Multiple beam splitting and redirection device for tomography equipment, tomography equipment, and method for acquiring three-dimensional tomographic images of a sample.

Abstract

To provide a multi beam splitting and redirecting apparatus (4), a tomographic apparatus (2) and a method for creating a three dimensional tomographic image of a sample (42).SOLUTION: A multi beam splitting and redirecting apparatus (4) comprises at least two beam splitters (11, 12, 13, 14, 15, 16), which are arranged on an incidence beam path (22) of a primary beam (20). Every beam splitter (11, 12, 13, 14, 15, 16) is configured to generate a beamlet (31, 32, 33, 34, 35, 36) by scattering the primary beam (20) and to attenuate the primary beam (20). The beam splitters (11, 12, 13, 14, 15, 16) are arranged to have a distance (18) to each other, and all the beamlets (11, 12, 13, 14, 15, 16) are directed to an inspection point (40) being distanced from the incidence beam path (22).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a multiple beam splitting and redirecting (changing the direction of a beam) device for tomographic apparatuses. The present invention further relates to a tomographic apparatus and a method for acquiring three-dimensional tomographic images of a sample (object).

Background Art

[0002] In many scientific and technical fields and their application fields, it is very important to acquire three-dimensional information about a sample. Established methods for three-dimensional imaging technology include computed tomography (CT) or computed laminography (CL), which analyze a sample using an X-ray beam. Typically, either the sample is rotated about a predetermined axis, or the light source and the detector are rotated around the sample. Projection images of the sample are captured from various angles, and three-dimensional data containing three-dimensional information of the sample is constructed by various algorithms.

[0003] This approach encounters problems when it is desired to improve the three-dimensional data acquisition time for acquiring dynamic three-dimensional information of very high-speed processes within a sample. To improve the acquisition time, the sample needs to be rotated faster than ever before, at which point centrifugal force begins to affect the sample. Additionally, when rotating the light source and the detector, increasing the rotation speed encounters physical limits at a certain point. As an attempt to circumvent this physical limit, multiple beam experimental arrangements have been proposed. In a multiple beam experimental arrangement, the sample is simultaneously irradiated by a plurality of beams from different angles.

[0004] Non-patent document 1 describes a method in which a single crystal is placed upstream of the sample to be analyzed, and an X-ray beam is incident on the single crystal. The single crystal acts as a beam splitter, scattering the incident X-ray beam across multiple lattice planes of the crystal, thereby generating multiple diffracted beamlets that irradiate the sample. As the multiple beamlets pass through the sample, projection images from multiple angles can be acquired simultaneously, from which a three-dimensional tomographic image can be obtained. However, this method requires the sample to be placed very close to the crystal, which limits the size of the sample to be analyzed and the types of measurements that can be performed.

[0005] Non-patent document 2 discloses a multi-beam X-ray optical system equipped with a silicon crystal having multiple blades arranged along a hyperbolic shape. When an X-ray beam is incident, Bragg diffraction generates X-ray beams from the silicon crystal, irradiating the sample from multiple angles. In this way, projection images within a certain angular range can be acquired simultaneously. However, the fabrication of the silicon crystal with multiple blades is complex, and this method requires a large-sized X-ray beam. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] "Hard x-ray multi-projection imaging for single-shot approaches," Optica, November 29, 2018, Vol. 5, No. 12. [Non-Patent Document 2] "Multibeam x-ray optical system for high-speed tomography," "Optica," May 12, 2020, Vol. 7, No. 5. [Overview of the project] [Problems that the invention aims to solve]

[0007] The object of the present invention is to provide a multi-beam splitting and redirection device, a tomography device, and a method for acquiring three-dimensional tomographic images of a sample, thereby enabling flexible and extremely fast data acquisition and overcoming the technical limitations of the prior art. [Means for solving the problem]

[0008] The objective is solved by a multiple beam splitting and redirection device for tomography equipment, which includes at least two beam splitters, both positioned along the path of the primary beam (incident beam), where all beam splitters are spaced apart from each other to generate beamlets by scattering the primary beam and attenuating the primary beam, and all beamlets are directed towards a measurement position (sample position) away from the incident beam path.

[0009] The primary beam is attenuated each time it is scattered by a beam splitter as it propagates along its path. At each beam splitter, the primary beam is scattered, thereby generating a beamlet. After being generated by the beam splitters, the beamlets propagate straight along their respective paths to the measurement point. The sample to be analyzed is placed at the measurement point. After passing through the sample, the intensity distribution of the beamlets is measured to obtain three-dimensional information about the sample. The measured intensity distribution is usually called a projection image in tomography. The set of projection images provides 3D image data suitable for obtaining a three-dimensional tomographic image.

[0010] Because beamlets are generated by beam splitters positioned at a distance from each other along the primary beam path, all beamlets reach the measurement point from different directions, providing a wide angular range for tomography. A single primary beam is sufficient to achieve this angular range, and there are no limitations on the size of the sample.

[0011] Compared to the state-of-the-art experimental setups described above, the multi-beam splitting and redirection apparatus of the present invention offers extremely high flexibility because the characteristics of the primary beam, the number of beamlets, the direction in which the beamlets reach the measurement point, and the energy of the beamlets can all be easily adjusted.

[0012] In the context of this specification, the term “tomography” refers to an imaging technique in which projection images of a sample are taken from different directions and then reconstructed using a commonly known reconstruction algorithm. Here, the tomographic image is obtained based on a mathematical process of tomographic reconstruction, thereby obtaining 3D image data containing 3D sample information. Tomography techniques, particularly those well known in the field of medical diagnosis, involve scanning the sample 360° around. However, this is not absolutely necessary for tomographic reconstruction of cross-sectional images. From this perspective, the term “tomography” should not be understood as being limited to 360° circumferential scanning techniques. In contrast to tomography techniques used in medical diagnosis, the tomography apparatus of the present invention is configured to perform tomography at scan angles of 360° or less, for example, in the range of 0° to 180°.

[0013] Furthermore, in the context of this specification, the terms “beam” and “beamlet” refer to a directional energy radiation beam, including electromagnetic wave beams and particle beams. These terms are understood not to be particularly limited to focused beams (beams directed towards a single point). Furthermore, the term “beamlet” is understood to refer to a beam resulting from the scattering / reflection of a portion of the primary beam, meaning that its intensity is weaker compared to the primary beam. The “beamlet” of this invention propagates toward the measurement point. Beams and beamlets are not necessarily focused, but they can be focused. Therefore, for example, the magnification of the projected image can be adjusted by focusing the beamlet upstream or downstream of the measurement point.

[0014] The distance between beam splitters is a predetermined, specific distance. This distance is predetermined by the prerequisite that the beamlet must be directed towards the measurement point. However, this does not mean the distance is fixed. The beam splitters may be movable, and as a result, the distance between them can be adjusted to a desired value. Even during measurement, the distance between beam splitters may be slightly altered to improve the beamlet's position. Specifically, the distances between at least two consecutive beam splitters are different. For example, the distance between the first and second beam splitters may be greater or less than the distance between the second and third beam splitters.

[0015] Preferably, at least two beam splitters are crystals, and they generate beamlets by scattering the primary beam through the lattice planes of the crystals. In this case, the beam splitters become amplitude splitters.

