Radiation detection panel and preparation method therefor, and radiation detector

Abstract

A radiation detection panel and a preparation method therefor, and a radiation detector. The radiation detection panel comprises a detection substrate (20) and a scintillator layer (10) located on one side of the detection substrate (20), wherein the scintillator layer (10) has scintillator units (100) arranged in an array; each scintillator unit (100) includes at least two layers of stacked scintillator sub-units; in any two adjacent layers of scintillator sub-units, the scintillator subunits on the side closer to the detection substrate (20) have a higher conversion rate for radiation rays than the scintillator subunits on the side farther away from the detection substrate (20), and the scintillator subunits on the side closer to the detection substrate (20) have a lower tolerance to the radiation rays than the scintillator subunits on the side farther away from the detection substrate (20). Therefore, the radiation detection panel can use a low-dose radiation source to achieve high-resolution radiation imaging.

Description

Radiation detection panel and its preparation method, radiation detector

[0001] Cross-references

[0002] This disclosure claims priority to Chinese Patent Application No. 202411710936.3, filed on November 26, 2024, entitled "Radiation Detection Panel and Preparation Method Thereof, Radiation Detector", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of high-energy ray detection technology, and more specifically, to a radiation detection panel and its preparation method, and a radiation detector. Background Technology

[0004] Currently, flat panel X-ray detectors (FPXD) are widely used in medical diagnostics, industrial non-destructive testing, and public security. With continuous technological advancements and increased public awareness of health, FPXD detectors are evolving towards lower radiation doses and higher resolution imaging. However, the limitations of scintillator materials in their use restrict their application in the medical field.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a radiation detection panel and its preparation method, as well as a radiation detector, which improves the performance of the radiation detection panel by using a scintillator layer with a composite scintillator.

[0007] According to one aspect of this disclosure, a radiation detection panel is provided, including a detection substrate and a scintillator layer located on one side of the detection substrate;

[0008] The detection substrate has an array of detection units; the scintillator layer has an array of scintillator units, and the scintillator units are correspondingly arranged with one or more detection units.

[0009] The scintillator unit comprises at least two stacked scintillator subunits;

[0010] In any two adjacent scintillator subunits, the luminous efficiency of the scintillator subunit closer to the detection substrate is greater than that of the scintillator subunit farther from the detection substrate, and the scintillator subunit closer to the detection substrate has less tolerance to radiation than the scintillator subunit farther from the detection substrate.

[0011] In one exemplary embodiment of this disclosure, the scintillator unit includes at least a second scintillator subunit closer to the detection substrate and a first scintillator subunit furthest from the detection substrate.

[0012] In one exemplary embodiment of this disclosure, the scintillator layer further includes a reflective layer having a back side facing the detection substrate and a front side facing away from the detection substrate;

[0013] The reflective layer is provided with a plurality of grooves corresponding one-to-one with the scintillator unit, and the grooves open on the back side;

[0014] The first scintillator subunit is located within the corresponding groove.

[0015] In one exemplary embodiment of this disclosure, the aspect ratio of the groove is between 5 and 10.

[0016] In one exemplary embodiment of this disclosure, at least a portion of the second scintillator subunit is located within the groove.

[0017] In one exemplary embodiment of this disclosure, the second scintillator subunit includes a regular crystal layer close to the detection substrate and an irregular crystal layer away from the detection substrate;

[0018] The irregular crystal layer is at least partially located within the groove.

[0019] In one exemplary embodiment of this disclosure, the second scintillator subunit includes a regular crystal layer close to the detection substrate and an irregular crystal layer away from the detection substrate;

[0020] The irregular crystal layer is located within the groove, and at least a portion of the regular crystal layer is located within the groove.

[0021] In one exemplary embodiment of this disclosure, the orthographic projection of the first scintillator subunit onto the detection substrate is located within the range of the orthographic projection of the regular crystal layer onto the detection substrate.

