Secondary image removal using a high-resolution X-ray transmission source

Abstract

The apparatus comprises a transmission X-ray source, which includes a window containing a target layer of at least one X-ray generating material, and an internal diaphragm configured to allow a first portion of the electron beam to collide with the target layer and to prevent a second portion of the electron beam from colliding with the target layer. The full width at half maximum of the first portion of the electron beam in the target layer is less than 1 micron. The window is spaced at a first distance D_1 from the internal diaphragm. The apparatus further comprises an X-ray detection system, which includes a scintillator, an optical assembly, at least one image sensor configured to receive visible light and generate an electrical signal in response to the received visible light, and an electric stage configured to controllably adjust the position of the scintillator so that it is spaced at a second distance D_2 from the window. (D2 2 ) / (D1+D2) 2 It is less than 0.2.

Description

[Technical Field]

[0001] Claim of priority This application claims priority to U.S. Patent Application No. 18 / 406851, filed on 8 January 2024, and U.S. Provisional Application No. 63 / 581225, filed on 7 September 2023, both of which are incorporated herein by reference in their entirety. [Background technology]

[0002] background field This application generally relates to a transmission X-ray source and an X-ray imaging system.

[0003] Explanation of related technologies In high-resolution transmission X-ray sources, a physical diaphragm can be used to reduce the area of ​​the X-ray target that the electron beam collides with (e.g., strikes). Such a diaphragm can shield a portion of the electron beam from reaching the X-ray target, thereby allowing the X-ray source to achieve an electron beam spot with a submicron diameter on the X-ray target. For example, Figure 1 schematically shows a cross-sectional view of a conventional transmission X-ray source 10. The conventional transmission X-ray source 10 has a diaphragm 12, and the electron beam 14 propagates along the electron beam propagation axis 15 and collides with an X-ray target 16 on the X-ray window 18. A first portion 14a of the electron beam 14 passes through the hole in the diaphragm 12 and collides with the X-ray target 16, generating primary X-rays 20 that propagate from the X-ray target 16 through the X-ray window 18 and out of the X-ray source 10. A second portion 14b of the electron beam 14 collides with the solid portion of the diaphragm 12, thus preventing it from colliding with the X-ray target 16. However, a second portion 14b of the electron beam 14 can generate secondary X-rays 22 by colliding with the solid portion of the aperture 12. For example, the electron beam 14 directly generates secondary X-rays 22 by colliding with the solid portion of the aperture 12. Additional secondary X-rays 22 can be generated by backscattered electrons from the X-ray target 16 colliding with the solid portion of the aperture 12. The angular distribution of secondary X-rays 22 emitted from the X-ray source 10 may be narrower than the angular distribution of primary X-rays 20 emitted from the X-ray source 10. In X-ray imaging using such an X-ray source 10, the secondary X-rays 22 can create a "secondary image" of the sample at the center of the tomographic data set, with smaller secondary images superimposed on larger "primary images".

[0004] Secondary images are present in most high-resolution X-ray sources with an aperture 12 and a micron-scale focal point (e.g., a spot size or width of 2 microns or more), but they are particularly pronounced for X-ray sources 10 with submicron focal spot sizes or widths (e.g., less than 1 micron), because the metallic X-ray target 16 (e.g., a tungsten film) that generates the primary X-rays 20 can be made thin (e.g., in the range of 500 nanometers to 2 microns). When operating such an X-ray source 10 at a higher acceleration voltage, the energy of most electrons is too high and interacts strongly with the thin metallic X-ray target 16, resulting in low primary X-ray generation and a high secondary-to-primary X-ray ratio. Furthermore, when operating such an X-ray source 10 with a smaller aperture to obtain a smaller spot size, more X-rays are shielded by the aperture 12, similarly increasing the secondary-to-primary X-ray ratio. For example, secondary X-rays 22 can reach up to 20% of the total X-rays, potentially leading to a significant decrease in image quality. Furthermore, secondary X-rays 22 may reduce the resolution of the X-ray imaging system.

[0005] Secondary X-rays 22 can be removed (e.g., shielded) by using an external aperture with an X-ray source having a larger spot size (e.g., a spot size of 2 microns or more). However, such external apertures are not used for most high-resolution applications. This is because (i) an external aperture can increase the distance from the source to the sample, reducing throughput, and (ii) increasing the minimum distance from the source to the sample necessitates increasing the overall length of the system to achieve higher resolution. For example, to achieve a geometric magnification of 1000x, if the minimum distance from the source to the sample is 2 millimeters, the overall length of the system will exceed 2 meters, and if the minimum distance from the source to the sample is 1 millimeter, the overall length of the stem will exceed 2 meters.

[0006] X-ray source manufacturers have devised a solution that utilizes "beam blanking" to move the electron beam 14 over the boundary separating two regions of a structured X-ray target 16 with different capabilities for generating X-rays 20, thereby subtracting the contribution of secondary X-rays 22 to the image by generating a separate "secondary" beam image (see, for example, U.S. Patent No. 10784069). However, such a solution also has its challenges. For example, this technique often sweeps the electron beam 14 between a tungsten target region and a non-target region with a low atomic number (e.g., diamond, beryllium). Since the amount of secondary X-rays 22 resulting from backscattered electrons from the X-ray target 16 depends on the target material being impacted, the target region and the non-target region do not have a 1:1 equivalence with respect to secondary X-rays 22. Furthermore, the deflection of the electron beam 14 from the target region to the non-target region can create differences in the location and amount of secondary X-rays 22 generated. Furthermore, the profiles of the electron beam 14 on the metal target layer 16 and the profiles of the deflected electron beam 14 on the low atomic number (Z) non-target material are different, resulting in a difference that cannot be subtracted in a simple way. In such cases, the image generated by the secondary X-rays 22, although reduced, still remains and can cause problems.

