Additive manufacturing of microstructures

Abstract

The present invention relates to an additive manufacturing method of a microstructure (10) for selective transmission of X-ray radiation or gamma-ray radiation, the method comprising: depositing (110) a powder layer on a build plate or on a layer from at least one previous manufacturing step on the build plate wherein the powder layer comprises a high Z material powder. In addition, the method includes selectively melting (120) and solidifying the powder to form a septum wall structure (20) by scanning an electron beam over the powder layer in a sequence of spots to sequentially expose a plurality of spots (40) on the powder layer to electron beam spots. The electron beam spot has a size of at most 150 [mu] m in diameter, preferably at most 75 [mu] m in diameter, and more preferably at most 50 [mu] m in diameter. The high Z material powder includes a high Z material having an atomic number Z of at least 40 and preferably of at least 70. The invention also relates to a microstructure for the selective transmission of X-ray radiation or gamma-ray radiation, said microstructure being obtained by said method, and to an imaging component comprising such a microstructure. The invention also relates to a method for manufacturing the imaging component.

Description

Technical Field

[0001] The present invention relates to an additive manufacturing method, and more particularly to a method for the additive manufacturing of a microstructure for selectively transmitting X-rays or gamma rays. The present invention also relates to a microstructure for selectively transmitting X-rays or gamma rays obtained by the method, and to an imaging component comprising such a microstructure. The present invention also relates to a method for manufacturing an imaging component. Background Art

[0002] Additive manufacturing techniques such as direct metal laser sintering or laser powder bed fusion show great promise for fabricating X-ray and gamma-ray transmissive selective microstructures, such as anti-scatter devices, 2D anti-scatter grids, etc. In some cases, e.g., for microstructures with high density, high purity, and / or low microcracks, other manufacturing techniques may be required.

[0003] US2021 / 0039322A1 describes a method for providing a control command set for an additive manufacturing apparatus. The method comprises: providing a parameter set comprising a plurality of parameters and a construction rule, the construction rule being adapted to geometrically describe at least one segment of an object as a plurality of linear or planar elements in space using the parameter set; generating a computer-based layer model of the segment of the object by determining, for each layer, the position and shape of a cross-section of the segment of the object within the layer; generating a control command set for an additive manufacturing apparatus, and implementing production of the segment of the object by the additive manufacturing apparatus based on the layer model.

[0004] WO2022 / 248519A1 provides a method and apparatus for making an anti-scatter grid for a radiographic imaging device identifiable. The method includes: forming a grid pattern according to product specifications for the anti-scatter grid to be provided by an additive manufacturing process; and forming a plurality of structural modifications in or at the grid pattern by the additive manufacturing process in such a manner that the plurality of structural modifications are identifiable based on an image when the anti-scatter grid is viewed in the viewing direction of a radiation source of the radiographic imaging device according to its intended use.

[0005] Electron beam powder bed fusion (E-PBF) uses an electron beam to selectively melt metal powder into a solid material in a vacuum chamber. Due to the higher build temperature, E-PBF can induce lower residual material stresses and reduced cracking. E-PBF is commonly used to build microstructures from materials such as titanium-aluminum, cobalt-chromium, or nickel-based alloys.

[0006] Research disclosure 697065 suggests the feasibility of additive manufacturing metal parts in refractory metals (e.g., tungsten and its alloys) using E-PBF.

[0007] US 2015 / 0017013 Al describes a method for manufacturing a turbine wheel comprising a hub and a plurality of blades using a powdered material in an additive manufacturing process. The method includes applying energy to the powdered material via a high-energy source and solidifying the powdered material. At least a large volume portion of the hub is irradiated, causing the powdered material to solidify within a lattice structure surrounded by an outer solid skin structure enclosing the lattice structure.

[0008] The publication “State of the arts of additive manufacturing by selective electron beam melting” by Mladenov Georgi et al. on June 5, 2016, reviewed the applications of electron beam additive manufacturing systems.

[0009] The E-PBF methods known in the literature are not suitable for the fabrication of X-ray and gamma-ray transmission-selective microstructures (e.g., anti-scatter grids), since such transmission-selective microstructures may advantageously have high surface quality, high resolution, high membrane wall density, etc. Therefore, there is a need to improve the fabrication of these microstructures. Summary of the Invention

[0010] It is an object of the present invention to provide an improvement in the production of microstructures for selective transmission of X-ray radiation or gamma-ray radiation.

