Pixelated scintillator

Abstract

The invention relates to a method of manufacturing a pixelated scintillator. According to the method, a plurality of first regions of a substrate are irradiated (S110) with a first laser radiation according to a predefined geometric configuration of a pixelated scintillator to cause a structural modification of a material in the plurality of first regions of the substrate, such that once the substrate is subjected to an etching, the material in the plurality of first regions of the substrate is exposed to the first laser radiation. The etching occurs at a higher rate at the plurality of first regions that are irradiated than at regions that are not irradiated. The etching is performed (S120) to form a plurality of first openings having a predefined geometric configuration of pixelated scintillators. The plurality of first openings are filled (S130) with at least one scintillator material to form a pixelated scintillator. The resulting pixelated scintillator embedded in the substrate may be bonded to a corresponding photosensitive readout sensor substrate. This may help to implement an economical, efficient, parallax-free, single-layer or multi-layer radiation detector with enhanced spatial resolution and sensitivity.

Description

Technical Field

[0001] The present invention relates to a pixelated scintillator and in particular to a method of manufacturing a pixelated scintillator, a pixelated scintillator obtainable by the method, a radiation detector, a manufacturing system and a computer program. Background Art

[0002] US2019 / 317226A1 describes an X-ray sensing device. The X-ray sensing device includes a substrate, a first material layer, a circuit element, a photoelectric sensing element, and a columnar structure. The first material layer is disposed above the substrate. The circuit element is disposed at the bottom portion of the first material layer. The photoelectric sensing element is disposed above the circuit element. The columnar structure is correspondingly disposed above the photoelectric sensing element and contacts the photoelectric sensing element.

[0003] US5981959A describes a pixelated scintillating layer in which high-aspect-ratio columns of scintillating material are formed. The size and spacing of the columns can correspond to the size and spacing of the underlying sensor array, or they can be sized so that there are multiple columns per pixel. A method for forming the pixelated scintillating layer includes the steps of forming openings, such as wells, vias, or channels, in a body, for example by etching a thick photoresist, ion beam etching, anodic etching, etc., and filling the openings with scintillating material.

[0004] CN108363090A discloses a detector module based on a flexible photodiode.

[0005] Huang Ji et al., “Fabrication of highly homogeneous and control lablenanogratings on silicon via chemical etching-assisted femtosecond laser modification,” Nanophotonics, Vol. 8, No. 5, May 1, 2019 (2019-05-01), pp. 869–878, describe a process for chemical etching-assisted femtosecond laser fabrication.

[0006] Radiation detectors currently used in medical imaging primarily consist of a non-pixelated micro-pillar scintillator layer bonded to a readout sensor substrate based on a large array of small, electronically addressable, photosensitive pixels. An inherent problem with these so-called indirect conversion radiation detectors can be reduced lateral resolution due to blurring of the scintillation light in the scintillator layer. Furthermore, the spatial resolution of such detectors can degrade from the center to the edges of the detector due to increasing parallax errors. These effects are likely to become more pronounced as X-ray detector pixel size decreases and / or as X-ray detectors incorporate multiple scintillator layers.

[0007] The above problems can be at least partially addressed by replacing non-pixelated scintillators with pixelated scintillators (i.e., arrays of scintillator elements, also known as voxels, embedded in or deposited on top of a substrate). Various approaches have been proposed to implement radiation detectors based on pixelated scintillators. However, most approaches may offer only limited detector performance gains and / or suffer from high manufacturing complexity. Summary of the Invention

[0008] It may be desirable to provide an improved method for manufacturing pixelated scintillators for use in radiation detectors, such as X-ray detectors or gamma-ray detectors.

[0009] The invention is defined by the independent claims. Advantageous embodiments are defined in the dependent claims. It should be noted that the aspects of the invention described below also apply to the method for manufacturing a pixelated scintillator, the pixelated scintillator obtainable by the method, and the radiation detector.

[0010] According to a first aspect of the present invention, there is provided a method for manufacturing a pixelated scintillator, the method comprising:

[0011] irradiating a plurality of first regions of a substrate with a first laser radiation according to a predefined geometric configuration of a pixelated scintillator to induce structural modification of the material in the plurality of first regions of the substrate such that upon subjecting the substrate to etching, the etching (preferably wet chemical etching) occurs at a higher rate at the irradiated plurality of first regions than at non-irradiated regions;

[0012] performing etching to form a plurality of first openings in the substrate, the first openings having a predefined geometric configuration of the pixelated scintillator; and

[0013] The plurality of first openings are filled with at least one scintillator material to form the pixelated scintillator.

[0014] The present disclosure provides a new method for manufacturing a pixelated scintillator (e.g., a focused pixelated scintillator). Laser micromachining (e.g., femtosecond laser micromachining) followed by etching is used to create a plurality of first openings having a predefined geometric configuration in a substrate (e.g., a glass or plastic substrate). The substrate is preferably transparent or at least partially transparent to the laser radiation. The etching is preferably performed by wet chemical etching of the substrate, such as using a KOH or HF-based solution. However, other forms of etching are also contemplated, such as plasma etching, etching using gases such as fluorine-containing gases, etc.

[0015] The openings can be arranged in an array. The great flexibility of laser beam writing makes it possible to produce openings with customized geometric configurations on the substrate, such as high aspect ratio openings, openings with different heights, wall thicknesses, aspect ratios, shapes, spacings, angular inclinations, etc. No additional masking steps, such as the use of photoresists or metal masks, are required. The method advantageously provides reduced complexity and cost of the process. The first openings and / or the walls between the openings can have a high aspect ratio, such as an aspect ratio of depth to width of at least 10, more preferably at least 50, and more preferably at least 100. Thereafter, these openings will be filled with one or more scintillating materials, for example by means of screen printing or adhesive jetting. The filled openings may be referred to as scintillator elements or voxels of a pixelated scintillator. Thus, the openings are filled so as to define the scintillator elements or voxels of the pixelated scintillator. Therefore, the scintillator elements and / or the walls between the scintillator elements may also have a high aspect ratio, such as an aspect ratio of depth to width of at least 10, more preferably at least 50, and more preferably at least 100. Thus, the customized geometry of the openings facilitates providing scintillator elements that also have customized geometry. The subsequent process of filling the openings can enable pixelated scintillators to be provided from a variety of scintillator materials and in different forms. For example, powder-based scintillator materials can be used. The process of filling the openings can also enable the use of cost-effective manufacturing methods for the pixelated scintillators, and the pixelated scintillators can be embedded in a solid large-area substrate and thus protected.