[0022] In one exemplary embodiment of this disclosure, the groove includes a first space and a second space, wherein the second space is located on the side of the first space near the opening of the groove;

[0023] The first space of the groove is filled with the first scintillator subunit; the second space is filled with the second scintillator subunit;

[0024] The depth of the second space is between 100 and 200 micrometers.

[0025] In one exemplary embodiment of this disclosure, a transparent protective layer is further included, which at least covers the scintillator layer.

[0026] In one exemplary embodiment of this disclosure, the first scintillator subunit is a gadolinium sulfide subunit, and the second scintillator subunit is a cesium iodide subunit.

[0027] According to another aspect of this disclosure, a radiation detector is provided, including the radiation detection panel described above.

[0028] According to another aspect of this disclosure, a method for fabricating a radiation detection panel is provided, comprising fabricating a scintillator layer located on one side of a detection substrate, the scintillator layer having scintillator units arranged in an array;

[0029] The preparation of the scintillator layer includes:

[0030] At least two scintillator sublayers are sequentially formed on the substrate layer, each scintillator sublayer containing scintillator subunits corresponding to each scintillator unit; wherein, in any two adjacent scintillator subunits, the luminous efficiency of the scintillator subunit closer to the detection substrate is greater than that of the scintillator subunit farther from the detection substrate, and the scintillator subunit closer to the detection substrate has less tolerance to radiation than the scintillator subunit farther from the detection substrate.

[0031] In one exemplary embodiment of this disclosure, the substrate layer is a reflective layer; the reflective layer has a back side facing the detection substrate and a front side facing away from the detection substrate;

[0032] The preparation method further includes:

[0033] Multiple grooves are formed on the back side of the reflective layer, and each of the multiple grooves corresponds to one of the multiple scintillator units; the grooves open on the back side.

[0034] The step of sequentially forming at least two scintillator sublayers on the substrate layer includes:

[0035] A first scintillator sublayer is formed, the first scintillator sublayer comprising a first scintillator subunit of each scintillator unit, the first scintillator subunit of each scintillator unit being located in a corresponding groove;

[0036] A second scintillator sublayer is formed, the second scintillator sublayer comprising the second scintillator subunits of each scintillator unit.

[0037] In one exemplary embodiment of this disclosure, the second scintillator subunit includes an irregular crystal layer and a regular crystal layer; the groove includes a first space and a second space, the second space being located on the side of the first space near the opening of the groove;

[0038] The formation of the first scintillator sublayer includes:

[0039] A corresponding first scintillator subunit is formed within the first space of each of the grooves;

[0040] The formation of the second scintillator sublayer includes:

[0041] A second scintillator sublayer is formed covering the first scintillator sublayer, such that the irregular crystal layer of the second scintillator subunit is at least partially located within the second space of the groove.

[0042] In one exemplary embodiment of this disclosure, the second scintillator subunit includes an irregular crystal layer and a regular crystal layer; the groove includes a first space and a second space, the second space being located on the side of the first space near the opening of the groove;

[0043] The formation of the first scintillator sublayer includes:

[0044] A corresponding first scintillator subunit is formed within the first space of each of the grooves;

[0045] The formation of the second scintillator sublayer includes:

[0046] A second scintillator sublayer is formed covering the first scintillator sublayer, such that the irregular crystal layer of the second scintillator subunit is located within the second space of the groove, and the regular crystal layer of the second scintillator subunit is at least partially located within the second space.

[0047] In one exemplary embodiment of this disclosure, the preparation method further includes: forming a transparent protective layer that at least covers the scintillator layer.

[0048] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0049] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0050] Figure 1-1 is a schematic cross-sectional view of a radiation detection panel in one embodiment of this disclosure.

[0051] Figures 1-2 are top views of the detection substrate in one embodiment of this disclosure.

[0052] Figure 2 is a schematic cross-sectional view of the detection substrate in one embodiment of this disclosure.

[0053] Figure 3 is a top view of the scintillator layer in one embodiment of this disclosure.

[0054] Figure 4 is a schematic cross-sectional view of the scintillator layer in one embodiment of this disclosure.

