JP2023053904A - Multi beam splitting and redirecting apparatus for tomographic apparatus, tomographic apparatus and method for creating three dimensional tomographic image of sample - Google Patents

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

The present invention relates to multiple beam splitting and redirecting devices for tomography. The invention further relates to a tomography apparatus and a method for acquiring a three-dimensional tomographic image of a sample (subject).

Acquiring three-dimensional information about a sample is of great importance in many scientific fields and their applications. Established methods of three-dimensional imaging technology include computed tomography (CT) or computer laminography (CL), which uses an X-ray beam to analyze a sample. Usually the sample is rotated about a given axis or the light source and detector are rotated about the sample. Projected images of the sample are taken from various angles, and three-dimensional data having three-dimensional information of the sample are constructed by various algorithms.

This approach faces problems when one wants to improve the 3D data acquisition time to acquire dynamic 3D information of very fast processes within the sample. To improve acquisition time, the sample needs to be spun faster than ever before, at which point centrifugal force begins to affect the sample. Also, when rotating the source and detector, at some point the increase in rotational speed will hit a physical limit. In an attempt to circumvent this physical limitation, multiple beam experimental arrangements have been proposed. In a multi-beam experimental configuration, the sample is simultaneously illuminated by multiple beams from different angles.

In Non-Patent Document 1, a single crystal is placed upstream of the sample to be analyzed and an X-ray beam is incident on the single crystal. A single crystal acts as a beam splitter, scattering an incident X-ray beam at multiple lattice planes of the crystal, thereby producing multiple diffracted beamlets that illuminate the sample. By transmitting a plurality of beamlets through the sample, projection images from a plurality of angles can be obtained simultaneously, and a three-dimensional tomographic image can be obtained from these images. However, this method requires the sample to be placed in close proximity to the crystal, limiting the size of the sample analyzed and the type of measurements possible.

Non-Patent Document 2 discloses a multi-beam X-ray optical system with a silicon crystal having multiple blades arranged along a hyperbolic shape. When an X-ray beam is incident, X-ray beams are generated from the silicon crystal by Bragg diffraction and irradiate the sample from multiple angles. In this way, projection images of a certain angular range can be acquired simultaneously. However, fabrication of silicon crystals with multiple blades is complicated, and this method requires a large size X-ray beam.

"Hard x-ray multi-projection imaging for single-shot approaches" "Optica" November 29, 2018, Vol. 5, No. 12 "Multibeam x-ray optical system for high-speed tomography" "Optica" May 12, 2020, Vol. 7, No. 5

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multiple beam splitting and redirecting device, a tomography device and a method for acquiring three-dimensional tomographic images of a sample, which allows flexible and very fast data acquisition. and can overcome the technical constraints of the prior art.

The object is solved by a multiple beam splitting and redirecting device for a tomography apparatus, the multiple beam splitting and redirecting device comprising at least two beam splitters, both of which are arranged on the path of a primary beam (incident beam), Here, all beam splitters generate beamlets by scattering the primary beam and are arranged at a distance from each other to attenuate the primary beam, and all beamlets are spaced apart from the incident beam path. is directed to the desired measurement position (specimen position).

A primary beam is attenuated each time it is scattered by a beam splitter while propagating along its path. At each beam splitter, the primary beam is scattered, thereby producing beamlets by each beam splitter. After being generated by the beam splitter, the beamlets propagate straight along their paths to the measurement point. A sample to be analyzed is placed at the measuring 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 projection in tomography. A set of projection images provides 3D image data suitable for acquiring 3D tomographic images.

The beamlets are generated by beamsplitters placed at a distance from each other on the primary beam path, so that all beamlets reach the measurement point from different directions, providing a wide angular range for tomography . Only a single primary beam is sufficient to achieve this angular range, and there is no limit to the size of the sample.

Compared to the state-of-the-art experimental arrangement described above, in the multiple beam splitting and redirecting device of the present invention, the properties of the primary beams, the number of beamlets, the direction in which the beamlets reach the measurement point, and the energy of the beamlets are Extremely flexible as everything is easily adjustable.

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 commonly known reconstruction algorithms. Here, the tomographic image is acquired based on the mathematical process of tomographic reconstruction, which yields 3D image data with 3D sample information. In tomographic techniques, which are well known, especially in the field of medical diagnostics, a specimen is scanned over a full 360° circumference. However, this is not absolutely necessary for tomographic reconstruction of cross-sectional images. From this point of view, the term "tomography" should not be understood as being limited to a full 360° examination technique. In contrast to tomography techniques used in medical diagnostics, embodiments of the tomography apparatus of the present invention are configured to perform tomography at scan angles of 360° or less, for example in the range of 0° to 180°. .

Further, in the context of this specification, the terms "beam" and "beamlet" refer to directed beams of energy radiation and include electromagnetic beams and particle beams. It is understood that these terms are not specifically limited to focused beams (beams pointing in the direction of a point). Furthermore, the term "beamlet" refers to a beam resulting from scattering/reflection of a portion of the primary beam, and is understood to mean that its intensity is weak compared to the primary beam. The "beamlet" of the present invention propagates towards the measurement point. Beams and beamlets are not necessarily focused, but can be. Thus, for example, the magnification of the projected image can be adjusted by focusing the beamlets upstream or downstream of the measurement point.

The distance between the beam splitters is a certain predetermined distance. The distance is pre-determined by the assumption that the beamlet needs to be directed to the measurement point. However, this does not mean that the distance is fixed. The beam splitters may be movable so that the distance between the beam splitters can be adjusted to the desired value. Even during the measurement it is possible to slightly change the distance between the beamsplitters in order to improve the position of the beamlets. Specifically, the distances between at least two consecutive beam splitters are different from each other. For example, the distance between the first beam splitter and the second beam splitter may be greater or less than the distance between the second beam splitter and the third beam splitter.

Preferably, the at least two beam splitters are crystals and they generate beamlets by scattering the primary beam by the lattice planes of the crystal. At this time, the beam splitter becomes an amplitude splitter.

In the context of this specification, an amplitude splitter is a beam splitter that splits the amplitude of an incoming beam. In contrast, a wavefront splitter is a beam splitter that splits the beam profile of an incident beam.

When an x-ray beam hits a solid, the beam is scattered by the atoms in the solid. If the solid is a crystal, when the X-ray beam hits the crystal at the proper angle of incidence, the constructive interference of the X-rays reflected by the lattice planes produces a scattered beam. A crystal used as one of the beam splitters scatters the primary beam on one of its lattice planes, thereby generating beamlets and attenuating the primary beam.