[0016] The resulting pixelated scintillator can be bonded to a corresponding photosensitive readout sensor substrate to achieve single-layer or multi-layer radiation detectors with enhanced spatial resolution and sensitivity.

[0017] The proposed method for manufacturing pixelated scintillators can meet the increasing demands for quality, versatility, precision, pixel aspect ratio, area uniformity, robustness, and / or cost reduction, which can in turn facilitate new medical imaging methods such as spectral X-ray imaging and phase contrast imaging. Utilizing the proposed method, the optimal size and shape of each individual scintillator element in the detector can be provided.

[0018] This will be explained in detail below, especially for Figure 1 and Figure 2 The example shown in .

[0019] According to an embodiment of the present invention, before filling the plurality of first openings with at least one scintillator material to form a pixelated scintillator, the method further comprises coating at least a portion of an inner surface of at least one first opening with an optically reflective material or an opaque material.

[0020] In some examples, the sidewalls of the first opening are coated with an optically reflective material or an opaque material. In this way, the light signal is confined within each scintillator element. This reduces the ability of the light signal to escape to adjacent photosensitive pixels on the readout sensor.

[0021] In some examples, the bottom surface of the first opening is coated with an optically reflective material.Adding a coating with an optically reflective material to the bottom of the scintillator element of the glass substrate can increase the scintillation light output of the pixelated scintillator.

[0022] In some examples, the sidewalls and bottom surface of the first opening are coated with an optically reflective material or an opaque material.

[0023] This will be explained in detail below, especially for Figure 3 and Figure 4 The example shown in .

[0024] According to an embodiment of the present invention, after the step of filling the plurality of first openings with at least one scintillator material to form the pixelated scintillator, the method further comprises coating at least one filled first opening with an optically reflective material or an opaque material.

[0025] In other words, one or more filled openings (also called scintillator elements, or voxels) can be coated with an optically reflective material or an opaque material. This can be used to create pixelated scintillators with a so-called "front-illuminated" geometry.

[0026] This will be explained below, especially for Figure 8 The example shown in .

[0027] According to an embodiment of the present invention, the method further includes:

[0028] irradiating one or more second regions of the substrate with a second laser,

[0029] performing etching, preferably wet chemical etching, to form one or more second openings, and

[0030] The one or more second openings are filled with an optically reflective material or an opaque material, wherein the one or more second regions are different from the plurality of first regions, and at least one second region is arranged between two adjacent first regions.

[0031] These additional steps can allow the manufacture of pixelated scintillators with reflective or opaque walls. First, high aspect ratio grooves, such as high aspect ratio angled grooves, are made in a substrate (e.g., a glass substrate) using laser exposure (e.g., femtosecond laser exposure) and then etching. A thin solid layer of glass is left as a supporting base substrate for the system for the grooves. Second, the grooves can be filled with an optically reflective material. For example, a reflective TiO2 pigment layer can be applied by capillary filling of a TiO2-based coating. Alternatively, the grooves formed by the etching step can be filled with opaque groove walls.

[0032] This will be explained below, especially for Figure 5 and Figure 6 The example shown in .

[0033] According to an embodiment of the present invention, the method further comprises bending the substrate in one or two dimensions according to a desired curvature to reshape the substrate.

[0034] In this embodiment, a curved radiation detector may be fabricated using a flexible substrate (eg, thin glass or plastic foil) for the scintillator.

[0035] According to an embodiment of the invention, at least one of the first laser radiation and the second laser radiation is generated by a focused pulsed femtosecond laser.

[0036] Femtosecond laser micromachining technology has demonstrated the manufacturability of various monolithic integrated devices (such as optofluidics, optomechanics, and photonic devices). Since glass (such as but not limited to fused quartz), polymers, dielectrics, or crystals are commonly used as transparent substrate materials, the laser beam can be focused almost anywhere inside the substrate material, and energy can be deposited almost anywhere in the volume. The energy deposition causes a change in the material structure, causing subsequent wet chemical etching to occur at a much higher rate in exposed areas than in non-exposed areas. This locally enhanced wet chemical etching sensitivity (etching selectivity) depends on various femtosecond laser parameters, such as pulse duration, pulse energy, and pulse repetition rate.

[0037] According to an embodiment of the invention, the plurality of first openings are angled towards a common focal point.

[0038] The resulting pixelated scintillator may have scintillator element sidewalls that are better aligned toward the X-ray or gamma-ray focal point, thereby reducing parallax effects and pixel edge effects. As a result, such an angled (focused) scintillator can provide a higher modulation transfer function and detective quantum efficiency during imaging. Figure 2 、 Figure 4 and Figure 6 An example of an angled pixelated scintillator is shown.

[0039] According to an embodiment of the present invention, at least one scintillator material filled in the plurality of first openings has a relatively greater thickness at the center of the substrate than at the edge of the substrate.

[0040] In this way, a uniform scintillator absorption depth across the entire detector can be achieved. This will be discussed in detail below, especially with respect to Figure 9 Examples shown in (a)-9(c).

[0041] According to an embodiment of the present invention, at least two scintillator materials having different scintillator light emission spectra are filled in the plurality of first openings.

[0042] The sensitivity of X-ray detectors using pixelated scintillators can be limited by incorrectly matching the spectral characteristics of the scintillator and the photodiode. By using multiple scintillator materials, the emission spectrum of the scintillator material in the scintillator element can be matched to the photodiode sensitivity spectrum.

[0043] This will be explained in detail below, especially for Figure 10 (a) and Figure 10 Example shown in (b).

[0044] According to one embodiment of the present invention, at least two scintillator materials are sequentially deposited in at least one first opening. Alternatively or additionally, at least one scintillator element in the pixelated scintillator comprises a plurality of sub-scintillator elements, and at least two sub-scintillator elements in the at least one scintillator element are filled with different scintillator materials.

[0045] This will be explained in detail below, especially for Figure 10 (a) and Figure 10 Example shown in (b).

[0046] According to an embodiment of the present invention, the substrate includes a glass material or a plastic material.