[0016] In the context of this specification, an amplitude splitter is a beam splitter that divides the amplitude of an incident beam. In contrast, a wavefront splitter is a beam splitter that divides the beam profile of an incident beam.

[0017] When an X-ray beam strikes a solid, the beam is scattered by the atoms in the solid. If the solid is a crystal, and the X-ray beam strikes the crystal at the appropriate angle of incidence, a scattered beam is generated by the constructive interference of X-rays reflected by the lattice planes. A crystal used as one of the beam splitters scatters the primary beam at one of its lattice planes, thereby generating a beamlet and attenuating the primary beam.

[0018] Since beam splitters commonly used in the visible light spectrum cannot be used for high-energy beams such as X-rays or gamma rays, the advantage of using crystals is that they can be used as beam splitters for these beams.

[0019] The angle at which an X-ray beam is scattered by a crystal depends on the wavelength of the beam, the spacing of the lattice planes that scatter the beam, and the order of diffraction, given as the Miller indices. Therefore, the crystal must be positioned in the appropriate orientation so that the primary beam is incident on the crystal at the appropriate angle, and primary beams of a specific wavelength are scattered by lattice planes with the desired Miller indices.

[0020] For example, the first beam splitter can be positioned to scatter the primary beam on the (111) grid plane, the second beam splitter can be positioned to scatter the primary beam on the (004) grid plane, and the third beam splitter can be positioned to scatter the primary beam on the (333) grid plane.

[0021] Specifically, at least one of the beam splitters is made of a crystal containing only a single element. Examples of crystalline materials include diamond, silicon, germanium, or tungsten, but it can be any element from lithium to uranium in the periodic table. The beam splitter may be a single crystal or a polycrystalline material, for example, a mosaic crystal or a defective single crystal. The beam splitter may also be composed of multiple chemical elements, for example, SiC, SiGe, GaAs, CdTe, but it can be any combination of chemical elements in the periodic table that take on a crystalline structure. The beam splitter can also be made from crystals of complex molecules that form organic crystals.

[0022] Instead of an amplitude splitter used as a beam splitter, a wavefront splitter, for example, a crystal, a diffraction grating, a multilayer film or a mirror may be used. In this case, although the beam size of each beamlet is small, an arrangement that can achieve a wider energy bandwidth is conceivable. As a wavefront splitter in such an arrangement, the use of asymmetric reflection that can expand the beam size is particularly useful. It can not only increase the energy bandwidth of the incident primary beam, but also increase the beam size of the beamlet, and can offset the effect of the primary beam being split into small parts by wavefront splitting. This arrangement is particularly useful in the case of a highly monochromatic primary beam. That is because, in this case, the arrangement using an amplitude splitter cannot be used since the most upstream beam splitter diffracts most of the primary beam. Even in the case of a highly monochromatic primary beam, generation of a plurality of beamlets can be achieved by using a series of wavefront splitters, and sufficiently large beamlets can be maintained due to the beam size expansion caused by asymmetric reflection.

[0023] According to the multiple beam splitting and redirecting device of an aspect of the present invention, for example, if synchrotron radiation is used, 3D information can be realized at a sampling rate on the order of kHz. An X-ray free electron laser (XFEL) can generate pulse trains at a sampling rate in the MHz range, and 3D information can be obtained at an MHz sampling rate by using each pulse generated at a repetition frequency in the MHz range. In the case of an XFEL capable of generating pulse trains from Hz rate to MHz rate, the present invention enables acquisition of 2D and 3D images at a sampling rate on the order of picoseconds to nanoseconds through exposure by a single X-ray pulse. With the technology of the multiple beam splitting and redirecting device, a group of fan-shaped beamlets that transmit through a sample and are angularly separated can be generated, and each beamlet can select a narrow energy bandwidth from an input spectrum, so projection images for different X-ray energies can be obtained by each beamlet. This enables the implementation of advanced tomography technology that can obtain energy-resolved 3D information. Since the multiple beam splitting and redirecting device splits a primary beam within one plane, the implementation can be performed on a plurality of planes when there are two or more primary beams. The number of incident beams on the sample determines the number of projection images. A high spatial resolution of less than 1 μm can be achieved by using a condensing optical system, for example, specifically a condensing element with a nanometer-scale focal size before the sample to utilize a magnifying optical system, or by arranging a magnifying / demagnifying optical system immediately after the sample in an arrangement similar to that of a visible light microscope, for example, a defocusing microscope.

[0024] Furthermore, by using the multiple beam splitting and redirecting device of the present invention, the limit determined by sample rotation in X-ray 3D imaging can be overcome, and it is possible to achieve a 3D image data acquisition rate up to MHz. 3D moving images may be acquired at frame intervals from milliseconds to nanoseconds. The acquisition rate of 3D images is not limited by the fundamental physical limit caused by the centrifugal force determined by the rotation speed of the sample itself or the rotation speed around the sample.

[0025] The multi-beam splitting and redirection apparatus of the present invention also overcomes the picosecond and femtosecond barriers for X-ray imaging. In the multi-beam splitting and redirection apparatus of the present invention, the 2D image acquisition rate is not limited by the detector's acquisition rate limit. In fact, no detectors operate at frame rates below nanoseconds, and the frame rate limit is determined by a fundamental physical limit, namely the charge carrier mobility of electrons within semiconductors, which prevents the sampling rate of a 2D detector from being less than 1 nanosecond. Therefore, detectors operating at picosecond frame rates have not existed. The experimental configurations described herein can circumvent this fundamental limitation.

[0026] Furthermore, the multi-beam splitting and redirection device of the present invention overcomes the picosecond barrier in 3D imaging, realizing 3D video with frame rates on the order of picoseconds, i.e., 3D GHz video. Using the multi-beam splitting and redirection device of the present invention, it is possible to record 3D images on a picosecond timescale. The 3D image acquisition rate is not limited by the fundamental physical limits determined by the rotation speed or by the frame rate limits of the detector.

[0027] The beamlets generated by the beam splitter pass through the sample, producing projected images of the sample from different projection directions. Each projected image may be recorded by a different detector for each beamlet, either by a single detector with a field of view sufficient to capture all projected images, or by a combination of detectors. Because each beamlet propagates through a different optical path before reaching the sample, each beamlet propagates a different distance, and therefore the projected images have a time difference equivalent to the time obtained by dividing the difference in propagation distance by the speed of light. This time difference depends on the distance between the beam splitters and can be set to the order of picoseconds to nanoseconds in practical applications. All projected images are recorded without moving the sample, beam splitters, light source, or detectors. Instead of rotating the sample or detector, the beam "rotates" around the sample. The difference in the time of acquisition of the projected images is on the order of picoseconds to nanoseconds.

[0028] The multi-beam splitting and redirection device can be used with three modalities.

[0029] For 3D MHz imaging, the time difference between all projected images only needs to be on the order of sub-microseconds or nanoseconds; picosecond time differences between projected images are not important. For kHz 3D imaging, picosecond time differences between projected images are even less important, in which case the time difference between all projected images only needs to be in the sub-millisecond or microsecond range. Therefore, for imaging at sampling rates of 3D MHz or kHz, if the sample velocity is appropriate, all projected images can be considered acquired simultaneously. From these projections, it is possible to reconstruct 3D MHz or kHz images, each image being a tomographic frame taken at the aforementioned sampling rate. Naturally, to acquire 3D MHz or kHz video, the camera or detector recording the projected images must operate at a frame rate of MHz or kHz.