[0007] Furthermore, the secondary X-ray problem is exacerbated by the use of standard X-ray detectors. Most microcomputed tomography (micro-CT) imaging systems use detectors (e.g., flat-panel detectors) with pixel sizes in the range of approximately 50 to 100 microns. Due to the large pixel size of these detectors, detectors spaced far from the X-ray source 10 are used to achieve high-resolution imaging. For example, to achieve a resolution of 0.5 microns for a 50-micron detector pixel, the detector is spaced at least 100 millimeters from the sample. When the distance from the X-ray source 10 is small (e.g., less than 10 millimeters), the ratio of secondary X-rays 22 to primary X-rays 20 is low, but as the distance from the X-ray source 10 to the detector increases, the ratio of secondary X-rays 22 to primary X-rays 20 increases. [Overview of the project] [Means for solving the problem]

[0008]

number

[0009] In another embodiment disclosed herein, the apparatus comprises an X-ray source, a sample stage configured to support and controllably move a sample, and at least one X-ray detector. The X-ray source includes an electron beam source configured to produce an electron beam, at least one aperture, at least one target, and a window. The at least one aperture is configured to allow a first portion of the electron beam to pass through the at least one aperture and to prevent a second portion of the electron beam from passing through the at least one aperture. The at least one target includes at least one X-ray generating material configured to produce a first divergent X-ray beam in response to an impact by the first portion of the electron beam. The at least one aperture is configured to produce a second divergent X-ray beam in response to an impact by a second portion of the electron beam and / or a collision by electrons backscattered from at least one target. The window is configured to emit the first X-ray beam and the second X-ray beam, both of which are substantially centered on an X-ray axis substantially perpendicular to the outer surface of the window. At least one X-ray detector is configured to receive X-rays from a first X-ray beam that has passed from the X-ray source through the region of interest of the sample, along the X-center beam axis, and the angle Φ between the center beam axis and the X-ray axis is 6° or greater.

[0010] In another embodiment disclosed herein, the apparatus comprises a transmission X-ray source configured to produce a primary X-ray beam having a first cone angle Θ1 and a secondary X-ray beam having a second cone angle Θ2 smaller than the first cone angle Θ1, wherein both the primary and secondary X-ray beams diverge and are symmetric with respect to the X-ray axis. The apparatus further comprises a sample stage configured to support and controllably move a sample. The apparatus further comprises at least one X-ray detector, the at least one X-ray detector having a region configured to receive X-rays transmitted from the transmission X-ray source through a region of interest of a sample along a beam axis that is a non-zero angle Φ with respect to the X-ray axis. The at least one X-ray detector is configured to generate an electrical signal indicating the X-rays received in the region.

[0011] In another embodiment disclosed herein, the apparatus comprises an electron beam source configured to generate an electron beam, an aperture, and a target. The aperture includes a first solid portion comprising at least one first atomic element having a first atomic number greater than 20 (e.g., at least 50% of the first solid portion is at least one first atomic element), a hole extending through the first portion, and a second solid portion covering at least one surface of the first solid portion (e.g., at least one layer coated on a first surface region facing the electron beam source, a second surface region at least partially extending into the hole, and / or a third surface region facing away from the electron beam source). The second solid portion comprises at least one second atomic element having a second atomic number less than 15 (e.g., at least 50% of the second solid portion is at least one second atomic element, and is configured to prevent at least 50% of the electron beam impacting the second solid portion from reaching the first solid portion). The target is configured to generate X-rays in response to collisions with electrons of the electron beam. The aperture is configured to allow a first portion of the electron beam to pass through the hole and collide with the target, while shielding a second portion of the electron beam from passing through the hole. The second portion of the electron beam collides with a second solid portion. In certain embodiments, the apparatus further comprises a vacuum chamber containing a vacuum region, an electron beam source configured to transmit an electron beam into the vacuum region, a vacuum chamber containing the electron beam source, an aperture, and a target. For example, the vacuum chamber may include a window that separates the vacuum region from a non-vacuum region outside the vacuum chamber. The window is substantially composed of one or more atomic elements having atomic numbers less than 15, and the target includes at least one metallic layer that is in thermal communication with the surface of the window facing the vacuum region. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic cross-sectional view of a conventional transmission X-ray source, which includes an aperture and an electron beam that strikes an X-ray target on an X-ray window. [Figure 2A]1 is a cross-sectional view schematically illustrating two exemplary transmissive X-ray sources in accordance with certain embodiments described in the present specification. [Figure 2B] 1 is a cross-sectional view schematically illustrating two exemplary transmissive X-ray sources in accordance with certain embodiments described in the present specification. [Figure 3A] 2 is a cross-sectional view schematically illustrating another exemplary transmissive X-ray source in accordance with certain embodiments described in the present specification. [Figure 3B] 3A and 3B are diagrams showing an X-ray image and an X-ray lineout of a portion of an exemplary first diverging X-ray beam and an exemplary second diverging X-ray beam 240 in accordance with certain embodiments described in the present specification. [Figure 3C] 4A and 4B are diagrams showing an X-ray image and an X-ray lineout of a portion of an exemplary first diverging X-ray beam and an exemplary second diverging X-ray beam 240 in accordance with certain embodiments described in the present specification. [Figure 3D] 5 is a diagram schematically illustrating an exemplary X-ray source having a substantially conical tip in accordance with certain embodiments described in the present specification. [Figure 4A] 6 is a cross-sectional view schematically illustrating an exemplary transmissive X-ray source in accordance with certain embodiments described in the present specification. [Figure 4B] 7 is a cross-sectional view schematically illustrating an exemplary transmissive X-ray source in accordance with certain embodiments described in the present specification. MODE FOR CARRYING OUT THE INVENTION

[0013] Detailed Description Certain embodiments described in the present specification provide various hardware techniques for reducing (e.g., eliminating) secondary images generated by secondary X-rays from a high-resolution transmissive X-ray source.

[0014] Figures 2A and 2B schematically illustrate cross-sectional views of two exemplary transmission X-ray sources 100 in accordance with specific embodiments described herein. The exemplary X-ray source 100 comprises an electron beam source 110 configured to generate an electron beam 112 (propagating along an electron beam propagation axis 111, for example), an aperture 120, and a target 130 configured to generate X-rays 140 in response to impingement of electrons from the electron beam 112 thereon (for example, irradiation of the target 130 by the electrons). The aperture 120 includes a first portion 122 comprising at least one first atomic element having a first atomic number greater than 20 (for example, greater than 40), a hole 124 extending through the first portion 122, and a second portion 126 covering at least one surface of the first portion 122, wherein the second portion 126 comprises at least one second atomic element having a second atomic number less than 15. The aperture 120 is configured to allow a first portion 112a of the electron beam 112 to transmit through the hole 124 and impinge on the target 130. The aperture 120 is also configured to block (for example, stop, suppress, prevent) a second portion 112b of the electron beam 112 from transmitting through the hole 124, wherein the second portion 112b impinges on the second portion 126.

[0015] In specific embodiments, the X-ray source 100 comprises a vacuum chamber 102 (for example, a vacuum-sealed tube) containing a vacuum region 104, and the electron beam source 110 is configured to transmit the electron beam 112 into the vacuum region 104. In specific embodiments, the vacuum chamber 102 accommodates the electron beam source 110, the aperture 120, and the target 130. In contrast to open-tube X-ray sources, the vacuum chamber 102 of specific embodiments is not actively evacuated.