It is an advantage of crystals that they can be used as beamsplitters for high energy beams such as X-rays or gamma rays, since beamsplitters commonly used in the visible spectral region cannot be used for these beams.

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 scattering the beam, and the order of diffraction given as the Miller index. For this reason, the crystal must be properly oriented so that the primary beam is incident on the crystal at the proper angle and the primary beam of a particular wavelength is scattered by the lattice planes of the desired Miller indices.

For example, a first beam splitter can be arranged to scatter the primary beam on the (111) grating planes, a second beam splitter can be arranged to scatter the primary beam on the (004) grating planes, and a third beam The splitter can be arranged to scatter the primary beam at the (333) grating planes.

Specifically, at least one of the beam splitters is a crystal containing only a single element. Crystalline materials include, for example, diamond, silicon, germanium, or tungsten, but can be any element from lithium to uranium in the periodic table of the elements. The beamsplitter may be a single crystal or polycrystalline material, for example a mosaic crystal or a single crystal with defects. The beamsplitter may also be composed of multiple chemical elements, for example SiC, SiGe, GaAs, CdTe, but may be any combination of chemical elements of the periodic table in a crystalline structure. Beam splitters can also be made from complex molecular crystals forming organic crystals.

Instead of amplitude splitters used as beam splitters, wavefront splitters such as crystals, gratings, multilayers or mirrors may be used. In this case, although the beam size of each beamlet is small, an arrangement that can widen the energy band width can be considered. The use of asymmetric reflection as a wavefront splitter in such an arrangement is particularly useful as it can expand the beam size, and not only can increase the energy bandwidth of the incident primary beam, but also can increase the beam size of the beamlets, which allows wavefront splitting to The effect of splitting the primary beam into smaller pieces can be offset. This arrangement is particularly useful for highly monochromatic primary beams. That is, in this case the arrangement with the amplitude splitter cannot be used to diffract most of the primary beam because the most upstream beam splitter cannot be used. Even for highly monochromatic primary beams, the generation of multiple beamlets can be achieved using a series of wavefront splitters to maintain beamlets large enough for beam size expansion by asymmetric reflection.

Multiple beam splitting and redirecting devices according to aspects of the present invention allow 3D information to be realized at sampling rates on the order of kHz, for example using synchrotron radiation. X-ray free electron lasers (XFEL) can generate pulse trains with sampling rates in the MHz range, and each pulse generated with repetition frequencies in the MHz range can be used to acquire 3D information at MHz sampling rates. For XFELs capable of generating pulse trains from Hz to MHz rates, the present invention enables the acquisition of 2D and 3D images at sampling rates on the order of picoseconds to nanoseconds by exposure with a single X-ray pulse. The technique of multiple beam splitting and redirecting devices can generate groups of angularly separated fan-like beamlets that pass through the sample, and each beamlet can select a narrow energy bandwidth from the input spectrum, so that each The beamlets can acquire projection images for different x-ray energies. This makes it possible to realize an advanced tomography technique capable of acquiring energy-resolved 3D information. Since the multiple beam splitting and redirecting device splits the primary beams in one plane, it can be implemented for multiple planes if there are more than one primary beams. The number of incident beams on the sample determines the number of projected images. A high spatial resolution of less than 1 μm can be achieved by using a collection optic, e.g. It can be realized by placing a /reduction optical system immediately after the sample to make it similar to a visible light microscope, for example, a defocus microscope.

Furthermore, with the multiple beam splitting and redirecting apparatus of the present invention, it is possible to overcome the limitations imposed by sample rotation in X-ray 3D imaging and achieve 3D image data acquisition rates up to MHz. 3D movies may be acquired with millisecond to nanosecond frame intervals. The acquisition rate of 3D images is not limited by fundamental physical limits due to the centrifugal force dictated by the rotation speed of the sample itself or around the sample.

The multiple beam splitting and redirecting apparatus of the present invention also overcomes the picosecond and femtosecond barriers to imaging with X-rays. With the multiple beam splitting and redirecting apparatus of the present invention, the 2D image acquisition rate is not limited by detector acquisition rate limitations. In fact, no detector operates below the nanosecond frame rate, and the frame rate limit is set by a fundamental physical limit, namely the limit of charge carrier mobility in semiconductors for electrons, and 2D detectors cannot be less than 1 ns sampling rate. Therefore, there have been no detectors operating at picosecond frame rates. The experimental arrangement described here can circumvent this fundamental limitation problem.

Moreover, the multiple beam splitting and redirecting apparatus of the present invention overcomes the picosecond barrier for 3D imaging and realizes 3D motion pictures with frame rates of time intervals on the order of picoseconds, i.e. 3D GHz motion pictures. Using the multiple beam splitting and redirecting apparatus of the present invention, it is possible to record 3D images on the picosecond time scale. The acquisition rate of 3D images is not limited by fundamental physical limits dictated by rotational speed or by detector frame rate limits.

The beamlets generated by the beam splitter pass through the specimen to produce projected images of the specimen from different projection directions. Each projection may be recorded by a different detector for each beamlet, by a single detector with a field of view sufficient to capture all projections, or by a combination of multiple detectors. may be taken by Since each beamlet reaches the sample after propagating a different optical path, each beamlet propagates a different distance, so the projected images have a time difference corresponding to the time obtained by dividing the difference in propagation distance by the speed of light. have. This time difference depends on the distance between the beam splitters and can be set on the order of picoseconds to nanoseconds in practical applications. All projection images are recorded without moving the sample, the beam splitter, the light source or the detector. Instead of rotating the sample or detector, the beam "rotates" around the sample. The difference in imaging time of the projected images is on the order of picoseconds to nanoseconds.

Multiple beam splitting and redirecting devices can be used in three modalities.

For 3DMHz imaging, the time difference between all projected images may be on the order of sub-microseconds or nanoseconds, and the time difference between projected images on the order of picoseconds is not important. The picosecond time difference of the projections is even less important for kHz 3D imaging, in which case the time difference of all projections may be in the sub-millisecond or microsecond time range. Therefore, for imaging with sampling rates on the order of 3 DMHz or kHz, all projections can be considered acquired simultaneously if the sample velocity is adequate. From these projections it is possible to reconstruct 3DMHz or kHz images, each image being a tomographic frame taken at the mentioned sampling rate. Of course, in order to obtain 3DMHz or kHz motion pictures, the cameras or detectors recording the projection images must operate at MHz or kHz frame rates.