[0030] In 2D GHz imaging, the time difference between projected images is on the order of picoseconds. By selecting various materials and lattice plane orientations as beam splitters, 2D images of dynamic phenomena can be recorded on a picosecond timescale, i.e., as GHz 2D videos. Using multiple beam splitting and redirection devices, 2D GHz videos can be acquired even with "slow" detectors by using single-bunch X-rays with pulse widths of less than picoseconds. In fact, images recorded by each detector have a time difference of the order of picoseconds from other detectors, and these can be incorporated into the GHz 2D video.

[0031] The multi-beam splitting and redirection devices described above can also be combined with other beam splitting methods and arrangements to achieve 3D GHz imaging. In fact, the primary beam can be split into two or more beams as the incident beams for the aforementioned multi-beam splitting and redirection devices, each with sufficient intensity to be used by a separate multi-beam splitting and redirection device. Thus, each branch of the primary beam can be used as the incident beam for the multi-beam splitting and redirection devices, and all of these devices image the same sample. By placing the multi-beam splitting and redirection devices and beam splitters at appropriate distances, the beamlets generated from all of the multi-beam splitting and redirection devices can be directed onto the sample from different directions at precisely the same time. Therefore, these beamlets generate projected images of the sample from different angles, precisely and simultaneously, and a 3D image of the sample can be reconstructed from the obtained projected images. Generally, the beamlets generated from each multi-beam splitting and redirection device have a time difference of the order of picoseconds. Therefore, the multiple beam splitting and redirection devices described above generate a set of projected images of the sample, each set having a picosecond-order time difference from another set, and each set can give multiple projected images taken precisely simultaneously but from different angles. An instantaneous 3D image of the sample can be reconstructed from each set, but since these 3D images have a picosecond-order time difference from another set, the time difference between each frame realizes a picosecond 3D video, i.e., 3D GHz video.

[0032] In addition to crystalline beam splitters, beam splitters can also be refractive or reflective beam splitters fabricated using micro and nano-fabrication processes. Micro and nano-fabrication beam splitters utilize coherent diffraction from periodic structures fabricated for beam splitting. Examples include diffraction gratings, periodic 2D structures fabricated on transparent support films, and zone plates. Refractive and reflective beam splitters, like beam splitters for visible light, use refraction or reflection instead of coherent diffraction for beam splitting. These types of beam splitters are primarily used for relatively low-energy beams, including UV light. Examples of these beam splitters include multilayer structures and structures fabricated using micro and nano-fabrication processes, such as capillary lenses and Laue lenses. Multilayer mirrors and micro-angle incidence mirrors can also be used and considered beam splitters. Typically, this type of beam splitter functions as a wavefront beam splitter, but if sufficiently thin, the mirror can also be used as an amplitude beam splitter.

[0033] Preferably, the configuration includes at least one of the at least two beam splitters, where at least one is configured to scatter the primary beam in a reflective arrangement, or at least one of the at least two beam splitters, where at least one is configured to scatter the primary beam in a transmission arrangement.

[0034] The reflection configuration, also known as the Bragg case, is particularly in the symmetric Bragg case, where the lattice planes diffracting the primary beam are parallel to the main surface of the crystal. The transmission configuration, also known as the Laue case, is particularly in the symmetric Laue case, where the lattice planes diffracting the primary beam are perpendicular to the main surface of the crystal. In the context of this invention, the main surface of the crystal is defined as the surface that the primary beam first strikes.

[0035] According to one embodiment of the present invention, each beam splitter is configured and / or tuned to scatter a specific energy spectral width (a different portion of the energy spectrum of the primary beam, with different average energies and energy bandwidths) of the energy spectrum of the primary beam by at least one of a configuration that selects a specific crystalline material and a configuration that adjusts the crystal orientation to diffract the primary beam at a specific lattice plane.

[0036] Multiple beam splitting and redirection devices can efficiently utilize a primary beam with an energy bandwidth by configuring and / or adjusting all beam splitters to scatter different portions of the primary beam's energy spectrum. In addition, it is ensured that all beamlets generated by the beam splitters still have sufficient and substantially the same energy, even if the intensity of the primary beam is continuously attenuated as it passes through the beam splitters.

[0037] Different crystalline materials provide different lattice plane spacings. By changing the material used in the beam splitter, and thereby changing the lattice plane spacing, beams of different energies are scattered at a certain angle. This allows for adjustment of the energy of the beamlet scattered in the direction of the measurement point. Adjustment of the beamlet energy can also be achieved by changing the orientation of a crystal to adjust the diffraction of the primary beam across a different lattice plane with a different lattice plane spacing.

[0038] Specifically, the primary beam is at least one of a white beam, a pink beam, or a monochromatic beam, where the energy bandwidth dE / E of the white beam is substantially 10 0 Therefore, the energy bandwidth dE / E of the pink beam is effectively 10 -2 Therefore, the energy bandwidth dE / E of the monochromatic beam is effectively 10 -4 Here, E is the average X-ray energy, and dE is half the energy bandwidth of the X-ray energy.

[0039] White and pink beams have an advantage in that they have a broad energy bandwidth spectrum. Because of the broad energy bandwidth of the spectrum, each beam splitter can scatter different portions of the primary beam's energy spectrum, even when a large number of beam splitters are present. Monochromatic beams offer a narrow energy bandwidth, allowing for imaging of the sample at a single energy, i.e., the energy of the primary beam.

[0040] Preferably, the primary beam is specifically a pulsed X-ray beam, gamma-ray beam, neutron beam, or extreme ultraviolet (EUV) beam, where the wavelength of the EUV beam is less than 120 nm. For example, the wavelength of the primary beam is 0.01 to 1 nm. This wavelength has been shown to be suitable for the primary beam. However, primary beams with longer or shorter wavelengths may also be used.

[0041] X-rays are a widely used tool for acquiring 3D data. Many high-brightness X-ray sources exist, from laboratory light sources to synchrotron sources and X-ray free electron laser (XFEL) sources, providing optimal X-ray beams for use as primary beams in multiple beam splitting and redirection devices. Gamma rays are also suitable as primary beams in multiple beam splitting and redirection devices, mainly because their sources differ from those of X-rays, and their energy spectra are not necessarily different. In addition, multiple beam splitting and redirection devices can also be used with neutron beams, as neutron diffraction is very similar to X-ray diffraction.

[0042] In neutron beam splitters, the same coherent diffraction mechanism as in X-ray beam splitters can be used. This is because neutrons, like X-rays, can be treated as waves. In embodiments of neutron beam splitters, it is preferable to use materials with a small scattering cross-section for neutron absorption, such as boron. Naturally, in these embodiments, the scattering angle of the beam splitter needs to be recalculated, as does the intensity of the beamlet.

[0043] For UV applications, all of the aforementioned types of beam splitters exist, including crystalline beam splitters, diffraction gratings, beam splitters fabricated by micro and nano processes, and refractive or reflective beam splitters.

[0044] Preferably, at least two beam splitters are configured to generate beamlets along the beamlet direction, where the beamlet direction of each beamlet is at a different angle with respect to the direction of the primary beam.