[0016] In a particular embodiment, the electron beam source 110 comprises a cathode configured to emit electrons and an electron optical system (e.g., electrodes, electromagnetic focusing column) configured to guide electrons to an electron beam 112 (e.g., using an accelerating voltage in the range of 30 kVp to 160 kVp) and to guide the electron beam 112 to a target 130 (e.g., focusing the electron beam 112 onto the target 130). For example, the electron beam source 110 can be configured to generate a focused electron beam 112 and to collide the focused electron beam 112 with the target 130 at a selectable maximum accelerating voltage in the range of 10 kVp to 250 kVp. The spot size of the electron beam on the target 130 (e.g., X-ray generation spot size), e.g., FWHM, width, and diameter, may be less than 2 microns (e.g., in the range of 0.3 microns to 1 micron, less than 1 micron, less than 0.6 microns, less than 0.5 microns, less than 0.3 microns).

[0017] In a particular embodiment, the target 130 is placed within a vacuum region 104 and configured to generate divergent X-rays 140 in response to collisions with electrons from the electron beam 112. The target 130 includes at least one X-ray generating material selected according to its X-ray spectral generation characteristics (e.g., characteristic X-ray energy) and / or other characteristics (e.g., atomic number Z, electron density) that affect the X-ray generation capability of at least one X-ray generating material. The at least one X-ray generating material may have a thermal conductivity high enough to dissipate the heat generated by the impact of the electron beam 112 at high power. The at least one X-ray generating material may have a thermal conductivity of 100 W / mK or higher and / or a melting point greater than 1000°C (e.g., greater than 2000°C). Examples of X-ray generating materials include, but are not limited to, Cr, Fe, Co, Ni, Cu, W, Rh, Mo, Au, Pt, Ag, SrB6, LaB6, CeB6, and other materials containing atomic elements with atomic numbers of 40 or higher.

[0018] As schematically shown in Figures 2A and 2B, the target 130 can be attached to (e.g., integrated with, a component of, or in contact with) the vacuum window 132 of the vacuum chamber 102. The vacuum window 132 separates the vacuum region 104 from the non-vacuum region outside the vacuum chamber 102. For example, the target 130 may include at least one metal layer that is thermally in communication with (e.g., attached to or deposited on) the surface of the vacuum window 132 facing the vacuum region of the vacuum chamber 102, and the vacuum window 132 may be electrically grounded. The thickness of at least one X-ray generating material of the target 130 (e.g., thickness along a direction substantially perpendicular to the outer surface 134 of the vacuum window 132) may be less than 15 microns (e.g., in the range of 0.1 to 10 microns, 2 to 5 microns, 0.2 to 3 microns, 0.5 to 2 microns, or 200 to 500 nanometers), and the thickness of the vacuum window 132 in a direction substantially perpendicular to the outer surface 134 of the vacuum window 132 may be in the range of 0.05 millimeters to 3 millimeters. The thickness of at least one X-ray generating material may be optimized to achieve high spatial resolution (e.g., by minimizing electron beam scattering within the material) and / or to achieve high system throughput (e.g., by maximizing the imparting of electron energy within at least one X-ray generating material). In certain embodiments, at least one X-ray generating material has a plurality of regions that can be impacted by an electron beam 112 (for example, by translating the electron beam focus), each region having a corresponding thickness along a direction substantially perpendicular to the outer surface 134 of the vacuum window 132. The electron beam 112 is guided by an electron beam source 110 and can impact selected regions having corresponding thicknesses to provide a selected trade-off between throughput and resolution.

[0019] In certain embodiments, the vacuum window 132 is made of an atomic element having an atomic number (Z) substantially less than 15 and is substantially penetrating to high-energy X-rays produced by at least one X-ray generating material of the target 130. For example, the vacuum window 132 may have a sufficiently high thermal conductivity to provide a heat conduit to prevent thermal damage (e.g., melting) to at least one X-ray generating material of the target 130. For example, one or more materials of the vacuum window 132 are selected from the group consisting of beryllium, diamond, boron carbide, silicon carbide, aluminum, sapphire, and beryllium oxide (BeO). Furthermore, the vacuum window 132 may provide a conductive path sufficient to dissipate charge from at least one X-ray generating material of the target 130 and / or from the vacuum window 132. In certain embodiments, the vacuum window 132 is configured to have an X-ray transmittance such that more than 50% of the X-rays produced by the target 130 having an energy greater than half of the selected maximum focused electron energy pass through the vacuum window 132.

[0020] In certain embodiments, the first portion 122 of the aperture 120 comprises a solid, substantially planar plate or sheet (see, for example, Figures 2A and 2B), while in other certain embodiments, the first portion 122 is non-planar (e.g., curved). In certain embodiments, at least 50% (e.g., at least 70%, at least 90%) of the first portion 122 is at least one first atomic element. Examples of the at least one first atomic element in the first portion 122 include, but are not limited to, molybdenum and tungsten.

[0021] In certain embodiments, the opening 124 (e.g., orifice, slit) of the aperture 120 has a width of less than 5 millimeters (e.g., less than 4 millimeters, less than 2 millimeters, less than 1 millimeter) in a direction substantially perpendicular to the electron beam 112. Various shapes around the opening 124 are adapted to the specific embodiments described herein (e.g., circular, elliptical, rectangular, square, polygonal, symmetrical, asymmetrical).

[0022] In certain embodiments, at least 50% (e.g., at least 70%, at least 90%) of the second portion 126 is at least one second atomic element. Examples of the at least one second atomic element include, but are not limited to, carbon. For example, the second portion 126 includes a graphite layer, diamond, and / or a polymer. The second portion 126 is conductive and can be electrically connected to ground so that the charge of the second portion 126 does not increase due to electron collisions.

[0023] In a particular embodiment, the second portion 126 of the aperture 120 includes at least one layer coated on at least one surface of the first portion 122. For example, at least one layer may be coated on a single surface region of the first portion 122 (e.g., the surface region facing the electron beam source 110). As another example (see, for example, Figure 2A), at least one layer may be coated on at least two surface regions of the first portion 122 (e.g., the surface region facing the electron beam source 110 and the surface region extending at least partially into the hole 124). As yet another example (see, for example, Figure 2B), at least one layer may be coated on at least three surface regions of the first portion 122 (e.g., the surface region facing the electron beam source 110, the surface region extending at least partially into the hole 124, and the surface region facing away from the electron beam source 110). A second portion 126 on the surface region of the first portion 122 facing away from the electron beam source 110 can face the target 130, thereby suppressing (e.g., reducing, preventing, or shielding) the generation of secondary X-rays by backscattered electrons from the target 130 colliding with the first portion 122.