[0047] According to a second aspect of the present invention, there is provided a pixelated scintillator that can be obtained by the method according to the first aspect and any related examples. The pixelated scintillator comprises a plurality of first openings in a substrate, wherein the plurality of first openings in the substrate are filled with at least one scintillator material. The pixelated scintillator can be a high aspect ratio pixelated scintillator. Preferably, the aspect ratio of the depth to the width of the walls between the plurality of first openings and / or the first openings of the pixelated scintillator is at least 10, more preferably at least 50, and even more preferably at least 100. The substrate is transparent or at least partially transparent to the laser radiation. For example, glass (such as but not limited to fused quartz), polymers, dielectrics or crystals can be used as transparent substrate materials. The pixelated scintillator is a focusing scintillator, wherein the plurality of first openings are angled towards a common focus. The focused pixelated scintillator can thereby provide an improved modulation transfer function and detection quantum efficiency during imaging.

[0048] Thus, pixelated scintillators can be manufactured with individual scintillator voxels of highly precise size and / or individual shaping. Using the manufacturing method described with respect to the first aspect of the present invention, scintillators with focused scintillator voxels in a transparent substrate can be manufactured. The high dimensional and dimensional stability enables robust optical coupling of the scintillator substrate with the sensor substrate, stacking of multiple scintillator substrates in a multi-layer detector, and the like. The walls can be smooth to reduce light scattering at the boundaries.

[0049] Glass may be a preferred transparent substrate for pixelated scintillators because it is strong, rigid, flat, chemically inert, and can be used as a large-area substrate. A glass substrate can ensure high-quality and robust optical coupling between the scintillator substrate and the photosensor substrate, which is also glass in most current medical X-ray detectors. This allows the scintillator and sensor substrates to share similar properties, such as thermal expansion coefficient.

[0050] According to a third aspect of the present invention, there is provided a radiation detector comprising a pixelated scintillator according to the second aspect and a pixelated and photosensitive readout sensor.

[0051] Optical crosstalk is caused by light-sensitive pixels on a sensor receiving light signals from multiple scintillator elements. The radiation detectors described herein can reduce this effect by providing improved lateral alignment between the light-sensitive pixels and the scintillator elements and minimizing the distance (gap) between the scintillator and the sensor.

[0052] Furthermore, the sensitivity of X-ray detectors using pixelated scintillators can be limited by a low fill factor. By providing precise alignment of the scintillator elements with the photosensitive areas of the pixels on the sensor, the fill factor for radiation detection as described herein can be improved.

[0053] This will be explained in detail below, especially for Figure 7 The example shown in .

[0054] According to an embodiment of the present invention, the radiation detector is a multi-layer detector comprising a plurality of stacked pixelated scintillators.

[0055] The resulting pixelated focused scintillator may be advantageous for multi-layer detectors because it reduces cross-contamination of signals between different detector layers. Multi-layer detectors comprising stacked pixelated scintillators may be advantageously used for spectral imaging. This will be explained below, particularly with respect to Figure 11 Examples shown in (a)-11(c).

[0056] According to one embodiment of the invention, the pixelated scintillator and the pixelated photosensitive readout sensor are configured and arranged to form a radiation detector in a so-called "back-illuminated" geometry or in a so-called "front-illuminated" geometry.

[0057] Pixelated scintillators can be integrated into X-ray detectors in any of the aforementioned geometric configurations. In front-illuminated geometry, X-rays or gamma rays first strike the scintillator, where they are absorbed. The resulting scintillation light is then detected by a photosensitive readout sensor. This is the most common geometry used in current X-ray detectors. In back-illuminated geometry, X-rays or gamma rays first strike the photosensitive readout sensor substrate. They pass through the substrate and are then absorbed by the scintillator. The resulting scintillation light is then detected by a photosensitive readout sensor.

[0058] Figure 7 An example of a radiation detector in a back-illuminated geometry is shown. Figure 8 An example of a radiation detector in a front-illuminated geometry is shown.

[0059] The pixelated scintillator can be manufactured using a manufacturing system including an optical laser system, an etching system and a material deposition system, and a control system including one or more controllers. The control system can be configured to control the optical laser system to irradiate multiple first areas of the substrate with a first laser radiation according to a predefined geometric configuration of the pixelated scintillator to cause structural modification of the material in the multiple first areas of the substrate, so that once the substrate is subjected to etching, the etching occurs at a higher rate at the irradiated multiple first areas than at the non-irradiated areas. The control system can be configured to control the chemical etching system to perform etching to form multiple first openings in the substrate, the first openings having the predefined geometric configuration of the pixelated scintillator. The control system can be configured to control the material deposition system to fill the multiple first openings with at least one scintillator material to form scintillator elements of the pixelated scintillator. This will be explained in detail below, in particular with respect to Figure 12 The example shown in .

[0060] There may be provided a computer program comprising instructions to cause a manufacturing system to perform the steps of the method according to the first aspect and any associated examples.

[0061] A computer readable medium storing the computer program may be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] These and other aspects of the invention will become apparent from and will be elucidated with reference to the following description, which is given by way of example, and to the accompanying drawings, in which:

[0063] Figure 1 A flow chart describing an example of a method of manufacturing a pixelated scintillator is illustrated.

[0064] Figure 2 The diagram shows Figure 1 Examples of relevant manufacturing processes.

[0065] Figure 3 A flow chart describing another example of a method of manufacturing a pixelated scintillator is illustrated.

[0066] Figure 4 The diagram shows Figure 3 Another example of a related manufacturing process.

[0067] Figure 5 A flow chart describing yet another example of a method of manufacturing a pixelated scintillator is illustrated.

[0068] Figure 6 The diagram shows Figure 5 Another example of a related manufacturing process.

[0069] Figure 7 Schematically shown are examples of radiation detectors fabricated by coupling a pixelated scintillator to a readout sensor in a back-radiating geometry configuration.

[0070] Figure 8 Schematically shown are examples of radiation detectors fabricated by coupling a pixelated scintillator to a readout sensor in a forward-radiating geometry configuration.

[0071] Figure 9 (a)-9(c) schematically illustrate how the spatial resolution of a radiation detector in a back-illuminated geometry can be improved by optimizing the design of the scintillator coupled to the readout sensor.

[0072] Figure 10(a) and 10(b) show examples of how scintillator elements composed of multiple scintillator materials can be used to improve the detection quantum efficiency (DQE) for specific clinical applications.

[0073] Figure 11 (a)-11(c) illustrate that pixelated focused scintillators are advantageous for multi-layer detectors to minimize cross-contamination of signals between different detector layers.

[0074] Figure 12 An example of a system for fabricating a pixelated scintillator is illustrated.