[0045] For example, in the case of a crystal beam splitter that scatters the primary beam by Bragg diffraction, the scattering from each beam splitter occurs at different Bragg angles.

[0046] By generating beamlets that form different beamlet angles with respect to the direction of the primary beam, all beamlets reach the measurement point from different directions, thereby providing a wide angular range for tomography.

[0047] The beam splitters preferably include a first beam splitter and a second beam splitter, where the first beamlet produced by the first beam splitter forms an angle with the second beamlet produced by the second beam splitter, and this angle is between 0.1° and 179.9°, and specifically between 0.1° and 90° or 0.1° and 60°.

[0048] A larger angle between beamlets allows for tomographic imaging over a wider angular range. Specifically, the angle between beamlets in a series of beam splitters is always greater than 0° and less than 180°.

[0049] For example, the angle between the beamlets of two consecutive beam splitters is at least 1°.

[0050] Preferably, at least one of the beam splitters is a configuration including a curved crystal and / or a mosaic crystal, and a crystal made of elements with atomic numbers 3 to 92, or a crystal containing elements with atomic numbers 3 to 92. More preferably, it is a configuration made of at least two elements selected from elements with atomic numbers 3, 6, 9, 32, and 49, and more preferably, a crystal containing at least two elements selected from elements with atomic numbers 3, 6, 9, 32, and 49.

[0051] The atomic number of lithium is 3, carbon is 6, fluorine is 9, germanium is 32, and indium is 49. By using curved crystals, mosaic crystals, and / or crystals made of elements with high atomic numbers, the crystal energy bandwidth, i.e., the energy bandwidth of the scattered beamlets, can be broadened. In crystals with a broad energy bandwidth, the crystal diffracts a wider energy width of the primary beam's energy spectrum. In addition, the divergence of the primary beam after passing through the crystal increases. The energy bandwidth of a crystal is the full width at half maximum (FWHM) of the energy of the beamlets scattered by the crystal.

[0052] Specifically, a crystal can be bent, for example, simply by the curvature of lattice planes within the crystal. This curvature of lattice planes can be achieved, for example, by introducing selective ion implantation and / or a clear compositional gradient. A mosaic crystal is a crystal composed of numerous crystallites with slightly different orientations from one another, or a crystal with internal defects or distortions.

[0053] The expansion of the crystal's energy bandwidth can also be achieved by using elements with higher atomic numbers, such as germanium or indium. In crystals composed of multiple elements, for example, when an antimony compound is selected as the beam splitter, the average atomic number of the crystal is specifically at least 32, for example, at least 49.

[0054] Specifically, the beamlet flux (number of X-ray photons per unit time) can be increased by at least one of the following: broadening the spectral acceptance of the crystal, and using asymmetric diffraction with a small-angle incidence configuration. In the latter case, the beam size is increased.

[0055] Preferably, at least two beam splitters are a single component, specifically a part of a single crystal, which consists of multiple scattering surfaces at different angles to each other. Specifically, this single component has multiple scattering surfaces by bending, grooves, or patterning. The single component includes, for example, a single crystal. This experimental setup is also called a single-splitter setup. An advantage of this setup is that the size of the scattering surfaces can be reduced to the order of 10 μm, resulting in a very space-saving setup. In this setup, the distance between diffracting elements can be reduced, allowing for a time delay between beamlets to the order of femtoseconds, enabling very fast 2D imaging at a THz sampling rate. Specifically, multiple single crystals are arranged along the incident beam path.

[0056] The single crystal used in a single-splitter configuration may be a grooved crystal, where the grooves can be created by mechanical processing, etching, laser processing, and / or other fabrication techniques.

[0057] The single crystal used in a single-splitter configuration may be a patterned crystal containing patterns of crystalline and amorphous materials, where the amorphization of a portion of the crystal can be achieved by chemical, thermal, mechanical, laser irradiation, ion implantation, and / or lithography.

[0058] Single crystals used in a single-splitter configuration may have different lattice plane spacings and different chemical compositions, and may be patterned crystals containing patterns of chemically doped crystalline material. Specifically, the crystalline material can be deposited by vapor deposition techniques, with or without chemical reaction with the substrate material, and other deposition techniques, specifically by sputter deposition or laser deposition. Alternatively, it can also be fabricated by generating stress within the crystalline material to change the lattice plane spacings and positions of several layers within the single crystal.

[0059] The single crystal used in a single-splitter configuration may be a patterned crystal, where the pattern can be introduced using standard lithography techniques or by radiation-induced or radiation-assisted erosion / ablation of the material. The pattern may be formed by some or more parts of the crystal surface acting as a radiation mask.

[0060] Specifically, the multi-beam splitting and redirection device includes a recombined crystal, which is configured and positioned to focus the beamlet generated by the crystal onto the measurement point. This enables imaging of large samples.

[0061] Preferably, the multiple beam splitting and redirection device includes at least one primary beam splitter and at least two beam splitter groups, each beam splitter group including the beam splitter, the primary beam splitter being positioned on the incident beam path and configured to generate a secondary beam by scattering the primary beam and attenuating the primary beam, the attenuated primary beam propagating downstream along the incident beam path and the secondary beam propagating downstream along the secondary beam path, one of the beam splitter groups being positioned on the incident beam path downstream of the primary beam splitter and another of the other beam splitter groups being positioned on the secondary beam path.

[0062] In other words, the primary beam is split into multiple branches and directed to multiple beam splitter groups. Advantageously, the angular range for tomography is further expanded because beamlets from different beam splitter groups are directed towards the measurement point from different sides. To further increase the angular range, the primary beam may be split multiple times. The primary beam is split by a primary beam splitter. Specifically, a primary beam splitter is a crystal used as an amplitude splitter or wavefront splitter, or a mirror used as a wavefront splitter. In particular, the primary beam splitter splits the primary beam, and as a result, the plane containing the beamlets generated by the first beam splitter group may be a plane non-parallel to the plane containing the beamlets generated by the second beam splitter group. This allows for 3D imaging from different viewpoints.

[0063] Preferably, the multiple beam splitting and redirection device is configured such that the time difference between the first and last beamlets among all beamlets generated from a single pulse of the pulsed primary beam reaching the measurement point is less than a microsecond, for example, less than a nanosecond, on the order of 1 picosecond to 1 nanosecond.

[0064] By maintaining the time difference between beamlets generated from a single pulse on the order of nanoseconds or picoseconds, it is possible to acquire three-dimensional tomographic images of extremely fast dynamic processes.

[0065] Specifically, the multiple beam splitting and redirection device includes at least two beam splitters made of different materials, where the difference in the lattice plane spacing between the different materials is, for example, less than 65%, less than 20%, and less than 5%.

[0066] By using two or more beam splitters with very similar lattice constants, two or more beamlets with very short time differences on the order of picoseconds or femtoseconds can be generated and used for interferometry. Even faster interferometry can be achieved by miniaturizing this optical system. In fact, the time difference between beamlets is proportional to the size of the optical system. Such a miniaturized optical system can be used with a crystal having concentration gradients of two different elements, for example, Si x Ge 1-x This can be achieved by cutting grooves into the crystal and bending it, resulting in a gradient of lattice constants on the crystal surfaces sandwiched in the grooves. Each surface functions as a slightly different material but has nearly the same lattice constant and diffracts beamlets of the same energy, but the time intervals between them are proportional to the distance between them. Because this type of optical system can be miniaturized to such an extent that the size of the crystal surfaces can be reduced to the order of 10 μm, and therefore the time distances between beamlets can be on the order of femtoseconds. Since these beamlets have the same energy, they interfere with each other, enabling femtosecond-order interferometry.