[0024] At least one layer of the second portion 126 may be configured to attenuate more than 50% of the electron flux colliding with the second portion 126 (for example, to prevent at least 50% of the electron flux colliding with the second portion 126 from reaching the first portion 122). For example, the thickness of at least one layer may be in the range of 50 to 300 microns, 50 to 100 microns, 100 to 300 microns, or greater than 300 microns. In another example, the thickness of at least one layer may be greater than or equal to the continuous deceleration approximation (CSDA) length of the average electron energy of electrons colliding with the second portion 126 (for example, in the range of 30 keV to 150 keV, 30 keV to 100 keV, 60 keV to 140 keV, 80 keV to 120 keV, or 100 keV to 150 keV). Using the NIST ESTAR database of electron stopping power and range tables, the CSDA range of a 150 keV electron is 3.174 × 10⁻⁶. -2 g / cm 2 It is approximately 144 microns (for example, 3.174 × 10⁻¹⁰). -2 g / cm 2 Density 2.2 g / cm³ 3 This corresponds to the CSDA range or thickness of carbon (the value obtained by dividing by ).

[0025] Figure 3A schematically shows a cross-sectional view of another exemplary transmission X-ray source 100 according to a particular embodiment described herein. In a particular embodiment, the X-ray source 100 includes an aperture 120 described herein with reference to Figures 2A and 2B, but in other particular embodiments, the X-ray source 100 does not include an aperture 120. In Figure 3A, the exemplary X-ray source 100 is shown as part of an X-ray tomography system 200 comprising a rotating stage 210 and at least one X-ray detector 220. The rotating stage 210 is configured to support and controllably move a sample 202 (for example, by placing the sample 202 on its upper surface and rotating the sample 202 around a rotation axis 212). As schematically shown in Figure 3A, the central beam axis 222 may be defined by a straight line extending from the X-ray generating spot of the target 130, a portion of the sample 202, and a portion of at least one X-ray detector 220. For example, the central beam axis 222 extends through the sample 202 to the center of the effective area of ​​at least one X-ray detector 220. In a particular embodiment, the X-ray tomography system 200 includes additional elements (e.g., X-ray attenuators, X-ray blockers) configured to prevent X-rays that strike other structures other than the sample 202 (e.g., a rotating stage 210) from reaching at least one X-ray detector 220.

[0026] In a particular embodiment, the distance between the X-ray source 100 and at least one X-ray detector 220 is less than 2 meters (e.g., less than 1.5 meters, less than 1 meter, less than 0.75 meters, less than 0.5 meters). In a particular embodiment, the X-ray tomography system 200 comprises a plurality of motors, which are configured to controllably adjust the distance from the source to the sample (e.g., the distance between the outer surface 134 of the vacuum window 132 and the sample 202) and the distance from the source to the detector (e.g., the distance between the sample 202 and the outer surface of at least one X-ray detector 220 facing the sample 202) by moving the X-ray source 100 and / or at least one X-ray detector 220 (e.g., along the direction toward and away from the rotation axis 212).

[0027] In a particular embodiment, the X-ray source 100 is configured to produce a first divergent X-ray beam 230 containing X-rays 140 (e.g., primary X-rays) from a target 130, and a second divergent X-ray beam 240 containing X-rays 22 generated by electrons colliding with the aperture 120. Both the first X-ray beam 230 and the second X-ray beam 240 are centered on an X-ray axis 250 (substantially parallel to the propagation axis 111 of the electron beam 112, substantially collinear with the propagation axis 111, substantially perpendicular to the outer surface 134 of the target 130 and / or vacuum window 132). At least 70% (e.g., at least 80%, at least 90%, at least 95%) of the X-rays 114 of the first divergent X-ray beam 230 lie within a first cone angle Θ1 of 130° or greater (e.g., 150°, 175°, 180° or greater) (e.g., symmetric with respect to the X-ray axis 250). At least 70% (e.g., at least 80%, at least 90%, at least 95%) of the X-rays 22 of the second divergent X-ray beam 240 lie within a second cone angle Θ2 that is smaller than the first cone angle Θ1 (e.g., symmetric with respect to the X-ray axis 250). For example, the second divergent X-ray beam 240 is collimated more than the first divergent X-ray beam 230 (see, for example, Figure 3A). For example, the second cone angle Θ² may be in the range of 2° to 30°, 2° to 10°, 6° to 10°, 10° to 20°, or 20° to 30°.

[0028] In certain embodiments, the X-ray source 100 and / or other parts of the X-ray tomography system 200 (e.g., the sample 202, the rotating stage 210, and at least one X-ray detector 220) are configured to move relative to each other to tilt the X-ray axis 250 so that it has a non-zero tilt angle Φ with respect to the central beam axis 222. The non-zero tilt angle Φ may be in the range of 0.5Θ2 to 0.5Θ1 (e.g., in the range of 5° to 30°, greater than 6°, in the range of 10° to 20°, or 15°).

[0029] For example, the X-ray source 100 may be mounted on a translational and / or rotating stage configured to adjust the tilt angle Φ and / or the distance between the outer surface 134 of the vacuum window 132 and at least one X-ray detector 220. In another example, the desired tilt angle Φ can be generated by moving the sample 202, the rotating stage 210 and at least one X-ray detector 220 (for example, using at least one translational and / or rotating stage) while the X-ray source 100 remains stationary. Figure 3A shows the X-ray source 100 tilted upward (for example, the X-ray axis 250 is below the central beam axis 222) with the rotation axis 212 in the plane containing the central beam axis 222 and the X-ray axis 250, but alternatively, the X-ray source 100 may be tilted downward (for example, the X-ray axis 250 is above the central beam axis 222) with the rotation axis 212 in the plane containing the central beam axis 222 and the X-ray axis 250. In other specific embodiments, the X-ray source 100 is tilted in a different direction such that the plane containing the central beam axis 222 and the X-ray axis 250 and the rotation axis 212 are not coplanar.