[0075] It should be noted that these drawings are purely schematic and not drawn to scale. In the drawings, elements corresponding to elements already described may have the same reference numerals. Examples, embodiments or optional features should not be understood as limiting the invention as claimed. DETAILED DESCRIPTION

[0076] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the present invention are shown. However, the present invention can be implemented in a variety of different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided to make this disclosure thorough and complete and to convey the scope of this disclosure to those skilled in the art. It will be understood by those skilled in the art that the following description of the embodiments of the present invention is illustrative and is not intended to be limiting in any way. For those skilled in the art who benefit from this disclosure, other embodiments of the present invention will readily become apparent. Throughout the text, similar reference numerals represent similar elements.

[0077] Although the following detailed description contains many details for illustrative purposes, it will be understood by those skilled in the art that many variations and modifications to the following details are within the scope of the invention. Therefore, the following embodiments of the invention are described without loss of generality and without imposing limitations on the claimed invention. In the following embodiments, wet chemical etching is used to illustrate etching of a substrate after irradiation with laser radiation. Such etching can preferably be performed using, for example, a solution based on KOH or HF. However, it is also contemplated that other forms of (chemical) etching can be used instead of wet chemical etching, such as plasma etching, etching using gases such as fluorine-containing gases, etc.

[0078] Various methods for manufacturing pixelated scintillators have been proposed in the past, but most of them have one or more disadvantages, including high cost. For example, dry reactive ion etching of silicon wafers followed by filling with CsI(Tl) during the melt process may not be suitable for producing focusing grooves in silicon because the etching process is very sensitive to the silicon crystal orientation. Laser machining (ablation) of CsI(Tl) thin films and then depositing a reflective coating in the laser-cut grooves can be used to improve the optical isolation between scintillator elements. However, this approach may suffer from a significant reduction in scintillator sensitivity, which is most likely due to laser-induced changes in the microstructure of the CsI(Tl) film. Additive manufacturing of scintillator elements, such as by 3D printing (e.g., photopolymerization) from scintillator particles in a binder powder system, can be used to produce 3D printed scintillator structures. However, such structures may not be mechanically robust enough to withstand the subsequent assembly processes required to manufacture X-ray detectors. The choice of scintillator may also be limited by the ability to make printable pastes.

[0079] To address one or more of the above-mentioned problems, the present disclosure proposes a method for manufacturing a pixelated scintillator, which can enable selection from a variety of low-cost scintillator materials (e.g., powder-based scintillator materials) and manufacturing methods to achieve a pixelated scintillator embedded and protected in a solid large-area substrate.

[0080] Figure 1 A flow chart describing a method 100 for manufacturing a pixelated scintillator (ie, an array of scintillator elements) is shown. Figure 2 Describe the method.

[0081] In step S110, first laser radiation 12a is irradiated to multiple first regions of the substrate 14 according to a predefined geometric configuration of the pixelated scintillator to cause structural modification of the material in the multiple first regions of the substrate, so that wet chemical etching occurs at a higher rate at the multiple irradiated first regions than at the non-irradiated regions.

[0082] The substrate can be made of a material that is transparent or at least partially transparent to the first laser radiation. For example, glass (such as, but not limited to, fused silica), polymers, dielectrics, or crystals can be used as transparent substrate materials because the laser beam can be focused almost anywhere inside the material and energy can be deposited almost anywhere in the volume.

[0083] Due to the nonlinear nature of the interaction between ultrafast lasers and matter, relatively low laser energy is absorbed locally wherever the laser spot is focused. The nonlinear absorption of laser energy makes it possible to use moderate average laser powers, despite the huge instantaneous powers reached locally during the laser irradiation. It is even possible to create features smaller than the wavelength of the laser itself (e.g. 1030 nm). As an example, the first laser radiation can be generated by a focused pulsed femtosecond laser. The "femtosecond printing" process uses femtosecond laser micromachining technology, which is a subtractive 3D printing technology that is capable of creating narrow and deep channels in glass with high trench aspect ratios (TAR>100), which are comparable to or higher than competing processes such as reactive ion etching (RIE).

[0084] Energy deposition causes changes in the material structure so that subsequent wet chemical etching occurs at a much higher rate in the exposed area (or areas) than in the non-exposed area (or areas). This locally enhanced wet chemical etching sensitivity (etching selectivity) depends on various laser parameters such as pulse duration, pulse energy, and repetition rate.

[0085] Examples of predefined geometric configurations of pixelated scintillators include, among others, one-dimensional (1D) designs, two-dimensional (2D) designs (e.g., rectangular or hexagonal scintillator elements), and custom scintillator element designs with flexible scintillator element spacing, scintillator element ratios, and / or scintillator element geometric configurations (e.g., 1D, 2 ... 1 / 2D). The predefined geometric configuration of the pixelated scintillator may include information such as height on the substrate, wall thickness, aspect ratio, scintillator element shape, scintillator element spacing, angular tilt, etc.

[0086] In step S120, wet chemical etching is performed to form a plurality of first openings having a predefined geometric configuration of the pixelated scintillator. Since wet chemical etching occurs at a much higher rate in the (one or more) exposed areas than in the (one or more) non-exposed areas, precise structures with a predefined geometric configuration can be created. The proposed method provides the possibility to optimize the size and shape of each individual scintillator element in the detector. The laser exposure can be flexibly programmed for the entire substrate. Thus, the openings can have customized geometric configurations, such as openings and / or walls with high aspect ratios on the substrate, openings with different heights, wall thicknesses, aspect ratios, shapes, spacings, angular inclinations, etc.

[0087] This approach enables the realization of multi-layer detectors for spectral imaging, where the respective scintillator elements of the top and bottom scintillator layers can be optimized and precisely positioned relative to each other.

[0088] like Figure 2As shown in , the laser exposure can be controlled in such a way that the first opening does not extend completely to the other side of the substrate 14. A thin layer of the substrate remains as a support substrate for the scintillator elements of the pixelated scintillator.

[0089] In some examples, such as Figure 2 As shown, an optical laser system that generates the first laser radiation can be designed and programmed to write a specified structure (e.g., an array) of first openings 16 characterized by a continuous, small increase in groove angle from the center toward the periphery of substrate 14. The optical laser system can also take into account the refractive index difference at the air-substrate interface and the increasing optical path length of the first openings 16 toward the periphery of substrate 14.

[0090] In step S130 , the plurality of first openings 16 are filled with at least one scintillator material 18 to form a pixelated scintillator 20 .