[0011] The invention is defined by the independent claims. Advantageous embodiments are defined in the dependent claims.

[0012] According to a first aspect of the present invention, there is provided a method for additive manufacturing of a microstructure that selectively transmits X-ray radiation or gamma-ray radiation. The method comprises:

[0013] depositing a powder layer on a build plate or a layer on the build plate from at least one previous fabrication step, wherein the powder layer comprises a high-Z material powder; and

[0014] The powder is selectively melted and solidified to form a diaphragm wall structure by scanning an electron beam in a spot sequence on the powder layer to sequentially expose multiple spots on the powder layer to electron beam spots, wherein the size of the electron beam spot is at most 150 μm in diameter, preferably at most 75 μm in diameter, and more preferably at most 50 μm in diameter.

[0015] The proposed fabrication method achieves high productivity of microstructures with high-density membrane walls for selective transmission of X-ray or gamma-ray radiation. These structures can be constructed without support structures and have few or no microcracks and excellent surface properties compared to previously known fabrication techniques. Typically, high electron beam densities used for powder bed spot melting are known to cause melting problems (e.g., charging events and smoke events). However, the inventors surprisingly discovered that, in conjunction with high-Z material powders, it is advantageous to use very small electron beam spot sizes, and therefore, for a given electron beam power, very high electron beam energy densities are used for spot melting of membrane wall structures. Due to the very high material density of the high-Z material, combined with the small electron beam spot size, the method achieves high-resolution fabrication of microstructures. Thus, the method achieves desired local-to-global functional properties (for selective transmission of X-rays or gamma rays) of the microstructures (e.g., anti-scatter grids). The electron beam current can be, for example, but not limited to, 10-100 mA, and the scanning speed can be, for example, up to or even greater than 2 m / s.

[0016] High-Z materials are materials (elements) with a high atomic number Z. The high-Z material is preferably a metal. The high-Z material may preferably be tungsten (Wolfram, W, atomic number 74). Other high-Z materials may be used alternatively, additionally, or in combination, such as, but not limited to, molybdenum (Mo, atomic number 42), tantalum (Ta, atomic number 73), niobium (Nb, atomic number 41), lead (Pb, atomic number 82), bismuth (Bi, atomic number 83), rhenium (Re, atomic number 75), silver (Ag, atomic number 47), or gold (Au, atomic number 79). Therefore, in the context of the present disclosure, the high-Z material has an atomic number Z of at least 40, and preferably at least 70. The high-Z material powder may alternatively, additionally, or in combination include an alloy containing at least one high-Z material.

[0017] According to an embodiment of the present invention, the high-Z material powder has a particle size distribution with a median diameter of at most 50 μm, preferably a median diameter of at most 25 μm, and most preferably a median diameter of at most 20 μm. Although the energy density of the electron beam is very high, it has been found that the best results can be achieved with a powder having a small particle size distribution.

[0018] According to an embodiment of the invention, the deposited powder layer has a layer thickness between 10 μm and 50 μm; the boundary 10 μm and 50 μm is included in the scope of the claims. Thin powder layers (for example in combination with small particle size and narrow electron beam) enable high-resolution manufacturing of high-density diaphragm walls.

[0019] According to an embodiment of the present invention, the method further includes selectively preheating spots of the powder by scanning the electron beam across the powder layer in a spot pre-sintering sequence, wherein the spot pre-sintering sequence is performed before the spot sequence. By preheating or pre-sintering the powder spots with the electron beam, subsequent melting of the powder using the spot sequence can be improved.

[0020] According to an embodiment of the present invention, for all spots, the scanning direction and the order of spots of the pre-sintering sequence are the same as the scanning direction and the order of spots of the spot sequence, or, for a plurality of spots, the scanning direction and the order of spots of the pre-sintering sequence are the same as the scanning direction and the order of spots of the spot sequence. Preheating and melting the powder according to the same or partially the same pattern may be advantageous for forming a diaphragm wall having a high density.