For 2D GHz imaging, the time difference between projected images is on the order of picoseconds. By choosing different materials and lattice orientations as beamsplitters, 2D images of dynamic phenomena can be recorded on the picosecond time scale, ie GHz 2D movies. Using multiple beam splitting and redirecting devices, 2D GHz movies can be imaged even with a "slow" detector by using a single bunch of X-rays with sub-picosecond pulse widths. In fact, the images recorded by each detector have a time difference of the order of picoseconds from the other detectors, which can be incorporated into a GHz 2D movie.

The multi-beam splitting and redirecting apparatus described above can also be combined with other beam splitting methods and arrangements to achieve 3D GHz imaging. In practice, the primary beam can be split into two or more beams as the incident beams of the multiple beam splitting and redirecting devices described above and have sufficient intensity to use the respective multiple beam splitting and redirecting devices. Therefore, each branch of the primary beam can be used as an input beam for multiple beam splitting and redirecting devices, all of which image the same sample. By placing the multiple beam splitting and redirecting devices and the beam splitters at appropriate distances, the beamlets originating from all the multiple beam splitting and redirecting devices can hit the sample exactly at the same time and from different directions. These beamlets can therefore produce projections of the sample from different angles exactly simultaneously, and from the resulting projections a 3D image of the sample can be reconstructed. In general, the beamlets emanating from each multiple beam splitting and redirecting device have time differences on the order of picoseconds. Thus, the plurality of multiple beam splitting and redirecting devices described above produces a set of projection images of the specimen, each set separated in time from another set on the order of picoseconds, each set being precisely simultaneously However, it can provide multiple projection images taken from different angles. An instantaneous 3D image of the sample can be reconstructed from each set, but since these 3D images have a time difference of the order of picoseconds from another set, a 3D movie with a time difference of picoseconds between each frame, i.e., a 3D GHz movie, is generated. come true.

Besides crystal beam splitters, the beam splitters can be refractive or reflective beam splitters made with micro- and nano-microfabrication processes. Micro- and nano-fabricated beam splitters use coherent diffraction due to periodic structures fabricated for beam splitting. Examples include diffraction gratings, periodic 2D structures fabricated on transparent support films, and zone plates. Refractive and reflective beamsplitters, like beamsplitters for visible light, use refraction or reflection instead of coherent diffraction for beam splitting. These types of beamsplitters are primarily used with relatively low energy beams, including UV light. These beam splitters include multilayer structures and structures fabricated by micro- and nano-processes, such as capillary lenses and Laue lenses. A multilayer mirror or a small angle incidence mirror can also be used and can be regarded as a beam splitter. Usually this type of beamsplitter functions as a wavefront beamsplitter, but if thin enough the mirror can also be used as an amplitude beamsplitter.

Preferably, at least one of the at least two beam splitters is configured to scatter the primary beam in a reflective configuration, or at least one of the at least two beam splitters scatters the primary beam in a transmissive configuration. configured to scatter and/or have a configuration.

The reflection configuration, also called the Bragg case, but especially in the symmetric Bragg case, the lattice planes that diffract the primary beam are parallel to the major surfaces of the crystal. The transmission configuration, also called the Laue case, especially in the symmetric Laue case, the lattice planes that diffract the primary beam are perpendicular to the major surfaces of the crystal. In the context of the present invention, the main surface of the crystal is defined as the surface first hit by the primary beam.

According to one embodiment of the present invention, each of the beamsplitters is specifically configured to select a particular crystalline material and to adjust the crystallographic orientation to diffract the primary beam at a particular lattice plane. and/or to scatter particular energy spectral widths of the energy spectrum of the primary beam (different portions of the energy spectrum of the primary beam, with different average energies and energy bandwidths) by at least one of adjusted.

A multiple beam splitting and redirecting device can efficiently use a primary beam having an energy bandwidth by configuring and/or adjusting all beam splitters to scatter different portions of the energy spectrum of the primary beam. In addition, all beamlets generated by the beam splitter may still have sufficient and substantially the same energy even though the intensity of the primary beam is continuously attenuated as it passes through the beam splitter. is also guaranteed.

Different crystalline materials provide different interplanar spacings. By changing the material used in the beam splitter and thereby changing the interplanar spacing, beams of different energies are scattered at certain angles. This makes it possible to adjust the energy of the beamlets scattered in the direction of the measurement point. Tuning of the energy of the beamlets can also be achieved by changing the orientation of one crystal to tune the diffracting of the primary beam on another lattice plane with a different lattice spacing.

Specifically, the primary beam is at least one of a white beam, a pink beam, and a monochromatic beam, wherein the energy bandwidth dE/E of the white beam is substantially ¹⁰⁰ , and the energy band of the pink beam The width dE/E is substantially 10 ⁻² and the energy bandwidth dE/E of the monochromatic beam is substantially 10 ⁻⁴ . E is the average x-ray energy and dE is half the energy bandwidth of the x-ray energy.

White beams and pink beams are advantageous in that they have broad energy bandwidth spectra. Due to the wide spectral energy bandwidth, each beamsplitter can scatter a different portion of the energy spectrum of the primary beam, even when multiple beamsplitters are included. A monochromatic beam provides a narrow energy bandwidth, allowing imaging of the sample at a single energy, ie the energy of the primary beam.

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

X-rays are a widely used tool for acquiring 3D data. A number of high brightness X-ray sources exist, ranging from laboratory sources to synchrotron sources and X-ray free electron laser (XFEL) sources, providing an optimal X-ray beam as the primary beam for multiple beam splitting and redirecting devices. Gamma rays are also suitable for the primary beam of multiple beam splitting and redirecting devices, primarily because they differ from x-rays in their primary source and not necessarily in their energy spectrum. In addition, multiple beam splitting and redirecting devices can also be used with neutron beams. This is because neutron diffraction is very similar to X-ray diffraction.

Neutron beamsplitters can use the same coherent diffraction mechanism as X-ray beamsplitters. This is because neutrons can be treated as waves like X-rays. In embodiments of the neutron beamsplitter, it is preferred to use a material that does not have a large scattering cross section for neutron absorption, such as boron. Of course, in these embodiments, the beamsplitter scattering angles need to be recalculated as well as the beamlet intensities.

For UV applications, all types of beamsplitters mentioned above exist, including crystalline beamsplitters, diffraction gratings, micro- and nanoprocessed beamsplitters, and refractive or reflective beamsplitters.

Preferably, the at least two beam splitters are arranged to generate beamlets along the beamlet direction. Here, the beamlet direction of each beamlet is assumed to form a different angle with respect to the direction of the primary beam.

