on the surface of layer 6406 having the well 6412 therein. Note that this layer may be the same or different material as the material of layer 6404. Furthermore, layer 6405 may be formed of plural sections, or a layer that is cut or notched, for example, along an intended fold line as described herein, or at the deepest portion of the well 6312. Now referring to FIG. 64C, the layer 6405 may optionally be coated with a bending layer 6414 formed of a material that has flexible characteristics, including but not limited to polyvinyl alcohol, silicone, or other suitable flexible and stretchable polymeric or other materials. Referring to FIG. 64D, the structure is folded so that angled portions of the well 6412 converge as shown. The bending layer or material 6414 may be removed. Referring to FIG. 64E, the tip edge the folded structure may be cut, grinded, polished, or otherwise removed to expose the probe tip active area 6420 of probe 6419 (derived from folded layer 6405) and probe tip active areas 6422, 6424 of probes 6421, 6423 (derived from sections of layer 6404). The dimension of the probe tip active area 6420 is defined by a multiple of the thickness t′ of the layer 6405, in this case 2t′, and the dimensions of probe tip active area 6422, 6424 are defined by the thickness of the layer 6404, in this case t. Furthermore, the spacing between tip active areas 6420, 6422 and between tip active areas 6420, 6424 may be controlled by, e.g., the thickness of the layer 6406, the angle of the walls of well 6412 and the degree of folding (i.e., at step 64D). Additionally, the angle allows for greater distances between the conductors at the end opposite the tip regions as compared to the distances between the conductors at the tip regions. This allows for molecular scale active areas at the probe tips, while maintaining greater distances at the back end, e.g., to facilitate interconnection or other form of interface to various energy sources, detection circuitry, other interconnecting or integrated functionality. In the multiple probe embodiments of FIG. 63F and FIG. 64E, one key benefit is the ability to form the probes 6319, 6321, 6323, and 6419, 6421, 6423, with tips at one set of distances apart from one another and back ends of the probe at an end opposite the probe tip end suitable for convenient connection to various sources, inputs and/or outputs. For example, in one embodiment, multiple probe devices may be formed with tips having active area dimensions t on the order of about 0.1 to about 10 nm, that are spaced apart by distances one the order of about 1 nm to about 100 nm, and further having back ends opposite the ends having the tip active areas that are spaced apart by distances on the order of about 10 nm to about 1000 nm. In particular, back ends opposite the ends having the tip active areas may be spaced apart by distances on the order of about 45 nm to about 300 nm, conventional semiconductor processing technology may be used to interconnect conventional line widths, with greater or less spacing possible depending on the desired line width of the electronics and/or photonics used for source, inputs and/or outputs. Referring now to FIG. 65, a probe 6510 as formed by various aspects of this invention may be utilized to assist in the folding. For example, probe 6510 may be used to contact within the well, whereby the mechanical forces assist in the folding processes. In further embodiments, vacuum suction may be applied through the probe 6510 to assist in the folding processes. Referring now to FIG. 66, a plurality of probes 5702 may be aligned and stacked, for example, by stacking edgewise on a platform 6630 and aligning by stacking the tips of the probes 5702 adjacent an alignment device 6634, or stacking the probes 5702 and displacing misaligned probes 5702 by pushing them into alignment with the alignment device 6634, thereby forming probe sets or probe arrays. In certain preferred embodiment, alignment device 6634 has a surface that contacts the tips and provides for sub-angstrom resolution motion to precisely displace and align the tips of the probes in an array or probe set. Note this may be adapted to form virtually any desired shape nano-tool by using a conforming form or other nano-manipulation methods. In certain embodiments, particularly advantageous if the surface that contacts the tips is atomically flat and smooth, for example, as may be produced by various methods described herein. Spacers or Particles Referring now to FIGS. 67A-67D and FIGS. 68A-68B, another method of forming probes according to the present invention is shown, particularly open tip probes. In particular, the tip opening dimensions t are defined by use of spacers such as particles, tubes, spheres, molecules, or other structures having precisely defined heights when disposed on a substrate. These spacers may have extremely small defined dimensions (e.g., a diameter of a sphere or tube that provides the height), such as in the ranges of 0.1 nanometers to about 10 nanometers, 10 nanometers to 100 nanometers, and 100 nanometers to 1000 nanometers. In one example, and referring to FIG. 67A-67D, a plurality of spacers 6714 are disposed generally in an orderly fashion upon the surface of a substrate 6710. As shown in FIG. 67A, the spacers 6714 may, for example, be aligned in groups along the x direction and spaced apart from one another in the y direction. Alternatively, the spacers 6714 may be in a contiguous form. Referring now to FIG. 67B, a superstrate 6720 is provided on the spacers 6714 to complete the probe or probe precursor by defining an opening 6724. Alternatively, and referring to FIGS. 67C and 67D, the probe may be cut into segments as shown by dashed lines in FIG. 67C. In another example, and referring to FIGS. 68A-68B, a plurality of spacers 6814 are disposed generally in a random fashion upon the surface of a substrate 6810. Referring now to FIG. 68B, a superstrate 6820 is provided on the spacers 6814 to complete the probe or probe precursor by defining an opening 6824. System Overview General System Referring now to FIG. 69, a schematic overview of a system of the present invention for analyzing extended object specimens is shown. The system 6900 generally includes a specimen platform 6928, a probe set 6930 and a detector sub-system 6932. The platform 6928 is operably coupled to a motion controller 6938, for controlling motion of the platform. Alternatively, the specimen may be moved within the platform. In a further alternative, the probe set (and optionally the associated detector sub-system) may be moved relative to the platform with the specimen. Further, the system 6900 includes a bias sub-system 6936 for control of field application (voltage applied across base and probe) and optionally other stimuli. In general, in certain systems described herein, when a hybridization event occurs, a measurable increase in current is detected. In certain embodiments, a low detection voltage may be applied in a constant manner across the probe set and the platform. However, biased voltage application may be utilized to minimize or eliminate noise. Data regarding the specimens is collected and processed by a processor sub-system 6934, which is coupled to an output sub-system (e.g., a display, data port, etc.) 6940. In operation, a specimen such as a single stranded polymer (e.g., a denatured strand of DNA) is directed through a path or channel in the platform. The probe set detects characteristic features of the polymer specimen, preferably detecting characteristic about each sequential monomer in the specimen polymer. The specimen is moved relative the probe set in a controlled manner, e.g., by step motion to allow the probe set to obtain characteristic information about each monomer or group of monomers. The sequence information is collected, processed and outputted. In certain embodiments, high resolution is attainted by utilizing a probe having a tip dimension, or an active tip area, that is equal to or less than a characteristic sub-object of the extended object, such as a nucleic acid within a DNA or RNA strand or fragment. In further embodiments, the width dimension of the probe is much larger than the width of thickness of the extended object, for example, having width w of about 10 nanometers to about 100 nanometers, 100 nanometers to 1000 nanometers, or several microns for analyzing specimens such as typical DNA strands or fragments. Further, the enlarged width dimension as compared to the tip or active area is useful in that additional tolerance is provided for the path of channel of the specimen and/or the stretching procedures. Referring now to FIG. 70, an embodiment of an ultra-fast DNA sequencing system 7000 is shown. The sequencing system uses a nozzle array 7010, as described herein. Further, the sequencing system uses a nano-metrology system 7020 to precisely guide denatured DNA strands across the individual nozzles in the nozzle array. Referring now to FIG. 71, a schematic of major components of the ultra-fast DNA sequencing system 7000 are shown. A nano-nozzle set array platform 7030 upon an N-channel specimen array platform 7028 is operably connected to a detector array 7032 associated with a processor 7034, generally for determining instances of hybridization events induced by the biases applied via a gated bias array control 7036. The DNA specimens are maintained and displaced in relation to the array with a stepped motion control 7038, which is also operably connected to the processor 7034. The array platform 7028 is movable at a velocity of about 0.1 to about 1 cm/s. Preferably, as shown, the motion is in a stepped manner, as described herein. The sequencing results are shown on a sequence display 7040. The stepped motion is important in preferred embodiments, as the motion and number of steps helps maintain knowledge of position on the ssDNA, and ultimately the position of hybridization events. The stepped motion may be from about 5% to about 100% of the nozzle opening dimension, preferably about 10% to about 25% of the nozzle opening dimension. The gating is also important in preferred embodiments, as extremely synchronized current measurements, bias, motion steps, or other excitations are crucial to ultra-fast real time DNA sequencing. Referring now to FIG. 72, a top view of the ultra-fast DNA sequencing system 7000 is shown. The DNA specimens are denatured and maintained within channels 7044. Referring now to FIGS. 73A-73B (wherein FIG. 73A is a section along line A-A of FIG. 72), each channel 7044 includes biasing systems for applying voltages across the DNA samples. As described in more detail herein, hybridization events induce measurable current variations across each of the nanonozzles within the nanonozzle set array platform. Preferably, the alignment between the nanonozzles and the channels is extremely precise. Referring now to FIGS. 74A-74C, a system 7400 including series of probe sets 7430, a probe set 7430 including nozzles or probes 7442, 7444, 7446 and 7448, and an enlarged view of probe 7448, respectively, are shown. The nanonozzle set array platform 7400 includes nanonozzles with wells, or nucleotide reservoirs, of A, C, T and G molecules. The strands are moved along the channel and molecules from the nucleotide reservoirs interact with the molecules of the strand through the nozzle. These molecules hybridize with one other molecule (e.g., A with T, C with G). In general, the hybridization event (e.g., as shown in FIG. 74C) produces measurable and detectable current pulses, thereby allowing identification of the molecule. Referring now to FIG. 75, detailed views of hybridization events are shown. In certain detection schemes described herein, a hybridization event at the nanonozzle results in a measurable current pulse. Referring now to FIG. 76, it is shown that, of all possible 16 combinations of A, T, G and C, only four produce desired current pulses upon a hybridization event. As mentioned above, only a hybridization event produces a measurable (nanoseconds) current pulse at the nozzle. For optimized operation, the following principles apply. All excitation sources, detectors and stepped motion are synchronized. Synchronized steps should be a fraction of the nozzle opening size (e.g., on the order of 5 nanometers). Nozzle locations should be known with nanometer or sub-nanometer precision in relation to a known reference position. Nanometer alignment is very important to optimal operation. Vibrations and other agitations should be minimized. A sub-system is provided to measure very low amplitude nanosecond pulses. For continuous real time measurement of millions, or even hundreds of millions, of base pairs, a wide dynamic range sub-nanometer stepper is preferred. To calibrate the system, it is desirable to use known samples.Stimuli In a preferred embodiment, the probes in the form of electrode conductors and/or other stimuli are applied in a gated manner. This reduces the signal to noise ratio thereby allowing for increased sensitivity and ability to resolve the sequence of the specimen. Detection of a hybridization event may be accomplished in certain embodiments by observing variations in resonant capacitance. For example, an AC bias is imposed through a probe and a grounded platform (or alternatively AC bias may be imposed through the platform and the probes are sequentially grounded). The AC bias will alternately deplete and accumulate the specimen. The change in capacitance ΔC is recorded, for example, using a lock-in technique. The measured value ΔC may be the value across the entire C-V curve when larger AC voltages are used, or measured value ΔC may be the differential capacitance dC/dV when smaller AC bias voltage is used. The variation in the load across the specimen occurs due to characteristics of the portion of the specimen to be resolved such as a monomer on a polymer strand, or due to creation of a hybridization event when the probe includes a hybrid pair counterpart. This load variation changes the resonant frequency of the system. Electrical conductors as probes according to preferred embodiments of the present invention, formed as described above with respect to FIGS. 1A-1D above (e.g., in the configuration with a very fine tip compared to the back end, or a “knife edge”) also serves to lower the resistance of the conductor. Various embodiments of stimuli application are possible. 1) voltage only; 2) voltage plus light (AND gate) (light is a noise reduction means); 3) synchronization with gating, pulsed voltage, light, and current gate leads to substantial noise reduction; 3a) controlled stepping; 3b) apply voltage and light (AND gate)—light of different wavelengths to enhance inelastic tunneling current; 3c) apply current gate (measure with ammeter); 4) kT (thermal energy) may be reduced under low temperature operating conditions, e.g., T between 4 and 100 K. Gated detection serves to minimize noise and allow for precise resolution of the extended object. Gated detection is necessary to ensure the detection of picoamp level currents in the presence of noise. One effective strategy is to apply all of the stimuli in the proper sequence, in the form of pulses. The pulse widths and heights are adjusted to achieve optimum results. The levels of voltage will be in the 10 s of millivolts up to about 1 volt. The pulse durations may be about 1 nanosecond to about 1000 nanoseconds, or longer if necessary. The protocol for gated detection is described in the following steps: 1) apply a pulse to step the specimen relative to the platform to a position to measure a portion of or a nucleotide of the specimen; 2) subsequent application of an electric field to provide contact between the specimen and the probe; 3) optional application of a laser pulse; 4) application of tunneling device voltage pulse; 5) applying a pulse to open the switch to the current measure device; 6) repeating 1-5 to measure the subsequent portion of the specimen or nucleotide to sequence. These steps 1-5 are synchronized pulses synchronized to a master clock. In the event that particle beams are applied, or intensifiers, these will also have appropriately applied excitation pulses to activate them synchronized with said clock. These gated synchronized methods allow one to measure the detectable interaction with a high signal to noise ratio. For example, referring now to FIG. 77, a sampling period 7700 of a series of synchronous excitations are charted on a plot 7702 relative to clock signals 7710. A stepping period is shown as a short pulse commencing at a certain time indicated on a horizontal axis 7720, e.g., at the start of the sequence. A contact period is shown as commencing after the stepping period as indicated on a horizontal axis 7730 and ending during of after measurement and/or processing and storage periods. A photon period is shown as increasing in amplitude after the commencement of the contact period as indicated on a horizontal axis 7740 and ending proximate the end of the contact period. A voltage bias period is shown as commencing during the photon period as indicated on a horizontal axis 7750 and ending proximate the end of the contact period. A current detection period is shown as commencing during the photon period and the voltage bias period as indicated on a horizontal axis 7760 and ending proximate the end of the contact period. A processing and storage period is shown as commencing near the end of the photon, voltage bias and current detection periods as indicated on a horizontal axis 7770 and ending after the end of the contact period. Detection of the portion of the specimen under examination may occur by various contribution. In general, the detection schemes allow for molecular level (or detection of one or more monomers, or certain groups of monomers, in an extended object to be analyzed) identification of monomers within a chain. Induce a hybridization event and measure conductance variation In a single strand specimen analysis systems having probes that induce a hybridization event, detection contribution includes elastic tunneling, inelastic tunneling, resonantly enhanced tunneling, and/or capacitance. FIG. 78 shows the typical Watson and Crick base pairing model. Referring now to FIG. 79, a system 7905 schematically shown including a probe 7910 and a substrate 7920 having a specimen 7930 thereon. The probe is designed to induce a hybridization event, as described herein, by including a complementary specimen in a well, on a substrate, or by other configurations. A voltage bias is applied, for example, that corresponds to the N—H bonds and O—H bonds formed during a hybridization event. Elastic Tunneling Contribution The elastic tunneling contribution in systems having probes that induce a hybridization event is generally due to the tunneling interaction variations that occur due to the distance between hybridized species. When a hybridization event occurs, the distance between the hybridized monomers (nucleotides) is modulated as the bond is created. As the tunneling barrier thickness decreases, tunneling probability increases and thereby increases the tunneling contribution. This will be manifested in the increase of conductance as measured in the current-voltage characteristics of the hybrid bond. When no hybridization event occurs, the distance between the probe capable of inducing a hybridization event and the specimen nucleotide remains relatively large, and hence the elastic tunneling contribution is relatively low. Referring now to FIG. 80, system 8005 schematically shown to illustrate the elastic tunneling contribution. When a bond is established as a result of the relatively shorter distance (thinner tunneling barrier) that results for the H-Bond. This manifests itself as an increase of the conductance, and hence higher current. Note this elastic tunneling contribution generally does not involve exciting a resonance. Inelastic Tunneling Contribution The inelastic tunneling contribution in systems having probes that induce a hybridization event is based on increased bond energies, especially hydrogen bond energies. During a hybridization event, as electrons tunnel, the electrons lose energy by exciting the hydrogen bond created as a result of the hybridization event. This leads to a tunneling contribution at a voltage correlating to the energy of the bond. When no hybridization event occurs, there is no hydrogen bond created, therefore there is no inelastic tunneling to excite such a bond, and therefore no conductance contribution should be observed. Referring now to FIG. 81, system 8105 schematically shown to illustrate the inelastic tunneling contribution. In addition to the above increase in current due to the elastic tunneling contribution, another increase will be detected due to an inelastic tunneling contribution resulting from exciting the resonance of the H-Bond. Resonantly Enhanced Tunneling Contribution The above may enhanced by applying a source tuned to the bond frequency, thus providing an optically enhanced inelastic tunneling contribution. For example, a tuned light source may be applied in conjunction with the measurement bias. This optically enhanced inelastic tunneling component contributes to minimizing the noise effect by acting as and “AND” gate, such that current signal detection is primarily when synchronous application of the optical signal “AND” the bias voltage (both tuned to the resonance). Referring now to FIG. 82, another embodiment of the present invention is shown. A specimen portion 8210 is within a probe system 8220 including a first probe 8230 and a light nozzle 8250. The light nozzle 8250 and the first probe 8230 are activated, either sequentially, simultaneously or overlapping in time, to facilitate current detection, measurement, or other impact of the detection contribution effect, as described above. The first prove 8230 may include any one of the above referenced types of probes. Alternatively, more than one probe may be used with a light nozzle 8250, for example, for photonic application, current measurement, voltage bias, or other functionality as described herein. The resonantly enhanced tunneling contribution in systems having probes that induce a hybridization event is based on measurement of excited bond energies, particularly hydrogen bonds. Stimuli such as light application is applied. A resonantly enhanced tunneling contribution may be observed when a light source such as a laser having a suitably tuned wavelength excites the hydrogen bond created upon hybridization. Hydrogen bonds from the hybridization events can be excited by tuning a laser beam to the same energy as the