[0021] According to an embodiment of the present invention, the diaphragm wall structure of the microstructure includes a first wall structure and a second wall structure, wherein the first wall structure is formed to have a respective longitudinal axis parallel to a first direction, and the second wall structure is formed to have a respective longitudinal axis parallel to a second direction, and wherein the second direction is angled with the first direction. When the diaphragm walls are angled in two different directions (for example, but not limited to, 90 degrees, 60 degrees, or 45 degrees), a grid microstructure (for example, a radiation anti-scatter grid) can be advantageously manufactured.

[0022] According to an embodiment of the present invention, the spot sequence for sequentially exposing a plurality of spots on the powder layer to the electron beam spots comprises a first sequence followed by a second sequence, wherein the first sequence comprises scanning the electron beam spots to sequentially expose the plurality of spots along the longitudinal axis parallel to the first direction, and wherein the second sequence comprises scanning the electron beam spots to sequentially expose the plurality of spots along the longitudinal axis parallel to the second direction. This specialized spot melting strategy about the longitudinal axis of the formed diaphragm wall can reduce the amount of sintered powder within a pixel of the grid, thereby achieving high resolution. Furthermore, this strategy can be used to achieve a desirable grain structure in each of the diaphragm walls.

[0023] According to an embodiment of the present invention, the first sequence comprises scanning the electron beam spot along a plurality of first diaphragm wall paths on the respective length axes parallel to the first direction, and wherein the second sequence comprises scanning the electron beam spot along a plurality of second diaphragm wall paths on the respective length axes parallel to the second direction. By first scanning the electron beam spot along the diaphragm wall path corresponding to the first direction and then along the diaphragm wall path corresponding to the second direction, it is possible to advantageously manufacture the diaphragm wall in the respective directions. In this context, scanning along the diaphragm wall path means that adjacent spots on the path are exposed to the electron beam spot in sequence, and the electron beam spot thus moves along the path. It should be noted that the movement of the spot along the first diaphragm wall path can be parallel or antiparallel to the first direction. Similarly, the movement of the spot along the second diaphragm wall path can be parallel or antiparallel to the second direction.

[0024] According to an embodiment of the present invention, the membrane wall structure has a wall thickness of at most 200 μm, preferably at most 100 μm, more preferably at most 70 μm.

[0025] According to an embodiment of the present invention, the diaphragm wall structure has a height-to-thickness aspect ratio of at least 100, preferably at least 200, and more preferably at least 400. Fabricating microstructures with thin diaphragm walls (for example, but not limited to, diaphragm walls having a thickness of at most 100 μm, and in particular diaphragm walls having a very large height-to-thickness ratio, for example, but not limited to, thin diaphragm walls having a height of at least 40 mm) can achieve microstructures with precise control over the transmission of X-ray radiation or gamma-ray radiation, for example, but not limited to, microstructures that effectively reduce radiation scattering while having low radiation intensity loss due to the thickness of the wall.

[0026] According to a second aspect of the present invention, there is provided a microstructure for selectively transmitting X-ray radiation or gamma-ray radiation, the microstructure being obtained by the method according to the first aspect or any embodiment thereof.

[0027] According to a third aspect of the present invention, there is provided an imaging component including a microstructure.

[0028] According to an embodiment of the present invention, the imaging component includes a plurality of stacked microstructures. Stacking a plurality of microstructures to form the imaging component may be advantageous for improving the simplicity of manufacturing.

[0029] According to an embodiment of the present invention, the imaging component includes one or more of the following:

[0030] X-ray or gamma-ray filters;

[0031] X-ray or gamma-ray collimators;

[0032] X-ray or gamma-ray anti-scatter equipment; and

[0033] X-ray or gamma-ray grating.

[0034] According to a fourth aspect of the present invention, a method for manufacturing an imaging component is provided, wherein the method comprises: manufacturing at least one microstructure according to the first aspect or any embodiment thereof, and forming the imaging component from the at least one microstructure. Forming the imaging component from the at least one microstructure may include, for example, adjusting the form factor, adding connections, adding layers or other components, modifying the surface, integrating the microstructure into a holder, frame, or similar structure, etc. The manufactured imaging component is suitable for use in an imaging system.