[0091] The plurality of first openings 16 can be filled with one or more selected scintillator materials using any suitable application method. Depending on the detector design and its imaging application, a variety of scintillator materials can be selected, such as GOS, CsI, perovskite nanoparticles, quantum dot materials, etc., as well as various additives such as dopants and binders, and in various forms including, but not limited to, powders, pastes, and suspensions. Furthermore, a wide range of scintillator deposition methods can be selected, including, but not limited to, 3D printing, binder jetting, screen printing, slot die coating, flexographic printing, spin coating, powder melting, etc.

[0092] The methods described herein enable selection from a variety of inexpensive (e.g., powder-based) scintillator materials and manufacturing methods to achieve pixelated scintillators embedded and protected in solid large-area substrates. In addition, the methods described herein can provide improved environmental and mechanical protection by embedding small, fragile scintillator structures in solid substrates (e.g., glass substrates). The fill factor can be improved by accurately aligning the scintillator elements with the active photosensitive area of ​​the pixels on the sensor. The method can enable the fabrication of focused scintillator elements with predefined geometric configurations and sharp boundaries. For example, Figure 2 The focused scintillator (i.e., angled scintillator) shown in

[15] can reduce pixel edge effects. The method described herein can reduce optical crosstalk in X-ray detectors by achieving lateral alignment between photosensitive pixels and scintillator elements and minimizing the distance (gap) between the sensor and the scintillator. This will be described below, particularly for Figure 7 The example shown in .

[0093] Pixelated scintillators may include a one-dimensional (1D), two-dimensional (2D), or three-dimensional (3D) array of scintillator elements. Pixelated scintillators may be used in radiation imaging detectors to detect and thereby image ionizing radiation such as X-rays and gamma radiation. Pixelated scintillators may be used, for example, in medical imaging systems such as positron emission tomography (PET), single photon emission computed tomography (SPECT), and computed tomography (CT) imaging systems. Pixelated scintillators may be used in non-medical imaging systems such as industrial radiography for inspecting industrial parts. The material of such scintillator elements is selected so that a pulse of scintillation light is generated in response to each received X-ray or gamma quantum. The scintillation light is then optically coupled to an array of photodetectors detected by the scintillator elements.

[0094] The point spread function of current radiation detectors, which are primarily based on continuous (non-pixelated) scintillators, can be broadened due to blurring of the scintillation light in the scintillator after X-rays or gamma rays interact with the scintillator. This is primarily due to scattering and reflection effects of the scintillator light at the scintillator grain boundaries. These effects are most pronounced in polycrystalline (powder) layers (such as GOS), but also occur in columnar structure layers (such as CsI). To this end, an option for the pixelated scintillator of the present disclosure is configured with optical isolation layers between the scintillator elements to provide optical separation of the scintillator so that scintillation photons generated in a scintillator element cannot easily escape from that scintillator element and enter another scintillator element. When scintillator elements are optically isolated, the majority of the generated scintillation photons are contained within the scintillator element in which they were generated, for example by total internal reflection. Examples of isolation materials can include, but are not limited to, optically reflective materials and opaque materials. In this way, the light signal is confined within each scintillator element, regardless of the type of scintillator material. It is almost impossible for the light signal to escape to adjacent photosensitive pixels on the readout sensor.

[0095] There are many ways to make pixelated scintillators with optical isolation layers.

[0096] Figure 3 An exemplary flow chart describing a method 100 for fabricating a pixelated scintillator having an optical isolation layer is shown. Figure 4 Describe the method.

[0097] In step S110, first laser radiation 12a is irradiated to multiple first regions of the substrate 14 according to a predefined geometric configuration of the pixelated scintillator to cause structural modification of the material in the multiple first regions of the substrate, so that wet chemical etching occurs at a higher rate at the multiple irradiated first regions than at the non-irradiated regions.

[0098] In step S120 , wet chemical etching is performed to form a plurality of first openings 16 having a predefined geometric configuration of the pixelated scintillator.

[0099] In step S122, at least a portion of the inner surface of at least one first opening 16 is coated with an isolation material 22, such as an optically reflective material or an opaque material. Figure 4 As shown, both the sidewalls and the bottom surface of the first opening are coated with the isolation material. In some examples (not shown), only the sidewalls of the first opening 16 are coated with the isolation material. There are many options for possible material coating methods for the isolation material. For example, atomic layer deposition (ALD) is a mature technology that can be used to deposit highly conformal multilayer coatings (e.g., SiO2 / Al2O3 / Al) in high aspect ratio trenches. Other material coating techniques may be based on thermal evaporation, thermal melting, capillary filling from a suspension, or pasting.

[0100] In step S130 , the plurality of first openings 16 are filled with at least one scintillator material 18 to form a pixelated scintillator 20 .

[0101] Figure 5 An exemplary flow chart describing a method 100 for fabricating a pixelated scintillator having reflective or opaque groove walls is shown. Figure 6 Describe the method.

[0102] In step S102, second laser radiation 12b is irradiated onto one or more second regions of the substrate 14. The first laser radiation 12a and the second laser radiation 12b may represent different laser exposure sequences.

[0103] In step S104, wet etching is performed to form one or more second openings 24. Similarly, laser exposure can be controlled in such a way that the second openings 24 do not completely extend to the other side of the substrate 14. A thin layer of solid substrate is retained as a support substrate for the second opening 24 system.

[0104] In step S106, one or more second openings 24 are filled with an insulating material 22, such as an optically reflective material or an opaque material. For example, a reflective TiO2 pigment layer may be applied by capillary filling of a TiO2-based coating. The one or more second regions are distinct from the plurality of first regions, and at least one second region is disposed between two adjacent first regions.

[0105] In step S110, first laser radiation 12a is irradiated to multiple first regions of the substrate 14 according to a predefined geometric configuration of the pixelated scintillator to cause structural modification of the material in the multiple first regions of the substrate, so that wet chemical etching occurs at a higher rate at the multiple irradiated first regions than at the non-irradiated regions.

[0106] In step S120 , wet chemical etching is performed to form a plurality of first openings 16 having a predefined geometric configuration of the pixelated scintillator.

[0107] In step S130 , the plurality of first openings 16 are filled with at least one scintillator material 18 to form a pixelated scintillator 20 .

[0108] exist Figure 5 and Figure 6 In the example shown, the reflective or opaque groove walls are formed before the scintillator elements. In some other examples (not shown), the isolation layer can be formed after the scintillator elements. In other words, steps S102 to S106 can be performed after steps S110 to S130.

[0109] In some examples, a protective layer may be added to the scintillator substrate of the pixelated scintillator, e.g. Figure 2 、 4 and the pixelated scintillator 20 shown in 6 to prevent loss of scintillator material from the scintillator elements and / or to prevent loss of isolation material from the trenches.