[0030] In a particular embodiment, the X-ray source 100 is tilted such that at least 70% (e.g., at least 80%, at least 90%, at least 95%, 100%) of the secondary X-rays (e.g., X-rays 22) do not enter a region (e.g., the central region) of at least one X-ray detector 220 configured to receive X-rays 114 from the sample 202 (e.g., X-rays 22 do not enter at least one X-ray detector 220). For example, the X-ray source 100 may be tilted with respect to the central beam axis 222 such that the tilt angle Φ between the central beam axis 222 and the X-ray axis 250 is expressed by the following equation.

[0031] Φ≧0.5×(Θ D +Θ2) In the formula, Θ D Θ is an angle defined by the region of at least one X-ray detector 220 (for example, symmetrical about the central beam axis 222), and Θ² is the second cone angle of the second divergent X-ray beam 240. According to this relationship, Θ DWhen Θ1=40° and Θ2=8°, the inclination angle Φ is 24° or more.

[0032] In a specific embodiment, the X-ray source 100 is tilted such that at least 70% (e.g., at least 80%, at least 90%, at least 95%, at least 99%, 100%) of secondary X-rays (e.g., X-rays 22) do not enter the central 1 / 3 region of the two-dimensional region of at least one X-ray detector 220. For example, the X-ray source 100 may be tilted relative to the central beam axis 222 such that the inclination angle Φ between the central beam axis 222 and the X-ray axis 250 is represented by the following formula.

[0033] Φ≧0.5×[(1 / 3·Θ D )+Θ2] According to this relational expression, when Θ D =40° and Θ2=8°, the inclination angle Φ is about 21.3° or more. In such a specific embodiment, the influence of secondary X-rays from the central region of interest (ROI) of an X-ray image can be reduced, but cannot be completely eliminated. Stitching and / or post-processing with additional data can further reduce the influence of secondary X-rays.

[0034] In a specific embodiment, the portion of the X-ray source 100 that includes the vacuum window 132 and is closest to the sample 202 (e.g., also referred to as the tip 106 of the X-ray source 100) is shaped to facilitate tilting of the X-ray source 100 relative to the central beam axis 222. For example, for a relatively small sample 202 (e.g., see FIG. 3A), the tip 106 may be substantially flat.

[0035] Figures 3B and 3C show partial X-ray images and X-ray lineouts, respectively, of an exemplary first divergent X-ray beam 230 and an exemplary second divergent X-ray beam 240, according to a particular embodiment described herein. The X-ray lineout is a plot of X-ray intensity along a line substantially perpendicular to the X-ray axis 250 (e.g., the dotted line in Figure 3B). The X-ray images and X-ray lineouts were measured with the X-ray source 100 operating at a 120 kV electron beam 112 and a spot size of 300 nanometers on the target 130, with no sample 202 placed between the X-ray source 100 and at least one X-ray detector 220, and with the X-ray source 100 and at least one X-ray detector 220 aligned (e.g., the central beam axis 222 and the X-ray axis 250 coincided with each other). As shown in Figure 3B, the X-ray image resembles a central bright circular area (e.g., due to a second divergent X-ray beam 240) surrounded by concentric ring portions (e.g., due to a first divergent X-ray beam 230) superimposed on the non-zero intensity distribution. As shown in Figure 3C, the X-ray lineout resembles a “top hat” shape that can be used to measure the second cone angle Θ2. For example, the second cone angle Θ2 can be calculated by dividing the diameter of the “top hat” shape (e.g., full width at half maximum or FWHM diameter, the diameter where the intensity is greater than 5% of the underlying non-zero intensity distribution) by the distance between the X-ray source 100 (e.g., the outer surface 134 of the X-ray window 132) and at least one X-ray detector 220. Using exemplary values ​​of a diameter of 17 millimeters and a distance of 220 millimeters, the second cone angle Θ2 is equal to approximately 7.7°.

[0036] In certain embodiments, a portion of the X-ray source 100 that includes a vacuum window 132 and is closest to the sample 202 (also referred to as the tip 106 of the X-ray source 100) is shaped to facilitate tilting of the X-ray source 100 with respect to the central beam axis 222. For example, for a relatively small sample 202 (see, e.g., Figure 3A) and / or a sample 202 relatively far from the X-ray source 100, the tip 106 does not significantly hinder the tilting of the X-ray source 100, and the tip 106 may be substantially flat. However, using an X-ray source 100 with such a substantially flat tip 106, for a relatively large sample 202 and / or a sample 202 relatively close to the X-ray source 100, the tip 106 hinders the tilting of the X-ray source 100, thereby reducing throughput and / or the X-ray flux to the sample 202, and / or limiting the maximum size of the sample 202.

[0037] Figure 3D schematically shows an exemplary X-ray source 100 having a substantially conical tip 106 according to a particular embodiment described herein. The tip 106 includes a vacuum window 132 and a portion of a vacuum chamber 102, the vacuum window 132 being attached to the portion of the vacuum chamber 102. In such a particular embodiment, the X-ray source 100 can be tilted so that, for example, a portion of the conical tip 106 is substantially parallel to the sample 202. For example, as shown in Figure 3D, the sample 202 may include a long cylinder positioned near the outer surface 134 of the vacuum window 132 (e.g., less than 10 mm, less than 5 mm, less than 2 mm, less than 1 mm).

[0038] In a particular embodiment, the rotating stage 210 includes a rotating stage (e.g., a mechanical rotating stage, an air-bearing rotating stage) and a three-axis (e.g., three orthogonal axes) translational positioning stage on the rotating stage. The rotating stage is substantially stationary (e.g., fixed to a large granite slab). The rotating stage may have a runout of less than 150 nanometers (e.g., less than 100 nanometers, less than 50 nanometers), and the three-axis translational positioning stage may be configured to position the sample 202 with respect to the central beam axis 222 and the outer surface 134 of the vacuum window 132. The three-axis translational positioning stage may be configured to translate the sample 202 by at least 40 millimeters (e.g., at least 50 millimeters, at least 100 millimeters) along each of the three axes.

[0039] In certain embodiments, submicron resolution imaging is affected by non-zero runout of the rotating stage (e.g., radial runout, axial runout), but because the rotation is sufficiently systematic, calibration can be used to align the tomographic projection. This corrects the runout and enables submicron (e.g., less than 1 micron, 0.5 microns, 0.3 microns) imaging. For example, substantially spherical calibration samples (e.g., solder balls, ruby ​​balls) can be placed at different positions around the center of rotation along the y-axis (e.g., rotation axis 212 which is perpendicular to the horizontal z-axis). The center of mass of the calibration samples can be measured at various positions along the y-axis. Using such measurements, the center of the projection can be shifted before reconstructing the tomographic image.