[0035] According to an embodiment of the present invention, manufacturing the imaging component includes stacking a plurality of the microstructures. Stacking a plurality of microstructures to form the imaging component may be advantageous for improving the simplicity of manufacturing.

[0036] According to an embodiment of the present invention, the imaging component includes one or more of the following:

[0037] X-ray or gamma-ray filters;

[0038] X-ray or gamma-ray collimators;

[0039] X-ray or gamma-ray anti-scatter equipment; and

[0040] X-ray or gamma-ray grating.

[0041] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A method for additive manufacturing of a microstructure selectively transmitting X-ray radiation or gamma-ray radiation according to an embodiment of the present invention is schematically illustrated.

[0043] Figure 2 A method for additive manufacturing of a microstructure selectively transmitting X-ray radiation or gamma-ray radiation according to an embodiment of the present invention is schematically illustrated, wherein the method includes a selective preheating step.

[0044] Figure 3a and Figure 3b A microstructure for selectively transmitting X-ray radiation or gamma-ray radiation according to an embodiment of the present invention is schematically illustrated.

[0045] Figure 4a and Figure 4bA spot sequence for additive manufacturing of a microstructure selectively transmitting X-ray radiation or gamma-ray radiation according to an embodiment of the present invention is schematically illustrated.

[0046] Figure 5 An optical surface image of a diaphragm wall produced by an additive manufacturing method according to an embodiment of the present invention is shown.

[0047] Figure 6 Shown are images of individual septum walls produced by an additive manufacturing method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The additive manufacturing method of the microstructure 10 for selectively transmitting X-ray radiation or gamma ray radiation according to an embodiment of the present invention is Figure 1 The flow chart is shown in FIG. Figure 1 The method comprises the step of depositing 110 a powder layer on a build plate or on a layer on the build plate from at least one previous manufacturing step, wherein the powder layer comprises a high-Z material powder. The high-Z material may comprise, for example, tungsten, molybdenum, tantalum, niobium, lead, bismuth, rhenium, silver or gold. Combinations of high-Z materials and / or alloys comprising at least one high-Z material may be used. As a non-limiting example, high-purity high-Z material powder may be used in combination with the method. In this way, a diaphragm wall of very high purity may be achieved. It may be particularly advantageous to use a high-Z material powder having a purity (weight % of high-Z material) greater than 99%, preferably greater than 99.9%, such as a high-purity tungsten powder (having a purity greater than 99%, preferably greater than 99.9%). The high-Z material powder may have a particle size distribution with a median diameter of at most 50 μm, preferably a median diameter of at most 25 μm, and most preferably a median diameter of at most 20 μm. Although the energy density of the electron beam is very high (for example, but not limited to, an electron beam with a beam current of up to or even greater than 100 mA), it has been found that optimal results can be achieved with powders having a small particle size distribution. The deposited powder layer can advantageously have a layer thickness between 10 μm and 50 μm.

[0049] exist Figure 1 In the next step 120 of the method shown, the powder layer is selectively melted and solidified to form the membrane wall structure 20. This is achieved by scanning an electron beam over the powder layer in a sequence of spots to form a plurality of spots 40 (e.g., Figure 4aThe method can achieve a high production rate of microstructures 10 having high density diaphragm walls 20 for selectively transmitting X-ray radiation or gamma-ray radiation. These structures can be built without supporting structures and have few or no microcracks and excellent surface properties compared to previously known manufacturing techniques. Due to the very high material density (high Z material), combined with the small electron beam spot size, the method enables high resolution manufacturing of microstructures. Thin powder layers (for example in combination with a small particle size) can also enable high resolution manufacturing of high density diaphragm walls 20.

[0050] Figure 2 The diagram is similar to Figure 1 The method of claim 1 further includes the following additional step 210: selectively preheating the powder spots before selectively melting and solidifying the powder in a spot sequence 120 . In this example, the powder spots 40 are selectively preheated 210 by scanning an electron beam across the powder layer in a spot pre-sintering sequence. Thus, the spot pre-sintering sequence is performed before the spot sequence. By selectively and accurately preheating or pre-sintering the powder spots 40 using the electron beam, subsequent melting of the powder using the spot sequence can be improved. For all or a plurality of spots 40 , the scanning direction and spot order of the pre-sintering sequence can be identical to the scanning direction and spot order of the spot sequence.