bond. This will enhance the detection of both the elastic and inelastic tunneling contribution and add a resonant enhanced tunneling contribution to the measurement current. Further, noise is minimized with suitable gating as described herein since the pulsed application of the laser light source is synchronized with application of a voltage and during the opening of the measurement current sensor. These simultaneous interactions have the effect of a logical “AND” gate. Capacitance Contribution The capacitance contribution in systems having probes that induce a hybridization event is based on enhanced permittivity. Since the tunneling area is very small, the application of a laser beam tuned at or near the bond energy creates a resonantly enhanced permittivity at the hybridized pair. This in effect is like a quantum capacitance. This quantum capacitance, added to a specific inductive element, an RF resonant circuit, or a RF resonant cavity, results when the hybridization even occurs. For example, the inductive element, RF resonant circuit or RF cavity are excited and can give a very large signal. Since RF frequencies are at higher frequencies than the DC voltages, there is low noise in that region (avoiding the 1/F noise). Referring now to FIG. 8384. system 8306 is schematically shown to illustrate the quantum capacitance contribution. The quantum capacitance contribution is a result of enhancement of polarizability of molecules by exciting suitable resonances, including O—H or N—H bonds, and further rotational, vibration, and electronic. These are represented in FIG. 83 by resonances hω1, hω2, and hω3. The energy is represented by:Eqc=½(Cq V2). RF measurement is conducted using special resonance circuits that include “quantum capacitance” which will be enhanced when O—H or N—H resonances are excited by external radiation tuned to these resonances. This is expected because the capacitance is related to the permittivity of the interaction between the probe 8310 and the sample 8330. This permittivity has a susceptibility component which in turn is given by the polarizability at the molecular level. The value of this polarizability has many resonant contributions, including vibrational, rotational, and electronic. It is well known that if any one of these resonances—vibrational, rotational, or electronic—are excited, even away from the specific bonds, a significant increase in the polarizability, and hence the capacitance, results. The optimum tank circuit, e.g., in microwave or millimeter wave, will be excited and detected. Since these are high frequencies, we will be far away from the 1/f noise regime, thus the signal to noise ratio is large. Probes that do not Induce a Hybridization Event and Measure Conductance Variation In a single strand specimen analysis systems having probes that do not induce a hybridization event, detection contribution includes inelastic tunneling, resonantly enhanced tunneling, and/or capacitance. Detection based on the elastic tunneling contribution is not particularly effective without a probe that induces a hybridization event. Since the distance between the probe (in a system that does not induce a hybridization event) and the specimen nucleotide reaming relatively large, the elastic tunneling contribution is relatively low for all nucleotides. Therefore, an elastic tunneling contribution is not suitable for measurement detection system when using probes that do not induce hybridization events. Inelastic Tunneling Contribution However, detection of measurement current variances due on inelastic tunneling contribution may be used. Since there is no hybridization event (e.g., the probes are formed of conductors or other style that does not induce a hybridization event), we rely on the inherent resonance of each nucleotide to be analyzed. Resonantly Enhanced Tunneling Contribution Further, the resonantly enhanced tunneling contribution is suitable, wherein a light source (e.g., laser wavelength) is tuned to the inherent unique resonances of the nucleotides to be analyzed. The nucleotides to be analyzed are be excited by tuning a laser beam to that unique resonance, which will enhance the detection of the inelastic tunneling contribution and other contributions to the current measurement. Further, noise is minimized with suitable gating as described herein since the pulsed application of the laser light source is synchronized with application of a voltage and during the opening of the measurement current sensor. These simultaneous interactions have the effect of a logical “AND” gate. Capacitance Contribution The capacitance contribution in systems having probes that do not induce a hybridization event is also based on enhanced permittivity analysis. Since the tunneling area is very small, the application of a laser beam tuned at or near the inherent unique resonance energies creates a resonantly enhanced permittivity of the signature. This in effect is like a quantum capacitance. This quantum capacitance, added to a specific inductive element, an RF resonant circuit, or a RF resonant cavity, results when the signature energy occurs. For example, the inductive element, RF resonant circuit or RF cavity are excited and can give a very large signal. Since RF frequencies are at higher frequencies than the DC voltages, there is low noise in that region (avoiding the 1/F noise). Measure AFM In other embodiments of the present invention, instead of, or in conjunction with, measuring a current variation, a probe is used by bringing it close to a specimen, at known distance, whereby an attraction force will be detected. Rather than detect current flowing there through, detecting attractive or repulsive motion. Knife edge AFM probe—contacts specimen, measures attractive or repulsive forces. It is well known that atomic force microscopy (AFM) is used to analyze nano-structures an atomic scale. One key element leading to the success of the AFM is attachment of a nano-tip to a cantilever that is made to deflect when the nano-tip measures forces of the interaction between said nano-tip an the structure under analysis. A laser beam reflecting from the cantilever measures the forces variations as the nano-tip scans the structure. Measure AFM—Probe Set By utilizing the inventive embodiments taught herein, it is possible to analyze an extended object such as a DNA sequence by measuring the force as in AFM, instead of or in conjunction with the tunneling currents. This is shown in FIG. 84. Here the attractive force that results when A bonds with T and C bonds with G as a result of hybridization is relied upon to detect certain species. The specificity of the sequencing is accomplished by utilizing a probe with characteristics that allow it to attract certain species, such as by attaching poly-A, poly-T, poly-C, and poly-G oligomers to nano-edge probes, for example, as described herein. Each of the 4 nano-edge probes is attached to a different cantilever. A detector measures the deflection of each different cantilever which modulates the reflection of laser beams of a different wavelengths in the response to the interactive forces between the edge or tip nano-probe and the specimen to be analyzed. The AFM sequencing processes and systems described herein may be further described by the following. An extended object such as a single strand DNA (SSDNA) is stretched and immobilized on a substrate. A sub-Angstrom resolution translation stage moves the specimen relative to the set of edge-nano-probes. The edge nano-probe with the poly-A attached to it will experience and attractive force when it is proximate to or lands on the specimen with a T base. This force will modulate the reflection of the laser beam of wavelength λA by the cantilever. The modulated reflected beam announces the presence of T at that location with the aid of a detector and processing electronics. The edge nano-probe with the poly-T attached to it will experience and attractive force when it lands on the specimen with a Abase. This force will modulate the reflection of the laser beam of wavelength λT by the cantilever. The modulated reflected beam announces the presence of A at that location with the aid of a detector and processing electronics. The edge nano-probe with the poly-C attached to it will experience and attractive force when it lands on the specimen with a G base. This force will modulate the reflection of the laser beam of wavelength λc by the cantilever. The modulated reflected beam announces the presence of G at that location with the aid of a detector and processing electronics. The edge nano-probe with the poly-G attached to it will experience and attractive force when it lands on the specimen with a C base. This force will modulate the reflection of the laser beam of wavelength λG by the cantilever. The modulated reflected beam announces the presence of G at that location with the aid of a detector and processing electronics. The edge nano-probes with the poly-A, poly-T, poly-C, or poly-G will experience a weaker (no force or repulsive) force when either non complementary base, e.g. AonA, TonT, ConC, G, on G, AonC, AonG, TonC, or TonG. In these cases the beams reflected from the cantilevers will have small force modulation. It is possible to use a single laser beam that is divided into 4 beam-lets, each is focused on different cantilever at certain positions, to minimize interference. This detector will specially resolve the positions of the beam-lets so as to differentiate and ensure specificity. Auxiliary laser beams may optionally be focused on the specimens, for example, that are tuned to certain frequencies that interact with the specimen. This can enhance the specificity and reduce errors of ambiguity. Multiple Pass Edge Nano-Probe Sequencer Instead of using 4 nano-probes in parallel whereby each reflects its own laser beam or beam-let, it is possible to have nano-probes that are inserted or activated sequentially. For example, an embodiment is this system is illustrated in FIG. 85. Here the probes are attached to a rotating mechanism (e.g., “daisy wheel style”) which rotates to expose the probe to the specimen one at a time. To sequence a DNA specimen, the probe functionalized with the poly-A oligomers is inserted (rotated in) and will scan the specimen. Then the poly-T is inserted to record the positions of the A nucleotide. This is repeated for the C and G nucleotides until the entire specimen is scanned with the four probes and the sequencing is completed. As shown in FIG. 86, this apparatus may be made more general and versatile by attaching to the daisy wheel a plurality of probes with different shapes, knife edge, single point, multiple tips, different functional group to recognize specific species, and nano-crystals of specific composition designed to search for and locate a specify material. This versatility is particularly useful as it affords the opportunity to use the system as an imaging tools first, as in normal AFM, then as a sequencing tool or more generally a chemical analysis tool. It is appreciated that instead of a daisy wheel arrangement, there may other more advantageous arrangements. In order for these apparatuses with sequential insertion of probes to function properly, precise alignment subsystem may be required located with precision a spatial reference point, relative to which all spatial information is recorded. This will minimize errors and ambiguity. Additional nano-probes may be attached to function as the locators of alignment marks purposely written on the substrate. Error Reduction Sub-Systems Arrays As descried herein, array of probes sets in 2d or 3d arrays can measure and re-measure the same sample. This is possible due to the low cost techniques. Further, multiple channels for parallel systems may be used. Mixed Probe Types As descried herein, array of probes sets in 2d or 3d arrays can measure and re-measure the same sample. This is possible due to the low cost techniques. Further, multiple channels for parallel systems may be used. Differential; Detection In another embodiment, and referring now to FIG. 87, a system is provided to use differential detection to minimize errors in reading the sequence. Arrays of nano probes/nozzles affords the opportunity, inexpensively, to consider repeated measurements to minimize the noise. For example, differential detection strategies may be used whereby system noise may be subtracted in real time. One or more probes or probe sets read the specimen and known samples A, C, T, G. Accuracy may be increase by performing differential detection, whereby noise may be determined and subtracted from the specimen reading. For example, we may read synonyms with the specimen analysis a current of a known sample (e.g., Arrays of A, C, T, and G). This gives us noise and the contribution of T at a particular instant of time. At the same instant of time, if a T is apparently determined to be the base of the specimen, the noise may easily be subtracted to confirm that the reading of T is accurate. Therefore, the following apply: Current (known sample)=noise+contribution of T (apply positive pulse) Current (specimen)=noise−contribution of T (apply negative pulse) The contribution of the signal is detected at certain modulation frequency, whereas the noise is random AAA, GGG, TTT, CCC also could be known AGAGAGAG, TCTCTCTC, so long as it is known. Various Sensing Techniques and Sub-Systems Many sensing techniques for determining a hybridization event include elastic quantum mechanical tunneling; inelastic quantum mechanical tunneling; resonantly enhanced tunneling; resonantly enhanced quantum capacitance in a tank circuit to boost the signal of hybridization events; fast cooling techniques to reduce noise (for example, such as the system that utilized liquid He or liquid N2 droplet cooling); ionic conductivity; quantum mechanical tunneling electron emission; photon emission, which can be amplified by photon multiplier techniques. Any one or more of these techniques may be used in conjunction with the herein described high spatial resolution (e.g., nucleotide monomer level resolution) probes, probe sets or probe arrays as a novel direct sequencing system. Knife Edge Configuration Another aspect of the present invention to minimize error is the extended configuration (e.g., “knife edge”) as described above with respect to FIGS. 1A-1D. In systems herein where metal contacts or probes are used to measure currents and voltages from small structures such as the monomers of the specimen, four probe tunneling devices may be used (e.g., shown in FIG. 109) to minimize contact and lead resistance. Also, preferred probe configuration provide for a larger end opposite the tip, for example, as shown with respect to FIG. 1A. Further, all contacts the probe are preferably much larger than the tip. This can, for example, reduce electrical resistance of the probe when end serves as a contact region. Increasing Electron Interactions Optimum specimen resolution and speed may be achieved by optimizing the detection system to increase the measurable signal, namely, ensuring that enough electrons are involved, and minimizing the ambient noise. The tunneling current densities involved, in such small tunneling areas (e.g., 0.5 square nanometers), makes it possible to involve 10 s of electrons and 10 s of picoamps. This is achieved by allowing the time aperture to excite and detect each nucleotide in the order of 1-1000 nano-seconds. This can achieve the desired result of sequencing the whole Human Genome of 3×109 base pair in a time of about 1 second to a few minutes. We have allowed for even higher speed and fewer electrons to be involved whereby intensification/amplification sub-systems are used to intensify few electrons or photons into a measurable signal. Gated Detection Gated electronic techniques are also used herein with a pulse protocol that is applied to ensure minimize noise. This is desirable to ensure the detection of picoamp level currents in the presence of noise. One effective strategy is to apply all of the stimuli in the proper sequence, in the form of pulses. The pulse widths and heights are adjusted to achieve optimum results. The levels of voltage will be in the 10 s of millivolts up to about 1 volt. The pulse durations may be about 1 nanosecond to about 1000 nanoseconds, or longer if necessary. The protocol for gated detection to minimize noise is described in the following steps: 1) apply a pulse to step the specimen relative to the platform to a position to measure a portion of or a nucleotide of the specimen; 2) subsequent application of an electric field to provide contact between the specimen and the probe; 3) optional application of a laser pulse; 4) application of tunneling device voltage pulse; 5) applying a pulse to open the switch to the current measure device; 6) repeating 1-5 to measure the subsequent portion of the specimen or nucleotide to sequence. These steps 1-5 are synchronized pulses synchronized to a master clock. In the event that particle beams are applied, or intensifiers, these will also have appropriately applied excitation pulses to activate them synchronized with said clock. These gated synchronized methods allow one to measure the detectable interaction with a high signal to noise ratio. Array of Repeated Species In another embodiment, referring now to FIG. 14B, a plurality of nano-probe sets are provided, wherein each nano-probe set is specific to a certain species (e.g., nucleotide). The specimen is measure several times (by each probe within the probe set) and stored by a the first single species probe set. The specimen is then sequentially measured with a second single species probe set, a third single species probe set, and a fourth single species probe set to obtain data from each group of probe sets and obtaining at least one hybridization event or other detection event, preferably duplicate events to ensure accuracy of determination. Each probe set may and the computer analysis provides a consensus of the identity of the species, after averaging or other suitable statistical analysis. Each species is measured several times by one group, then another, then the 3rd, then the 4th. For example, if a probe set is optimized to detect an event with a T species, the following detection readout may be determined at that probe set for that base: TTCT. As the specimen and hence a particular base is moved across the array of 4 probe sets, A/T/C/G, the following detection readout may be determined at that probe array for that base: TTCT/- -G -/C- - -/- - A -. Thus, some of the individual probes within the sets may provide erroneous results (e.g., the C within the first TTCT, the G within the second group, the C within the third group and the A within the fourth group), statistical analysis will determine that the particular base is indeed a T base. Note that more or less probes that four may be in each probe set. Further a scheme may be provided with various degrees of redundancy, including differing numbers of probes within the probe sets, combinations of homogeneous and heterogeneous probe sets, combinations of probe type for various detectable Interactions (e.g., nucleotide filled wells, solid state nucleotides, metal conductor, metal plus known nucleotide stand, open well or funnel for particle beams, electron beam emission, ion beams, x-rays or the like, or flexible membrane probes. Signal-to-Noise Ratio One important factor of these method and strategies for error reduction is obtaining a sufficient signal to noise ratio. The system is preferably gated and synchronized such that the ammeter will only detect a signal when a nucleotide is directly below a nozzle. The bias applied may be positive, negative, or even alternating, as to maximize the change in conductivity. Cooling may be desirable to reduce the thermal noise. Alternatively, each DNA or protein strand may be passed under several arrays of nozzles, thereby averaging out the noise. Certain embodiments show array configurations, e.g., that may average out noise and increase SNR. These features will help in assuring an excellent SNR. However, if we assume a 10 picoamp current change under one applied volt, and 10 nanoseconds for detection, the signal is orders of magnitude larger than the thermal noise, even at room temperature. The sequencing speed would be enormous. Allowing 30 nanoseconds to move a nozzle from one nucleotide to the next (a speed of about 1 cm/sec), it would take only 40 nanoseconds to sequence one base pair, which is equivalent to 1.5 Billion base pairs a minute. Cooling Sub-System In certain embodiments, fast cooling techniques may be incorporated. As shown in FIG. 88, for example, a specimen portion 8810 is within a probe system 8820 including a first probe 8830 and a cooling droplet supply nozzle 8840. The cooling droplet supply nozzle 8840 may include liquid He, liquid N2, or other suitable coolant suitable for fast cooling application. The first probe may include any one of the above referenced types of probes. Alternatively, more than one probe may be used with a cooling droplet supply nozzle 8840, for example, for photonic application, current measurement, voltage bias, or other functionality as described herein. AND Gate Referring now to FIG. 82, another embodiment of the present invention is shown. A specimen portion 8210 is within a probe system 8220 including a first probe 8230 and a light nozzle 8250. The light nozzle 8250 and the first probe 8230 are activated, either sequentially, simultaneously or overlapping in time, to facilitate current detection, measurement, or other impact of the detection contribution effect, as described above. The first probe 8230 may include any one of the above referenced types of probes. The light nozzle 8250 may provide various types photonic energy, for example, visible, UV, X-Ray, THZ, IR, or FRIR. Specimen/Probe Orientation In other embodiments described herein, and referring back to FIGS. 12A-126F, the probes may be oriented at various angles with respect to the specimen. Referring to FIGS. 12A and 12B, all probes and probe sets described herein may be configured with respect to the specimen at various angles. For example, referring to FIG. 12A, a probe set 1230 may be oriented generally perpendicular (in the length direction) to a specimen 1250. Further, referring to FIG. 12B, a probe set 1230 may be oriented (in the length direction) generally at an angle θ with respect to a specimen 650. Referring to FIG. 12C, a system 1260 is presented whereby the orientation of plural probe sets 1230 relative a specimen 1250 varies. Because the objects of the specimen 1250 (e.g., bases within