For example, in the case of a crystal beamsplitter that scatters the primary beam by Bragg diffraction, scattering by each beamsplitter occurs at a different Bragg angle.

By generating beamlets with 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.

The at least two beam splitters preferably comprise a first beam splitter and a second beam splitter, wherein a first beamlet produced by the first beam splitter is produced by the second beam splitter. with the second beamlet, the angle being between 0.1° and 179.9°, specifically between 0.1° and 90°, may be between

Larger beamlet angles allow for tomography over a wider range of angles. The angle between beamlets of successive beam splitters is, in particular, always higher than 0° and lower than 180°.

For example, the angle between beamlets of two successive beam splitters is at least 1°.

Preferably, at least one of the beam splitters is of a configuration comprising a curved crystal and/or a mosaic crystal, a crystal consisting of an element with an atomic number of 3-92, or a crystal containing an element with an atomic number of 3-92. Further, more preferably, the structure is composed of at least two elements selected from elements having atomic numbers of 3, 6, 9, 32, and 49, and more preferably, atomic numbers of 3, 6, 9, 32, A crystal containing at least two elements selected from the 49 elements.

Lithium has an atomic number of 3, carbon has an atomic number of 6, fluorine has an atomic number of 9, germanium has an atomic number of 32, and indium has an atomic number of 49. The use of curved crystals, mosaic crystals, and/or crystals composed of high atomic number elements broadens the crystal energy bandwidth, and thus the energy bandwidth of the scattered beamlets. In a wide energy band crystal, the crystal diffracts a wider energy band in the energy spectrum of the primary beam. In addition to this, the divergence of the primary beam after transmission through the crystal increases. The energy bandwidth of a crystal is the full width at half maximum (FWHM) of the energy of beamlets scattered by the crystal.

Specifically, the crystal, for example, is bent simply by the curvature of the lattice planes within the crystal. Curvature of lattice planes in the crystal can be achieved, for example, by introducing selective ion implantation and/or a well-defined compositional gradient. Mosaic crystals are crystals composed of a large number of crystallites with slightly different orientations from each other, or crystals with internal defects or distortions.

Broadening the energy band width of the crystal can also be achieved by using higher atomic number elements such as germanium or indium. In a multi-element crystal, for example when an antimony compound is selected as the beam splitter, the average atomic number of the crystal is in particular at least 32, for example at least 49.

Specifically, the beamlet flux (number of X-ray photons per unit time) can be increased by broadening the spectral acceptance of the crystal and/or using asymmetric diffraction with a low-angle incidence geometry. . The latter expands the beam size.

Preferably, the at least two beam splitters are part of one single piece, in particular a single crystal, which single piece consists of a plurality of scattering surfaces at different angles to each other. Specifically, this single piece is bent, grooved, or patterned to have multiple scattering surfaces. The single component includes, for example, a single crystal. This experimental arrangement is also called the single splitter arrangement. The advantage of this arrangement is that the size of the scattering surface can be reduced to the order of 10 μm, so that a very space-saving arrangement can be realized. This arrangement allows for small spacing between the diffractive elements, allowing time delays between beamlets on the order of femtoseconds, enabling very fast 2D imaging at THz sampling rates. Specifically, a plurality of single crystals are arranged along the incident beam path.

The single crystal used in the single splitter arrangement can be a grooved crystal, where grooves can be made by mechanical machining, etching, laser machining, and/or another fabrication technique.

A single crystal for use in a single splitter arrangement can be a patterned crystal comprising a pattern of crystalline and amorphous material, wherein the amorphization of a portion of the crystal is accomplished by chemical methods, thermal methods, It can be achieved by mechanical methods, laser irradiation, ion implantation, and/or lithography.

The single crystals used in the single splitter arrangement can be of different lattice spacings, different chemical compositions, and can be patterned crystals containing patterns of crystalline material with chemical doping. Specifically, the crystalline material can be deposited by vapor deposition techniques, with or without chemical reaction with the substrate material, and other deposition techniques, particularly sputter deposition or laser deposition. made by Alternatively, it can be made using a technique that induces stress in the crystalline material to alter the interplanar spacing of several layers and their position within the single crystal.

A single crystal for use in a single splitter arrangement may be a patterned crystal, where the pattern is produced using standard lithographic techniques or by radiation-induced or radiation-assisted material. can be introduced by erosion/ablation of A pattern may be formed by a portion or portions of the crystal surface acting as a mask for the radiation.

Specifically, the multiple beam splitting and redirecting apparatus includes a recombined crystal, which is constructed and arranged to focus the beamlets produced by the crystal onto a measurement point. This allows imaging of large samples.

Preferably, the multiple beam splitting and redirecting device comprises at least one primary beam splitter and at least two beam splitter groups, said beam splitter group comprising said beam splitter, the primary beam splitters being arranged on the incident beam path. is configured to scatter the primary beam to produce a secondary beam and to attenuate the primary beam, the attenuated primary beam propagating downstream along the incident beam path and the secondary beam being the secondary beam Propagating downstream along the path, one of the beam splitter groups is positioned on the incident beam path downstream of the primary beam splitter and another of the other beam splitter groups is positioned on the secondary beam path. placed on the beam path.

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 since the beamlets from different beam splitter groups are directed from different sides to the measuring point. To further increase the angular range, the primary beam can be split multiple times. The primary beam is split by the primary beam splitter. A primary beam splitter is in particular a crystal used as an amplitude splitter or wavefront splitter or a mirror used as a wavefront splitter. In particular, the primary beamsplitter splits the primary beam so that the plane containing the beamlets produced by the first group of beamsplitters is different from the plane containing the beamlets produced by the second group of beamsplitters. Can be non-parallel planes. This enables 3D imaging from different viewpoints.

Preferably, the multiple beam splitting and redirecting device is such that the time difference between the arrival of the first and last beamlets of all beamlets generated from a single pulse of the pulsed primary beam at the measuring point is less than microseconds, e.g. , sub-nanoseconds, on the order of 1 picosecond to 1 nanosecond.

By keeping the time difference between beamlets generated from a single pulse on the order of nanoseconds or picoseconds, it is possible to acquire 3D tomographic images of very fast dynamic processes.