[0040] In a particular embodiment (see, for example, Figure 3D) in which the X-ray source 100 is tilted and the rotation axis 212, the central beam axis 222, and the X-ray axis 250 are coplanar, the sample 202 is movable within a certain position range along a direction substantially perpendicular to the beam central axis 222 (e.g., along the rotation axis 212). This ensures that the sample 202 does not substantially intersect with the second divergent X-ray beam 240 (e.g., centered on the X-ray axis 250). The non-zero tilt angle Φ makes the position range wider when the distance from the source to the sample is greater (e.g., the distance between the outer surface 134 of the vacuum window 132 and the sample 202) than when the distance from the source to the sample is smaller. In a particular embodiment, the three-axis translational positioning stage of the rotating stage 210 is configured to position the sample 202 such that the X-rays transmitted through the region of interest (ROI, e.g., an ROI imaged by at least one X-ray detector 220) of the sample 202 substantially include primary X-rays 114 over more than 50% of the distance from the source to the sample. For example, the primary X-rays 114 are more than 70%, more than 80%, more than 90%, more than 95%, or more than 99% of the X-rays transmitted through the ROI.

[0041] Figures 4A and 4B schematically show cross-sectional views of two exemplary transmission X-ray sources 100 according to a particular embodiment described herein. In a particular embodiment, the X-ray source 100 includes an aperture 120 as described herein with reference to Figures 2A and 2B, but in other particular embodiments, the X-ray source 100 does not include an aperture 120. The aperture 120 may be positioned at a first distance D1 from the vacuum window 132 (for example, the distance between the surface of the aperture 120 facing the target 130 and the outer surface 134 of the vacuum window 132 facing away from the target 130). For example, the first distance D1 may be greater than 4 millimeters (for example, in the range of 4 to 7 millimeters, greater than 7 millimeters, in the range of 5 to 20 millimeters, in the range of 20 to 50 millimeters, greater than 50 millimeters). The first distance D1 may be large enough to reduce (e.g., minimize) the beam of secondary X-rays 22 emitted from the X-ray source 100.

[0042] In certain embodiments, the X-ray source 100 is part of an X-ray tomography system 200 comprising a rotating stage 210 and at least one X-ray detector 220, the rotating stage 210 being configured to place a sample 202 on it and rotate the sample 202 around a rotation axis 212. In the X-ray tomography system 200 in Figures 4A and 4B, the central beam axis 222 coincides with the X-ray axis 250 (e.g., the tilt angle Φ is substantially equal to zero), but in certain other embodiments, as described herein with reference to Figures 3A to 3C, the X-ray source 100 and / or other parts of the X-ray tomography system 200 (e.g., the sample 202, the rotating stage 210, and at least one X-ray detector 220) are configured to move relative to each other in order to tilt the X-ray axis 250 so that it has a non-zero angle Φ with respect to the central beam axis 222. In a particular embodiment, the X-ray tomography system 200 includes additional elements (e.g., X-ray attenuators, X-ray blockers) configured to prevent X-rays that strike other structures other than the sample 202 (e.g., the rotating stage 210) from reaching at least one X-ray detector 220.

[0043] In a particular embodiment, as shown in Figures 4A and 4B, at least one X-ray detector 220 comprises at least one scintillator 310, at least one optical element 320, and at least one visible light sensor 330. At least one scintillator 310 (e.g., a fluorescent screen) has an outer surface 314 and is configured to receive X-rays from a sample 202 and generate visible light in response to the received X-rays. In a particular embodiment, the fluorescent screen comprises a single-crystal material. In a particular embodiment, the fluorescent screen comprises cesium iodide (e.g., CsI(Tl)), gadolinium oxysulfide (e.g., GD2O2S, GadO xThe material comprises at least one material selected from the group consisting of ), gadolinium-aluminum-gallium-garnet (GAGG), and yttrium-aluminum-garnet (YAG). In certain embodiments, the fluorescent screen may have a thickness of 100 microns or less in a direction substantially parallel to the central beam axis 222.

[0044] At least one optical element 320 (e.g., an optical assembly) is configured to receive visible light from at least one scintillator 310 and to allow the visible light to propagate to at least one visible light sensor 330. For example, as shown in Figure 4A, at least one optical element 320 includes at least one lens (e.g., an objective lens), and as shown in Figure 4B, at least one optical element 320 includes at least one optical fiber (e.g., an optical fiber conduit). At least one lens may include a high aperture objective lens (e.g., similar to those used in visible light microscopes) with a magnification of 4x or more (e.g., in the range of 5x to 10x, 10x to 20x). The optical fiber conduit is tapered and can produce magnifications of 0.3x or more (e.g., 0.3x, 0.5x, 1x, 1.5x, 2x, 3x). In certain embodiments, the fluorescent screen may have a thickness of 5 times or less the depth of field of at least one lens (e.g., 3 times or less the depth of field, 2 times or less the depth of field, or less the depth of field) in a direction substantially parallel to the central beam axis 222. In certain embodiments, the fluorescent screen of at least one scintillator 310 has a thickness of less than 200 microns (e.g., less than 150 microns, less than 100 microns, or 50 microns or less).

[0045] At least one visible light sensor 330 (e.g., a spatially resolved sensor, a charge-coupled device (CCD) image sensor, or a complementary metal-oxide-semiconductor (CMOS) image sensor) is configured to generate an electrical signal indicating that at least one X-ray detector 220 has received X-rays from the sample 202 in response to visible light. At least one visible light sensor 330 may have a pixel size (e.g., width or diameter) of less than 20 microns (e.g., less than 18 microns, less than 10 microns, in the range of 1 to 5 microns, less than 1 micron). Exemplary visible light sensors 330 that fit the specific embodiments described herein are available from Sony Corporation (Tokyo, Japan) and GPixel Microelectronics Inc. (Changchun, China).

[0046] In a particular embodiment, at least one visible light sensor 330 has a pixel size greater than 10 microns, and at least one scintillator 310, at least one optical element 320, and at least one visible light sensor 330 are arranged to obtain a visible light magnification that produces an effective pixel size of less than 20 microns (e.g., less than 18 microns, less than 10 microns, in the range of 1 to 5 microns, in the range of 2 to 5 microns, less than 5 microns, in the range of 1 to 2 microns, less than 1 micron, less than 0.5 microns, less than 0.3 microns, less than 0.15 microns). Figures 4A and 4B show at least one visible light sensor 330 having a front surface that is substantially parallel to at least one scintillator 310, but in other particular embodiments, the front surface of at least one visible light sensor 330 may be at a non-zero angle (e.g., substantially perpendicular) to at least one scintillator 310 (e.g., if at least one optical element 320 includes a 45-degree mirror).