[0055] Figure 5 is a schematic diagram of the scintillator layer groove structure in one embodiment of this disclosure.

[0056] Figure 6 is a schematic cross-sectional view of the scintillator layer in one embodiment of this disclosure.

[0057] Figure 7 is a cross-sectional schematic diagram of a radiation detection panel in one embodiment of this disclosure.

[0058] Figure 8 is a schematic flowchart of a method for preparing a scintillator layer in one embodiment of this disclosure.

[0059] The following are the reference numerals in the attached figures: 10, scintillator substrate; REL, reflective layer; 100, scintillator unit; SCU, scintillator subunit; SCU1, first scintillator subunit; SCU2, second scintillator subunit; RL, regular crystal layer; IRL, irregular crystal layer; IND, groove; IND1, first space; IND2, second space; 20, detection substrate; 200, detection unit; RP, backplate; AA, detection area; BB, peripheral area; TFT, thin film transistor; GT, gate layer; GI, gate insulating layer; SCL1, first semiconductor layer; ACT, active layer; SD, source / drain metal layer; CL1, first conductive layer; CL2, second conductive layer; SCL2, second semiconductor layer; IL1, first insulating layer; IL2, second insulating layer; PLN, planarization layer; TRL, transparent protective layer. Detailed Implementation

[0060] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore detailed descriptions of them will be omitted. Furthermore, the drawings are merely illustrative of this disclosure and are not necessarily drawn to scale.

[0061] The terms “a,” “one,” “the,” “the,” and “at least one” are used to indicate the existence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms “first,” “second,” etc. are used only as markers and are not a limitation on the number of objects.

[0062] The term "luminous efficiency of a scintillator subunit" refers to the luminous efficiency of a scintillator, which is the ratio of the average energy of the emitted photons to the energy of the absorbed high-energy radiation. For the same type of high-energy radiation (e.g., X-rays), different scintillator materials have different luminous efficiencies. For example, if a scintillator material absorbs X-rays with energy 'a' and emits visible light with an average energy 'b', then the luminous efficiency of that scintillator material is a / b.

[0063] The term "radiation tolerance" refers to the property of scintillator materials to maintain stable performance over a long period of time when exposed to high-energy radiation.

[0064] This disclosure provides a radiation detector that can be used for the detection of high-energy rays, particularly X-rays. For example, it can be used in medical X-ray imaging devices or in industrial product quality inspection devices to determine product conformity.

[0065] In one example, the radiation detector includes a radiation detection panel; referring to Figure 1-1, the radiation detection panel includes a scintillator layer 10 and a detection substrate 20, the scintillator layer 10 including an array of scintillator units 100. In application, X-rays (as a form of radiation) pass through the target and are converted into visible light by the scintillator layer 10. The visible light is transmitted to the detection substrate 20, which converts the visible light signal into an electrical signal and processes the electrical signal to obtain the desired image information.

[0066] In one embodiment of this disclosure, as shown in Figures 1-2, the detection substrate 20 includes an array of detection units 200, which are used to convert visible light signals into electrical signals. In one example, as shown in Figure 2, the detection substrate 20 includes a backplane RP, a photodiode and a thin-film transistor (TFT) disposed on the backplane RP, and a planarization layer PLN covering the photodiode and the TFT. The TFT can be a top-gate TFT, a bottom-gate TFT, or a dual-gate TFT, depending on its ability to effectively control the transistor.

[0067] In one example, the thin-film transistor (TFT) is a metal-oxide-slim thin-film transistor, which can reduce leakage current in the control circuit and improve the accuracy of the detection results.

[0068] Optionally, the detection unit 200 may include a photodiode and a control circuit, the control circuit including one or more thin-film transistors (TFTs). The scintillator units 100 may be configured in a one-to-one correspondence with the photodiodes, or one scintillator unit 100 may be configured in a correspondence with multiple photodiodes, such that the visible light generated by the scintillator unit 100 can illuminate the corresponding photodiode. Furthermore, the visible light generated by the scintillator unit 100 illuminates only the corresponding photodiode and not other photodiodes, so that the radiation detection panel has high resolution and high contrast.