[0067] In a specific experimental setup, a crystal with a flat surface and / or a normalization mask are placed in front of a multi-beam splitting and redirection device on the primary beam path, where the former is configured and positioned to diffract the primary beam in a transmission configuration. The advantage of the crystal with a flat surface is that it can smooth out beam inhomogeneities caused by a phenomenon called the Bormann triangle. In one embodiment, the crystal with a flat surface is made of diamond or a lighter material. According to another embodiment, the crystal with a flat surface is made of a material heavier than diamond. The normalization mask is configured to remove the spatial structure of the primary beam. Alternatively, the spatial structure of the primary beam can also be removed by an image analysis algorithm.

[0068] The object of the present invention is further achieved by a tomography apparatus. The tomography apparatus includes a light source, at least one image detector, and a multiple beam splitting and redirection device according to any of the embodiments described above, wherein the light source is configured to generate a primary beam, wherein at least one image detector is arranged and configured to measure the intensity of a beamlet after it has passed a measurement point, wherein the tomography apparatus is configured to obtain a three-dimensional image dataset of the sample at the measurement point from the intensity of each beamlet measured by the image detector and the angle that each beamlet makes with the primary beam.

[0069] The tomography system embodies the same or similar functions, advantages, and characteristics as the multi-beam splitting and redirection system, and therefore this should not be repeated.

[0070] In addition, the tomography device generates three-dimensional tomographic images from a three-dimensional image dataset using tomography techniques well known in the art.

[0071] The light source may be an X-ray source, a gamma-ray source, and / or a neutron source. Specifically, the light source is at least one of a laboratory light source, a synchrotron light source, an XFEL light source, and any other suitable light source of any type.

[0072] The image detector is specifically an indirect imaging type X-ray, gamma, neutron, and / or UV image detector, and specifically includes a scintillator and visible light detector, such as a charge-coupled device (CCD), or complementary metal-oxide-semiconductor (CMOS), or scientific measurement CMOS (sCMOS). According to another embodiment, the image detector is a direct imaging type photon counting or integrating detector. For example, the image detector includes at least one camera and / or a large-area image detector.

[0073] In one embodiment, a single image detector is positioned to detect all beamlets passing through the measurement point. The single detector is, for example, a curved detector. According to another embodiment, beamlets are detected by multiple image detectors. For example, all beamlets are detected by different image detectors. For example, at least one of the detectors is a camera, where the position of at least one camera and the number of cameras are selected based on a desired field of view and acquisition time.

[0074] Preferably, the tomography apparatus includes a crystal spectrometer located downstream of a multiple beam splitting and redirection device on the incident beam path, where the crystal spectrometer is, for example, a curved crystal, which is configured to substantially diffract the entire energy spectrum of the primary beam to produce a diffracted spectrometer beam, where a spectrometer image detector configured to image the diffracted spectrometer beam is located on the beam path of the diffracted spectrometer beam, where the spectrometer image detector is specifically a two-dimensional detector.

[0075] A crystal spectrometer consists of a flexible, curved crystal that imparts numerous Bragg angles to the primary beam. Using a crystal spectrometer and a spectrometer image detector, the energy width used in the beamlet can be investigated, which is useful for aligning the beam splitter.

[0076] Preferably, the tomography apparatus includes at least one light-gathering element, which is positioned on at least one path of the beamlet, upstream and downstream of the measurement point.

[0077] Specifically, the focusing element is at least one of an X-ray focusing element, a gamma-ray focusing element, and a neutron focusing element. An X-ray focusing element is, for example, a focusing or defocusing X-ray lens. The advantage of the focusing element is that it can magnify or reduce the beamlet. For example, when using a direct imaging detector, a visible light lens cannot be used for magnification, but magnified imaging is possible using an X-ray focusing element.

[0078] Another specific example of a tomography system includes at least two light sources, each generating a primary beam, which are then incident on different multiple beam splitting and redirection devices. The advantage of this system is that it allows for the acquisition of projected images over a wide angular range exceeding 180° and in different planes.

[0079] The object of the present invention is further achieved by a method for acquiring a three-dimensional tomographic image of a sample. Here, the sample is placed at a measurement point, a primary beam propagates along the incident beam path, and at least two beam splitters are placed on the incident beam path at a certain distance from each other, each generating beamlets and attenuating the primary beam by scattering it, all of which propagate toward a measurement point located away from the incident beam, the intensity of the beamlets after passing through the incident beam and the measurement point is measured using at least one image detector, and a three-dimensional image dataset of the sample at the measurement point is configured to be acquired from the intensity of each beamlet measured by at least one image detector and the angle each beamlet makes with the primary beam.

[0080] Furthermore, this method embodies the same similar features, advantages, and characteristics as tomography equipment and the multi-beam splitting and redirection device of the present invention.

[0081] To cover the entire 360° circumference of the sample, the sample may be rotated after the acquisition of the first image and before the acquisition of the second image.

[0082] According to one embodiment of this method, the two beam splitters are crystals, and beamlets are generated by scattering the primary beam across the lattice planes of the crystals. For example, the beam splitters here are amplitude splitters.

[0083] Preferably, at least one of the at least two beam splitters is configured to scatter the primary beam in a reflective arrangement, and at least one of the at least two beam splitters is configured to scatter the primary beam in a transmission arrangement.

[0084] Each beam splitter preferably scatters different portions of the primary beam's energy spectrum by at least one of a configuration that specifically selects a particular crystalline material and a configuration that adjusts the crystal orientation, thereby diffracting the primary beam through a specific lattice plane.

[0085] Preferably, the primary beam is, for example, a pulsed X-ray beam, a gamma-ray beam, or a neutron beam.

[0086] At least two beam splitters preferably generate beamlets along the beamlet direction, where the beamlet direction of each beamlet has a beamlet angle different from the direction of the primary beam.

[0087] Preferably, the beam splitter includes at least two beam splitters, a first beam splitter and a second beam splitter, where the first beamlet produced by the first beam splitter forms an angle with the second beamlet produced by the second beam splitter, where the angle is between 0.1° and 179.9°, and specifically, may be between 0.1° and 90° or between 0.1° and 60°.

[0088] At least one of the beam splitters is preferably a curved crystal and / or a mosaic crystal, and a crystal consisting of elements 3 to 92, or a crystal containing elements with atomic numbers 3 to 92. More preferably, it is a configuration consisting of at least two elements selected from elements with atomic numbers 3, 6, 9, 32, and 49, and more preferably, a crystal containing at least two elements selected from elements with atomic numbers 3, 6, 9, 32, and 49.

[0089] According to one embodiment, at least two beam splitters are parts of a single crystal, which is grooved and bent to include a plurality of scattering surfaces, the plurality of scattering surfaces making an angle with respect to each other.