a DNA strand) may have different orientations, it may be desirable to sequence with a plurality of probe sets 630. The plurality of probe sets 1230 may have different angles θ1, θ2, θ3, θ4, θ5, . . . θn (e.g., 20° to 160° in suitable increments, arranged sequentially, randomly or in another desirable arrangement. During measurement as described further herein, a controller may determine which orientation of the probe set yields the best signal for a particular base at its inherent orientation. This allows one to measure the data from the probe sets of the array, and determine the optimum signal for certain bases or groups of bases. In another embodiment, and referring to FIGS. 12D-12F, the angles of orientation in the height direction may also be varied. For example, referring to FIG. 6D, probe set 630 may be oriented in the height direction generally perpendicular (90°) with respect to the specimen 650. Further, as shown in FIG. 12E, probe set 1230 may be oriented in the height direction generally at an angle c with respect to the specimen 1250. Referring to FIG. 12F, a system 1270 is presented whereby the orientation in a height direction of plural probe sets 1230 relative a specimen 1250 varies. Because the objects of the specimen 1250 (e.g., bases within a DNA strand) may have different orientations, it may be desirable to sequence with a plurality of probe sets 1230. The plurality of probe sets 1230 may have different angles ω1, ω2, ω3 . . . ωn (e.g., 20° to 160° in suitable increments, arranged sequentially, randomly or in another desirable arrangement. By measuring at these various angles, the opportunities for errors and misreading are minimized or eliminated. Contacting In another embodiment, and referring now to FIGS. 89A and 89B, a bendable membrane material 8910 having a nano-scale probe attached thereto is provided. The nano-scale probe 8912 may one of the aforementioned probes such as a known nucleotide strand, functionalized group, or other molecular probe. Preferably the bendable membrane material 8910 include a metallic surface with the probe 8912 attached thereto to facilitate current measurement. Using a suitable MEMS device or other plunger 8920, a flexible metal membrane 8916 is pulsed to make contact with the specimen 8940 to resolve it. As with the other probe types described herein, a 2D or 3D array may be provided. Further, these arrays may include homogeneous or heterogeneous probe types. Furthermore, in general, the probe may make contact with the assistance of other known devices such as angstrom or sub-angstrom precision actuators, MEMs devices, or other mechanical devices. Sample Preparation and Manipulation Referring now to FIG. 90, a structure 9005 is shown that facilitates attraction and transport polymeric structures such as DNA fragments, RNA molecules, proteins, or other polymeric structure. A substrate 9010 is provided with one or more coaxing lines 9020. These coaxing lines or regions may be in the form of channels, channels including a suitable coaxing material, lines or regions of the surface of the substrate 9010 treated with a suitable coaxing material, a ridge or other protrusion defining the one or more coaxing lines 9020, or a ridge or other protrusion defining the one or more coaxing lines 9020 treated with a suitable coaxing material. A coaxing material may include materials such as amino-silane, biotin, other known bonding materials, charged conductive particles such as platinum, gold or other suitable material. In general, a the specimens may include magnetic portions, or suitable chromophores or fluorophores to help guide and manipulate the specimens. Note that the substrate 9010 may be in the form of a glass slide, e.g., on the order of 1-2 cm by 3-5 cm. Alternatively, the substrate 9010 may be in the form of a disc or wafer. The form factor of the slide will generally be a function of the analysis tools and/or manipulation tools used to work with the specimen. This structure 9005 may be used with DNA sequencing tools, for example, described in conjunction with U.S. patent application Ser. No. 10/775,999 filed on Feb. 10, 2004 entitled “Micro-Nozzle, Nano Nozzle and Manufacturing Methods Therefor”, U.S. Provisional Patent Application Ser. No. 60/669,029 filed on Apr. 7, 2005 entitled “DNA Sequencing Method and System”, and U.S. Provisional Patent Application Ser. No. 60/699,619 filed on Jul. 15, 2004 entitled “Molecular Analysis Probe, Systems and Methods, including DNA Sequencing”, all of which are incorporated by reference herein. Further, these structures 9005 may be used with various other types of analytical tools such as optical imaging tools. Certain useful optical imaging tools that may benefit from the structures 9005 described herein are described in U.S. patent application Ser. No. 10/800,148 filed on Mar. 12, 2004 entitled “Microchannel Plates And Biochip Arrays, And Methods Of Making Same” and U.S. Provisional Patent Application Ser. No. 60/674,012 filed on Apr. 22, 2005 entitled “Microchannel Plate And Method Of Making Microchannel Plate”, all of which are incorporated by reference herein. Referring now to FIG. 91, a structure 9105 is shown that facilitates attraction and transport polymeric structures such as DNA fragments, RNA molecules, proteins, or other polymeric structure. A substrate 9110 is provided with a plurality of coaxing lines 9120. Referring now to FIG. 92, a structure 9205 is shown that facilitates attraction and transport polymeric structures such as DNA fragments, RNA molecules, proteins, or other polymeric structure. A substrate 9210 is provided with one or more virtual coaxing lines 9225 defined by plural electrodes 9230 therealong. These virtual coaxing lines or regions may be in the form of channels with suitable electrodes 9230, virtual lines or regions on the surface of the substrate 9210 with suitable electrodes 9230, a ridge or other protrusion defining the one or more virtual coaxing lines 9220 with suitable electrodes 9230. Accordingly, with plural discontinuous electrodes 9203, the virtual coaxing line 9225 is defined. The electrodes in these embodiments may include pre-charged particles, include an on-board battery, or include electrodes that are activated by suitable devices with the system reader. Referring now to FIG. 93, a structure 9305 is shown that facilitates attraction and transport polymeric structures such as DNA fragments, RNA molecules, proteins, or other polymeric structure. A substrate 9310 is provided with one or more coaxing lines 9320 having plural electrodes 9330 therealong. These coaxing lines or regions may be in the form of channels, channels including a suitable coaxing material, lines or regions of the surface of the substrate 9310 treated with a suitable coaxing material, a ridge or other protrusion defining the one or more coaxing lines 9320, or a ridge or other protrusion defining the one or more coaxing lines 9320 treated with a suitable coaxing material, wherein the coating material may be the same as those described above, or alternatively may include materials that have attraction forces when subjected to the electric fields created by the electrodes 9330. In certain embodiments, an electric field may be applied at a desired start position 9340 on the structure 9305. Further, in the various embodiments of the structures that facilitate attraction and transport of specimens, various features may be aligned to other system features described herein. For example, and referring now to FIGS. 94A-94F, a method of coaxing strands onto a structure 9005, 9105, 9205 or 9305. A structure 9405 is inserted into a solution containing one or more polymeric structures such as DNA strands or fragments. One or more fragments will attach to said structure 9405 as shown by arrows in FIG. 94C. Referring to FIGS. 94D-F, structure 9405 having one or more polymeric strands attached thereto is then pulled out of the liquid. Preferably, the structure 9405 is removed in a direction along the axis of the coaxing line such that the liquid flow direction and gravity also contribute to the attractive forces of the coaxing lines. Accordingly, since the liquid flow forces, gravitational forces and the contribution of the coaxing line are in substantially the same direction, the strands are coaxed toward alignment. In certain embodiments, an electric field may be applied at a desired start position on the structure 9405. Stretching To assist the denaturing in conjunction with the precise stepwise motion, the DNA strand can be straightened bay various methods. In one embodiment, electrostatic fields may be used to attract the negatively charged strands. In another embodiment, a magnetically attractive bead may be applied to an end of the DNA strand, and the strand pulled with magnetic force. In a further embodiment, viscosity optimization may be employed, such that while dragging the strand through a liquid proximate or in the channel, it will straighten upon optimal dragging velocity and fluid viscosity conditions. Further, hydrophilicity may be used, e.g., by suitable material treatment at or in the nozzles and channel walls, to attract nucleotides. In other embodiment, hydrophobicity may be used, e.g., by suitable material at or in the nozzles and channel walls, to maintain the fluid within the channel. Coarse Shuttle Referring now to FIG. 95, an overview of a coarse shuttle system 9510 is shown. System 9510 serves to facilitate displacement of the extended object 9520, and in particular to move and stretch an extended object 9520 such as a DNA or RNA strand or fragment through a path 9514 (which may be a channel or along the surface of a substrate) between two sides 9530, 9540. In general, each side 9530, 9540 has a plurality of electrode pairs arranged about the path 9514. For example, as shown in FIG. 95, the channel 14 includes a wider opening area 9516, for example, to increase the likelihood of extended object 9520 encountering the channel 9514. Electrode pairs 9531, 9541 through 9538, 9548 are arranged on the sides 9530, 9540. In the example where the extended object 9520 is a negatively charged extended object, such as a DNA strand, positive charges are applied across the Electrode pairs 9531, 9541 through 9538, 9548, thereby coaxing the extended object 9520 into and through the path 9514. Note that the path 9514 may be in the form of a channel, e.g., having partially enclosed walls such as a concave groove, V-shaped groove, U-shaped groove, or other suitable shape. Alternatively, the path 9514 may instead be defined by suitable surface treatment, as described further herein. Alternatively, the path 9514 may be an elevated ridge treated or pattered with electrodes, either along the sides as shown with respect to the molecular shuttle herein or along all or portions of the length of the path 9514. Fine-Shuttle FIGS. 96A-96C show an embodiment of a molecular shuttle 9607, for example, for fine displacement of an extended object 9612. In general, the molecular shuttle 9607 may be used to controllably displace an extended object 9612, for example, from a first location 9616 to a second location 9618 to a third location 9620, and so on. The extended object 9612, such as a DNA strand, DNA fragment, RNA molecule, protein molecule, or various other types of polymer and extended object, is typically charged, in this case shown as negatively charged. The molecular shuttle 9607 includes a plurality of spatially opposing probes 9622, 9624 within or upon substrates or substrate regions 26, 28 thereby defining a path 9630 therebetween. In certain preferred embodiments, these probes 9622, 9624 are formed as probes as described herein. As shown in FIG. 96A, the extended object 9612 is outside of the path 9630. By applying a positive charge at probes 9622, 9624 at the end of the molecular shuttle 9607 (as indicated by “+” signs in FIG. 96A), the extended object 9612 will be attracted to an opening 9632 of the path 9630. Referring to FIG. 96B, when another positive charge is applied through the probes 9622, 9624 at a location indicated by line 9618, with negative charges provided by probes or electrodes between position 9618 and the positive charge at opening 9632, the extended object 9612 will be attracted to the position 9618 within the channel path 9630. Referring to FIG. 96C, the process is continued to shuttle the extended object 9612, for example, to a position 9620 within the path 9630. Referring now to FIGS. 97A-97D, a molecular shuttle 9707 may be formed of various shapes, including but not limited to a curved or semicircle channel (FIG. 97A), a Y-shaped channel (FIG. 97B), a series of channels directed in a radial manner to or from a central point (FIG. 97C), or T-shaped (FIG. 97D), for example. Note that the path 9630 may be in the form of a channel, e.g., having partially enclosed walls such as a concave groove, V-shaped groove, U-shaped groove, or other suitable shape. Alternatively, the path 9630 may instead be defined by suitable surface treatment, as described further herein. Alternatively, the path 9630 may be an elevated ridge treated or pattered with electrodes, either along the sides as shown with respect to the molecular shuttle herein or along all or portions of the length of the path 9630. Motion and Sub-Systems During Measurement Metrology Referring now to FIG. 98, a reference position and precision nanometer metrology system is shown. A reference position probe (RPP), e.g., formed of platinum or other suitable material, or in the form of a nano-light guide, or other excitation probe structure, is included in the probe set or nanonozzle array set. The positions of each probe or nanonozzle relative the RPP is known. This reference position probe provides a known starting point when sequencing commences for precise metrology. Stepped Motion Referring now to FIG. 99, the stepped motion of ssDNA is shown relative to a known position of the RPP. Base—Specimen Configuration In certain embodiments, the specimen may be within a channel of the base. A channel may include suitable fluid, or the specimen may be coaxed through a channel with little or no fluid. In other embodiments, the specimens may be embedded within the base, e.g., in a biochip. Electron Intensifier In certain embodiments, an electron or photon intensifier such as a micro-channel intensifier may be used. For example, referring to FIGS. 100A and 100B, these embodiments are shown. Referring to FIG. 100A, the probe emitter interacts selectively with the specimen in an elastic or inelastic manner, whereby energy is lost, and the event lead to the release of photons or electrons that have specific energy indicative of the nature of the molecule or monomer. These electrons or photons may be too few to be measured directly. Therefore, the invention herein provides for an intensification or amplification sub-system such as micro-channel plate intensifiers known in the art, e.g., night vision goggles or photo-multipliers. Referring now to FIG. 100B, where the probe is either metallic and/or a molecular probe, interaction with the specimen may be through inelastic tunneling current. Rather than measuring this tunneling current directly, it is possible to provide a sub-system for allowing either photons or electrons to be emitted. The photons or electrons to be emitted may occur upon a hybridization event, or by applying suitable voltage energy to emit inelastic electrons indicative of the spectra of the specimen. This electron is also detected my an intensifier/amplification sub-system described above with respect to FIG. 100A. Referring now to FIG. 100C, an array of intensifiers/amplifier sub-systems as described with respect to FIG. 100A or 100B may be provided. For example, the exciting probe beams or other probe types may be tuned or optimized from a particular monomer, for example, in a DNA sequencing system, A, T, C, G, such that the electrons or photons are emitted are signatures of each type of nucleotide to be detected. Applications DNA Sequencing Sequencing extended objects including but not limited to DNA and RNA (including genomes, epigenomes and methylation codes and environmental methylation effects), proteins in general, other polymers, oligomers, and other nano-scale structures. Thus, as shown and described, the herein system including nano-nozzles and nano-nozzle arrays are very well suited for ultra fast real time DNA sequencing operations. General Purpose Molecular Probe In addition to sequencing or analyzing DNA strands or fragments, probes and systems according to the present invention may be used for various types of extended objects including but not limited to DNA, RNA, proteins in general, other polymers, oligomers, and other nano-scale structures. General Purpose Manipulator Referring now to FIG. 101, a probe 10102 having extremely small tip dimensions t (or array or set of such probes) may be used as a general purpose manipulator for manipulating materials on the molecular or atomic level. For example, using the probe 10102 provides for a high field strength, in part due to its symmetry. This high field that is advantageously localized due to the small probe dimensions will enable attraction of DNA strands, proteins, graphene layers, nanoparticles, other molecules, mono-molecular layers, or N such layers. Nanolithography Referring to FIG. 102, a general system is depicted for using the herein probes for ultra high resolution nanolithography. A probe set may be provided, for example, wherein each probe includes the same or different materials. In further embodiments, three-dimensional nanostructures may be fabricated using the probes herein. Nano Stretching DNA Shuttle FIGS. 96A-C show an embodiment of a molecular shuttle 9607. In general, the molecular shuttle 9607 may be used to controllably displace an extended object 9612, for example, from a first location 9616 to a second location 9618 to a third location 9620, and so on. The extended object 9612, such as a DNA strand, DNA fragment, RNA molecule, protein molecule, or various other types of polymer and extended object, is typically charged, in this case shown as negatively charged. The molecular shuttle 9607 includes a plurality of spatially opposing probes 9622, 9624 within or upon substrates or substrate regions 26, 28 thereby defining a channel 9630 therebetween. In certain preferred embodiments, these probes 9622, 9624 are formed as probes as described herein. As shown in FIG. 96A, the extended object 9612 is outside of the channel 30. By applying a positive charge at probes 9622, 9624 at the end of the molecular shuttle 9607 (as indicated by “+” signs in FIG. 96A), the extended object 9612 will be attracted to an opening 9632 of the channel. Referring to FIG. 96B, when another positive charge is applied through the probes 9622, 9624 at a location indicated by line 9618, with negative charges provided by probes or electrodes between position 9618 and the positive charge at opening 9632, the extended object 9612 will be attracted to the position 9618 within the channel. Referring to FIG. 96C, the process is continued to shuttle the extended object 9612, for example, to a position 9620 within the channel. Referring now to FIGS. 97A-97D, a molecular shuttle 9707 may be formed of various shapes, including but not limited to a curved or semicircle channel (FIG. 97A), a Y-shaped channel (FIG. 97B), a series of channels directed in a radial manner to or from a central point (FIG. 97C), or T-shaped (FIG. 97D), for example. Making Atomically Smooth Surface Referring to FIG. 103, a method is shown to use the probes according to the present invention to create atomically smooth surfaces. For example, a probe 10310 with an attached voltage source is swept over a surface 10350. In the configuration of the probe as shown in FIG. 103, the probe produces a very high localized field strength. This field can be used to sweep a surface to make it atomically smooth. Atomic Force Tunneling Membrane Microscopy Another embodiment of the present invention exploits the ability to make atomically smooth ultra-thin films as taught in the present invention FIGS. 26-31 above. These films can used as flexible substrates for analyzing or sequencing unknown specimens. As shown in FIG. 104, this flexible membrane may replace the flexible cantilevers in FIGS. 84-86. FIG. 104 shows a system 10410a membrane 10412 between supports 10414. As the specimen 10430 passes under a probe 10420, atomic interactions occur, generally as described above with respect to FIGS. 84-86. However, the probes 10420 are fixed, thus the membrane 10412 is deflected by those atomic forces. The deflection of the membrane 10412, in response to atomic forces, is detected by measuring the reflection of the incident laser beam 10440 on the membrane 10412. By separating the deflection from the probe, a more general purpose apparatus results, namely, combing AFM capability with STM imaging as well sequencing tools all in one device. As shown in 104, one or more probes 10420 are connected to suitable voltage sources and the supports 10414. Other stimuli may also be provided for certain applications, such as scanning tunneling and other sequencing functionality. For specificity, the prove may be a specifically formed probe, such as a nucleotide specific probe as described above. A device particularly suited for sequencing DNA strands includes one that incorporates at least a set of 4 probes, include nucleotide specific probes for A, C, T and G, for example, in a configuration as described herein with respect to FIG. 85, with the flexible membrane 10412. This membrane deflecting apparatus allows for the possibility of replacing the laser beam with a parallel conducting plate directly underneath the membrane separated by an appropriate distance. As shown in FIGS. 105A-105B, this forms a capacitance that varies according to the deflection of the membrane. FIGS. 105A-105B show the deflection of the substrate membrane in response to the forces at different probe positions. Therefore, the capacitance value variation or modulation can be related to the atomic forces experienced by the membrane. This happens because the fixture holding the probes is held substantially fixed, thereby forcing only the membrane to respond to the forces. Such as system could readily be used in combination, for example, whereby the membrane AFM capacitance is read and STM tunneling is read, for example, using a system of FIG. 86. Further, alignment marks may be provided to increase accuracy. The capacitance value is designed to be in the range of 0.1 to 10 nano-Farad so that it can be part of a resonant circuit, FIG. 105C, comprising