[0069] In one example, as shown in Figure 2, the detection substrate 20 includes a gate layer GT, a gate insulating layer GI, a first semiconductor layer SCL1, a source / drain metal layer SD, a first insulating layer IL1, a first conductive layer CL1, a second semiconductor layer SCL2, a second conductive layer CL2, a second insulating layer IL2, and a planarization layer PLN, which are sequentially stacked on one side of the backplane RP. The gate layer GT, the gate insulating layer GI, the first semiconductor layer SCL1, and the source / drain metal layer SD form a thin-film transistor (TFT). The first semiconductor layer SCL1 forms the active layer ACT of the TFT, which includes a source contact region, a conductive channel region, and a drain contact region connected in sequence. The gate layer GT forms the gate of the TFT. The source / drain metal layer SD forms the source and drain of the TFT, which overlap with the source and drain contact regions, respectively. The first insulating layer IL1 protects the active layer ACT and the source and drain of the TFT. The first conductive layer CL1, the second semiconductor layer SCL2, and the second conductive layer CL2 form a photodiode. The first conductive layer CL1 can form the first electrode and electrode lead of the photodiode, and the electrode lead is used to electrically connect the drain of the thin-film transistor (TFT) and the first electrode of the photodiode. The second conductive layer CL2 forms the second electrode of the photodiode, and the second electrode is used to apply a bias voltage or driving voltage to the photodiode. The second insulating layer IL2 is used to protect the TFT and the photodiode, and the planarization layer PLN is used to planarize the structure of the TFT and the photodiode, and to facilitate the alignment and connection of the detection substrate 20 and the scintillator layer 10. The scintillator layer 10 is used to convert the projected X-rays into visible light. After receiving the visible light, the photodiode converts the light signal into an electrical signal. Under the control of the control circuit corresponding to the photodiode, each electrical signal can be read directly or indirectly, thereby determining the intensity of the visible light. For example, the photodiode stores charge on its own capacitance according to the intensity of the visible light, and the amount of stored charge in each photodiode is proportional to the intensity of the incident X-rays. Under the action of the control circuit formed by the TFT, the stored charge of each photodiode can be scanned and read to obtain the electrical signal.

[0070] Optionally, a light-shielding layer may be provided on the side of the first insulating layer IL1 away from the backplane RP. This light-shielding layer has multiple light-shielding portions corresponding to the detection unit 200. These light-shielding portions can block light from reaching the conductive channel region of the thin-film transistor. Thus, the light-shielding portions can prevent light (natural light and visible light converted by the scintillator layer 10, etc.) from reaching the conductive channel region and affecting its semiconductor characteristics, thereby avoiding the influence of light on the performance of the thin-film transistor and improving the stability of the scintillator panel.

[0071] It is understood that the structure of the detection substrate 20 shown in FIG2 is merely one example of the detection substrate 20. In other embodiments of this disclosure, the detection substrate 20 may also employ other structures.

[0072] In one example, as shown in Figures 1-2, the detection substrate 20 has a detection area AA and a peripheral area BB disposed on at least one side of the detection area AA. The peripheral area BB has a bonding area; pins are disposed in the bonding area for bonding and connection with external circuits. A detection unit 200 is disposed in the detection area AA, and the signal detected by the detection unit 200 can be transmitted to the peripheral area BB. The peripheral area BB also has a bending area and a chip area (IC area), and a control chip is bonded to the chip area. The control chip in the chip area can control each detection unit 200 in the detection area AA, and cause the signal generated by each detection unit 200 to be transmitted to the external circuit through the pins in the bonding area. The detection substrate 20 can be bent in the bending area so that the external circuit can be bent to the back of the detection substrate 20, reducing the bezel of the radiation detection panel. Furthermore, the backplate RP of the detection substrate 20 is a flexible substrate, and the detection substrate 20 is a flexible substrate.