[0090] Preferably, at least one primary beam splitter is located on the incident beam path and generates a secondary beam by scattering the primary beam, thereby attenuating the primary beam, the attenuated primary beam propagating downstream along the incident beam path, and the secondary beam propagating downstream along the secondary beam path, where one of at least two beam splitter groups, each containing at least two beam splitters, is located downstream of the primary beam splitter on the incident beam path, and the other of the at least two beam splitter groups is located on the secondary beam path.

[0091] Preferably, the time difference between the first and last beamlets, out of all beamlets generated from a single pulse of the pulsed primary beam, reaching the measurement point is less than a microsecond, for example, less than a nanosecond.

[0092] According to one embodiment, a crystal spectrometer is positioned downstream of a multiple beam splitting and redirection device on the incident beam path, and the crystal spectrometer includes a curved crystal configured to substantially diffract the entire energy spectrum of the primary beam and generate a diffracted spectrometer beam, and a spectrometer image detector is positioned on the beam path of the diffracted spectrometer beam and images the diffracted spectrometer beam, where the spectrometer image detector is, for example, a two-dimensional detector.

[0093] Preferably, at least one focusing element is positioned upstream and / or downstream of the measurement point on at least one path of the beamlet.

[0094] For example, since each beamlet has a different energy, energy-resolved tomography can be achieved by rotating the sample. That is, it is possible to acquire multiple 3D images corresponding to different X-ray energies with each rotation of the sample. Energy-resolved tomography can also be achieved by combining a primary beam splitter or multiple light sources. That is, by creating a multi-beam splitting and redirection device that images the same sample, and transmitting beamlets of the same energy through the sample from different directions, it is possible to acquire multiple 3D images corresponding to different X-ray energies without rotating the sample.

[0095] Further features of the present invention will become apparent from the description of embodiments according to the present invention, along with the claims and drawings. Embodiments according to the present invention may satisfy individual characteristics or combinations of several characteristics.

[0096] The present invention is described below. However, the following exemplary embodiments are not intended to limit the general teachings of the present invention. The following describes the drawings, which disclose details related to all aspects of the present invention that are not described in detail in the text. The drawings are shown below. [Brief explanation of the drawing]

[0097] [Figure 1] This is a schematic diagram of one embodiment of the reflective arrangement of a tomography system equipped with a multi-beam splitting and redirection device. [Figure 2] This is a schematic diagram of one embodiment of the transmission arrangement of a tomography system equipped with a multi-beam splitting and redirection device. [Figure 3] This is a schematic diagram of one embodiment of a tomography apparatus equipped with a crystal spectrometer. [Figure 4] This is a schematic diagram of one embodiment of a tomography apparatus equipped with a primary beam splitter and a plurality of beam splitter groups. [Figure 5] This is a schematic diagram of one embodiment of a tomography apparatus having a single crystal with multiple scattering surfaces. [Figure 6]This is a schematic diagram of one embodiment of a tomography apparatus equipped with multiple single crystals that function as beam splitters. [Figure 7] This is a schematic diagram of a single-component beam splitter, including optical and non-optical components. [Figure 8] This is a schematic diagram of a two-dimensional, single-component beam splitter, including optical and non-optical components. [Modes for carrying out the invention]

[0098] In drawings, the same or similar elements, or their corresponding parts, are given the same reference numeral to prevent duplication of items.

[0099] Figure 1 shows a schematic diagram of a first embodiment of the tomography apparatus 2. The tomography apparatus 2 includes a light source 5, a multi-beam splitting and redirection device 4, and an image detector 6. The light source 5 is, for example, an X-ray source that generates a primary beam 20 along an incident beam path 22. The multi-beam splitting and redirection device 4 includes a plurality of beam splitters 11, 12, 13, and 14 arranged on the incident beam path 22. The beam splitters 11, 12, 13, and 14 are crystals, each scattering the primary beam 20 by Bragg diffraction, and thus generating diffracted beamlets 31, 32, 33, and 34, and attenuating the primary beam 20. Each beamlet 31, 32, 33, and 34 propagates in the beamlet direction 31a, 32a, 33a, and 34a, and is focused at a measurement point 40, where the sample 42 is placed. An image detector 6 is positioned along the paths of beamlets 31, 32, 33, and 34 downstream of the measurement point 40, and captures the intensity distribution generated by beamlets 31, 32, 33, and 34. Since beamlets 31, 32, 33, and 34 transmit light through the sample 42 from different directions, a 3D image dataset of the sample 42 can be obtained by measuring the intensity distribution. A 3D tomographic image of the sample 42 can be calculated from the 3D image dataset. The image detector 6 may be an indirect imaging image detector or a direct imaging image detector.

[0100] To focus the beamlets 31, 32, 33, and 34 onto the measurement point 40, the distance 18 between the beam splitters 11, 12, 13, and 14, and the beamlet angles θ1, θ2, θ3, and θ4 that the beamlets 31, 32, 33, and 34 make with the direction of the primary beam 20 must be appropriately adjusted. According to Bragg's law, the beamlet angles θ1, θ2, θ3, and θ4 correspond to the scattering angles (twice the Bragg angle) and depend on the wavelength of the primary beam 20 and the spacing between the lattice planes that scatter the primary beam 20. Therefore, to change the beamlet angles θ1, θ2, θ3, and θ4 of a primary beam 20 with a given wavelength, the spacing between the lattice planes must also be changed. This is done by selecting a material with an appropriate lattice constant and adjusting the orientation of the crystal so that the primary beam 20 is scattered by lattice planes with the desired Miller indices.

[0101] For example, when a monochromatic X-ray primary beam with a wavelength of approximately 0.069 nm is incident on three beam splitters, the first beam splitter is made of germanium, with the crystal orientation adjusted so that the primary beam is scattered at the (022) lattice plane, and a beamlet is generated at a beamlet angle of approximately 10°. The second beam splitter is made of silicon, with the crystal orientation adjusted so that the primary beam is scattered at the (004) lattice plane, and a beamlet is generated at a beamlet angle of approximately 14°. The third beam splitter is made of carbon, with the crystal orientation adjusted so that the primary beam is scattered at the (333) lattice plane, and a beamlet is generated at a beamlet angle of approximately 30°.

[0102] When a primary beam 20 with a broad energy spectrum, such as a pink beam or a white beam, is used, beam splitters 11, 12, 13, and 14 can be configured to scatter different portions of this energy spectrum, respectively. This makes it possible to utilize the majority of the primary beam's energy spectrum for tomography. Naturally, the beam splitters 11, 12, 13, and 14 must be made from suitable materials and positioned at the correct orientation and distance 18 from each other, so that the beamlets 31, 32, 33, and 34 generated from different portions of the energy spectrum are still focused on the measurement point 40.

[0103] The angle δ between the beamlet from the first beam splitter 11 and the beamlet from the last beam splitter 14 of the multi-beam splitting and redirection device 4 defines the projection angle range of the tomography device 2 shown in Figure 1. To achieve a wide angle range for tomography, the angle δ needs to be selected to be as large as possible.

[0104] Figure 2 shows a schematic diagram of a second embodiment of the tomography apparatus 2. In this embodiment, the primary beam 20 is generated by a large light source not shown in Figure 2, such as a synchrotron light source or an XFEL light source. In addition, the beam splitters 11, 12, 13, and 14 are configured to scatter the primary beam 20 in a transmission configuration (Laue case) instead of a reflection configuration (Bragg case).