Specifically, the multiple beam splitting and redirecting device includes at least two beam splitters made of different materials, wherein the lattice spacing difference of the different materials is less than 65%, less than 20%, less than 5%, for example. is less than

By using two or more beamsplitters 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. Higher speed interferometry can be realized by miniaturization of this optical system. In practice, the time difference between beamlets is proportional to the size of the optical system. Such miniaturized optics can be realized by grooving and bending a crystal with a concentration gradient of two different elements, such as Si _x Ge _1-x , so that The surfaces of the crystal have gradients of lattice constants, each surface acting as a slightly different material but having approximately the same lattice constant and diffracting beamlets of the same energy, but the time interval being the distance between them. proportional to This type of optics can be made very compact, so that the size of the crystal surfaces can be reduced to the order of 10 μm spacing between them, thus the temporal distance between beamlets can be reduced to the order of femtoseconds. can be. Since these beamlets have the same energy, they interfere allowing femtosecond-order interferometry.

In a specific experimental arrangement, a flat-surfaced crystal and/or a normalizing mask were placed in front of a multiple beam splitting and redirecting device on the primary beam path, where the former diverts the primary beam in a transmissive arrangement. Constructed and arranged to diffract. An advantage of flat-surfaced crystals is that they can smooth out beam non-uniformities caused by a phenomenon called the Bormann triangle. In one embodiment, the flat-surfaced crystals are made of diamond or lighter materials. According to another embodiment, the flat-surfaced crystal 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 is also removed by image analysis algorithms.

The objects of the invention are further achieved by a tomography apparatus. The tomography apparatus includes a light source, at least one image detector, and a multiple beam splitting and redirecting apparatus according to any of the preceding embodiments, wherein the light source is configured to generate primary beams, wherein at least one The two image detectors are arranged and configured to measure the intensity of the beamlets after passing the measurement point, wherein the tomography apparatus measures a three-dimensional image data set of the sample at the measurement point with the image detector. and the angle each beamlet makes with the primary beam.

The tomography device embodies the same or similar functions, advantages and characteristics as the multiple beam splitting and redirecting device, so this should not be repeated.

In addition, the tomography apparatus generates a three-dimensional tomographic image from the three-dimensional image data set using tomographic techniques well known in the art.

The light source can 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 type of suitable light source.

The image detectors are in particular indirect X-ray, gamma, neutron and/or UV image detectors, in particular scintillators and visible light detectors such as charge-coupled devices (CCD). , or complementary metal oxide semiconductor (CMOS), or scientific instrumentation CMOS (sCMOS). According to another embodiment, the image detector is a direct imaging photon counting or integrating detector. For example, the image detector includes at least one camera and/or a large area image detector.

In one embodiment, a single image detector is positioned to detect all beamlets passing through the measurement point. A single detector is for example a curved detector. According to another embodiment, the 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 the at least one camera and the number of cameras are selected based on the desired viewing angle and acquisition time.

Preferably, the tomography apparatus comprises a crystal spectrograph arranged downstream of the multiple beam splitting and redirecting device on the incident beam path, wherein the crystal spectrograph is for example a curved crystal, which has the energy spectrum of the primary beam substantially entirely diffracted to produce a diffracted spectrograph beam, wherein a spectroscopic image detector configured to image the diffracted spectrograph beam is positioned on the beam path of the diffracted spectrograph beam , where the spectroscopic image detector is specifically a two-dimensional detector.

A crystal spectrograph consists of a bendable curved crystal that provides multiple Bragg angles to the primary beam. A crystal spectrograph and a spectroscopic image detector can be used to examine the energy spread used by the beamlets and thus aid in the alignment of the beamsplitter.

Preferably, the tomography apparatus comprises at least one light collection element, which is arranged on at least one path of the beamlets upstream and/or downstream of the measuring point.

Specifically, the light-collecting element is at least one of an X-ray light-collecting element, a gamma-ray light-collecting element, and a neutron light-collecting element. The X-ray concentrating element is for example a focused or defocused X-ray lens. An advantage of the focusing element is that the beamlet can be expanded or contracted. For example, when a direct imaging image detector is used, a lens for visible light cannot be used for magnification, but an X-ray condensing element can be used for magnification imaging.

Another tomography apparatus embodiment includes at least two light sources, each producing a primary beam, each primary beam being incident on a different multiple beam splitting and redirecting device. The advantage of this device is that it allows the acquisition of projection images over a wide angular range of more than 180° and allows the acquisition of projection images in different planes.

The object of the invention is further achieved by a method of acquiring a three-dimensional tomographic image of a sample. Here the sample is placed at the measurement point, the primary beam propagates along the incident beam path, and at least two beam splitters are placed on the incident beam path at a distance from each other, each scattering the primary beam. generates beamlets and attenuates the primary beam, all beamlets propagate in the direction of the measurement point away from the incident beam, which is the intensity of the beamlet after passing the incident beam, the measurement point is measured using at least one image detector, and the three-dimensional image data set of the sample at the measurement point is composed of the intensity of each beamlet measured with the at least one image detector and the intensity of each beamlet measured with the primary beam. configured to obtain from an angle to make.

This method also embodies the same similar features, advantages and properties as the tomography apparatus and the multiple beam splitting and redirecting apparatus of the present invention.

In order to cover the entire 360° circumference of the sample, the sample may be rotated after acquiring the first image and before acquiring the following second image.

According to one embodiment of this method, the two beamsplitters are crystals and generate beamlets by scattering the primary beams at lattice planes of the crystals. For example, the beam splitter here is an amplitude splitter.

Preferably, at least one of the at least two beam splitters is arranged to scatter the primary beam in the reflective configuration and at least one of the at least two beam splitters is arranged to scatter the primary beam in the transmissive configuration. , at least one of

Each beamsplitter preferably scatters a different portion of the energy spectrum of the primary beam by means of a configuration that specifically selects a particular crystal material and/or a configuration that adjusts the orientation of the crystal to identify the primary beam. is diffracted by the lattice planes of

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

The at least two beam splitters preferably generate beamlets along beamlet directions, where the beamlet direction of each beamlet forms a different beamlet angle with the direction of the primary beam.

Preferably, the at least two beam splitters comprise a first beam splitter and a second beam splitter, wherein a first beamlet produced by the first beam splitter is produced by the second beam splitter. with the second beamlet, where the angle is between 0.1° and 179.9°, specifically between 0.1° and 90°, between 0.1° and 60° ° may be between.

At least one of the beam splitters is preferably a curved crystal and/or mosaic crystal configuration and a crystal of 3-92 elements or a crystal containing elements of atomic number 3-92. More preferably, the composition consists of at least two elements selected from elements with atomic numbers of 3, 6, 9, 32, and 49, and more preferably with atomic numbers of 3, 6, 9, 32, and 49. A crystal containing at least two elements selected from the elements.