an inductance to oscillate at frequencies in the ranges of 10 KHz-1 MHZ or 1 MHz to several GHz. By coupling an tunable sweep oscillator, it is possible to monitor the power absorbed by the system as a function of frequency. FIG. 105D shows the intensity, I107 may be plotted as a function of frequency, ω=(LC)1/2, for different probe positions. Measuring frequency shifts can be related to the capacitance variation that results from the varying forces Fω at different positions. FIG. 105E illustrates the dependence of the F107 on the frequency for attractive and repulsive forces. In a first position, the probe experiences a repulsive force, causing the capacitance to decrease, and shifting the frequency to ω1. In a second and third probe positions, the forces are attractive, shifting the requires upward to ω2 and ω3 respectively. Versatile AFTM with Addressable 2D Nano-Probe Array FIG. 106A illustrates yet another embodiment of the present invention whereby a tool for analyzing specimens including specific application of sequencing DNA, RNA and atomic force imaging is provided. A probe according the teachings of the present invention is attached to a flexible membrane or cantilever. According to the exploded view in FIG. 106B, a first thin film inductor connected to a first thin film plat of a capacitor are deposited on the flexible membrane on the surface opposite the probe. A second thin film inductor connected to a second thin film plate of a capacitor are deposited on a rigid member on the surface facing the flexible membrane. The rigid member and flexible membrane and attached to each other with a suitable spacer having a thickened that determines a desired capacitance value. The spacer also may contain an integrated circuit for processing and/or analyzing the signals which result from the interaction of the probe with the specimen. This signal is manifested in the variation of the capacitance as a result of the forces that cause the membrane deflection. FIG. 106C shown the circuit model for analysis and processing. Similar detection principles apply as those employed in the apparatus described FIGS. 105A to 105E. This integrated atomic force probe can be used as in conventional ATM modes, as well as for sequencing. The latter is accomplished by sequentially inserting different integrated probes functionalized to specify different nucleotides. Alternatively, it is preferred to integrate several capacitive probes in a single structure to perform parallel sequencing and analysis functions as shown in FIG. 107. This fully integrated system allows the flexibility to have probes of different shapes and functionalized to recognize predetermined certain specimens. The system can be addressed to select one of many modes, including but not limited to STM, AFM, sequencing, magnetic analysis, or other suitable functionalities, because it has a unique activation/deactivation feature. This is accomplished with an integrated circuit that supplies a DC voltage to the plates of the capacitor that is selected to deactivate. This causes the flexible membrane to be attached permanently to the upper rigid plate. The removal of the DC voltage releases the membrane and selects it and its probe for activation. FIG. 108 illustrates the system of FIG. 107 further including nucleotide specific probes for increases specificity, for example, particularly suitable for imaging, analyzing and sequencing DNA specimens. The fully integrated probe illustrated in FIGS. 106-108 can be advantageously manufactured by the methods and systems described in Applicant's multi-layered manufacturing methods, as described in U.S. Non-provisional application Ser. No. 09/950,909, filed Sep. 12, 2001 entitled “Thin films and Production Methods Thereof”; Ser. No. 10/222,439, filed Aug. 15, 2002 entitled “MEMs And Method Of Manufacturing MEMs”; Ser. No. 10/017,186 filed Dec. 7, 2001 entitled “Device And Method For Handling Fragile Objects, And Manufacturing Method Thereof”; PCT Application Serial No. PCT/US03/37304 filed Nov. 20, 2003 and entitled “Three Dimensional Device Assembly and Production Methods Thereof”; U.S. Pat. No. 6,857,671 granted on Apr. 5, 2005 entitled “Method of Fabricating Vertical Integrated Circuits”; U.S. Non-provisional application Ser. No. 10/717,220 filed on Nov. 19, 2003 entitled “Method of Fabricating Multi Layer MEMs and Microfluidic Devices”; Ser. No. 10/719,666 filed on Nov. 20, 2003 entitled “Method and System for Increasing Yield of Vertically Integrated Devices”; Ser. No. 10/719,663 filed on Nov. 20, 2003 entitled “Method of Fabricating Multi Layer Devices on Buried Oxide Layer Substrates”; all of which are incorporated by reference herein. However, other types of semiconductor and/or thin film processing may be employed. While the above examples apply to the sequencing of DNA, it is appreciated that the probes can be functionalized to have the ability to recognize other molecules with precise specificity making these methods more general for the recognition and analysis on unknown chemicals. It will have applications not only as a scientific tools, but also for medical as well as for sensing hazardous materials. Protein Conformation Another embodiment of the present invention exploits the ability to use certain embodiments and configurations of the herein probes to control protein conformation through complex electric field applied. Functions of proteins are closely related to their structures. Modification of protein structures allows one to modify or “tune” a function of the protein. If structure of a single protein molecule can be modified in real time using external stimuli, various application are possible. For example, real time conformation of proteins can be used as a bio-sensor with tunable detection characteristics which has low false positives and high detection probability. It can also lead to developing improved countermeasures against chemical or biological attack where the design of proteins suited against harmful bio-agents or chemical agents can be done very rapidly. Fundamentally real time conformation of proteins can advance study of relationships between function and structure of protein molecules. Mechanical or optical methods of achieving this task are too cumbersome and/or not adequate. Herein described is a probe device that can facilitate such real time protein conformation. In conventional approaches, to modify protein structure mechanically, plural nano-probe tips need to be attached to protein molecule and moved in complex fashion to achieve the desired structure modification. Attaching tethers and beads to molecule and then stretching the beads is possible but too cumbersome. In optical methods one can trap a bio-molecule or stretch a micro-particle [J. Guck et al, “Optical Deformability of Soft Biological Dielectrics,” Phys. Rev. Lett. 84, 5451(2000)]. However, this technique cannot be used to stretch a nanometer size molecule. Proteins are complex distributions of electric charges, dipoles and multi-poles. Protein structure modifications happen through electrostatic stimuli. Thus electric field stimulus may be used to modify the structure of a protein molecule. Electric fields in proteins are of the order of 107 V/m [S. Dao-pin et al, “Electrostatic fields in the active sites of lysozymes,”, PNAS Biophysics, 86, 5361 (1988)]. Protein structures may be modified if electric fields of this magnitude can be applied [A. Budi et al, “Electric Field Effects on Insulin Chain-B Conformation,” J. Phys. Chem. B., 109, 22641 (2005)]. However, to achieve desired modification of conformation, a complex electric field of such magnitude needs to be applied. This may be achieved using various devices of the present invention. FIG. 110 shows a sectional view of a device 11010 positioned relative a protein molecule 11030. The device 11010 includes plural electrodes 11015, 11020 and 11025. Device 11010 may be manufactured according to various embodiments described hereinabove, with probe tip active areas on the order of 0.1 to about 10 nanometers thick, with an edge of any suitable dimension, such as on the order of microns or millimeters, e.g., to provide a “knife edge” configuration as described herein. Using the device 11010, complex electric field stimuli may be applied to a protein molecule alter its characteristics in real time. The probes may be spaced apart by suitable molecular dimensions, for example, so that the plural probes may all be applied to a single molecule or cell as desired. Accordingly, the probes may be spaced apart by a distance of about 0.5 to about 25 nanometers. In certain embodiments, it may be desirable to space the probes apart by greater distances, for example, wherein the structure to be probed is larger. Notably, each probe may have different potentials (in terms of magnitude and polarity), and these potentials may vary as desired, for example, by control of a suitable controller device. For example, referring now to FIGS. 111A-111C, isometric views (with the substrate between probes not shown for clarity of exposition) are shown of a protein structure with no voltage applied (FIG. 111A), with a positive voltage applied at the outer probes and a negative voltage applied at the middle probe (FIG. 111B), and with a negative voltage applied at the left probe as viewed in the figure and positive voltages applied at the middle and right probe as viewed in the Figure (FIG. 111C). Note the variation of the protein structure as shown in the different FIGS. 11A-11C. Furthermore, the electrodes or probes can be charged at different combination of electric potentials to create complex electric fields between them to modify the structure of single protein molecule in vicinity and thus tune its function, for example, as shown in FIGS. 112A-112H. Thus various magnitudes of electric fields with various directions can be applied to protein molecule to modify its function and thus its properties. Thus with tens of nanometer distance between electrodes voltages of few volts can be applied to electrodes to modify the structure of protein molecule. While the various embodiments described above related to molecular conformation describe proteins, other molecular structures may be probed according to the described methods to induce confirmation, for detection, for imaging, or other applications as described herein. Furthermore, while various embodiments depict a multi-probe device with three probe tips, one may accomplish the various molecular confirmations or multi-probe tip imaging, detection or other application with a multi-probe device with two tip areas, three tip areas, or any desired greater number of tip areas may be provided depending, for example, on the desired complexity of the confirmation structure or combinations of fields to be applied to the molecular structure. Double Stranded It is known that the replication and transcription of DNA involves the separation of the two strands to reveal the base sequence of the single stand to be replicated or transcribed. This is accomplished with a helicase enzyme which causes the complementary strands to separate in a first position to complete the transcription or replication processes. When this is completed, the two complementary strands bind again and the helicase separates them at a second adjacent position to repeat the process. This is repeated along the entire DNA length until the replication or transcription is done. The present invention which teaching the analysis of an extended object in general, and a single DNA strand sequence in particular, may be extended to also sequence double strand specimens. This may be accomplished according the embodiments of the present invention by causing the nano-probe to interact with the nucleotide bases in the major and minor groves of the helical structure of the DNA strand or fragment. This process may optionally be facilitated further by the use of a suitable catalyst or enzyme such as helicase to cause local separation of the complementary strands to reveal the bases to be sequenced and to cause them to interact optimally with the nano-probe as described herein. The catalyst or enzyme may be attached to or dispensed from the analyzing nano-probe or attached to or dispensed from an auxiliary nano-probe or nano-funnel in close proximity to the analyzing nano-probe. Except for this additional step using the catalyst, the procedure to analyze the double stranded DNA is carried out using the embodiments taught herein for analyzing the single strand DNA. While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.
051494930	claims	1. An installation for regeneration of cold traps loaded with hydride and oxide of a liquid metal, wherein said installation includes a regeneration circuit filled with liquid metal on which is disposed at least one trap to be regenerated, said regeneration circuit being provided with means to establish a circulation of the liquid metal in the regeneration circuit and through the trap, means to adjust the temperature of the liquid metal to values sufficient to dissolve the oxide and the hydride which decompose to give off hydrogen, tritium and oxygen, and a device to draw off the dissolved hydrogen and tritium and a first dump equipped with an oxygen retention device, said device to draw off the dissolved hydrogen and tritium comprising a membrane through which hydrogen and tritium permeate, said membrane having one face communicating with the liquid metal regeneration circuit and another face communicating with a partial vacuum pumping circuit with respect to the liquid metal regeneration circuit, and a tank disposed on the partial vacuum pumping circuit which is lined with a solid for fixing the hydrogen and the tritium. 2. Regeneration installation according to claim 1, wherein the liquid metal regeneration circuit includes a second dump on which the device is installed so as to draw off the hydrogen and the tritium, and an additional heating device upstream of said device. 3. Regeneration installation according to claim 1, wherein the oxygen retention device is another cold trap where the existing temperature is less than the oxide crystallization temperature and greater than the hydride crystallization temperature.
	description	This invention relates to a pressurised water nuclear reactor with an integrated and compact design. The invention is particularly applicable to small and medium power nuclear reactors, in other words particularly reactors with a power less than or equal to approximately 600 MWe. Existing pressurised water nuclear reactors normally include a vessel containing the reactor core, primary circuits connecting the vessel to steam generators located outside the vessel, and primary pumps circulating pressurised water in each of the primary circuits, to transfer heat generated by the nuclear reaction in the reactor core, as far as the steam generators. A pressuriser, also located outside the vessel, pressurizes the water contained in the vessel and in the primary circuits. In these existing nuclear reactors, secondary circuits connect each of the steam generators to a turbine that drives an alternator to transform heat originating from the primary circuit into electrical current. More precisely, in steam generators, this heat transforms water, circulated in the secondary circuits by secondary pumps, into steam. The steam that drives the turbine is then converted to the liquid state in a condenser. “Integrated” pressurised water nuclear reactors and “compact” pressurised water nuclear reactors are also known. Integrated reactors are different from previous reactors due to the fact that steam generators are located inside the reactor vessel, in an annular region delimited between the peripheral wall of the vessel and a partition inside the vessel. However, primary pumps remain located outside the vessel, to which they are connected by appropriate pipes. Control mechanisms of control bars are also located on the outside of the vessel, as in traditional reactors. A leaktight containment provides global confinement of the primary circuit. In compact reactors, a single steam generator forms the vessel cover. Conventionally designed pressurised water nuclear reactors of the integrated type or the compact type have been successfully used for many years, and many projects have been constructed using them. However, they have a number of disadvantages that are a direct result of their design. A first disadvantage relates to their design. The primary pumps and the pressuriser are located on the outside of the vessel. Control rods are driven by motors located on the outside of the vessel and the mechanism contains a bevel gear. The complexity of these devices makes it impossible to design high power cores in this way (more than 500 or 1000 MW thermal) due to the dimensions necessary for the large number of control rods. A second disadvantage is their investment cost, particularly due to the architecture of buildings imposed by the design mentioned above. Another disadvantage lies in the existence of a certain number of accident situations also inherent to the design of existing reactors. These situations make a large number of protection and residual power evacuation systems necessary, which significantly increase the cost of these reactors. Moreover, existing pressurised water nuclear reactors only enable the use of traditionally designed nuclear fuel assemblies. Some more recently designed assemblies have substantial advantages that it would be desirable to be able to use. The purpose of the invention is to solve at least some of the problems that arise with existing pressurised water nuclear reactors. More precisely, the purpose of the invention is particularly to propose a compact pressurised water nuclear reactor with an innovative design that makes it more economic in construction and inherently safer than existing reactors, while possibly enabling use of different types of nuclear fuel assemblies. According to the invention, this objective is at least partially achieved by means of a compact pressurised water nuclear reactor comprising a vessel closed by a cover, a reactor core housed in the vessel, a steam generator forming the cover of the vessel, primary pumping means capable of making water circulate between the reactor core and the steam generator, and a pressuriser for pressurising water, characterised in that the pumping means and the pressuriser are housed in the reactor vessel so as to form a primary circuit fully integrated into the said vessel. The fully integrated design of the reactor according to the invention reduces investment costs, particularly by simplifying the building architecture. This integrated design also eliminates a certain number of accident situations that are difficult to manage in terms of safety and for which expensive management systems are necessary. According to one preferred embodiment of the invention, control mechanisms for the control rods are also integrated into the reactor vessel. In the preferred embodiment of the invention, an approximately annular partition projects downwards from the cover and delimits a peripheral region and a central region inside the vessel. The reactor core is then housed in the bottom of the central region, the pressuriser is housed in the top of the central region, and the pumping means are housed in the top of the peripheral region. Preferably, the pressuriser comprises an annular shaped reservoir with an inverse U-shaped cross-section, open downwards and the top of which communicates with a tank forming a steam source, means being provided for supplying water to the said tank taken from the peripheral region, below the pumping means. Advantageously, a venturi system, supplied with water contained in the central region, is located in the peripheral region to create a natural water circulation in this region, from top to bottom, if there is a failure of the pumping means. An emergency cooling exchanger may also advantageously be placed in the peripheral region below the venturi system. In one preferred embodiment of the invention, the reactivity of the reactor core is controlled without any soluble neutron poison in the cooling water. As shown diagrammatically in the single FIGURE, the compact pressurised water nuclear reactor according to the invention comprises a vessel 10 with a vertical axis. The top end of the vessel 10 comprises an opening normally closed by a steam generator 12 thus forming the cover of the vessel. The closed volume contained inside the vessel 10, below the cover materialised by the steam generator 12, is delimited on the inside by an approximately annular partition 15 that projects downwards from the said cover. The partition 15, centred on the vertical axis of the vessel 10, thus separates this closed volume into a central region 16 and a peripheral region 18, which communicate with each other through the bottom of the vessel 10. The reactor core 14 is located in the bottom of the central region 16. It is formed from nuclear fuel assemblies arranged in bundles along a vertical direction. These assemblies may be of a conventional design or they may be of a different type. If a different type is used, assemblies with a more recent design may particularly be used, such as advanced assemblies, for example actinide consumers. As a non-limitative example, the core 14 of the reactor may in particular consist of 157 assemblies of 17×17 rods, as used in existing 900 MWe pressurised water reactors. However, the specific power is 25% less than these reactors. This power reduction means that the soluble neutron poison usually used to control the core reactivity can be eliminated. It also makes it possible to envisage the use of different types of fuels, using the margins available on the critical flow due to the drop in the operating point and the drop in the power density. The drop in the power density also makes it possible to extend cycle durations, and therefore to increase availability. The steam generator 12 comprises a horizontal base plate 20 forming the vessel cover itself and an outer enclosure 22 connected in a leaktight manner around the peripheral edge of the base plate 20 and delimiting a secondary closed space 24 with it. The steam generator 12 also comprises an inverted U-shaped tube bundle 26, located in the closed secondary space 24. More precisely, the two ends of each tube 26 are fixed to the base plate 20 such that one of these ends opens up in the central region 16 and the other end opens up in the peripheral region 18. The closed volume delimited inside the vessel 10 and inside the tubes 26 forms the primary circuit of the