[0105] A focusing element 60 is positioned in front of the measurement point 40 on the beam path of the beamlet 31, and another focusing element 61 is positioned downstream of the measurement point 40. The focusing elements 60 and 61 are, for example, X-ray focusing elements, which magnify and reduce the X-rays to change the spatial size of the beamlet 31 as it passes through the measurement point 40.

[0106] Figure 3 shows a schematic diagram of a third embodiment of the tomography apparatus 2. In this embodiment, only two beam splitters 11 and 12 are arranged on the incident beam path 22. A separate image detector 6 is provided for each beamlet 31 and 32 generated by the beam splitters 11 and 12. In addition, a crystal spectrometer 50 is located downstream of the beam splitters 11 and 12 on the incident beam path 22. The crystal spectrometer 50 is, for example, a flexible curved crystal, which provides numerous surfaces on which the primary beam 20 is scattered, thereby generating a diffraction spectrometer beam 52. The spectrometer image detector 54 is, for example, a two-dimensional detector, which photographs the diffraction spectrometer beam 52 to measure the total energy spectrum of the primary beam 20. Thus, it is possible to determine which portion of the total energy spectrum is scattered as beamlets 31 and 32 by the beam splitters 11 and 12. By monitoring the energy of the primary beam 20 scattered as beamlets 31 and 32, the beam splitters 11 and 12 can be aligned. The primary beam camera 56 is positioned downstream of the crystal spectrometer 50 on the incident beam path 22 to measure the intensity distribution of the remaining primary beam 20.

[0107] Figure 4 shows a schematic diagram of a fourth embodiment of the tomography apparatus 2. In this embodiment, the primary beam splitter 70 is positioned in front of the beam splitters 11, 12, 13, and 14 of the first beam splitter group 71, on the path of the first beam 20. The primary beam splitter 70 splits a portion of the primary beam 20 into a secondary beam 74, which forms an angle with the primary beam 20. In the example shown in Figure 4, this angle is approximately 90°. However, the angle between the primary beam 20 and the secondary beam 74 can be any angle between 0° and 180°. A second beam splitter group 72, comprising beam splitters 15 and 16, is positioned on the secondary beam path 76 of the secondary beam 74. Similar to beam splitters 11, 12, 13, and 14, beam splitters 15 and 16 are configured and positioned to generate beamlets 35 and 36 by scattering the secondary beam 74, and to focus the beamlets 35 and 36 onto the measurement point 40.

[0108] Using the tomography apparatus 2 according to this embodiment, the beam splitters 11, 12, 13, 14, 15, and 16 can be positioned on different sides of the sample 42, thereby enabling tomography over a wider angular range. The beam splitters 11, 12, 13, and 14 of the first beam splitter group 71 and the beam splitters 15 and 16 of the second beam splitter group 72 may be part of a single multiple beam splitting and redirection apparatus 4, or they may constitute different multiple beam splitting and redirection apparatuses 4 as separate beam splitter groups 71 and 72.

[0109] To further increase the angular range, the primary beam 20 and / or secondary beam 74 may be split multiple times by multiple primary beam splitters 70, and more beam branches may be generated using each beam splitter group 71, 72.

[0110] Figure 5 shows a schematic diagram of a fifth embodiment of the tomography apparatus 2 with the single-splitter configuration described above. In this embodiment, the beam splitters 11, 12, and 13 are realized as a single component, in this case a single crystal 80. That is, the single component includes a single crystal, specifically consisting of a single crystal 80. Hereafter, this single component will be described as the single crystal 80. The single crystal 80 has grooves cut into it to separate multiple scattering surfaces 81, 82, and 83, and by bending, two of the scattering surfaces 81, 82, and 83 form an angle. Therefore, the generated beamlets 31, 32, and 33 reach the measurement point 40 from slightly different positions and at slightly different angles. The crystal 80 in Figure 5 has only three scattering surfaces 81, 82, and 83, but any number of scattering surfaces can be given to the crystal 80.

[0111] Since the scattering surface size of single crystal 80 can be reduced to the order of 10 μm, using single crystal 80 as beam splitters 11, 12, and 13 allows for miniaturization of the experimental setup. In addition, the optical path length difference between beamlets 31, 32, and 33 is very small, and the time delay between beamlets 31, 32, and 33 is on the order of femtoseconds. This enables a THz sampling rate for 2D imaging.

[0112] Figure 6 shows a schematic diagram of one embodiment of a tomography apparatus 2 using multiple single crystals 80 as beam splitters. All single crystals 80 are placed on the incident beam path 22, and beamlets 31, 32, and 33 are generated from all scattering surfaces 81, 82, and 83 of all single crystals 80 and propagate to the measurement point 40.

[0113] Figure 7 shows a schematic diagram of a single crystal 80 including an optical element 84 and a non-optical element 85. The optical element 84 is configured to scatter the primary beam 20 in the direction of the measurement point 40 and to function as scattering surfaces 81, 82, and 83 of the single crystal 80. The non-optical element 85 separates the regions of the optical element 84 from each other. The single crystal 80 may be a grooved crystal or a patterned crystal. The pattern may be a pattern of crystalline material having crystalline and amorphous materials, different lattice plane spacings, different chemical compositions, or different doping elements / concentrations, and / or a pattern obtained by lithography techniques or local ablation of the material. The last example may be achieved by masking a portion of the crystal surface for ablation.

[0114] Figure 8 is a schematic diagram of a two-dimensional single-component beam splitter including optical elements 84 and non-optical elements 85. The optical elements 84 are patterned in a grid pattern. The primary beam 20 is scattered two-dimensionally toward the measurement point 40 by each optical element.

[0115] All named characteristics, including those obtained solely from the drawings, and individual characteristics disclosed in combination with other characteristics, are considered important to the present invention, both individually and in combination. Embodiments of the present invention may be realized by individual characteristics or combinations of several characteristics. Characteristics described in combination with the words “in particular,” “specifically,” or “for example” should be treated as preferred embodiments. [Explanation of Symbols]

[0116] 2. Tomography equipment 4. Multiple beam splitting and redirection device 5 light source 6 Image detector 11,12,13,14,15,16 Beam Splitter 18 distance 20 Primary beam 22 Incident beam path 31, 32, 33, 34, 35, 36 Beamlet 31a, 32a, 33a, 34a Beamlet direction 40 measurement points 42 samples 50 Crystal Spectrometer 52 Diffraction Spectrometer Beam 54 Spectrometer Image Detector 56 Primary beam camera 60 light-gathering elements 61 Light-gathering element 70 Primary Beam Splitter 71, 72 Beam Splitter Group 74 Secondary beam 76 Secondary beam path 80 Single Crystals 81,82,83 scattering surface 84 Optical Components 85 Non-optical components δ angle θ1, θ2, θ3, θ4 Beamlet angles