According to one embodiment, the at least two beam splitters are part of a single crystal, wherein the single crystal is grooved and bent to include a plurality of scattering surfaces, the plurality of scattering surfaces at an angle to each other form.

Preferably, at least one primary beam splitter is arranged in the incident beam path to scatter the primary beam to produce a secondary beam and to attenuate the primary beam, wherein the attenuated primary beam is in the incident beam path and the secondary beam propagates downstream along the secondary beam path, wherein one of the at least two beam splitter groups comprising at least two beam splitters is on the incident beam path and the other of the at least two beam splitter groups is arranged on the secondary beam path.

Preferably, the time difference between the arrival of the first and the last beamlet of all beamlets generated from a single pulse of the pulsed primary beam at the measuring point is less than microseconds, for example less than nanoseconds.

According to one embodiment, the crystal spectrograph is arranged downstream of the multiple beam splitting and redirecting device on the incident beam path, wherein the crystal spectrograph substantially diffracts the entire energy spectrum of the primary beam and A curved crystal configured to generate a spectroscopic beam, wherein a spectroscopic image detector is positioned in the beam path of the diffracted spectroscopic beam to image the diffracted spectroscopic beam. Here, the spectroscopic image detector is, for example, a two-dimensional detector.

Preferably, at least one focusing element is arranged upstream and/or downstream of the measuring point on the path of at least one of the beamlets.

For example, since each beamlet has a different energy, rotating the sample can achieve energy-resolved tomography. That is, it is possible to acquire multiple 3D images corresponding to different X-ray energies for each rotation of the sample. Energy-resolved tomography can also be achieved with a primary beam splitter or in combination with multiple light sources. That is, creating multiple beam splitting and redirecting devices that image the same sample and transmit the sample from different directions with beamlets of the same energy, thereby accommodating different x-ray energies without rotating the sample. Multiple 3D images can be acquired.

Further features of the invention will become apparent from the description of embodiments according to the invention together with the claims and the drawings. Embodiments according to the invention may fulfill individual characteristics or a combination of several characteristics.

The invention is described below. However, the following exemplary embodiments are not intended to limit the general teachings of the invention. The following refers to the drawings that disclose content related to all of the details that are not described in detail in the text but that accompany the present invention. The drawing shows:

1 is a schematic diagram of an embodiment in a reflection arrangement of a tomography apparatus with multiple beam splitting and redirecting devices; FIG. 1 is a schematic diagram of an embodiment in a transmission configuration of a tomography apparatus with multiple beam splitting and redirecting devices; FIG. 1 is a schematic diagram of an embodiment of a tomography apparatus with a crystal spectrograph; FIG. 1 is a schematic diagram of an embodiment of a tomography apparatus with a primary beam splitter and multiple beam splitter groups; FIG. 1 is a schematic diagram of an embodiment of a tomography apparatus having a single crystal with multiple scattering surfaces; FIG. 1 is a schematic diagram of an embodiment of a tomography apparatus with multiple single crystals acting as beam splitters; FIG. 1 is a schematic diagram of a single piece beamsplitter, including optical and non-optical members; FIG. 1 is a schematic diagram of a two-dimensional, single-component beamsplitter, including optical and non-optical components; FIG.

In the drawings, the same or similar elements or respective corresponding parts are labeled the same to avoid duplication of items.

FIG. 1 shows a schematic illustration of a first embodiment of a tomography device 2 . The tomography apparatus 2 includes a light source 5 , a multiple beam splitting and redirecting device 4 and an image detector 6 . Light source 5 is, for example, an X-ray source that produces a primary beam 20 along an incident beam path 22 . Multiple beam splitting and redirecting device 4 includes a plurality of beam splitters 11 , 12 , 13 , 14 arranged on incident beam path 22 . The beam splitters 11 , 12 , 13 , 14 are crystals and each scatter the primary beam 20 by Bragg diffraction, thus producing diffracted beamlets 31 , 32 , 33 , 34 and attenuating the primary beam 20 . Each beamlet 31 , 32 , 33 , 34 propagates in a beamlet direction 31 a , 32 a , 33 a , 34 a and is focused at a measurement point 40 at which a sample 42 is located. An image detector 6 is arranged on the path of the beamlets 31 , 32 , 33 , 34 downstream of the measuring point 40 to photograph the intensity distribution produced by the beamlets 31 , 32 , 33 , 34 . Since the beamlets 31, 32, 33, 34 pass through the sample 42 from different directions, a three-dimensional image data set of the sample 42 can be obtained by measuring the intensity distribution. A three-dimensional tomographic image of the sample 42 can be calculated from the three-dimensional image data set. The image detector 6 can be an indirect imaging image detector or a direct imaging image detector.

In order to focus the beamlets 31 , 32 , 33 , 34 to the measuring point 40 , the distance 18 between the beam splitters 11 , 12 , 13 , 14 and the direction of the beamlets 31 , 32 , 33 , 34 to the direction of the primary beam 20 . It is necessary to appropriately adjust the beamlet angles θ ₁ , θ ₂ , θ ₃ , and θ ₄ . According to Bragg's law, the beamlet angles θ ₁ , θ ₂ , θ ₃ , θ ₄ correspond to the scattering angles (twice the Bragg angle), the wavelength of the primary beam 20 and the lattice plane scattering the primary beam 20 . It depends on the lattice spacing. Therefore, changing the beamlet angles θ ₁ , θ ₂ , θ ₃ , θ ₄ of the primary beam 20 with a given wavelength also requires changing the lattice spacing. This is done by choosing a material with an appropriate lattice constant and orienting the crystal so that the primary beam 20 is scattered by lattice planes with the desired Miller indices.

For example, if a monochromatic X-ray primary beam with a wavelength of about 0.069 nm is incident on three beam splitters, the first beam splitter is made of germanium so that the primary beam is scattered at the (022) lattice planes. The crystal orientation is adjusted to produce beamlets with a beamlet angle of about 10°. The second beam splitter is made of silicon and the crystal is oriented so that the primary beam is scattered at the (004) lattice planes, producing beamlets with a beamlet angle of about 14°. The third beam splitter is made of carbon and the crystal is oriented so that the primary beam is scattered at the (333) lattice planes, producing beamlets with a beamlet angle of about 30°.