reactor. This primary circuit is fully integrated and is filled with pressurised water. Water is circulated in the reactor primary circuit by primary pumping means materialised by a certain number of primary pumps 28 housed directly in the top part of the peripheral region 18. When they are in operation, the primary pumps 28 circulate water in the direction of the arrows shown in FIG. 1. In other words, the pumps 28 circulate water towards the bottom of the vessel 10 in the peripheral region 18, and then upwards through the core 14 in the central region 16 and finally from bottom to top, then from top to bottom in the tubes 26 of the steam generator 12. In practice, the primary pumps 28 may be in different forms. Some useable pumps include particularly radial pumps, injector pumps and axial turbo-pumps. Radial pumps are immersed rotor pumps arranged at the top of the vessel and oriented along a radial direction from the vertical axis of the vessel. This type of pump is described in reference [1]. In the case of injector pumps, the top part of the peripheral region 18 comprises a series of injectors or jet pumps. The injector is supplied at a low flow and high pressure so that most of the heat transporting fluid is circulated without it coming outside the vessel. The high-pressure supply flow to the injector originates from a pump outside the vessel. Finally, vertical turbo-pumps may also be placed near the top of the peripheral region 18. The turbine is then supplied by high-pressure primary water originating from a pump located outside the vessel. The axial turbo-pump fulfils the same “hydraulic transformer” function as the injector in the previous case, but with a rotating part. In the case of the vertical turbo-pump, the turbine may be replaced by an electric motor in which the windings are covered by a leaktightness skin to isolate them from the heat transporting fluid. According to the invention, the pressuriser 30 is also integrated into the reactor vessel 10. More precisely, the pressuriser 30 is in the form of an annular shaped reservoir located in the top of the central region 16 of the vessel 10, immediately below the base plate 20. This reservoir is delimited by a wall that has an inverted U-shaped cross-section. The reservoir forming the pressuriser 30 is open downwards so as to open up directly into the central region 16 of the vessel 10. The top part of the reservoir forming the pressuriser 30 is filled with steam. The top of the said reservoir is supplied with a two-phase steam-water mix through a pipe 34 connected to a small volume tank 32 located outside the vessel 10 and acting as a steam source. In this respect, the tank 32 is provided with heating rods 36. The water supply to the tank 32 is provided by another pipe 38 that connects the said tank to the peripheral region 18 of the vessel 10, just on the output side of the primary pumps 28. Control rods 40 used to control reactivity in the reactor core 14 are also shown diagrammatically in FIG. 1. Advantageously, the control rods 40 and their control mechanisms are also integrated into the reactor vessel. This arrangement is dictated by the fact that it is impossible to use standard mechanisms (electromagnetic mechanisms located outside the vessel) due to the presence of the steam generator above the vessel 10. The particularly compact nature of the integrated control mechanisms enables the use of a control rod 40 for one or two nuclear fuel assemblies and eliminates the need for local power excursions due to ejection of a control rod, as is possible in a pressurised water reactor with the standard design. This means that the control rods 40 alone are capable of controlling reactivity in the core, which means that the soluble neutron poison in the cooling water of the reactor core 14 can be eliminated. It is also possible to eliminate soluble neutron poison in the cooling water of the reactor core 14 due to the fact that the low power density makes it possible to accommodate slightly higher local power peaks than in pressurised water reactors with a standard design. The low power per unit volume and the lowering of the operating point compared with these standard reactors reduce reactivity control needs and also help to make it possible to eliminate soluble boron. The choice of a core without a soluble neutron poison is also facilitated by the integrated design, which eliminates the possibility of several control rod control mechanisms becoming blocked due to a large primary break. Note that elimination of the soluble neutron poison in the reactor core enables a major simplification of ancillary systems and a reduction of effluent disposal necessary to manage soluble poison, resulting in a significant reduction in the investing cost and maintenance and operating costs. However, it would be possible to envisage injection of a neutron poison such as borated water in an accident situation. The control rods with control mechanisms integrated in the reactor vessel 10 may be composed either of a system of rods controlled by a hydraulic device, or by a system of fluid rods, or by both of these systems combined to provide redundancy. Control rods controlled by a hydraulic device are described particularly in reference [2]. This type of mechanism consists of a hollow piston and a mobile cylinder. The piston is fixed to the support plate of the core and the cylinder is grooved near the bottom. The geometries of the piston and the cylinder grooves are identical. The cylinder is held in position by allowing a given flow of primary fluid inside the piston. The cylinder can thus be raised or lowered by a height equal to the pitch of the grooves, by temporarily increasing or reducing this primary fluid flow. Document FR-A-2 765 722 describes the fluid rods system. In this system, a liquid salt containing neutron absorbents is displaced in the core through a bundle of guide tubes. These absorbents are moved by means of a gas acting as a piston and acting on the salt. The absorbent salt reserve is located above the assemblies. The core power can be cut off automatically by introducing absorbents quickly. The axial and radial distributions of the absorbent salt may be controlled in order to flatten the flux shape in the core. The operating point of the compact reactor according to the invention is advantageously chosen at a relatively low pressure and temperature. Thus, a pressure of about 80 to 90 bars in the primary circuit is used. With these operating characteristics, it is possible to envisage a significant reduction in the thicknesses of components resisting pressure, such as the vessel, the steam generator and the thickness of the steam generator base plate 20, a significant increase in the combustion rate, a reduction in duct corrosion and a simplification of protection systems. For this operating point, the pressure in the secondary circuit is about 30 bars, which leads to a net efficiency of 30%. The thermal power of the core is 2000 MW. As is also illustrated in the single figure, the compact reactor according to the invention is preferably provided with protection or safety systems. These protection systems include means of evacuating the residual power, means of a safety injection and means of controlling the primary pressure. Means of evacuating the residual power are placed firstly on the primary circuit and secondly on the secondary circuit of the reactor. This arrangement enables diversity of means as a function of the abnormal transient, taking account of the fact that the reactor comprises a single steam generator. The power evacuation system installed on the primary circuit includes heat exchangers 42 located in the peripheral region 18 of the vessel. These exchangers are connected to a standby cooling circuit (not shown) outside the reactor vessel 10. The system located on the primary circuit also includes a venturi system 44 located in the peripheral region 18 above the exchangers 42. The venturi system 44 is formed between the partition 15 and a shell 46 connected to the peripheral wall of the vessel 10. The shape of the shell 46 is such that the flow cross-section progressively reduces towards the bottom in the inside of the peripheral region 18, as far as a throttle formed at the bottom of the venturi system 44. The venturi system is supplied with water from the central region 16 at this throttle through openings 48 provided for this purpose in the partition 15. The venturi is sized such that during normal operation, the pressure at 44 is approximately equal to the pressure at 48. In this way, the short circuit flow between the region 16 and the region 18 may be minimised. In the pumps shutdown situation, the openings 48 enable natural convection between the core 14 and exchangers 42 to evacuate power released in the core. In particular, the residual power evacuation system installed on the secondary circuit, which does not form part of the invention, may include a condensation system at the secondary associated with a thermal valve, or a system with a steam injector. In the first case, the condensation system at the secondary may in particular be of the type described in reference [3] and the thermal valve may be of the type described in document FR-A-2 725 508. Moreover, a steam injector system may be made in the manner described in reference [4]. Safety injection means may also be provided to ensure that sufficient water is present in the primary circuit in case of accident. However, a low flow system is sufficient due to the fact that large breaks are eliminated by the completely integrated design of the reactor. If the pressure in the primary circuit is low, the discharge pressure from the safety injection system may for example be about 25 bars. Concerning control of primary pressure in the case of a failure of all protection systems except for the passive system installed in the primary circuit, studies have shown that accident transients can be managed by avoiding a meltdown of the pressurised core, without a specific depressurisation system in the primary circuit (reference [5]). In particular, confinement of the compact reactor that has just been described may include a pressure elimination containment 47 containing the primary circuit. This containment may then be limited to the volume of the compartment located under the horizontal junction plane of the vessel 10 and the steam generator 12. The steam generator is then located in a pool 48 above this plane, used for core reloading and maintenance operations. In this arrangement, the confinement containment can be made inert over a small volume. The consequence of this is to limit the investment cost and to enable relatively easy management of the risk of explosion due to the presence of hydrogen. In the case of a serious accident, corium can be cooled by reflooding the vessel sump but there would be no need to provide an external recuperator. This is made possible due to the fact that the power and the power density in the core are smaller than the corresponding values in an existing 900 MWe pressurised water reactor. Obviously, the invention is not restricted to the embodiment that has just been described as an example. In particular, the shape of the pressuriser 30 may be different from the shape illustrated in FIG. 1, without departing from the scope of the invention. [1] “Design of Safe Integral Reactor”, R. A. Matzie, Nuclear Engineering and design, vol. 136 (1992) p. 72–83. [2] de Bathéja P. et al. “Design and testing of the reactor internal hydraulic control rod drive for the nuclear heating plant”, Nuclear technology, 1987, vol. 79, pages 186 to 195. [3] “A 900 MWe PWR residual heat removal with a passive secondary condensing system”, ICONE 5 proceedings, May 29–30, 1997, Nice (France). [4] “Design and testing of passive heat removal system with Ejector-Condenser.—Progress in Design, research and development and testing of safety systems for advanced water cooled reactors” by K. I. Soplenkov & al. in Proceedings of a Technical Committee meeting held in Piacenza, Italy, May 16–19 1995. [5] G. M. Gautier, Passive heat removal system with the “Base operation passive heat removal” strategy, ICONE 7 proceedings—Apr. 19–23, 1999, Tokyo (Japan).
	claims	1. A method for preparing a phosphosilicate apatite having the formula (I): M t Ca x Ln y Hf w Pu zxe2x88x92w (PO 4 ) 6xe2x88x92u (SiO 4 ) u F 2 xe2x80x83xe2x80x83(I) wherein: M represents an alkaline metal, Ln represents at least one cation selected from lanthanides, and t, x, y, z, w and u are such that: 0xe2x89xa6txe2x89xa61, 8xe2x89xa6xxe2x89xa610, 0xe2x89xa6yxe2x89xa61, 0 less than zxe2x89xa60.5, 0xe2x89xa6w less than z, and 0 less than uxe2x89xa6y+2z, and the total number of positive charges provided by the alkaline metal, Ca x Ln, Hf and Pu cations are equal to 20+u; said method comprising: a) preparing a first mixture of powders containing plutonium dioxide, calcium pyrophosphate, a silicone compound and optionally one or more compounds selected from alkaline metal compounds, hafnium compounds and lanthanide compounds; b) preparing a second mixture of powders by mixing the first mixture of powders with at least one powdered fluorinated reagent; c) grinding said second mixture of powders to a particle size of less than 50 xcexcm; d) compressing the ground second mixture of powders in a mould under pressure from 100 to 500 MPa to obtain a compressed product, and e) submitting said compressed product to a sintering-reaction in a neutral or reducing atmosphere, at atmospheric pressure and at a temperature of 1500 to 1600xc2x0 C. to obtain a sintered product. 2. The method of claim 1 , wherein the first mixture of powders comprises calcium carbonate and the method comprises between step a) and step b) an additional step of thermally treating said first mixture of powders in order to decompose said calcium carbonate. claim 1 3. The method of claim 1 , wherein the preparation of the first mixture of powders comprises the steps of: claim 1 mixing the powders containing plutonium dioxide, calcium pyrophosphate, the silicone compound and optionally the compound(s) selected from alkaline metal compounds, hafnium compounds and lanthanide compounds, in acetone, evaporating the acetone to obtain a dry residue, and grinding said dry residue to a particle size of less than 50 xcexcm. 4. The method of claim 1 , wherein the preparation of the second mixture of powders comprises the step of: claim 1 mixing the first mixture of powders and the powdered fluorinated reagent in acetone, and evaporating the acetone. 5. The method of claim 1 , wherein the grinding of the second mixture of powders is performed in water and the method comprises between step b) and step c) an additional step of drying the ground second mixture of powders. claim 1 6. The method of claim 1 , wherein the fluorinated reagent(s) is added to the first mixture of powders in quantities corresponding to the stoichiometric proportions required to obtain the phosphosilicate apatite according to formula (I). claim 1 7. The method of claim 1 , wherein the calcium pyrophosphate is a xcex2 calcium pyrophosphate obtained by calcining anhydrous or dihydrate calcium hydrogen phosphate at approximately 1000xc2x0 C. claim 1 8. The method of claim 1 , wherein the plutonium dioxide is in the form of powder with an average particle size of 2 xcexcm to 50 xcexcm. claim 1 9. A method for preparing a phosphosilicate apatite having the formula (I): M t Ca x Ln y Hf w Pu zxe2x88x92w (PO 4 ) 6xe2x88x92u (SiO 4 ) u F 2 xe2x80x83xe2x80x83(I) wherein: M represents an alkaline metal, Ln represents at least one cation selected from lanthanides, and t, x, y, z, w and u are such that: 0xe2x89xa6txe2x89xa61, 8xe2x89xa6xxe2x89xa610, 0xe2x89xa6yxe2x89xa61, 0 less than zxe2x89xa60.5, 0xe2x89xa6w less than z, and 0 less than uxe2x89xa6y+2z, and the total number of positive charges provided by the alkaline metal, Ca, Ln, Hf and Pu cations are equal to 20+u; said method comprising: a) preparing a first mixture of powders containing plutonium dioxide, calcium pyrophosphate, a silicone compound and optionally one or more compounds selected from alkaline metal compounds, hafnium compounds and lanthanide compounds; b) preparing a second mixture of powders by mixing the first mixture of powders with at least one powdered fluorinated reagent; c) grinding said second mixture of powders to a particle size of less than 50 xcexcm; d) submitting the ground second mixture of powders to a sintering-reaction in a neutral or reducing atmosphere, at a pressure of 10 to 25 MPa and at a temperature of 1100 to 1500xc2x0 C. to obtain a sintered product. 10. The method of claim 9 , which further comprises the steps of: claim 9 grinding the sintered product, compressing the ground sintered product at a pressure of 100 to 500 MPa, and submitting the compressed sintered product to an annealing treatment in a neutral or reducing atmosphere, at atmospheric pressure and at a temperature of 1200 to 1600xc2x0 C. 11. The method of claim 9 , wherein the preparation of the first mixture of powders comprises the steps of: claim 9 mixing the powders containing plutonium dioxide, calcium pyrophosphate, the silicone compound and optionally the compound(s) selected from alkaline metal compounds, hafnium compounds and lanthanide compounds, in acetone, evaporating the acetone to obtain a dry residue, and grinding said dry residue to a particle size of less than 50 xcexcm. 12. The method of claim 9 , wherein the preparation of the second mixture of powders comprises the step of: claim 9 mixing the first mixture of powders and the powdered fluorinated reagent in acetone, and evaporating the acetone. 13. The method of claim 9 , wherein the grinding of the second mixture of powders is performed in water and the method comprises between step b) and step c) an additional step of drying the ground second mixture of powders. claim 9 14. The method of claim 9 , wherein the fluorinated reagent(s) is added to the first mixture of powders in quantities corresponding to the stoichiometric proportions required to obtain the phosphosilicate apatite according to formula (I). claim 9 15. The method of claim 9 , wherein the calcium pyrophosphate is a xcex2 calcium pyrophosphate obtained by calcining anhydrous or dihydrate calcium hydrogen phosphate at approximately 1000xc2x0 C. claim 9 16. The method of claim 9 , wherein the plutonium dioxide is in the form of powder with an average particle size of 2 xcexcm to 50 xcexcm. claim 9 17. A method for preparing a phosphosilicate apatite having the formula (I): M t Ca x Ln y Hf w Pu zxe2x88x92w (PO 4 ) 6xe2x88x92u (SiO 4 ) u F 2 xe2x80x83xe2x80x83(I) wherein: M represents an alkaline metal, Ln represents at least one cation selected from lanthanides, and t, x, y, z, w and u are such that: 0xe2x89xa6txe2x89xa61, 8xe2x89xa6xxe2x89xa610, 0xe2x89xa6yxe2x89xa61, 0 less than zxe2x89xa60.5, 0xe2x89xa6w less than z, and 0 less than uxe2x89xa6y+2z, and the total number of positive charges provided by the alkaline metal, Ca, Ln, Hf and Pu cations are equal to 20+u; said method comprising: a) preparing a first mixture of powders containing plutonium dioxide, calcium pyrophosphate, a silicone compound and optionally one or more compounds selected from alkaline metal compounds, hafnium compounds and lanthanide compounds; b) preparing a second mixture of powders by mixing the first mixture of powders with at least one powdered fluorinated reagent; c) grinding said second mixture of powders to a particle size of less than 50 xcexcm; d) submitting the ground second mixture of powders to a sintering-reaction at a temperature of 1100 to 1600xc2x0 C., in a neutral or reducing atmosphere, with application of pressure before or during the sintering-reaction. 18. A method for preparing a plutonium confinement block, said block comprising a phosphosilicate apatite matrix including the plutonium to be confined, said method comprising the step of preparing a phosphosilicate apatite by the method of claim 17 . claim 17 19. The method of claim 1 , wherein said alkaline metal comprises Na. claim 1 20. The method of claim 9 , wherein said alkaline metal comprises Na. claim 9 21. The method of claim 17 , wherein said alkaline metal comprises Na. claim 17
045284547	claims	1. A container for the storage and transportation and radioactive material comprising: an elongated vessel receiving said material and having a wall thickness and composition attenuating radioactive transmission therefrom, said vessel having an open end formed with an annular thickened portion defining a mouth communicating with the interior of said vessel; a radiation-shielding cover received in said mouth and having a plug-forming portion juxtaposed with a complementary seat-forming portion of said vessel at said mouth, and a flange extending outwardly from said plug-forming portion, said vessel being provided with a wall bore communicating at one end with the interior of said vessel and open at its opposite end, said radiation-shielding cover extending outwardly beyond said wall bore, said radiation-shielding cover being provided with a connecting bore registering with said wall bore; an obturating element received in said connecting bore and adapted to block said wall bore; a further cover secured directly to said vessel outwardly of said radiation-shielding cover and overlying said wall bore and said radiation-shielding cover, said radiation-shielding cover being formed with at least one control bore in the region of said seat-forming portion and covered by said further cover, said further cover defining with said radiation-shielding cover a control compartment into which said control bore and said connecting bore open and provided with means whereby the sealing effectiveness of said radiation-shielding cover can be monitored; said vessel being provided with a recess, said further cover being received in said recess against a shoulder formed by said vessel outwardly of said radiation-shielding cover; and another cover lying outwardly of said further cover and at least partly received in said recess. 2. The container defined in claim 1 wherein said other cover defines a second control compartment with said further cover whereby leakage from the interior of said vessel can be monitored. 3. The container defined in claim 1 wherein a control cover is secured to said vessel above said other cover and defines a second control compartment therewith whereby leakage from the interior of said vessel can be monitored. 4. The container defined in claim 1, claim 2 or claim 3 wherein said wall bore opens at said other end at said seat-forming portion.