[0110] In some examples, a reflective layer (e.g., a layer of optically reflective material) may be added to the back side of the sensor substrate coupled to the pixelated scintillator, e.g., Figure 2 、 4 and the pixelated scintillator 20 shown in FIG6. This will be explained below, in particular with respect to Figure 7 and Figure 8 The exemplary radiation detector shown in FIG.

[0111] In some examples, the scintillator may be pixelated (e.g., Figure 2 and 4 A reflective layer (eg, a layer of optically reflective material) is added to the bottom of the scintillator element in the substrate of the pixelated scintillator 20 shown, or a layer of optically reflective material is added to the bottom of the scintillator element in the substrate of the pixelated scintillator (eg, Figure 2 and 6 A reflective layer is added to the back side of the substrate of the pixelated scintillator 20 shown. This may increase the scintillation light output of the pixelated scintillator.

[0112] In some examples, an X-ray imaging system may have a curved pixelated scintillator rather than a flat pixelated scintillator. In this case, micromachining of the scintillator element can still be performed on a flat, flexible substrate, such as a thin glass or plastic foil, which can then be slightly bent in one or two dimensions to meet the desired curvature, for example, using a high-temperature mold, to enable the fabrication of curved radiation detectors.

[0113] The point spread function of current radiation detectors (most of which are based on continuous scintillators, i.e. non-pixelated scintillators) may be broadened due to parallax errors caused by variations in the absorption depth of incident X-rays in the scintillator layer on the detector. These effects are less pronounced at the center of the detector (where the X-rays are incident vertically), but they become stronger at the edges (where the X-rays are incident obliquely). To this end, another option for the pixelated scintillator disclosed herein is to be configured with different scintillator thicknesses along the substrate to achieve a uniform scintillator absorption thickness for all pixels across the substrate. For example, at least one scintillator material filled in the plurality of first openings may have a thickness that decreases from the center of the substrate to the edge of the substrate. This structure can be used to reduce parallax effects and pixel edge effects. This will be explained in detail below, in particular with respect to Figure 9 Examples shown in (a)-9(c).

[0114] The sensitivity of X-ray detectors based on pixelated scintillators may be limited due to the mismatch in the spectral characteristics of the scintillator and the photodiode. Using the methods described in this article, the emission spectrum of the scintillator material in the scintillator element can be matched to the photodiode sensitivity spectrum to improve DQE. To this end, one option of the pixelated scintillator of the present disclosure is to be configured with a composite scintillator material including multiple scintillator materials. In some examples, the at least two scintillator materials are continuously deposited in at least one of the first openings. Alternatively or additionally, at least one scintillator element in the pixelated scintillator includes a plurality of sub-scintillator elements, and at least two sub-scintillator elements in at least one scintillator element are filled with different scintillator materials. This will be explained in detail below, in particular with respect to Figure 10 (a) and Figure 10 Example shown in (b).

[0115] The pixelated scintillator 20 can be integrated into radiation detectors of various different geometric configurations. For example, the pixelated scintillator 20 can be integrated into radiation detectors having a front-illuminated geometry or a back-illuminated geometry, as described above.

[0116] Figure 7 An example of a radiation detector 40 fabricated by coupling a pixelated scintillator 20 with a pixelated and photosensitive readout sensor 30 in a back-illuminated geometry is schematically shown. In this example, the pixelated scintillator 20 is shown with Figure 4 However, it should be understood that other configurations (such as Figure 2 and 6 The pixelated scintillator 20 shown can also be used in a radiation detector 40. The pixelated photosensitive readout sensor 30 includes a sensor substrate 32 and a photodetector array comprising a plurality of photosensitive pixels 34 in optical communication with the scintillator array 20. In some examples, the photodetector array 34 can be an array of silicon photomultipliers (SiPMs), such as a Philips digital photon counting SiPM photodetector array. Alternatively, the photodetector array 34 can include an array of avalanche photodiodes, photomultipliers, position-sensitive photodetectors, and the like. In these examples, the photodiodes, photomultipliers, and photodetectors form the photosensitive pixels. By aligning the scintillator elements 18 with the photosensitive pixels 34 across the sensor substrate area, the fill factor (i.e., X-ray sensitivity) can be improved. Furthermore, the blank areas between the scintillator elements 18 accurately overlap the dead areas between the photosensitive pixels 34. Compared to front-illuminated geometries, back-illuminated geometries can improve the spatial resolution and sensitivity of the radiation detector. Furthermore, back-illuminated geometries can reduce the effective distance between the pixelated scintillator and the readout sensor. The effective distance may indicate the average distance from an X-ray absorption event to a readout sensor. The scintillator may be bonded to the sensor by gluing, using an adhesive film, or mechanically clamping. The radiation detector 40 may be used, for example, in a SPECT, PET, X-ray, or CT imaging system.

[0117] Optionally, a reflective layer (not shown) (eg, a layer of optically reflective material) can be applied to the back side of the sensor substrate to reflect some of the scintillation light from the backlight beneath the scintillator substrate back toward the photodiodes.

[0118] Figure 8 Another example of a radiation detector 40 fabricated by coupling a pixelated scintillator 20 to a readout sensor 30 in a front-illuminated geometry is schematically shown. Figure 7 The radiation detection shown is compared to Figure 8 The pixelated scintillator shown in FIG is arranged towards the X-rays or gamma rays. Thus, the X-rays or gamma rays first pass through the pixelated scintillator 20 and then strike the readout sensor 30. The openings defining the scintillator elements may be angled accordingly.

[0119] Optionally, a reflective layer (not shown) (e.g., a layer of optically reflective material) can be applied to the back side of the scintillator substrate. Optionally, an opaque material can be applied to the first opening wall (also referred to as the scintillator element wall) of the scintillator substrate. Compared to optically reflective materials, the use of opaque materials (e.g., light-absorbing materials) may reduce sensitivity but increase spatial resolution, which may be interesting for non-medical applications where dose is less critical.

[0120] Next, Figures 9 to 11 Further radiation detector configurations are shown. Although these figures may show Figure 4 The pixelated scintillator of the configuration shown in FIG, but it will be understood that other pixelated scintillators, such as Figure 2 and Figure 6 The pixelated scintillator 20 shown can also be implemented in these radiation detector configurations.