If a primary beam 20 with a broad energy spectrum is used, for example a pink beam or a white beam, the beam splitters 11, 12, 13, 14 can each be arranged to scatter different parts of this energy spectrum. This makes it possible to utilize most of the energy spectrum of the primary beam for tomography. Of course, the beamsplitters 11, 12, 13, 14 must be made of suitable materials and placed at the correct orientation and distance 18 from each other so that they are produced from different parts of the energy spectrum. Beamlets 31 , 32 , 33 , 34 are still focused on measurement point 40 .

The angle δ between the beamlets from the first beam splitter 11 and the last beam splitter 14 of the multiple beam splitting and redirecting device 4 defines the projection angle range of the tomography apparatus 2 shown in FIG. . In order to achieve a wide angular range for tomography, the angle δ should be chosen as large as possible.

FIG. 2 shows a schematic illustration of a second embodiment of the tomography device 2 . In this embodiment the primary beam 20 is produced by a large light source not shown in FIG. 2, for example a synchrotron light source or an XFEL light source. In addition, the beam splitters 11, 12, 13, 14 are arranged to scatter the primary beam 20 in transmission configuration (Laue case) instead of in reflection configuration (Bragg case).

On the beam path of beamlet 31 , a collecting element 60 is arranged in front of measuring point 40 and another collecting element 61 is arranged downstream of measuring point 40 . The focusing elements 60 , 61 are for example X-ray focusing elements, which expand and contract the X-rays to change the spatial size of the beamlets 31 as they pass the measurement point 40 .

FIG. 3 shows a schematic illustration of a third embodiment of the tomography device 2 . In this embodiment only two beam splitters 11 , 12 are arranged on the incident beam path 22 . A separate image detector 6 is provided for each beamlet 31,32 generated by the beam splitter 11,12. Additionally, a crystal spectrograph 50 is positioned downstream of the beam splitters 11 , 12 on the incident beam path 22 . Crystal spectrograph 50 is, for example, a bendable curved crystal, which provides a number of surfaces from which primary beam 20 scatters, thereby producing diffracted spectrograph beam 52 . The spectroscopic image detector 54 is, for example, a two-dimensional detector, and photographs the diffraction spectroscopic beam 52 to measure the total energy spectrum of the primary beam 20 . It is thus possible to investigate which part of the total energy spectrum is scattered by the beamsplitters 11,12 as beamlets 31,32. Monitoring the energy scattered as beamlets 31,32 of the primary beam 20 allows alignment of the beamsplitters 11,12. A primary beam camera 56 is positioned downstream of the crystal spectrograph 50 on the incident beam path 22 to measure the intensity distribution of the remaining primary beam 20 .

FIG. 4 shows a schematic illustration of a fourth embodiment of the tomography device 2 . In this embodiment, the primary beam splitter 70 is placed in front of the beam splitters 11 , 12 , 13 , 14 of the first beam splitter group 71 on the path of the first beam 20 . Primary beam splitter 70 splits a portion of primary beam 20 into secondary beams 74 that make an angle with primary beam 20 . In the example shown in FIG. 4, this angle is approximately 90°. However, the angle between primary beam 20 and secondary beam 74 can be any angle between 0° and 180°. A second beam splitter group 72 with beam splitters 15 , 16 is arranged on the secondary beam path 76 of the secondary beam 74 . Similar to beam splitters 11 , 12 , 13 , 14 , beam splitters 15 , 16 generate beamlets 35 , 36 by scattering secondary beams 74 and focus beamlets 35 , 36 to measurement point 40 . constructed and arranged as follows:

When the tomography apparatus 2 according to this embodiment is used, the beam splitters 11, 12, 13, 14, 15, 16 can be arranged on different sides of the sample 42, so that tomography can be realized in a wider angular range. The beam splitters 11 , 12 , 13 , 14 of the first beam splitter group 71 and the beam splitters 15 , 16 of the second beam splitter group 72 may be part of a single multiple beam splitting and redirecting device 4 . Alternatively, a different multiple beam splitting and redirecting device 4 may be configured for each beam splitter group 71,72.

To further increase the angular range, the primary beam 20 and/or the secondary beam 74 may be split multiple times by multiple primary beam splitters 70 to provide more beams with each beam splitter group 71,72. A beam branch can be generated.

FIG. 5 shows a schematic view of a fifth embodiment of the aforementioned single splitter arrangement tomography apparatus 2 . In this embodiment the beam splitters 11 , 12 , 13 are realized as a single piece, in this case a single crystal 80 . That is, a single component includes a single crystal, and specifically consists of a single crystal 80 . Hereinafter, this single component will be described as a single crystal 80 . The single crystal 80 is grooved to separate a plurality of scattering surfaces 81, 82, 83 and is bent so that two of the scattering surfaces 81, 82, 83 form an angle. there is The generated beamlets 31, 32, 33 therefore arrive at the measurement point 40 from slightly different positions and at slightly different angles. Although crystal 80 in FIG. 5 has only three scattering surfaces 81, 82, 83, crystal 80 can be provided with any number of scattering surfaces.

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

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

FIG. 7 shows a schematic diagram of a single crystal 80 including optical members 84 and non-optical members 85 . Optical member 84 is configured to scatter primary beam 20 in the direction of measurement point 40 and to act as scattering surfaces 81 , 82 , 83 of single crystal 80 . Non-optical members 85 separate regions of optical member 84 from each other. Single crystal 80 can be a grooved crystal or a patterned crystal. Patterns are patterns of crystalline and amorphous materials, patterns of crystalline materials with different interplanar spacings, different chemical compositions, or different doping elements/concentrations, and/or patterns obtained by lithographic techniques or localized ablation of materials. obtain. A final example can be achieved by masking a portion of the crystal surface against ablation.

FIG. 8 is a schematic diagram of a two-dimensional single-component beamsplitter including an optical member 84 and a non-optical member 85. FIG. The optical member 84 is patterned in a lattice. The primary beam 20 is two-dimensionally scattered toward the measurement point 40 by each optical member.

All named features, including those that can only be taken from the drawings, and individual features disclosed in combination with other features, alone and in combination, are considered to be material to the invention. Embodiments according to the invention can be realized by means of individual characteristics or combinations of several characteristics. Features combined with the words "particularly", "specifically" or "for example" should be treated as preferred embodiments.