052456447	claims	1. A spacer for a fuel assembly of a pressurized water reactor, comprising: a first group of first webs standing on end and extending parallel to one another in a plane, each of said first webs having longer sides and shorter sides, one of said longer sides of each of said first webs having a slit formed therein with a narrowed point and an impressed indentation; a second group of second webs standing on end and extending at right angles to said first webs, each of said second webs having longer sides and shorter sides, another of said longer sides of each of said second webs having a slit formed therein with a narrowed point and an impressed indentation; each respective one of said first webs being connected to a respective one of said second webs to form a grid by inserting said webs into each other at said slits and locking said narrowed point of one web into place in said impressed indentation of another web with a plug-in connection. a first group of first webs standing on end and extending parallel to one another in a plane, each of said first webs having longer sides and shorter sides, one of said longer sides of each of said first webs having a slit formed therein; a second group of second webs standing on end and extending at right angles to said first webs, each of said second webs having longer sides and shorter sides, another of said longer sides of each of said second webs having a slit formed therein; means for narrowing each of said slits disposed at a given first location; indentation means forced in each of said first and second webs at a given second location; and each respective one of said first webs being connected to a respective one of said second webs to form a grid by inserting said webs into each other at said slits and locking said narrowed point of one web into place in said impressed indentation means. 2. The spacer according to claim 1, wherein said impressed indentation of one web has lateral beads serving as guide surfaces for said longer side having said slit of the other web, in each of said plug-in connections. 3. The spacer according to claim 1, wherein each of said webs has two lateral pinches forming said narrowed point. 4. The spacer according to claim 2, wherein each of said webs has a pinch forming said impressed indentation, and said lateral beads are formed of material positively displaced by pinching. 5. The spacer according to claim 1, wherein said webs are welded together. 6. A spacer for a fuel assembly of a pressurized water reactor, comprising: 7. The spacer according to claim 6, wherein said indentation of one web is an impressed indentation having lateral beads serving as guide surfaces for said longer side having said slit of the other web. 8. The spacer according to claim 6, wherein said narrowing means are formed by two lateral pinches disposed at said first location in each of said first and second webs. 9. The spacer according to claim 7, wherein each of said webs has a pinch forming said impressed indentation, and said lateral beads are formed of material positively displaced by pinching. 10. The spacer according to claim 6, wherein said webs are welded together.
047599014	abstract	A nuclear reactor installation located in the cavity of a pressure vessel comprises a nuclear reactor with a core traversed from top to bottom by a cooling gas, a plurality of main loops consisting of heat exchangers and blowers, together with auxiliary loops for the removal of decay heat. According to the invention, the auxiliary loops contain no heat exchangers but a bundle of heat pipes independent of each other, the heat absorbing part of which is arranged in the pressure vessel cavity. As a heat sink, an external cooling water loop is provided for each bundle of heat pipes in which water is circulated. The cooling water is recooled in a cooling tower. In a preferred embodiment the heat transferring part of the heat pipes of each bundle terminates in an external water reservoir to which the cooling water loop is connected. For a certain period of time, in case of a sufficient volume of water, the decay heat may be removed only by evaporation from the water reservoir.
	claims	1. A heat transfer cask comprising:shielding defining an internal cavity and limiting ionizing radiation from passing from the cavity to an environment surrounding the heat transfer cask;a heat transport path including a heat pipe extending from inside the shielding to outside the shielding;a heater to warm the cavity; anda convection jacket surrounding the cavity, wherein the convection jacket is configured to distribute heat evenly within the cavity, and wherein the heater extends into the convection jacket. 2. The cask of claim 1, wherein the heat transport path includes a directional change through the shielding to block the ionizing radiation. 3. The cask of claim 1, further comprising:nuclear material contained within the cavity, wherein the nuclear material is at least one of fresh nuclear fuel, spent nuclear fuel, radiation sources, irradiated waste, and radioactive-contaminated waste. 4. The cask of claim 3, wherein the heat transport path is configured to transport heat outside the cask so that the cavity does not exceed 650° C. 5. The cask of claim 4, wherein the heat transport path includes at least 20 1 kW heat pipes. 6. The cask of claim 1, further comprising:a damper enclosure at an end of the cask, wherein the heat transport path extends into the damper enclosure, and wherein the damper enclosure can be opened to enhance fluid convection about the heat transport path and closed to limit fluid convection about the heat transport path. 7. The cask of claim 1, further comprising:a convection jacket surrounding the cavity, wherein the convection jacket is configured to distribute heat evenly within the cavity. 8. The cask of claim 7, wherein the convection jacket contains only metal sodium configured to melt and circulate to distribute the heat evenly within the cavity. 9. The cask of claim 7, wherein the heat transport path has an end in the convection jacket. 10. The cask of claim 1, further comprising:a damper enclosure at an end of the cask, wherein the heat transport path extends from the convection jacket into the damper enclosure, and wherein the damper enclosure can be closed to limit fluid convection about the heat transport path when the heater is heating the convection jacket. 11. A heat transfer cask for storing nuclear material below 650° C., the cask comprising:shielding defining an internal cavity and limiting ionizing radiation from passing from the cavity to an environment surrounding the heat transfer cask; anda heat transport path having a first closed end inside the shielding to and a second closed end outside the shielding such that no fluid exits the heat transport path, wherein the heat transport path is shaped so that no straight line passes through both the first and the second ends of the heat transport path and not the shielding, and wherein the cask is fabricated only of materials configured to maintain their chemical identities when exposed to ionizing radiation from spent nuclear fuel. 12. The heat transfer cask of claim 11, wherein the heat transport path is at least one of a heat pipe and a solid conductive rod. 13. The heat transfer cask of claim 11, further comprising:a convection jacket surrounding the cavity, wherein the heat transport path extends into the convection jacket, wherein the convection jacket is configured to melt by 200° C. and distribute heat evenly within the cavity. 14. The cask of claim 13, further comprising:a heater to warm the cavity, wherein the heater extends into the convection jacket. 15. A method of storing nuclear fuel in a heat transfer cask including, shielding defining an internal cavity and limiting ionizing radiation from passing from the cavity to an environment surrounding the heat transfer cask, a convection jacket surrounding the cavity and configured to melt by 200° C. and distribute heat evenly within the cavity, and a heat transport path from inside the shielding into the convection jacket and to outside the shielding, the heat transport path being shaped so that no straight line internal to the heat transport path passes through both ends of the heat transport path, the cask being fabricated only of materials configured to maintain their chemical identities when exposed to ionizing radiation from spent nuclear fuel, wherein the method comprises:loading fresh fuel from the internal cavity of the cask into a reactor; andunloading the spent fuel or nuclear material from the reactor into the internal cavity of the cask. 16. The method of claim 15, wherein the cask is not closed during or between the loading and unloading. 17. The method of claim 15, further comprising:activating a heater in the cask to warm the fresh fuel to at least 200° C.
	description	The present application is a continuation of U.S. application Ser. No. 10/060,909, filed on Jan. 30, 2002, now U.S. Pat. No. 6,840,640, which is a continuation of PCT/EP00/07258, filed on Jul. 28, 2000. PCT/EP00/07258 claimed priority of German Patent Application No. 199 35 568.1, filed on Jul. 30, 1999, and German Patent Application No. 299 15 847.0, filed on Sep. 9, 1999. The content of all of the above applications is hereby incorporated by reference. 1. Field of the Invention The invention relates to a multi-mirror-system for an illumination system, especially for lithography with wavelengths ≦193 nm comprising an imaging system. 2. Description of the Related Art EUV-lithography constitutes one of the most promising candidates for next generation lithography. The evolution of semiconductor fabrication demands reduced feature sizes of 50 nm and beyond. This resolution is obtained by the application of a short wavelength of 13.5 nm and moderate numerical apertures of 0.2 to 0.3. The image quality of the lithography system is determined by the projection optics as well as by the performance of the illumination system. Illumination system design is one of the key challenges of EUV lithography. In today's lithographic systems, the illuminator has to deliver invariant illumination across the reticle field. For EUV, several additional requirements have to be addressed. EUV imaging systems need to be realized as reflective optical systems. For this reason, an unobscured pupil and a highly corrected image field can only be achieved in a small radial range of the image. Hence the field shape is a ring-field with high aspect ratio of typically 2 mm (width)×22-26 mm (arc length) at wafer level. The projection systems operates in scanning mode. EUV illumination systems will in general be non-centred systems formed by off-axis segments of aspherical mirrors. The reflectivity of multilayer-coated surfaces is approximately 70% for normal incidence and 90% for grazing incidence. In order to maximize throughput, the number of reflections has to be minimized and grazing incidence elements should be used whenever possible. In order to achieve the requirements of the illumination system with a limited number of optical components, the complexity of the components has to be increased. Consequently, the surfaces will be segmented or aspherical. The shape and size of aspherical mirrors and segmented elements, together with stringent requirements for the surface quality put a major challenge on manufacturing these components. Several EUV-light sources are currently being discussed. They differ in system aspects, but also in important illuminator-related aspects. System aspects are e.g. output power, repetition rate, footprint. For the illumination system size and divergence of the radiating plasma, radiation characteristics and geometrical vignetting are relevant. The illumination design has to account for these properties. It is well known from basic physics that the étendue is invariant in optical systems. The étendue delivered by the source has to be smaller than the étendue of the illuminator, otherwise light will be lost. For current sources, however, the étendue is approximately one order of magnitude smaller, therefore either field or pupil of the optical system is not filled completely. In addition, the ring-field with high aspect ratio requires an anamorphotic étendue, which has to be formed by the illuminator. According to Helmholtz-Lagrange, the product of field A and numerical aperture NA is invariant in classical optical systems. For unobscured and circular pupils the Helmholtz-Lagrange-Invariant HLI or étendue can be written as:étendue=A·π·NA2 (1) In general, the invariance of the étendue can be interpreted as the optical equivalent to the invariance of the phase space volume in conservative systems. The étendue can be written as a volume integral in four dimensions,étendue=∫F(x,y,Px,Py)dxdydPxdPy (2)with the function F describing the occupied volume in phase space and P=(n sin θ cos φ,n sin θ sin φ,n cos θ)the vector of optical direction cosines, which corresponds to the pupil coordinates. For centred systems, the optical direction cosine integration in equation (2) can be written in polar coordinates (θ, φ): e ' ⁢ tendue = ∫ F ⁡ ( x , y , θ , φ ) ⁢ ⅆ A ⁢  ∂ ( P x , P y ) ∂ ( θ , φ )  ⁢ ⅆ θ ⁢ ⅆ φ = ∫ F ⁡ ( x , y , θ , φ ) ⁢ ⅆ A ⁢ ⁢ sin ⁢ ⁢ θ ⁢ ⁢ cos ⁢ ⁢ θ ⁢ ⅆ θ ⁢ ⅆ φ ( 3 ) The illumination field at the reticle is arc-shaped with dimensions of approx. 8 mm×88 mm. Thus the étendue to be provided by the illumination system has to be almost isotropic in angular domain, but highly anamorphotic in space domain with an aspect ration of 1:10. The different light sources, however, show an almost isotropic behaviour in space as well as in angular domain. In addition, the étendue of all known light sources is too small, although an optimum collection efficiency is assumed. In EUV illumination systems it is therefore essential to transform the étendue of the light source without changing the isotropy in angular domain. Array elements offer the most promising methods to transform the étendue. With optical array elements the field formation with high aspect ratio as well as the filling of the required aperture can be achieved. The étendue is not increased, but only transformed by the introduction of a segmentation in the entrance pupil. Examples for array elements are the ripple-plate (an array of cylindrical lenses) and the fly's eye-integrator. Both are capable of forming a field with high aspect ratio and introduce a segmentation in the entrance pupil. Partial coherent image simulations show that, the influence of the segmentation of the pupil can be tolerated, as far as a reasonable number of segments is chosen. Illumination systems with fly's-eye integrator are described in DE 199 03 807 A1 and WO 99/57732, the content of said applications is incorporated herein by reference. Illumination systems with ripple plates are known from Henry N. Chapman, Keith A. Nugent, “A novel Condensor for EUV Lithography Ring-Field Projection Optics”, Proceedings of SPIE 3767, pp. 225-236, 1999. The content of said article is also fully incorporated herein by reference. The illumination system has to be combined with the lens system and it has to meet the constraints of the machine layout The mechanical layout of non-centred reflective systems strongly depends on the number of mirrors and the folding angles. Within this setup, the mirrors and special components must be mounted with tight tolerances. Heat load and natural frequencies of the frame structure have to be considered. In EUV, each reflection will suffer from 30% light loss. The light is absorbed or dissipated leading to a heating of the mirrors. To avoid deformations of the optical elements as well as the mechanical structure, a cooling of mirrors is required. This is especially challenging because the complete optical system has to be under vacuum and hence only conduction can be used for cooling. Furthermore in an illumination system for lithography it is desirable to introduce means for cutting off the field e.g. by a field stop. An illumination system for lithography with a field stop is shown in U.S. Pat. No. 4,294,538. The content of said document is incorporated herein fully by reference. The system according to U.S. Pat. No. 4,294,538 comprises a slit plate on which an arcuate image of the light source is formed. By varying the radial length and the length in direction of the circular arc of the opening of the slit it is possible to adjust the radial length and the length in the direction of the circular arc of the arcuate image of the light source on a mask. Therefore the slit plate can also be designated as a field stop. Between the slit plate and the mask there are two mirrors arranged for imaging the arc-shaped field in the plane of the slit plate onto a reticle-mask. Since the illumination system known from U.S. Pat. No. 4,294,538 is designed for a light source comprising a ultra high tension mercury lamp emitting light in the visible region the system is totally different to a illumination system for wavelengths ≦193 nm. For example said system has no means for enhancing the étendue of the light source e.g. by raster elements of a fly's-eye integrator, which is essential for EUV-systems. The mirrors according to U.S. Pat. No. 4,294,538 are impinged by the rays travelling through the system under an angle of 45°, which is not possible in EUV-systems, since normal incidence mirrors in EUV-systems are comprising more than 40 pairs of alternating layers. A large number of alternating layers leads to phase effects if the mean angle of incidence becomes more than 30° or is lower than 70°. Using an angle of incidence of 45° in an EUV-system as in the state of the art would lead to a total separation of s- and p-polarisation and one of both polarisation is lost completely according to Brewster law. Furthermore such a mirror would function as a polarizing element. Another disadvantage of the system according to U.S. Pat. No. 4,294,538 are the rays impinging the reticle in the object plane telecentric, which is not possible in EUV-systems using a reflection mask. Furthermore the system known from U.S. Pat. No. 4,294,538 is a 1:1 system. This means that the field stop in the object plane of the imaging System has the same size as the field in the image plane. Therefore the field stop has always to be moved with the same velocity as the reticle in the image plane. Furthermore said illumination system should be applicable in high throughput systems working with much higher velocities of reticle and mask than conventional systems e.g. systems known from U.S. Pat. No. 4,294,538. Object of the invention is to provide an imaging system imaging an object, e.g. a field stop into an image, e.g. a reticle-mask for an illumination system for lithography with wavelengths ≦193 nm. Especially losses should be minimized, while the quality of the image especially regarding edge sharpness in scanning direction should be as high as possible. Said object of the invention is solved in a first embodiment by a multi-mirror-system comprising an imaging system with at least a first and a second mirror, whereby said first mirror and said second mirror are arranged in the optical path of the imaging system in such a position and having such a shape, that the edge sharpness of the arc-shaped field in the image plane is smaller than 5 mm, preferably 2 mm, most preferably 1 mm in scanning direction. In an advantageous embodiment the edge sharpness of the arc-shaped field in the image plane is smaller than 5 mm, preferably 2 mm, most preferably 1 mm also in the direction perpendicular to the scanning direction. While the field in the image plane is always arc-shaped, in an first embodiment of the invention the object in the object plane is also an arc-shaped field; which means that the inventive imaging system is not comprising any field forming components. Advantageously the rays travelling from the object plane to the image plane in the imaging system are impinging the first and the second mirror defining a first and a second used area on the mirrors, whereby the rays are impinging the first and the second mirror in the used area with an incidence angle relative to the surface normal of the mirror ≦30° or ≧60°, especially ≦20° or ≧70°, in order to minimize light losses in the system. To move the field stop in the object plane and the reticle in the image plane of the imaging system with different velocities the magnification ratio of the imaging system is unequal to 1. In a preferred embodiment the inventive imaging system is a non centred system. Advantageously an aperture stop is located on or close to the plane conjugate to the exit pupil of the imaging system. Preferably the first and/or the second mirror of the imaging system is an aspheric mirror. In a preferred embodiment of the invention the first mirror is a concave mirror having a nearly hyperbolic form or a nearly elliptic form and is defining a first axis of rotation. Furthermore also the second mirror is a concave mirror having a nearly hyperbolic