[0047] In certain embodiments, as shown in Figures 4A and 4B, at least one X-ray detector 220 is mechanically connected (e.g., mounted or placed) to at least one controllable (e.g., motorized) translational stage 340, which is configured to controllably adjust a second distance D2 (e.g., the distance from the source to the detector) between the vacuum window 132 and the at least one X-ray detector 220. For example, the second distance D2 may be the distance between the outer surface 134 of the vacuum window 132 and the outer surface of the at least one X-ray detector 220 facing the sample 202 (e.g., the outer surface 314 of the at least one scintillator 310). In certain embodiments, at least one X-ray detector 220 may be positioned closer to the sample 202. For example, the second distance D2 may be less than 20 millimeters (e.g., less than 10 millimeters, less than 5 millimeters). Such a second distance D2 is smaller than the distance from sample to detector used in conventional systems. For example, a conventional flat-panel detector having 50-micron pixels may have a second distance D2 of about 210 millimeters relative to a sample placed 3 millimeters away from the X-ray source in order to achieve an imaging pixel resolution of about 0.7 microns. In contrast, according to certain embodiments described herein, an exemplary X-ray detector 220 having an effective pixel size of 1.7 microns may have a second distance D2 of 4.3 millimeters relative to a sample placed 3 millimeters away from the X-ray source (e.g., a reduction of about 1 / 50th) in order to achieve an imaging pixel resolution of about 0.7 microns.

[0048]

number

[0049] In certain embodiments, the target 130 has a fine structure and includes a plurality of discrete (e.g., separated, spaced apart) metallic regions. For example, the electron beam 112 may be deflected between at least one region of the target 130 containing at least one X-ray generating material and at least one non-target region containing a material with a lower atomic number (e.g., diamond, beryllium). Such electron beam deflection may be used for "beam blanking" and may be used in combination with a second-to-first-order suppression technique using a small pixel detector positioned at a small D2 value.

[0050] In certain embodiments, at least one X-ray detector 220 comprises multiple X-ray detectors mechanically communicating with a translational and / or rotating stage, the translational and / or rotating stage configured to position one of the multiple X-ray detectors 220 at a location to receive X-rays from the sample 202. For example, the first X-ray detector 220 may have a first effective pixel size of less than 10 microns (e.g., less than 5 microns), and the second X-ray detector (e.g., a conventional flat-panel detector) may have a second effective pixel size of more than 40 microns (e.g., in the range of 50 to 100 microns) and / or a maximum field of view (FOV) of at least 100 millimeters in at least one lateral direction. The first X-ray detector 220 may be used for high-resolution imaging with a small D2 value to suppress the contribution of the secondary X-ray beam 240. The second X-ray detector may be used for coarser-resolution imaging with a larger FOV (e.g., using a movable external aperture positioned between the X-ray source 100 and the sample 202).

[0051] Commonly used terminology is used to describe the systems and methods of particular embodiments for ease of understanding, but in this specification, these terms are used so as to have the broadest reasonable interpretation. Various aspects of this disclosure have been described with respect to exemplary examples and embodiments, but the disclosed examples and embodiments should not be construed as limiting. Conditional language such as “can,” “could,” “might,” or “may” is intended to convey that a particular embodiment includes a particular feature, element, and / or step, but other embodiments do not, unless otherwise specified or understood in the context in which it is used. Thus, such conditional language is not generally intended to suggest that a feature, element, and / or step is required in any way in one or more embodiments. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, utilized, or combined with other elements, components, or steps that are not explicitly referenced.

[0052] Conjunctions such as "at least one of X, Y, and Z" should be understood in contexts where they are commonly used to indicate that an item, term, etc., may be X, Y, or Z, unless otherwise specified. Therefore, such conjunctions are generally not intended to suggest that a particular embodiment requires the presence of at least one X, at least one Y, and at least one Z.

[0053] The terms "approximately," "about," "generally," and "substantially" as used herein still refer to values, quantities, or characteristics that are close to the stated values, quantities, or characteristics that perform the desired function or achieve the desired result. For example, the terms "approximately," "about," "generally," and "substantially" may refer to quantities that are within ±10%, ±5%, ±2%, ±1%, or ±0.1% of the stated quantity. As another example, the terms "generally parallel" and "substantially parallel" refer to values, quantities, or characteristics that are off by ±10°, ±5°, ±2°, ±1°, or ±0.1° from exactly parallel. Similarly, the terms "generally perpendicular" and "substantially perpendicular" refer to values, quantities, or characteristics that are off by ±10°, ±5°, ±2°, ±1°, or ±0.1° from exactly perpendicular. Furthermore, the scope disclosed herein includes all overlaps, sub-scopes, and combinations thereof. Terms such as “up to,” “at least,” “greater than,” “less than,” and “between” include the numbers listed. Where used herein, “a,” “an,” and “said” include multiple references unless the context explicitly indicates otherwise. Structures and / or methods are described herein with respect to elements labeled by ordinal adjectives (e.g., first, second, etc.), but the ordinal adjectives are used simply as labels to distinguish one element from the other, and are not used to indicate these elements or the order in which they are used.

[0054] Various configurations have been described above. It should be understood that the embodiments disclosed herein are not mutually exclusive and can be combined with each other in various configurations. While the invention has been described with reference to these specific configurations, the description is intended to illustrate the invention, not to limit it. Those skilled in the art can conceive of various modifications and applications without departing from the true spirit and scope of the invention. Thus, for example, in any method or process disclosed herein, the actions or operations constituting the method / process may be performed in any preferred order and are not necessarily limited to any specific order disclosed. By combining features or elements from the various embodiments and examples described above, alternative configurations compatible with the embodiments disclosed herein can be produced. Various aspects and advantages of the embodiments have been described as necessary. It should be understood that not all aspects or advantages are necessarily achieved according to any particular embodiment. Thus, for example, various embodiments may be performed in a manner that achieves or optimizes one or a group of advantages taught herein without necessarily achieving other aspects or advantages taught or suggested herein.