2 tomograph 4 multiple beam splitting and redirecting 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 beamlets 31a, 32a, 33a, 34a beamlet direction 40 measurement point 42 sample 50 crystal spectrograph 52 diffraction spectrograph beam 54 spectroscopic image detector 56 primary beam camera 60 condenser element 61 condenser element 70 primary beam splitter 71, 72 beam splitter group 74 secondary beam 76 secondary beam path 80 single crystal 81, 82, 83 scattering surface 84 optical member 85 non-optical member δ angles θ ₁ , θ ₂ , θ ₃ , θ ₄ beamlet angles

Claims (15)

A multiple beam splitting and redirecting device (4) for a tomography device (2), comprising:
comprising at least two beam splitters (11, 12, 13, 14, 15, 16) arranged 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 said primary beam (20), and
configured to attenuate said primary beam (20), wherein said beam splitters (11, 12, 13, 14, 15, 16) are arranged at a distance (18) from each other;
A multiple beam splitting and redirecting device (4), wherein said beamlets (11, 12, 13, 14, 15, 16) are directed to a measuring point (40) remote from said incident beam path (22). said beam splitters (11, 12, 13, 14, 15, 16) are crystals,
generating said beamlets (31, 32, 33, 34, 35, 36) by scattering said primary beam (20) onto lattice planes of said crystal;
Device (4) according to claim 1, characterized in that said beam splitters (11, 12, 13, 14, 15, 16) are amplitude splitters. At least one of said beam splitters (11, 12, 13, 14, 15, 16) is configured to scatter said primary beam (20) in a reflecting arrangement; 12, 13, 14, 15, 16) are arranged to scatter said primary beam (20) in a transmission configuration and/or have a configuration of Apparatus (4) according to clause 1. Each of said beamsplitters (11, 12, 13, 14, 15, 16) has a configuration that selects a particular crystal material and orients the crystal to diffract said primary beam (20) at a particular lattice plane. 2. The apparatus (4) of claim 1, characterized in that a tuning arrangement scatters a particular energy spectral width of the primary beam (20) by at least one of: said primary beam (20) is a pulsed X-ray beam, a gamma ray beam, a neutron beam, or an extreme ultraviolet (EUV) beam;
Device (4) according to claim 1, characterized in that the extreme ultraviolet (EUV) beam has a wavelength of less than 120 nm. The beam splitters (11, 12, 13, 14, 15, 16) direct the beamlets (31, 32, 33, 34, 35, 36) along the beamlet directions (31a, 32a, 33a, 34a). configured to generate
The beamlet directions (31a, 32a, 33a, 34a) of each of the beamlets (31, 32, 33, 34, 35, 36) have different beamlet angles ( Device (4) according to claim ₁ , characterized in that it forms ?1, ? ₂ , ? ₃ , ? ₄ ). The beam splitters (11, 12, 13, 14, 15, 16) comprise a first beam splitter (11) and a second beam splitter (14),
A first beamlet (31) generated by said first beam splitter (11) forms an angle (δ) with a second beamlet (34) generated by said second beam splitter (14). none,
Device (4) according to claim 1, characterized in that said angle (δ) is between 0.1° and 179.9°. at least one of said beam splitters (11, 12, 13, 14, 15, 16) comprises curved and/or mosaic crystals;
A device (4) according to claim 1, characterized in that it has at least one of the composition being a crystal consisting of or containing elements with atomic numbers from 3 to 92. said beamsplitters (11, 12, 13, 14, 15, 16) are part of a single piece (80) comprising a single crystal,
2. The device (4) of claim 1, wherein said single component comprises a plurality of scattering surfaces (81, 82, 83) oriented differently from each other. comprising 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 scatters the primary beam (20) to produce a secondary beam (74) and attenuates the primary beam (20). is configured to
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);
One of said beam splitter groups (71, 72) is arranged downstream of said primary beam splitter (70) on said incident beam path (22) and the other said beam splitter group (71, 72) ) is positioned on the secondary beam path (76). the time difference between the first and last beamlets (31, 32, 33, 34, 35, 36) generated from a single pulse of the pulsed primary beam (20) reaching said measuring point (40); A device (4) according to claim 1, wherein is arranged to be less than microseconds. A tomography apparatus (2) comprising a light source (5), at least one image detector (6) and an apparatus (4) according to any one of claims 1 to 11,
said light source (5) is arranged to generate said primary beam (20),
said image detector (6) is arranged and arranged to measure the intensity of said beamlets (31, 32, 33, 34, 35, 36) after passing said measurement point (40);
The tomography apparatus (2) converts a three-dimensional image data set of the sample (42) at the measurement point (40) into the beamlets (31, 32, 33, 34) measured by the image detector (6). , 35, 36) and the beamlet angles (θ ₁ , θ ₂ , θ ₃ , θ ₄ ),
The beamlet angles (θ ₁ , θ ₂ , θ ₃ , θ ₄ ) are the angles between the beamlets (31, 32, 33, 34, 35, 36) and the primary beam (20), respectively. A tomography apparatus (2). a crystal spectrograph (50) positioned downstream of said multiple beam splitting and redirecting device (4) on said incident beam path (22);
said crystal spectrograph (50) comprising a curved crystal configured to diffract substantially the entire energy spectrum of said primary beam (20) to produce a diffracted spectrograph beam (52);
a spectroscopic image detector (54) for imaging the diffracted spectroscopic beam (52) is arranged on a beam path of the diffracted spectroscopic beam (52);
13. The tomography apparatus (2) of claim 12, wherein the spectroscopic image detector (54) is a two-dimensional detector. at least one focusing element (60) arranged upstream and/or downstream of said measuring point (40) on the path of at least one of said beamlets (31, 32, 33, 34, 35, 36) , 61). A method for acquiring a three-dimensional tomographic image of a sample (42), comprising:
The sample (42) is placed at a measurement point (40),
the primary beam (20) propagates along an incident beam path (22),
At least two beamsplitters (11, 12, 13, 14, 15, 16) are arranged on said incident beam path (22) at a distance (18) from each other, each for beamlets (31, 32, 33) , 34, 35, 36), said primary beam (20) being attenuated by scattering,
all said beamlets (31, 32, 33, 34, 35, 36) propagate towards said measurement point (40) located away from said incident beam path (22),
the intensity of said beamlets (31, 32, 33, 34, 35, 36) is measured with at least one image detector (6) after passing said measurement point (40);
A three-dimensional image data set of the sample (42) at the measurement point (40) is the beamlet (31, 32, 33, 34, 35, 36) measured with the at least one image detector (6). and the beamlet angles (θ ₁ , θ ₂ , θ ₃ , θ ₄ ), obtained by
the beamlet angles (θ ₁ , θ ₂ , θ ₃ , θ ₄ ) are the angles each of the beamlets (31, 32, 33, 34, 35, 36) makes with the primary beam (20); Method.

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