[0121] Figure 9 (a)-9(c) schematically illustrate how the spatial resolution of a radiation detector in a back-illuminated geometry can be improved by optimizing the design of the scintillator coupled to the readout sensor. Figure 9 As shown in (a), for non-pixelated scintillators, the resolution decreases from the center to the edge of the detector, which is mainly due to the increasing parallax effect caused by obliquely incident X-rays or gamma rays. Figure 9 (b) shows an example of a pixelated non-focused scintillator, wherein the at least one scintillator material filled in the plurality of first openings has the same or similar thickness. In this radiation detector configuration, pixel edge effects originating from the sidewalls of the scintillator element still reduce the spatial resolution toward the edge of the detector. Figure 9 (c) shows an example of a pixelated focused scintillator. In this radiation detector configuration, both parallax effects and pixel edge effects can be reduced because the scintillator element sidewalls are aligned toward the X-ray focal spot or gamma-ray beam. In addition, by slightly reducing the scintillator thickness from the center to the edge, a uniform scintillator absorption depth across the detector can be achieved. Although Figure 9 (a)-9(c) may illustrate radiation detectors in a back-illuminated geometry by way of example, but it will be understood that radiation detectors may also be configured according to Figure 9 The embodiment shown in (c) optimizes the design of the scintillator coupled to the readout sensor to improve radiation detection in a front-illuminated geometry.

[0122] Figure 10 Figures 10(a) and 10(b) show examples of how scintillator elements comprising multiple scintillator materials can be used to improve the DQE for specific clinical applications. Generally, this can be achieved by maximizing the overlap between the scintillator emission spectrum and the photodiode sensitivity spectrum and / or maximizing the scintillator's X-ray or gamma-ray absorption.

[0123] Figure 10 The example of (a) shows that three different scintillator layers comprising scintillating materials 18a, 18b and 18c are deposited consecutively in each scintillator element, which can be achieved using a binder jetting device. For example, each photosensitive pixel is bonded to a scintillator element that is filled with multiple scintillator layers stacked on top of each other. In order to improve light collection in a back-illuminated geometry, the light emission and radiation absorption of the layer sequence can be selected so that all layers closest to the readout sensor are transparent to the light emission of all layers farther away from the sensor. Although Figure 10 (a) Three scintillator layers may be shown by way of example, but it will be understood that in some other examples, the radiation detector may contain a different number of scintillator layers, such as two scintillator layers, four scintillator layers, or more scintillator layers.

[0124] Figure 10 The example of (b) shows that each scintillator element is composed of three sub-scintillator elements, each of which is filled with a different material. For example, a photosensitive pixel may include several smaller photosensitive sub-pixels, such as Figure 10 (b) shows sub-pixels 34a, 34b and 34c, which are coupled to corresponding scintillator sub-elements filled with different scintillator materials, such as Figure 10 (b) Scintillator materials 18a, 18b, 18c are shown. The radiation absorption characteristics of the scintillator sub-elements can be selected to achieve maximum discrimination between object materials in spectral imaging. Figure 10 (b) Three sub-pixels may be shown by way of example, but it will be understood that in some other examples, each photosensitive pixel may include a different number of sub-pixels, such as two sub-pixels, four sub-pixels, or more sub-pixels.

[0125] Although Figure 10 (a) and 10(b) may illustrate, by way of example, radiation detectors in a back-illuminated geometry, but it will be understood that it is also possible to Figure 10 Scintillator elements comprising multiple scintillator materials are shown in Figures 10(a) and 10(b) to improve radiation detection in a front-illuminated geometry.

[0126] Figure 11 Figures (a)-11(c) illustrate the benefits of pixelated, focused scintillators for multi-layer detectors, minimizing cross-contamination of signals between different detector layers. Precise positioning on a glass substrate using femtosecond laser microstructuring enables accurate stacking and alignment of the corresponding focused scintillator elements, ensuring reduced cross-contamination of signals between detector layers.

[0127] Figure 11 (a) shows a double-layer radiation detector based on two sensors, Figure 11 (b) shows a three-layer radiation detector based on three sensors. Both radiation detectors adopt a back-radiating geometry with a standard sensor stack. Figure 11 (c) shows an alternative three-layer radiation detector based on two sensors. In this case, the bottom sensor is photosensitive on both sides (a so-called "bidirectional" sensor), i.e. the pixels are designed to capture the scintillation light emitted by the scintillator element at both the top and bottom. Figure 11 (a)-11(c) may illustrate radiation detectors in a back-illuminated geometry by way of example, but it will be understood that radiation detection in a front-illuminated geometry may also utilize Figure 11 (a)-11(c) are modified. In some examples, such as Figure 11 As shown in (c), the radiation detector can be configured to have both a front-irradiation geometry and a back-irradiation geometry.

[0128] Figure 12 An example of a system 200 for fabricating a pixelated scintillator is shown. The system 200 includes an optical laser system 210, a chemical etching system 220, a material deposition system 230, and a control system 240.

[0129] The control system 240 may include one or more controllers. Examples of controller components that may be used in various embodiments of the present disclosure include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field programmable gate arrays (FPGAs).

[0130] The control system 240 is configured to control the optical laser system 210 to irradiate the first laser radiation to the plurality of first regions of the substrate according to a predefined geometric configuration of the pixelated scintillator to induce structural modification of the material in the plurality of first regions of the substrate such that wet chemical etching occurs at a higher rate at the plurality of irradiated first regions than at non-irradiated regions. The optical laser system 210 may include a femtosecond laser.

[0131] The control system 240 is configured to control the chemical etching system 220 to perform wet chemical etching to form a plurality of first openings having a predefined geometric configuration of the pixelated scintillator, thereby forming scintillator elements of the pixelated scintillator. The wet chemical etching can be performed using, for example, a KOH or HF-based solution. Huang Ji et al., "Fabrication of highly homogeneous and controllable nanogratings on silicon via chemical etching-assisted femtosecond laser modification," provide an example of wet chemical etching using KOH after irradiation with a femtosecond laser.

[0132] The control system 240 is configured to control the material deposition system 230 to fill the plurality of first openings with at least one scintillator material to form a pixelated scintillator. The material deposition system 230 may include a system that deposits using techniques such as 3D printing, binder jetting, screen printing, slot die coating, flexographic printing, spin coating, powder melting, etc.

[0133] In a further exemplary embodiment of the present invention, a computer program or a computer program element is provided, characterized in that it is adapted to perform the method steps of the method according to one of the preceding examples on a suitable system.