[0051] Figure 3a and Figure 3b A microstructure 10 manufactured using a method according to an embodiment of the present invention is schematically shown. The microstructure 10 enables selective transmission of X-ray radiation or gamma-ray radiation and can therefore be advantageously used in imaging components, such as X-ray or gamma-ray filters, X-ray or gamma-ray collimators, X-ray or gamma-ray anti-scatter devices and / or X-ray or gamma-ray gratings. The microstructure 10 may include a diaphragm wall structure 20 in one or more directions. Figure 3a and Figure 3b In the example of FIG, the microstructure 10 is a grid-like structure having membrane walls 20 in a first direction d1 and a second direction d2. Such a structure can be used, for example, for a two-dimensional anti-scattering grid. Figure 3a and Figure 3b In the example shown, the angle between the membrane walls 20 in the first direction d1 and the second direction d2 is approximately 90 degrees. However, other structures with different angles between the walls are also conceivable, such as, but not limited to, honeycomb structures. Figure 3a A side view of an exemplary microstructure 10 is shown. In this case, Figure 3aThe diaphragm wall 20 , as seen in a side view of , has a length in a first direction d1 and a height h. Figure 3b The same structure 10 is shown from above. As shown, the microstructure 10 has membrane walls 20 in the direction d1 , which in this case are orthogonal in the direction d2 .

[0052] The wall has a thickness w. Figure 3b In the embodiment, all diaphragm walls have the same thickness w, but different walls may also have different thicknesses. The diaphragm walls 20 are dense structures that can efficiently absorb or reflect radiation. The spaces between the walls form transmissive portions 30 that allow radiation to pass through. Using the manufacturing method according to an embodiment of the present invention, dense and thin diaphragm walls 20 can be manufactured. The diaphragm walls can have a wall thickness w of at most 200 μm, preferably at most 100 μm, or more preferably at most 70 μm. Each diaphragm wall 20 has a height h and a thickness w. The aspect ratio of the height h to the thickness w of the diaphragm wall 20 can be at least 100, preferably at least 200, and more preferably at least 400. For example, the diaphragm wall 20 used for the anti-scatter grid can advantageously have a thickness w of 70-100 μm and a height h of 40-50 mm. Such a microstructure 10 having a large ratio of height h to thickness w can achieve precise control of the transmission of X-ray radiation or gamma-ray radiation through the transmission portion 30 while having low radiation intensity loss due to the thickness w of the wall 20. To produce an imaging component having such a microstructure 10, a plurality of microstructures 10 can be stacked and / or tiled together to achieve a component having desired specifications of total height, area, etc.

[0053] Figure 4a and Figure 4b The schematic diagram shows a spot sequence for additive manufacturing of microstructures that selectively transmit X-ray radiation or gamma ray radiation according to an embodiment of the present invention. In each spot sequence, a plurality of spots 40 on a layer of high-Z material powder are sequentially exposed to an electron beam spot to melt and solidify the powder during the process of forming the diaphragm wall structure 20. Figure 4a The diagram shows the sequence of spots in the direction d1, and Figure 4b The sequence of spots in the direction d2 is shown. Figure 4a and Figure 4b The example microstructure 10 in has three membrane walls 20 parallel to direction d1 and three membrane walls parallel to direction d2. In this particular example, d1 is orthogonal to d2, but angles other than 90 degrees between the directions are possible, depending on the specifications of the microstructure 10 at hand. Figure 4a and Figure 4bThe total spot sequence for (completely or partially) melting and solidifying the powder to build a layer for each of the 3×3 diaphragm walls 20 may include three sequences parallel to the d1 direction and three sequences parallel to the d2 direction. For example, the sequence may begin with three paths along the three diaphragm walls 20 in the d1 direction, e.g., at Figure 4a The paths A to B, C to D, and E to F in are followed by three sequential paths parallel to direction d2, e.g. Figure 4b Paths G to H, I to J, and K to L in FIG. For each path, a plurality of spots 40 are sequentially exposed to the electron beam. The electron beam current can be, for example, 10-100 mA, and the scanning speed can be, for example, up to or even greater than 2 m / s. The spot sequence strategy can enable the desired grain structure (equiaxed / columnar) of the fabricated diaphragm wall 20 to be achieved. In addition, the amount of sintered powder within the transmissive portion (pixel) 30 of the microstructure 10 can be reduced.