Claims

1. A multi-beam splitting and redirection device (4) for a tomography device (2), The system comprises at least two beam splitters (11, 12, 13, 14, 15, 16) positioned on the incident beam path (22) of the primary beam (20), All beam splitters (11, 12, 13, 14, 15, 16) generate beamlets (31, 32, 33, 34, 35, 36) by scattering the primary beam (20), The primary beam (20) is configured to be attenuated, and the beam splitters (11, 12, 13, 14, 15, 16) are arranged at a distance (18) from each other. The beamlets (31, 32, 33, 34, 35, 36) are directed towards a measurement point (40) located away from the incident beam path (22). The beam splitters (11, 12, 13, 14, 15, 16) are configured to generate the beamlets (31, 32, 33, 34, 35, 36) along the beamlet direction (31a, 32a, 33a, 34a), Each of the beamlets (31, 32, 33, 34, 35, 36) has a beamlet direction (31a, 32a, 33a, 34a) that is different from the beamlet angle (θ1, θ2, θ3, θ4) with respect to the direction of the primary beam (20). The angle between the beamlets (31, 32, 33, 34, 35, 36) of adjacent beam splitters (11, 12, 13, 14, 15, 16) is at least 1°. The beamlets (31, 32, 33, 34, 35, 36) propagate straight from the beam splitters (11, 12, 13, 14, 15, 16) to the measurement point (40). Multiple beam splitting and redirection device (4).

2. The beam splitters (11, 12, 13, 14, 15, 16) are made of crystal, The beamlets (31, 32, 33, 34, 35, 36) are generated by scattering the primary beam (20) onto the lattice plane of the crystal. The apparatus (4) according to claim 1, characterized in that the beam splitters (11, 12, 13, 14, 15, 16) are amplitude splitters.

3. The apparatus (4) according to claim 1, characterized in that at least one of the beam splitters (11, 12, 13, 14, 15, 16) is configured to scatter the primary beam (20) in a reflective arrangement, or at least one of the beam splitters (11, 12, 13, 14, 15, 16) is configured to scatter the primary beam (20) in a transmission arrangement.

4. The apparatus (4) according to claim 1, wherein each of the beam splitters (11, 12, 13, 14, 15, 16) is characterized by scattering a specific energy spectral width of the primary beam (20) by at least one of a configuration that selects a specific crystalline material and a configuration that adjusts the orientation of the crystal so as to diffract the primary beam (20) at a specific lattice plane.

5. The primary beam (20) is a pulsed X-ray beam, gamma-ray beam, neutron beam, or extreme ultraviolet (EUV) beam. The apparatus (4) according to claim 1, characterized in that the wavelength of the extreme ultraviolet (EUV) beam is less than 120 nm.

6. The beam splitters (11, 12, 13, 14, 15, 16) include a first beam splitter (11) and a second beam splitter (14), The first beamlet (31) generated by the first beam splitter (11) forms an angle (δ) with the second beamlet (34) generated by the second beam splitter (14). The apparatus (4) according to claim 1, characterized in that the angle (δ) is between 0.1° and 179.9°.

7. At least one of the beam splitters (11, 12, 13, 14, 15, 16) has a configuration including a curved crystal and / or a mosaic crystal, The apparatus (4) according to claim 1, characterized in that it has at least one of the following: a structure which is a crystal consisting of or containing elements with atomic numbers 3 to 92.

8. The beam splitters (11, 12, 13, 14, 15, 16) are part of a single component (80) that includes a single crystal. The apparatus (4) according to claim 1, wherein the single component includes a plurality of scattering surfaces (81, 82, 83) that are oriented in different directions from one another.

9. It comprises at least one primary beam splitter (70) and at least two beam splitter groups (71, 72), The beam splitter group (71, 72) includes the beam splitters (11, 12, 13, 14, 15, 16), The primary beam splitter (70) is positioned on the incident beam path (22) and is configured to generate a secondary beam (74) by scattering the primary beam (20) and to attenuate the primary beam (20). The attenuated primary beam (20) propagates downstream along the incident beam path (22), and the secondary beam (74) propagates downstream along the secondary beam path (76). The apparatus (4) according to claim 1, wherein one of the beam splitter groups (71, 72) is located downstream of the primary beam splitter (70) on the incident beam path (22), and the other beam splitter group (71, 72) is located on the secondary beam path (76).

10. The apparatus (4) according to claim 1, wherein the time difference between the first and last beamlets (31, 32, 33, 34, 35, 36) that reach the measurement point (40) from a single pulse of the pulsed primary beam (20) is configured to be less than 1 microsecond.

11. A tomography apparatus (2) comprising a light source (5), at least one image detector (6), and the apparatus (4) according to any one of claims 1 to 10, The light source (5) is configured to generate the primary beam (20), The image detector (6) is arranged and configured to measure the intensity of the beamlets (31, 32, 33, 34, 35, 36) after they have passed through the measurement point (40). The tomography apparatus (2) obtains a three-dimensional image dataset of the sample (42) at the measurement point (40) using the intensity of the beamlets (31, 32, 33, 34, 35, 36) measured by the image detector (6), and the beamlet angle (θ １ , θ ２ , θ ３ , θ ４ ) and configured to be obtained from, The beamlet angle (θ １ , θ ２ , θ ３ , θ ４ ) is the angle between the beamlets (31, 32, 33, 34, 35, 36) and the primary beam (20), respectively, in the tomography apparatus (2).

12. The system includes a crystal spectrometer (50) positioned downstream of the multiple beam splitting and redirection device (4) on the incident beam path (22), The crystal spectrometer (50) includes a curved crystal configured to substantially diffract the entire energy spectrum of the primary beam (20) and generate a diffracted spectrometer beam (52), The spectrometer image detector (54) for capturing the diffraction spectrometer beam (52) is positioned on the beam path of the diffraction spectrometer beam (52), The tomography apparatus (2) according to claim 11, wherein the spectrometer image detector (54) is a two-dimensional detector.

13. The tomography apparatus (2) according to claim 11, comprising at least one focusing element (60, 61) positioned upstream and downstream of the measurement point (40) on at least one path of the beamlets (31, 32, 33, 34, 35, 36).

14. A method for acquiring a three-dimensional tomographic image of a sample (42), The sample (42) is placed at the measurement point (40), The primary beam (20) propagates along the incident beam path (22), At least two beam splitters (11, 12, 13, 14, 15, 16) are positioned on the incident beam path (22) at a distance (18) from each other, and each generates beamlets (31, 32, 33, 34, 35, 36) along the beamlet direction (31a, 32a, 33a, 34a), and the primary beam (20) is attenuated by scattering. All of the beamlets (31, 32, 33, 34, 35, 36) propagate straight from the beam splitters (11, 12, 13, 14, 15, 16) toward the measurement point (40) located away from the incident beam path (22). The intensity of the beamlets (31, 32, 33, 34, 35, 36) is measured using at least one image detector (6) after passing through the measurement point (40). The three-dimensional image dataset of said sample (42) at said measurement point (40) is acquired from the intensity of said beamlets (31, 32, 33, 34, 35, 36) measured by said at least one image detector (6) and the beamlet angles (θ １ , θ ２ , θ ３ , θ ４ ), and The beamlet angle (θ １ , θ ２ , θ ３ , θ ４ ) is the angle that each of the beamlets (31, 32, 33, 34, 35, 36) makes with the primary beam (20), The angle between the beamlets (31, 32, 33, 34, 35, 36) of adjacent beam splitters (11, 12, 13, 14, 15, 16) is at least 1°. method.

Images