[0134] The computer program element can therefore be stored on a computing unit, which can also be part of an embodiment of the present invention. The computing unit can be adapted to perform the steps of the above-described method or to cause the steps of the above-described method to be performed. In addition, it can also be adapted to operate components of the apparatus described above. The computing unit can be adapted to operate automatically and / or to execute user commands. The computer program can be loaded into the working memory of a data processor. The data processor can therefore be equipped to implement the method of the present invention.

[0135] This exemplary embodiment of the invention covers both a computer program that right from the start uses the invention and a computer program that by means of an up-date turns an existing program into a program that uses the invention.

[0136] Furthermore, the computer program element may be able to provide all necessary steps to implement the procedures of an exemplary embodiment of the method as described above.

[0137] According to another exemplary embodiment of the present invention, a computer-readable medium, such as a CD-ROM, is proposed, wherein the computer-readable medium has a computer program element stored thereon, the computer program element being as described in the previous section.

[0138] The computer program may be stored and / or distributed on suitable media, such as optical storage media or solid-state media provided with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

[0139] However, the computer program may alternatively be provided over a network like the World Wide Web and may be downloaded from such a network into the working memory of a data processor. According to a further exemplary embodiment of the present invention, a medium for making a computer program element available for downloading is provided, said computer program element being arranged to perform one of the previously described embodiments of the present invention.

[0140] It should be noted that embodiments of the present invention are described with reference to different subject matters. In particular, some embodiments are described with reference to method claims, while other embodiments are described with reference to apparatus claims. However, a person skilled in the art will appreciate from the above and following descriptions that, unless otherwise indicated, any combination of features relating to different subject matters, in addition to any combination of features belonging to the same type of subject matter, is also considered to be disclosed by this application. However, all features can be combined to provide synergistic effects that exceed the simple sum of the features described.

[0141] Although the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description should be considered illustrative or exemplary rather than restrictive. The present invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention by studying the drawings, the disclosure, and the appended claims.

[0142] In the claims, the word "comprising" does not exclude other elements or steps, and the word "a" or "an" does not exclude a plurality. A single processor or other unit may perform the functions of several items recited in a claim. Measures recited in mutually different dependent claims may be advantageously combined. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. A method for manufacturing a pixelated scintillator, the method comprising: irradiating (S110) a plurality of first regions of a substrate with a first laser radiation according to a predefined geometric configuration of the pixelated scintillator to cause structural modification of the material in the plurality of first regions of the substrate such that once the substrate is subjected to etching, the etching occurs at a higher rate at the irradiated plurality of first regions than at non-irradiated regions; performing ( S120 ) the etching to form a plurality of first openings in the substrate, the first openings having the predefined geometric configuration of the pixelated scintillator; as well as The plurality of first openings are filled (S130) with at least one scintillator material to form the pixelated scintillator.

2. The method according to claim 1, in, Before the step of filling (S130) the plurality of first openings with the at least one scintillator material to form the pixelated scintillator, the method further comprises: At least a portion of an inner surface of the at least one first opening is coated (S122) with an optically reflective material or an opaque material.

3. The method according to claim 1 or claim 2, in, After the step of filling (S130) the plurality of first openings with at least one scintillator material to form the pixelated scintillator, the method further comprises: The at least one filled first opening is coated with an optically reflective material or an opaque material.

4. The method according to any one of the preceding claims, further comprising: irradiating (S102) one or more second regions of the substrate with a second laser, performing (S104) etching to form one or more second openings, and The one or more second openings are filled ( S106 ) with an optically reflective material or an opaque material, wherein the one or more second regions are different from the plurality of first regions, and at least one second region is arranged between two adjacent first regions.

5. The method according to any one of the preceding claims, further comprising: The substrate is bent in one or two dimensions to reshape the substrate according to a desired curvature.

6. The method according to any one of the preceding claims, in, At least one of the first laser radiation and the second laser radiation is generated by a focused pulsed femtosecond laser.

7. The method according to any one of the preceding claims, in, The plurality of first openings are angled toward a common focal point.

8. The method according to any one of the preceding claims, in, The at least one scintillator material filled in the plurality of first openings has a relatively greater thickness at the center of the substrate than at an edge of the substrate.

9. The method according to any one of the preceding claims, in, The plurality of first openings are filled with at least two scintillator materials (18a, 18b, 18c) having different scintillator emission spectra.

10. The method according to claim 9, in, The at least two scintillator materials are deposited successively in at least one of the first openings; and / or The pixelated scintillator comprises a plurality of scintillator elements, and at least one scintillator element in the pixelated scintillator comprises a plurality of sub-scintillator elements, and at least two sub-scintillator elements in the at least one scintillator element are filled with different scintillator materials.

11. The method according to any one of the preceding claims, in, The substrate includes a glass material or a plastic material.

12. A pixelated scintillator (20) obtainable by a method according to any one of the preceding claims, wherein The pixelated scintillator comprises a plurality of first openings in a substrate that is transparent or at least partially transparent to laser radiation, wherein the plurality of first openings in the substrate are filled with at least one scintillator material, and wherein the plurality of first openings are angled towards a common focus.

13. A radiation detector (40), comprising: The pixelated scintillator (20) according to claim 12; as well as A pixelated and light-sensitive readout sensor (30).

14. The radiation detector according to claim 13, in, The radiation detector is a multi-layer detector comprising a plurality of stacked pixelated scintillators.

15. The radiation detector according to claim 13 or claim 14, in, The pixelated scintillator and the pixelated and photosensitive readout sensor are configured and arranged to form a radiation detector in a back-illuminated geometry or a front-illuminated geometry.

16. A manufacturing system for manufacturing a pixelated scintillator according to the method of claims 1-11, the system comprising: Optical laser systems, Etching system, Material deposition systems, and a control system comprising one or more controllers, wherein the control system is configured to control the optical laser system to irradiate a plurality of first regions of a substrate with a first laser radiation according to a predefined geometric configuration of the pixelated scintillator to cause structural modification of the material in the plurality of first regions of the substrate, so that once the substrate is subjected to etching, the etching occurs at a higher rate at the irradiated plurality of first regions than at non-irradiated regions, wherein the control system is configured to control the etching system to perform the etching to form a plurality of first openings in the substrate, the first openings having the predefined geometric configuration of the pixelated scintillator, and The control system is configured to control the material deposition system to fill the plurality of first openings with at least one scintillator material to form scintillator elements of the pixelated scintillator.

17. A computer program comprising instructions for causing a manufacturing system according to claim 16 to perform the steps of the method according to claims 1-11.

18. A computer readable medium having stored thereon the computer program according to claim 17.

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