Claims

1. It is a device, Equipped with a transmission-type X-ray source, The aforementioned transmission X-ray source is A window including a target layer made of at least one X-ray generating material configured to generate X-rays in response to electron collisions, The electron beam includes an internal aperture configured to allow a first portion of the electron beam from an electron beam source to collide with the target layer and to prevent a second portion of the electron beam from colliding with the target layer, wherein the full width at half maximum of the first portion of the electron beam in the target layer is 1 micron or less, and the window is at a first distance D from the internal aperture. １ The devices are separated by the device, Equipped with an X-ray detection system, The aforementioned X-ray detection system is A scintillator configured to receive X-rays transmitted through a sample from the X-ray source and to generate visible light in response to the received X-rays, An optical assembly configured to receive the visible light from the scintillator, At least one image sensor configured to receive visible light from the optical assembly and generate an electrical signal in response to the received visible light, The scintillator is at a second distance D from the window. ２ Includes an electric stage configured to controllably adjust the position of the scintillator so that it is separated by a certain distance, [Math 1] The device is less than 0.

2.

2. The apparatus according to claim 1, wherein the motorized stage includes a translational stage attached to at least one of the X-ray detectors.

3. The first distance D １ The apparatus according to claim 1, wherein the diameter is greater than 4 millimeters.

4. The apparatus according to claim 3, wherein the effective pixel size of the X-ray detection system is less than 20 microns.

5. The apparatus according to claim 1, wherein the full width at half maximum of the electron beam in the target layer is less than 0.5 microns.

6. It is a device, Equipped with an X-ray source, The aforementioned X-ray source is, An electron beam source configured to generate an electron beam, The system includes at least one aperture, the at least one aperture being configured to allow a first portion of the electron beam to pass through the at least one aperture and to prevent a second portion of the electron beam from passing through the at least one aperture. The present invention comprises at least one target containing at least one X-ray generating material, the at least one X-ray generating material configured to generate a first X-ray beam that diverges in response to an impact by the first portion of the electron beam, and the at least one aperture configured to generate a second X-ray beam that diverges in response to an impact by the second portion of the electron beam and / or collisions by electrons backscattered from the at least one target. The apparatus includes a window configured to emit the first X-ray beam and the second X-ray beam, both of which are substantially centered on an X-ray axis substantially perpendicular to the outer surface of the window, and the apparatus is configured to emit the first X-ray beam and the second X-ray beam, both of which are substantially centered on an X-ray axis substantially perpendicular to the outer surface of the window, A sample stage configured to support and controllably move a sample, An apparatus comprising at least one X-ray detector, wherein the at least one X-ray detector is configured to receive X-rays of the first X-ray beam that has passed from the X-ray source through the region of interest of the sample along the central beam axis, and the angle Φ between the central beam axis and the X-ray axis is 6° or more.

7. The apparatus according to claim 6, wherein the electron beam source includes a cathode configured to emit electrons and an electron optical system configured to guide the electrons into the electron beam and accelerate the electron beam toward the at least one target using an acceleration voltage in the range of 30 kVp to 160 kVp.

8. The apparatus according to claim 6, wherein the spot diameter of the electron beam at at least one target is less than 2 microns.

9. The surface of the aperture facing the at least one target is located at a distance D greater than 4 millimeters from the outer surface of the window facing away from the at least one target. １ The apparatus according to claim 6, which is separated by a certain distance.

10. The apparatus is fixed to the at least one X-ray detector, and the second distance D is between the outer surface of the window and the outer surface of the at least one detector facing the sample. ２ The system further comprises at least one translational stage configured to be controllably adjustable, The second distance D ２ The apparatus according to claim 9, wherein the diameter is less than 20 millimeters. [Request Item 11] [Number 2] The apparatus according to claim 10, wherein is less than 0.

2.

12. The aforementioned window contains a diamond, The apparatus according to claim 6, wherein the at least one X-ray generating material of the at least one target includes at least one metal layer on the window.

13. The at least one X-ray detector includes a first X-ray detector, The first X-ray detector is, A scintillator configured to receive X-rays from the sample and generate visible light in response to the received X-rays, At least one optical element configured to receive the visible light from the at least one scintillator, The apparatus according to claim 6, further comprising at least one visible light sensor configured to receive the visible light from the at least one optical element.

14. The apparatus according to claim 13, wherein the at least one optical element includes at least one lens and has a magnification of 4 times or more.

15. The apparatus according to claim 13, wherein the at least one optical element includes at least one tapered optical fiber conduit configured to produce a magnification of 1x or more.

16. The at least one visible light sensor includes at least one spatially resolved image sensor, The apparatus according to claim 13, wherein the at least one spatially resolved image sensor has a pixel width of less than 20 microns.

17. The at least one visible light sensor includes at least one spatially resolved image sensor, The apparatus according to claim 13, wherein the at least one spatially resolved image sensor has an effective pixel width of less than 5 microns.

18. The at least one X-ray detector further includes a second X-ray detector, The second X-ray detector includes a flat panel detector with pixels having an effective pixel width greater than 40 millimeters. The apparatus according to claim 13, wherein the first and second X-ray detectors are mechanically connected to a translational and / or rotary stage configured to position one of the first and second X-ray detectors at a position for receiving X-rays from the sample.

19. The apparatus according to claim 6, wherein the angle Φ is in the range of 10° to 20°.

20. The apparatus according to claim 6, wherein the sample stage includes an air bearing rotating stage.

21. It is a device, comprises a transmission type X-ray source, wherein the transmission type X-ray source has a first cone angle Θ １ and is configured to generate a primary X-ray beam having the first cone angle Θ １ and a secondary X-ray beam having a second cone angle Θ smaller than the first cone angle Θ ２ , both the primary X-ray beam and the secondary X-ray beam are divergent and symmetrical with respect to an X-ray axis, and the apparatus: A sample stage configured to support and controllably move a sample, An apparatus comprising at least one X-ray detector, wherein the at least one X-ray detector has a region configured to receive X-rays transmitted from the transmission X-ray source through a region of interest of the sample along a beam axis that is at a non-zero angle Φ with respect to the X-ray axis, and the at least one X-ray detector is configured to generate an electrical signal indicating the X-rays received in the region.

22. The first cone angle Θ １ It is 130° or more, The second cone angle Θ ２ The apparatus according to claim 21, wherein the range is 2° to 30°.

23. The aforementioned non-zero angle Φ is 0.5Θ ２ ~0.5Θ １ The apparatus according to claim 21, which is within the range.

24. The apparatus according to claim 21, wherein at least 70% of the secondary X-ray beam does not enter the region of the at least one X-ray detector.

25. The aforementioned non-zero angle Φ is 0.5 × (Θ Ｄ +Θ ２ ) and in the formula, Θ Ｄ The apparatus according to claim 21, wherein is an angle defined by the region of the at least one X-ray detector.

Images