[0054] Different options for spot sequences can be considered, e.g. Figure 4a In , each path in the graph can be from right to left or from left to right. Similarly, in Figure 4b In the figure, each path can be from top to bottom or from bottom to top. For illustration, non-limiting examples of the sequence in the direction d1 can be A to B, D to C and E to F; or F to E, C to D, B to A; or E to F, C to D and A to B, etc. Similarly, it can be considered Figure 4b The path in the diaphragm 20 may be varied from top to bottom or bottom to top. This specialized spot melting strategy can reduce the amount of sintered powder within a pixel of the grid to achieve high resolution. Furthermore, this strategy can be used to achieve a desired grain structure in each of the diaphragm walls 20.

[0055] In another example, Figure 4a and Figure 4b The sequences in the diagram can be performed in an alternating manner, wherein one sequence in the d1 direction is followed by a sequence in the d2 direction. For example, but not limited to, A to B, followed by G to H; C to D, followed by I to J; and E to F, followed by K to L. Moreover, in this case, many variations in the direction and / or order of the sequences are contemplated.

[0056] Notice, Figure 4a and Figure 4b The sequences in the d1 direction or the d2 direction are shown schematically only. Any sequence in the d1 direction or the d2 direction can be shorter or longer than shown in the figure. As a non-limiting example, a sequence in the d1 direction or the d2 direction can be shortened and / or skipped over a spot 40 so that it is not repeatedly melted in a spot 40 that is melted with a corresponding d2 sequence or d1 sequence, for example.

[0057] In an example of a method comprising the additional step 210 of selectively preheating the spots 40 of the powder before selectively melting and solidifying 120 the powder in a spot sequence, it may be advantageous if the scanning direction and spot order of the pre-sintering sequence are the same or similar to the scanning direction and spot order of the spot sequence. Figure 4a and Figure 4b In the example shown in FIG. 1 , the same scanning sequence is also followed for the spots 40 for selectively preheating the powder. This may be the case for all spots 40, or, for a plurality of spots 40, the scanning direction and spot order of the pre-sintering sequence may be the same or similar to the scanning direction and spot order of the spot sequence. Preheating and melting the powder according to the same or partially the same pattern may be advantageous for forming the diaphragm walls 20 having a high density. Fabricating the diaphragm walls 20 in this manner to achieve a high density may be particularly advantageous for manufacturing microstructures 10 for selectively transmitting X-ray radiation or gamma-ray radiation, such as structures included in, for example, a 2D anti-scatter grid.

[0058] Figure 5 An optical surface image of a membrane wall produced by an additive manufacturing method according to an embodiment of the present invention is shown. The left and right sides of the figure show the same portion of the surface under different illumination conditions of an optical microscope. These images clearly illustrate the pattern of individual exposed spots 40 that are part of the spot melting strategy.

[0059] Figure 6 An image of an individual diaphragm wall produced by an additive manufacturing method according to an embodiment of the invention is shown. In this case, a plurality of walls in a first direction (eg in d1 ) have been produced.

[0060] It should be noted that the above embodiments illustrate rather than limit the present invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any figure signs placed between brackets should not be interpreted as limiting the claims. The word "comprising" does not exclude the presence of elements or steps other than those listed in the claims. The word "one" or "an" before an element does not exclude the presence of multiple such elements. The concept "at most" means "equal to or less than", and the concept "at least" means "equal to or greater than". The present invention can be implemented by means of hardware comprising several different elements and / or by a suitably programmed processor. In a device-type claim that lists several units, several of these units may be embodied by the same hardware item. The measures recorded in different dependent claims can be used advantageously in combination.