form or a nearly elliptic form and is defining a second axis of rotation. Preferably the first and the second mirror are comprising a used area in which the rays travelling through the imaging system are impinging the first and the second mirror; the used area is arranged off-axis in respect to the first and second axis of rotation. In advantageous embodiment the first axis of rotation and the second axis of rotation subtend an angle γ. Said angle γ is calculated from a COMA-correction of the system. The first mirror and the second mirror are defining a first magnification for the chief ray travelling through the centre of the field and the centre of the exit pupil, a second magnification for the upper COMA ray travelling through the centre of the field and the upper edge of the exit pupil and a third magnification for the lower COMA ray travelling through the centre of the field and the lower edge of the exit pupil. If the system is COMA corrected the first, the second and the third magnification are nearly identical. Said condition defines the angle γ between the first and the second axis of rotation. In an second embodiment of the invention a multi-mirror-system for an illumination system with wavelengths ≦193 nm is comprising an imaging system, whereby said imaging system comprises at least a first mirror and a field forming optical component In such an embodiment of the invention the field in the object plane can be of arbitrary shape, e.g. a rectangular field. In case of a rectangular field the rectangular field is formed into an arc-shaped field in the image plane by the field forming optical component of the imaging system. The advantage of the second embodiment of the invention is the fact, that no extra optical components for forming the field in the light path arranged before the inventive multi-mirror-system are necessary. This reduces the total number of mirrors in the illumination system and therefore the losses within the illumination system. Preferably the aforementioned field forming component of the second embodiment comprises at least one grazing incidence mirror. Grazing incidence mirrors have the advantage that they must not be coated, whereas normal incidence mirrors in the EUV-range are always multilayer systems with high losses. In a preferred embodiment the field forming component comprises two mirrors, a first grazing incidence mirror with positive optical power and a second grazing incidence mirror for rotating the field. Another preferred embodiment employs a single grazing incidence field lens with negative optical power to achieve an arc-shaped field with the desired orientation. Apart from the imaging system the invention provides an illumination system, especially for lithography with wavelengths ≦193 nm with a light source, a multi-mirror system comprising an imaging system, whereby the imaging system comprises an object plane. The illumination system further comprises an optical component for forming an arc-shaped field in the object plane of the multi-mirror-system, in the light path arranged before the multi-mirror system. The multi-mirror-system is a system according to the invention for imaging the field from the object plane into the image plane of the imaging system. To enhance the étendue said illumination system could comprise at least one mirror or one lens which is or which are comprising raster elements for forming secondary light sources. The aforementioned illumination system could be used in an EUV projection exposure unit comprising a mask on a carrier system, said mask being positioned in the image plane of the imaging system, a projection objective with an entrance pupil, said entrance pupil is situated in the same plane as the exit pupil of the illumination system and a light sensitive object on a carrier system. In FIG. 1 an EUV-illumination system comprising an inventive imaging system 1 comprising an object plane 3, a first mirror 5, a second mirror 7 and an image plane 9 is shown. In the object plane 3 the field stop of the system is located. Furthermore the field in the object plane 3 is already arc-shaped. The imaging system 1 images the arc-shaped field from the object plane 3 into the image plane 9. In the image plane 9 the reticle or mask of the EUV-illumination system is located. Also shown is the exit pupil 10 of the imaging system 1, which is identical with the exit pupil of the total EUV-illumination system. The exit pupil 10 falls together with the entrance pupil of the projection optical system. Furthermore the EUV-illumination system shown in FIG. 1 comprises a light source 12, a collector 14, means 16 for enhancing the étendue of the light source 12 and field forming mirrors 18, 20 for forming the arc-shaped field in the object plane 3 of the imaging system 1. Also shown are a first plane 40 conjugate to the exit pupil 10 and a second plane 42 conjugate to the exit pupil 10. Furthermore the distance eP0 between first field forming mirror 18 and the first plane 40 conjugated to the exit pupil 10, the distance e01 between the first 18 and the second 20 field forming mirror, the distance SE1′ between the second field forming mirror 20 and the second plane 42 conjugate to the exit pupil 10, the distance SR1′ between the second field forming mirror 20 and the object plane 3 and the distance SE2 between the second plane 42 conjugate to the exit pupil 10 and the first imaging mirror 5 is depicted. Throughout the system examples shown hereinafter some parameters remain constant The design principles as shown below however, can also be applied to other sets of parameters. In all embodiments shown in this application the incidence angle at the image plane 9 of the imaging system is 6° and the numerical aperture at the image plane 9 is NA=0.05. It corresponds for example to a NA=0.0625 of the projection lens and a σ=0.8. The projection lens arranged in the light path after the EUV-illumination system has typically a 4×-magnification and thus NA=0.25 at the light sensitive object e.g. the wafer of the EUV-projection exposure unit. FIG. 2 shows the EUV-illumination system depicted schematic in FIG. 1 in greater detail. Same components as in FIG. 1 are designated with the same reference numbers. The system according to FIG. 2 comprises a light source 12 and a collector-mirror 14. Regarding the possible EUV-light sources reference is made to DE 199 038 07 A1 and WO 99/57732, the content of said documents is incorporated herein by reference. The collector mirror 14 of the system according to FIG. 2 is of elliptical shape. The means 16 for enhancing the étendue comprises two mirrors with raster elements 30, 32 so called fly-eyes integrators. The first mirror with raster elements 30 comprises an array of 4×64 field facets; each field facet being of plane or elliptical, toroidal or spherical shape (R≈−850 mm). The second mirror with raster elements 32 comprises an array of 16×16 pupil facets or a spherical or hexagonal grid with pupil facets, each pupil facet being of hyperbolic, toroidal or spherical shape (R≈−960 mm). The second mirror 32 is located in a plane conjugate to the exit pupil 10 of the illumination system. An illumination system with a first and a second mirror comprising raster elements as described before is known from DE 199 038 07 A1 and WO 99/57732; the content of said applications is incorporated herein by reference. For forming the arc shaped field in the object plane of the imaging system comprises two field forming mirrors 18, 20. The second field forming mirror 20 is a grazing incidence mirror. In principle one mirror, here the mirror 20, would be sufficient for field forming. But mirror 18 is required to control the length of the system and the size of the pupil facets. In order to achieve a large field radius of ≈100 mm mirror 20 must have low optical power. The size of the field and the pupil facets are related to the étendue of the system. The product of the size of the field facets and the size of the pupil plane is determined by the étendue. The pupil plane is a first plane 40 conjugate to the exit pupil 10 of the illumination system. In said plane the second mirror with raster elements 32 is located. Due to the aforementioned relation restrictions to the size of the field facets and the pupil facets are given. If the magnification for the pupil facets is very large, i.e. the pupil facet is very small, field facets become very large. To avoid large magnification of the imaging of the pupil facets into a second plane 42 conjugate to the exit pupil 10 of the system either the distance between mirror 20 and the second mirror with raster elements 32 increases or an additional mirror 18 has to be introduced. The first field forming mirror 18 has almost all power of the imaging system consisting of a first field forming mirror 18 and a second mirror 20 for imaging the pupil facets of the second field forming mirror with raster elements 32 into the second plane 42 conjugate to the exit pupil 10 of the system. The data for the first field mirror 18 and the second field mirror 20 are given in table 1: TABLE 1Data for the first and the second field mirrorfirst field mirror 18second field mirror 20shapehyperbolaellipsoidf≈1616 mm≈605 mmincidence angle versus7°75°surface normal(grazing incidence)conic section layoutfor pupil imagingfor pupil imagingβpupil imaging7.46429−0.05386 The magnification between the first plane 40 conjugate to the exit pupil 10 and the second plane 42 conjugate to exit pupil 10 is β40→42≈−0.4. The field radius of the arc-shaped field in the object plane 3 is controlled by the second field mirror 20. If the magnification βimage=−1 of the imaging system and RField=100 mm the field radius to be formed by the second field forming mirror 20 is RObj=−100 mm. There are three means to control the radius RObj: The optical power, see table 1, f≈605 mm, the chief ray distance between the second field forming mirror 20 and the object plane 3: SR1′≈250 mm and the grazing incidence angle. With the further values for the system layout eP0=1400 mm e01=1550 mm SE1′≈637 mm SF2≈−262.965 mm the system can be derived with first order optical formulas. In the second plane 42 conjugate to the exit pupil 10 an accessible aperture stop for the illumination system could be located. Also shown in FIG. 2 is the inventive multi-mirror-system comprising an imaging system 1 with a first 5 and a second 7 imaging mirror for imaging the arc-shaped field from the object plane 3, which is conjugate to the field plane, into the image plane 9, which corresponds to the field plane of the illumination system and in which the reticle or mask of the illumination system is located. The conjugate field plane 3 could be used as a plane for reticle masking. Said plane is located near to the second field forming mirror 20 at the limit for construction, e.g. SR′≈250 mm chief ray distance for ≈15° grazing incidence reflection on the mirror. The field in the conjugate field plane which is the object plane 3 is arc-shaped by field forming mirror 20, thus rema blades need to be almost rectangular. Small distortions of a following rema system can be compensated for. Since all mirrors of the illumination system have positive optical power, the field orientation in the conjugate field plane 3 after positive mirror 20 is mirrored by negative magnification of the inventive imaging system 1. The field orientation in the field plane 9 is then correct. Since the second field forming mirror 20 is off-axis in order to compensate the distortion due to this off-axis arrangement, the pupil facets have to be arranged on the second mirror with raster elements 32 on a distorted grid. With pupil facets arranged on a pre-distorted grid optimized pupils with respect to telecentricity and ellipticity can be achieved. The derivation of a multi-mirror-system comprising an imaging system for imaging a REMA-blade situated in the object-plane or REMA-plane 3 of the inventive multi-mirror-system into the image plane or field plane 9, wherein the reticle is situated will be described in detail hereinbelow. FIG. 3 shows in a schematic refractive view the elements of the inventive imaging system and abbreviations used in table 1. Furthermore components with reference numbers used in FIGS. 1 and 2 are designated with the same reference numbers. Furthermore in FIG. 3 is shown the virtual image 3′ of the field plane and the virtual image 10′ of the exit pupil. The imaging system according to FIG. 3 and table 2 is a hyperbolic-ellipsoid combination as a first order starting system. The data of the first order system are given in table 2. TABLE 2First order system layoutsecondHyperboloidimagingEllipsoidfirst Imaging mirror 5field imagingmirror 7pupil imaginge23650.0f768.1818f650.0Pupil imagingSE2−262.9651SE3−1049.8383SE2′−399.8383SE3′1706.6772β21.5205β3−1.6257Field imagingSR2−650.0SR3−4875.0SR2′−4225.0SR3′750.0β26.5β3−0.15385 For the results of table 2, well-known first-order lens-formulas where used, e.g. β = S ′ / S ⁢ ⁢ S i + 1 = S i - e i , i + 1 ⁢ ⁢ f = 1 / ( 1 / S ′ - 1 / S ) ⁢ ⁢ ( “ lens ⁢ - ⁢ maker ” ⁢ - ⁢ equation ) ( 4 ) where S and S′ stands for SE and SE′ or SR and SR′, respectively. In the next step designing an imaging system according to the invention the first order system shown in table 2 is optimized and COMA corrected. The first mirror 5 of the imaging system is a hyperbolic mirror, optimized for field imaging, which means imaging of the field in the REMA plane 3 into the field plane 9. The second mirror 7 of the imaging systems is an elliptical mirror optimized for pupil imaging, which means imaging of the second plane 42 conjugate to the exit pupil into the exit pupil 10. The overall system comprising the first 5 and the second 7 imaging mirror with abbreviations used in table 3 for the COMA corrected system is shown in FIGS. 3 to 5. Identical components as in FIG. 1, FIG. 2 and FIG. 3 are designated with the same reference numbers. Apart from the elements already shown in FIGS. 1 and 2 in FIG. 3; FIG. 4 shows: the axis of rotation 50 of the first imaging mirror 5 the axis of rotation 52 of the second imaging mirror 7 the centre 54 of the first imaging mirror the vertex of the first imaging mirror 56 the virtual image 3′ of the field plane 3 the centre 58 of the second imaging mirror the vertex of the second imaging mirror 60 the virtual image 10′ of the exit pupil 10 of the illumination system the chief ray 62 As is apparent from FIG. 4 the axis 50 of the hyperbolic mirror 5 and the axis of the elliptic mirror 7 subtend an angle γ. FIG. 5 shows in detail the first imaging mirror 5, which is in this embodiment a hyperboloid, of the inventive imaging system according to FIG. 4 and FIG. 6 the second imaging mirror 7 of the imaging system according to FIG. 4, which in this embodiment is a ellipse. The same elements as in FIG. 4 are designated in FIG. 5 and FIG. 6 with the same reference numbers. In FIG. 5 depicting the first hyperbolic mirror 5 the abbreviation used for the following equations calculating the parameters of the hyperbola are known: With positive angles ω2 and δ2 followsd2=−SR2·sin(ω2)=−SR2′·sin(δ2) (5)ω2=2α2−δ2 (6) ⇒ β field = SR2 SR2 ′ = sin ⁢ ⁢ ( 2 ⁢ ⁢ α 2 - δ 2 ) sin ⁢ ⁢ ( δ 2 ) = sin ⁢ ⁢ ( 2 ⁢ α 2 ) tan ⁢ ⁢ ( δ 2 ) - cos ⁢ ⁢ ( 2 ⁢ ⁢ α 2 ) ( 7 ) ⇒ δ 2 = arctan ⁡ ( sin ⁢ ⁢ ( 2 ⁢ ⁢ α 2 ) β field + cos ⁢ ⁢ ( 2 ⁢ ⁢ α 2 ) ) ( 8 ) Then the angle between incident chief ray and hyperbola axis is:ω2=2α2−δ2 Hyperbola Equation: z 2 a 2 - d 2 b 2 = 1 ; a = e 2 - b 2 ( 9 ) insertion and solution for b2 gives:b4+(z2+d2−e2)b2−d2=0 (10) ⇒ b 2 = - ( z 2 + d 2 - e 2 ) + ( z 2 + d 2 - e 2 ) 2 - 4 ⁢ d 2 ⁢ e 2 2 ( 11 ) with equation (5) andz2=e+SR2·cos(ω2) (12a) e = ( - SR2 · cos ⁢ ⁢ ( ω 2 ) - SR2 ′ · cos ⁢ ⁢ ( δ 2 ) ) 2 ( 12 ⁢ b ) the parameters defining the hyperbola can be calculated. In FIG. 6 depicting the second elliptic mirror 7 the abbreviations used for the following equations calculating the parameters of the ellipse are shown: With positive angles ω3 and δ3 followsd3=−SE3·sin(ω3)=+SE3′·sin(δ3) (13)ω3=2α3+δ3 (14) ⇒ - β pupil = SE3 ′ - SE3 = sin ⁢ ⁢ ( 2 ⁢ ⁢ α 3 + δ 3 ) sin ⁢ ⁢ ( δ 3 ) = sin ⁢ ⁢ ( 2 ⁢ ⁢ α 3 ) tan ⁡ ( δ 3 ) + cos ⁡ ( 2 ⁢ ⁢ α 3 ) ( 15 ) ⇒ δ 3 = arctan ⁡ ( - sin ⁡ ( 2 ⁢ ⁢ α 3 ) β field + cos ⁢ ⁢ ( 2 ⁢ ⁢ α 3 ) ) ( 16 ) The angle between incident chief ray and the hyperbola axis is defined by equation (14). Ellipsoid Equation: z 2 a 2 + d 2 b 2 = 1 ; a = e 2 + b 2 ( 17 ) insertion and solution for b2 gives:b4+(e2−z2−d2)b2−d2e2=0 (18) ⇒ b 2 = - ( e 2 - z 2 - d 2 ) + ( e 2 - z 2 - d 2 ) 2 - 4 ⁢ d 2 ⁢ e 2 2 ( 19 ) with equation (13) andz3=e−SE2·cos(ω3) (20a) e = ( SE3 · cos ⁢ ⁢ ( ω 3 ) + SE3 ′ · cos ⁡ ( δ 3 ) ) 2 ( 20 ⁢ b ) the parameters defining the ellipsoid can be calculated. Furthermore for ellipse and hyperbola following equations are well known: p = b 2 a ⁢ ⁢ curvature ⁢ ⁢ at ⁢ ⁢ node ⁢ ⁢ R = - p ( 21 ) ɛ = e a ⁢ ⁢ eccentricity ( 22 ) K=−ε2 conic constant (23) By COMA-correcting the first order system according to table 2 with an analytical calculation angle γ is determined. The COMA-correction uses for calculating γ the magnification of the imaging for the chief ray 62 and the coma-rays not shown in FIG. 46. The differences in magnifications can be reduced by minimization of the angle of incidence α3 (7°) and corresponding selection of α2. In this example the equations are minimized by the gradient method, which means choose a start system e.g. according to table 2, calculate the magnifications, change the angle α2 and calculate a new magnifications. From the difference in magnifications the next α2 can be calculated. Repeat this algorithm until difference in magnification for the chief ray and the upper and lower COMA-ray is less than e.g. 0.5%. The COMA-correction will be described hereinbelow in detail with reference to FIG. 7. Identical elements as in FIG. 1 to 6 are designated with the same reference numbers. Furthermore in FIG. 7 is shown the lower COMA ray 70. The calculation of the magnifications along the chief ray 62 is clear from the first order derivation. The calculation for the COMA or rim rays is shown with regard to the lower COMA ray 70. The COMA rays 70 for the imaging 3→3′ at the hyperbola is straight forward. The COMA or rim rays in the object plane 3 can be defined by the angles between rays and hyperbola axis: ω 2 ⁢ c = ω 2 ∓ arscin ⁢ ⁢ (  NA reticle · β rema , field  ) ( 24 ) with ω2 as shown in FIG. 5. The distances between the image points 3 and 3′ and the intersection point I2c of the mirror with the COMA or rim rays are given by hyperbola formulas in polar co-coordinates: S c = RI 2 ⁢ c _ = p 1 + ɛ ⁢ ⁢ cos ⁡ ( ω 2 ⁢ c ) ( 25 ) S′c= I2cR′=Sc+2a (26) α, ε, p: hyperbola parameters To calculate the lengths at the ellipse is more complicated, because the COMA or rim rays will not intersect in the plane 9 any more. However the magnification can be calculated approximately after calculating the intersection point I3c. Withω3c=δ2c±γ (27)for given γ, ω3c and thus the intersection point I3c can be calculated. WithLc= R′I3c (28)L′c= I3cR″ (29)the magnification of the rema-imaging system for the rim or COMA rays follows β c ± = L c ′ L c · S c ′ S c ( 30 ) As shown in FIG. 7 this derivation is not exact, because the rim rays will not intersect in the image plane 9 exactly. However, magnification can be calculated with reasonable accuracy, sufficient for a minimisation of the COMA error. An optimisation with the gradient method described before leads to the solution given in table 3. TABLE 3COMA corrected system starting fromthe system according to table 1.first imaging mirror 5second imaging mirror 7Design parameters (abbreviation see FIGS. 4 to 6)α216.328°α37.0°δ24.2034δ320.26125ω228.4526ω334.26125d2 = YDE309.6806d3 = YDE591.0246z21821.0739z31234.3716a1787.5a1378.2578b1590.3439b1328.5797e2392.5614e366.7021R−1414.9336R−1280.6922eps = e/a1.3385eps = e/a0.2661K = −eps{circumflex over ( )}2−1.7916K = −eps{circumflex over ( )}2−0.0708ZDE = z2 − a33.5616ZDE = a − z3143.8861 YDE and ZDE are the y- and z-components of the decenter vector of the nearest vertex point of the conic section. For a COMA-corrected system according to table 3 the magnification difference due to COMA is approx. 0.1% and is identical for the upper and the lower COMA-ray. The data for the magnification β of the inventive two mirror imaging system for the chief ray, the upper and lower COMA-ray after COMA correction is shown in table 4. TABLE 4Magnification β for chief ray, upper and lower COMA-rayComa-correction of Field imagingUpper COMA-rayChief rayLower COMA-rayMagnification1.00121.00001.0012 In FIG. 8 the COMA-corrected imaging system is shown. Identical elements as in FIGS. 1 to 7 are designated with the same reference numbers. In FIG. 8.1 the arc-shaped field in the field or reticle plane with carthesian coordinates x and y is shown. Reference number 100 designates a field point in the centre of the arc-shaped field and 102, a field point at the edge of the arc-shaped field. The y-axis denotes the scanning direction and the x-axis the direction perpendicular to the scanning direction. In FIG. 8.2 the spot diagram for a field point 100 and in FIG. 8.3 the spot diagram for a field point 102 of a COMA-corrected multi-mirror-system according to FIGS. 4 to 8 is depicted. The spot diagram is the diagram resulting from a multiplicity of rays travelling through the system with the aperture NAobject and impinging the field or reticle plane in a predetermined field point, e.g. the centre of the field 100. The aperture is NAobject=0.05 in the system described in FIGS. 4 to 8. As is apparent from the spot-diagrams 8.2 and 8.3 the edge sharpness EDS in scanning direction, corresponding to the y-axis of the arc shaped field, in COMA corrected system is smaller than 2 mm. The edge sharpness EDS of a system in scanning direction is defined as the difference of the points with the greatest value and the smallest value in y-direction for an edge field point, e.g. edge field point 102 as shown in FIG. 8.3. For further optimizing the inventive imaging system astigmatism and spherical aberration has to be considered. Nevertheless a balanced system can be found with only hyperbolic and elliptical mirrors. FIG. 9 and table 5 shows a system which is corrected for spot aberrations <1 mm in scanning direction. Because the rema blades are essentially required to avoid the overscan in scanning direction, it is sufficient to achieve the required performance in scanning direction; here in y-direction. In FIG. 9 the same elements as in FIGS. 1 to 8 are designated with the same reference numbers. In FIG. 9.1 and 9.2 the spot-diagrams for a point in the centre of the field 100 and for an edge point 102 is depicted. The optical data of the system according to FIG. 9 are shown in table 5. The embodiment according to FIG. 9 is again a 1:1 imaging system and is derived from the embodiment according to FIG. 8. TABLE 5System corrected for COMA, astigmation and spherical aberrationsecondimagingfirst imaging mirror 5Hyberbolamirror 7Ellipseα28.9395α36.4304δ21.9988δ320.5977ω215.8802ω333.4585d2 = YDE283.1433d3 = YDE587.5428a25949.4780a31371.5001b2942.2505b1329.5276e6637.2529e336.7028R−1455.0585R−1288.8396eps = e/a1.1156eps = e/a0.2455K = −eps{circumflex over ( )}2−1.2446K = −eps{circumflex over ( )}2−0.0603ZDE29.4941ZDE143.7641 The image plane 9 comprising the reticle is tilted with respect to the chief ray by 6°-angle of incidence. For a minimized spot aberration also the object plane 3 has to be tilted. In the example the optimized tilt angle of the object plane 3, where the field stop or rema has to be placed, is approximately 0.9768°. Also shown in FIGS. 8 and 9 are the complete first hyperbolic imaging 5 and the complete second elliptic imaging mirror 7 of the imaging system with the first axis of rotation 50 and the second axis of rotation 52. As is apparent from FIG. 9 the rays impinging the mirrors of the imaging system off-axis; this means that the used area of the two mirrors are situated off-axis with regard to the axis of rotation of the two mirrors. Also clearly shown the angle γ between the two axis of rotation. In FIG. 10 an even better performing imaging system than the system according to FIG. 8 is shown. The same reference numbers as for the system according to FIG. 9 are used. The system according to FIG. 10 is derived from a more balanced optimization. This time the magnification is β≈−0.85. The limiting aberrations in the imaging system according to the invention is COMA and astigmatism. For field imaging a mirror 5 near to conjugate pupil plane 42 is used. This mirror 5 is aimed not to affect pupil imaging. If one looks at the aberrations in a plane which contains the focus, for field points different from the focus there are field aberrations. That is the case of the hyperbola, which is actually limited by astigmatism. For a given field of view size the smaller the tilt angle of the hyperbola, the smaller the angle of the field objects and, therefore, the smaller the astigmatism. An elliptical mirror 7 is chosen for pupil imaging. The ellipse case is more complicated because the parameters are found to give stigmatic imaging at the centre of the exit pupil, not in the field plane 7. When used off axis for other conjugates different than the two geometrical foci, the ellipse introduces coma, and this is what can be seen in the field plane 7. Once more, the way of reducing this coma is minimising the tilt and balancing COMA between the first mirror 5 and the second mirror 7 of the imaging system. The spot diagrams for the centre field point 100 and an edge field point 102 for a system according to FIG. 10 are depicted in FIGS. 10.1 and 10.2. As is apparent from FIG. 10.2 the edge sharpness EDS for an edge field point is better than 1 mm in the scanning direction as well as in the direction perpendicular to the scanning direction. Said embodiment is a preferred embodiment since the required imaging performance of the imaging system is also achieved in the direction perpendicular to the scanning direction; here in the x-direction. The data of the system according to FIG. 10 are given in Code-V-format in table 6. TABLE 6Code V-table of a imaging system with β = −0.85Surface!Radiusdistance to next surfacetypS0 00DAR;ADE 6.0;S 0−369.481REFLS 0−110.093S6964.670REFL!first imaging mirror 5CONK−205.127DAR;ADE−19.23631;YDE149.7571;ZDE50.40653S 00ADE−36.0;S 0500.9524S 00ADE 10.0;S−898.38670REFL!Second imaging mirror 7CONK−0.2302684DAR;ADE 5.464502;YDE164.4807;ZDE−0.638CIR1000S 0−797S 00REFLBEN;ADE −6.0;CIR500SI 00!ReticleDARADE 6.0 In FIG. 11 a EUV-illumination system with a ripple-plate 200 as field-forming component and an multi-mirror-system comprising an imaging system 1 according to the invention is shown. The system comprising a light source 12, a collector unit 14, a ripple-plate 200 as a field-forming component for the arc-shaped field and a field mirror (202) is known from Henry N. Chapman et al. aa.O; the content of said article is incorporated herein by reference. The imaging system shown in FIG. 11 is identical to the imaging systems according to FIGS. 1 to 10. The same elements as in FIGS. 1 to 10 are designated with the same reference numbers. Other setups then those of FIG. 11 are possible, in which the light is not collimated before the ripple plate 200, but converging to a focal point. In this case the grooves of the ripple plate are not parallel, but conically, i.e. the prolongation of the grooves meet in one point corresponding to the focal point of the incident wave. The shape of the ripple plate 200 can be derived theoretically, but has to be optimized. The pupil formation with the ripple design leads to an elliptical illumination of the exit pupil after the illumination system corresponding to the entrance pupil of the lens system. Therefore an aperture stop is required in a conjugate pupil plane. This aperture stop will also lead to light less. The ellipticity of the pupil increases with the lateral coordinate, along the arc field perpendicular to scanning direction. The light loss has to be compensated for by shaping the ripple plate aspherically. Next, two examples of hyperbola-ellipsoid-combinations for the imaging mirrors 5, 7 are shown with β=−1.5. The first order system is analytically derived, as described before. The second system is optimized for a better performance in scanning direction. The parameters are given in tables 7 to 9: TABLE 7First-order parameters for βrema = −1.5 - system.secondfirst imagingimagingmirror 5Hyberboloidmirror 7Ellipsoide 23650.00f2495.9484f3721.5351pupil imagingSE2−271.5174SE3−1250.0000SE2′−600.0000SE3′1706.6772β22.2098β3−1.3653field imagingSR2−482.9048SR3−19011.2108SR2′−18361.2108SR3′750.0000β238.0224β3−0.0395 If one corrects the coma of the system of table 7 according to analytic solution of ellipsoid and hyperboloid, as shown before, a system as shown in table 8 and FIG. 12 results. The spot aberrations are shown in FIG. 12.1 and FIG. 12.2 for a centre field point 100 and an edge field point 102. TABLE 8COMA corrected systemfirst imaging mirror 5second imaging mirror 7α28.4600α36.5000δ20.4278δ329.9146ω216.4922ω342.9146d2 = YDE137.04894d3 = YDE851.1340α28939.1530α31478.3386b2945.3024b1441.2091e9411.8682e281.9172R−970.4282R−1424.5774eps = e/a1.0529eps = e/a0.1907K = −eps{circumflex over ( )}2−1.1086K = −eps{circumflex over ( )}2−0.0364ZDE = z − a9.9779ZDE = a − z280.9593 The embodiment according to FIG. 13 and table 9 is optimized to achieve spot aberration less than 1 mm in scanning direction: TABLE 9Optimized designfirst imaging mirror 5second imaging mirror 7α28.0302α36.2127δ20.1706δ330.3800ω216.2310ω342.8054d = YDE139.9744d = YDE848.9438R−967.1380R−1415.0130K = −eps{circumflex over ( )}2−1.1933K = −eps{circumflex over ( )}2−0.04913ZDE = z − a11.3839ZDE = a − z284.2995 In the following section an illumination system with an arbitrary field, e.g. a rectangular field in the object plane 3 is discussed. The schematic set-up for such systems are shown in FIGS. 14 and 15. In both examples the imaging system images a rectangular field 300 into an arc-shaped field 302. Consequently arc-shaped rema blades or field stop 304 have to be applied to compensate for the deformation induced by the imaging with grazing incidence field mirror 306 as shown in FIG. 16. Furthermore in FIG. 16 the clipping 308 in the image or rema-plane 9 is shown. The system according to FIGS. 14 and 15 comprises: an object plane 3 at least, a first imaging normal incidence mirror 5 and at least one grazing incidence mirror 306 for forming the arc-shaped field in the image plane 9. A realisation of a system with one grazing incidence mirror 306 is given in FIG. 17. To achieve the desired orientation for the ring field, a field lens with negative optical power is required. The radius of the arc-shaped field is approximately 138 mm, however, by the angle of incidence and the optical power of the first imaging mirror 5 almost any desired field radius is achievable. Table 10 gives the data for such a system, where for the magnification βimage=−1.2 was chosen. TABLE 10grazingimagingfirst imagingmirrormirror 5ellipsoid306hyperboloidα112.0α278.0e 12500.00f1382.1450f2−868.3020pupil imagingSE1−609.7360SE2523.8000SE1′1023.8000SE2′1320.2146β1−1.6791β22.5205field imagingSR1−810.6258SR2222.9651SR1′722.9651SR2′300.0000β1−0.8919β21.3455surface parametersδ127.9820δ214.2042ω151.9820ω238.2042e264.2854e434.1220d480.3602d323.9526b772.8280b172.8956a816.7680a398.2073p = R−731.2519p = R75.0687eps0.3236eps1.0902K−0.1047K−1.1885z639.8277z845.7300 The arcuate field is demonstrated in FIG. 17.1. A rectangular aperture was ray-traced through the system until the reticle plane. Here the arc-shaped field arises due to the grazing incidence reflection at the grazing incidence mirror 306. However, the spot diameter is in this un-optimized example about 10 mm. Due to the imaging with one normal incidence and one grazing incidence mirror, a large amount of coma is introduced, which can not be reduced effectively. A reduction of coma is possible by insertion of a second normal incidence mirror 7. An example is shown in FIG. 18, the corresponding data are given in table 11 (with βimage=−1.272). The illumination at reticle field is shown in FIG. 18.1. The system has capability to be optimized further to similar performance as system examples given before by similar straight forward optimization, which means proper selection of reflection and folding angles. TABLE 11secondgrazingfirst imagingimagingincidencemirror 5ellipsoidmirror 7hyperboloidmirrorhyperboloidα08.0α111.0α212.0e01450.0000e12500.000f0686.2745f11055.0641f2−868.302pupil imagingSE0−700.0360SE13455.9SE2523.8SE0′35000.0SE1′1023.8SE2′1320.2146β0−50.0β10.0296β22.5205field imagingSR0−914.8405SR12296.8290SR2222.9651SR0′2746.8290SR1′722.9651SR2′300.0β0−3.0025β10.3148β21.3455δ07.6903δ121.3810193242δ214.2042ω023.6903ω10.6189806758ω238.2042b1569.789b5838.1891964484b172.8956a1830.8348a16763.1000000000a398.2073p = R−1345.9639p = R−2033.3024973619p = R−75.0687eps0.5146eps1.0589128053eps1.0902K−0.2448K−1.1212963293K−1.1885e942.1881e17750.6612469375e434.122d367.5763d373.24505478583d323.9526z1779.9356z−16797.3226034857z845.73 1: imaging system 3: object plane=field plane 3′: virtual image of the field plane 5: first imaging mirror 9: image plane 10: exit pupil 10′: virtual image of the exit pupil 12: light source 14: collector 16: means for enhancing the entendu 18: first field forming mirrors 20: second field forming mirrors 30: first mirror with raster elements 32: second mirror with raster elements 40: first plane conjugate to the exit pupil 42: second plane conjugate to the exit pupil 50: axis of rotation of the first imaging mirror 52: axis of rotation of the second imaging mirror 54: centre of the first imaging mirror 56: vertex of the first imaging mirror 58: centre of the second imaging mirror 60: vertex of the second imaging mirror 62: chief ray 70: lower COMA ray 100: field point in the centre of the arc shaped field 102: field point at the edge of the arc shaped field 200: ripple plate 300: rectangular field 302: arc shaped field 304: field stop 306: grazing incidence mirror 308: clipping eP0: distance between first mirror and first plane conjugate to the exit plane e01: distance between first and second field forming mirror EDS: edge sharpness SE1′: distance between second field forming mirror and second plane conjugate to the exit pupil SR1′: distance between second field forming mirror and object plane SE2: distance between second plane conjugate to the exit pupil and first imaging mirror x: direction perpendicular to the scanning direction y: direction in scanning direction γ: angle between the axis of rotation 50, 52 fi: focal length of optical component i αi: angle of incidence of chief ray with respect of surface normal of mirror i βpupil: magnification for pupil imaging between conjugate pupil planes βfield: magnification for field imaging between conjugate field plane and reticle plane βi: magnification for the intermediate imaging at a single optical element, either for pupil or for field imaging (depending on context) R: field radius S: working distances SEi: working distance with respect to entrance pupil imaging between mirror i on object side SEi′: working distance with respect to entrance pupil imaging between mirror i on image side SRi: working distance with respect to field imaging between mirror i on object side SRi′: working distance with respect to field imaging between mirror i on image side eij: distance between optical element i and j ωi: angle between incident chief ray and rotation axis of optical element i δi: angle between reflected chief ray and rotation axis of optical element i a,b,e, ε, p, K: conic section parameters for individual mirror di: transversal co-ordinate of intersection point of chief ray with mirror i with respect to rotation axis zi: longitudinal co-ordinate of intersection point of chief ray with mirror i with respect to centre of conic section βc±: magnification for upper or lower coma or rim rays YDE, ZDE: decenter vector components as usual in optical design programs (e.g. CODE V).
	summary
	abstract	A radio-pharmaceutical pig for transporting a syringe containing a radio-pharmaceutical includes a first cylindrical member having a first tungsten body defining a first cavity therein. A second cylindrical member has a second tungsten body defining a second cavity therethrough and is capable of engagement with the first cylindrical member so that the first cavity is in substantial alignment with the second cavity. A third cylindrical member includes a third tungsten body defining a third cavity and is capable of engagement with the second cylindrical member so that the third cavity is in substantial alignment with the second cavity. The first cavity, the second cavity and the third cavity are shaped so as to be complimentary in shape of the syringe.
047773626	summary	TECHNICAL FIELD The invention relates generally to devices which characterize the effect of particle bombardment on electronic circuits or devices. In particular, the invention relates to devices for measuring extremely fast electrical waveforms produced when an atomic or subatomic particle strikes an electronic circuit or device. BACKGROUND OF THE INVENTION Atomic and subatomic particles, such as alpha particles, are constantly streaming through the universe and striking objects at random intervals. While more frequent in outer space, many of these particles exist in earth's atmosphere as well. When such a particle strikes a sensitive electronic circuit, it can generate unwanted electron-hole pairs which can upset the operation and output of the circuit. Either or both of two techniques can be used to accommodate these particles. First, the circuit can be shielded. This is not entirely satisfactory since a shield will stop only those particles having less than a certain energy level. Second, the circuit can be designed so as to compensate for the particular electrical waveform which a particle causes. This technique has not been completely satisfactory because the waveforms, which typically have rise times on the order of 5 picoseconds, are too fast to measure with today's technology. However, there have been recent advances in devices which can sample picosecond waveforms. These devices have almost exclusively used Josephson junctions to perform the sampling and have time resolutions that today approach 2 picoseconds. So far, Josephson samplers have mostly been used to investigate electrical waveforms of circuits on the same chip and in the same cryogenic environment as the samplers. Apparatus and techniques to allow connection of a Josephson sampler to an external environment without degrading the resolution of the sampling are now being made available as sampling applications have increased. With the advent of picosecond samplers, a controlled test environment can be established to methodically inject atomic or subatomic particles onto an electronic circuit or device. The resultant electrical waveforms produced by the bombarded electronic device can then be measured with high resolution and the electronic device can thus be re-designed for compensation. Control of the characteristics of the injected particles, such as, particle type, velocity, and angle of incidence, allows an electronic circuit or device to be tested and designed for a particular application whether in space or on earth. SUMMARY OF THE INVENTION The foregoing problem is obviated by the present invention which comprises: Apparatus for measuring the electrical waveform generated by an atomic or subatomic particle incident on an electronic device, comprising: means for detecting the incidence of the particle on the device a first time interval before the particle strikes the device; means for sampling a point on the said waveform at a second time interval following detection of the incidence of the particle by the means for detecting; and means for moving the sampling point timewise along the said waveform during succeeding particle incidences so that the means for sampling measures the entirety of the said waveform. The means for detecting is chosen to have as small an effect as possible on the path and energy of the particle, so that the particle will strike the device under test in substantially the same manner as it would in actual operation. Alternatively, the means for detecting should have a predictable effect on the path and energy of the particle so that such effect can be countered later on. After the electrical waveform is sampled at one point, the invention continues to detect succeeding particle strikes which, under controlled conditions, produce the same electrical waveform. Thus, the invention can sample different points of the waveform until the entire waveform is measured. It is advantageous to average several samples at each point in order to reduce the effects of noise and the like.
	abstract	The invention relates to a method for the computer-assisted analysis of the reliability of a technical system comprising a plurality of technical components. According to the method, the reliabilities of the components are respectively described by a component function that depends on at least one parameter and a parameter interval of the at least one parameter, which is associated with the components and influences the reliability of the components; a system reliability of the technical system is determined from the reliabilities of the components; a variation value is respectively determined for at least some of the components f&, constituting a value for the variation of the system reliability according to the variation of the parameter interval of the respective component; and an influence quantity relating to the influence of the respective components on the system reliability is respectively determined for at least some of the components from the variation value.

Subsets and Splits

No community queries yet

The top public SQL queries from the community will appear here once available.