Claims

1. A method for additive manufacturing of a microstructure (10) that selectively transmits X-ray radiation or gamma-ray radiation, the method comprising: depositing (110) a powder layer on a build plate or a layer on the build plate from at least one previous fabrication step, wherein the powder layer comprises a high-Z material powder, wherein the high-Z material powder comprises a high-Z material having an atomic number Z of at least 40 and preferably at least 70; and The powder is selectively melted (120) and solidified to form a diaphragm wall structure (20) by scanning an electron beam in a spot sequence over the powder layer to sequentially expose the powder layer to a plurality of electron beam spots (40), wherein the size of the electron beam spots is at most 150 μm in diameter, preferably at most 75 μm in diameter, and more preferably at most 50 μm in diameter.

2. The method according to claim 1, wherein The high-Z material powder includes tungsten and / or molybdenum and / or tantalum and / or niobium and / or lead and / or bismuth and / or rhenium and / or silver and / or gold.

3. The method according to claim 1 or 2, wherein: The high-Z material powder has a particle size distribution with a median diameter of at most 50 μm, preferably a median diameter of at most 25 μm, most preferably a median diameter of at most 20 μm.

4. The method according to claim 1, 2 or 3, wherein: The deposited powder layer has a layer thickness of between 10 μm and 50 μm.

5. The method according to any one of the preceding claims, wherein The method further includes selectively preheating (210) spots (40) of the powder by scanning the electron beam across the powder layer in a spot pre-sintering sequence, and wherein the spot pre-sintering sequence is performed before the spot sequence.

6. The method according to claim 5, wherein: For all spots (40), the scanning direction and spot order of the pre-sintering sequence are the same as the scanning direction and spot order of the spot sequence, or wherein, for multiple spots (40), the scanning direction and spot order of the pre-sintering sequence are the same as the scanning direction and spot order of the spot sequence.

7. The method according to any one of the preceding claims, wherein The diaphragm wall structure (20) of the microstructure (10) includes a first wall structure (20) and a second wall structure (20), wherein the first wall structure is formed to have a respective length axis parallel to a first direction (d1), and the second wall structure is formed to have a respective length axis parallel to a second direction (d2), and wherein the second direction (d2) is at an angle to the first direction (d1).

8. The method according to claim 7, wherein: The spot sequence for sequentially exposing a plurality of spots (40) on the powder layer to the electron beam spots comprises a first sequence followed by a second sequence, wherein the first sequence comprises scanning the electron beam spots to sequentially expose a plurality of spots (40) on the length axis parallel to the first direction (d1), and wherein the second sequence comprises scanning the electron beam spots to sequentially expose a plurality of spots (40) on the length axis parallel to the second direction (d2).

9. The method according to claim 8, wherein The first sequence comprises scanning the electron beam along a plurality of first diaphragm wall paths on the respective length axes parallel to the first direction (d1), and wherein the second sequence comprises scanning the electron beam along a plurality of second diaphragm wall paths on the respective length axes parallel to the second direction (d2).

10. The method according to any one of the preceding claims, wherein The membrane wall structure (20) has a wall thickness (w) of at most 200 μm, preferably at most 100 μm, and more preferably at most 70 μm.

11. The method according to any one of the preceding claims, wherein The membrane wall structure (20) has a height (h) to thickness (w) aspect ratio of at least 100, preferably at least 200, and more preferably at least 400.

12. A microstructure (10) for selective transmission of X-ray radiation or gamma-ray radiation, obtained by a method according to any one of the preceding claims.

13. An imaging component comprising the microstructure (10) according to claim 12.

14. The imaging component according to claim 13, wherein The imaging component includes a plurality of stacked microstructures (10).

15. The imaging component according to claim 13 or 14, wherein The imaging component includes one or more of the following: X-ray or gamma-ray filters; X-ray or gamma-ray collimators; X-ray or gamma-ray anti-scatter equipment; and X-ray or gamma-ray grating.

16. A method for manufacturing an imaging component, wherein: The method comprises: manufacturing at least one microstructure (10) according to the method according to any one of claims 1 to 11, and forming the imaging component from the at least one microstructure (10).

17. The method according to claim 16, wherein Forming the imaging member includes stacking a plurality of the microstructures (10).

18. The method according to claim 16 or 17, wherein The imaging component includes one or more of the following: X-ray or gamma-ray filters; X-ray or gamma-ray collimators; X-ray or gamma-ray anti-scatter equipment; and X-ray or gamma-ray grating.

Images