[0073] In the example of Figure 1-2, the electrical signal generated by the detection unit 200 can be transmitted to the analog-to-digital conversion unit and converted into a digital signal, which can be further processed by image processing to form a digital image of X-rays.

[0074] In the example of Figure 1-2, the detection substrate 20 employs COP (chip on panel) technology. It is understood that the detection substrate 20 can also employ other technologies to reduce the bezel, such as COF (chip on film) technology.

[0075] In one embodiment of this disclosure, as shown in FIG3, the scintillator layer 10 includes an array of scintillator units 100, which are correspondingly disposed with detection units 200 on the detection substrate 20. In one example, as shown in FIG1-1, the scintillator units 100 and detection units 200 are disposed in a one-to-one correspondence; the orthographic projection of the scintillator unit 100 on the backplane RP is located within the range of the orthographic projection of the detection unit 200 on the backplane RP; in particular, the orthographic projection of the scintillator unit 100 on the backplane RP is located within the orthographic projection of the photodiode on the backplane RP. In another example, one scintillator unit 100 can be correspondingly disposed with multiple detection units 200, so that the visible light signal output by one scintillator unit 100 can be processed by multiple detection units, thereby improving the resolution of the final imaging. Each of the scintillator units 100 includes a scintillator material layer, which absorbs radiation (e.g., X-rays) and emits visible light, and the intensity of the emitted visible light is proportional to the absorbed radiation. Thus, after the radiation passes through the target object, it irradiates the scintillator layer 10; the scintillator material in each scintillator unit 100 emits visible light of corresponding intensity according to the intensity of the irradiated radiation. The intensity of the visible light emitted by each scintillator unit 100 can be processed to form a digital image, which can then be used for related detection in medical, industrial, scientific research and other fields.

[0076] In related technologies, commonly used scintillator materials for the scintillator unit 100 include cesium iodide (CsI), sodium iodide (NAI), gadolinium oxysulfide (GSO), or yttrium lutetium silicate (LYSO). Detectors made with gadolinium oxysulfide as the scintillator material have fast imaging speed, low afterglow, stable performance, simple manufacturing process, and low cost. However, gadolinium oxysulfide has low luminous efficiency and low light conversion rate for high-energy rays, resulting in low luminous intensity and resolution of the corresponding detector. To improve luminous intensity and resolution, the radiation dose needs to be increased, thus increasing the risk of harm to the user or operator. Scintillator units made with sodium iodide have high luminous efficiency, good thermal stability, and strong temperature adaptability. However, sodium iodide is susceptible to radiation damage, and its scintillation performance decreases under prolonged irradiation, reducing the performance and lifespan of the radiation detector. Cesium iodide has a stronger ability to convert X-rays into visible light than gadolinium oxysulfide, with a higher light conversion rate. Meanwhile, cesium iodide can be processed into a columnar crystal structure, which can further improve the ability to capture X-rays and reduce the scattering of visible light converted from X-rays, resulting in detectors made using cesium iodide as a scintillator material having higher luminous intensity and resolution. However, cesium iodide scintillator material is expensive and easily destroyed by X-rays, and its stability is not as good as gadolinium oxysulfate. Scintillator units made of lutetium yttrium silicate have good light output, short decay time, and virtually no afterglow, but lutetium yttrium silicate material is expensive, and the slow growth of lutetium yttrium silicate crystals further increases the cost. Thus, it is difficult to achieve high light output, low afterglow, and stable performance under high-energy radiation irradiation while meeting the requirements of simple processing and low cost when using the above-mentioned scintillator materials alone.

[0077] To address the aforementioned issues, as shown in Figures 1-1, 3, and 4, the radiation detection panel provided in this embodiment includes a scintillator layer 10 comprising an array of scintillator units 100, each scintillator unit 100 containing at least two stacked scintillator subunits (SCUs). In any two adjacent SCUs, the luminous efficiency of the scintillator subunit closer to the detection substrate 20 is greater than that of the scintillator subunit further from the detection substrate 20, and the scintillator subunit closer to the detection substrate 20 has lower radiation tolerance than the scintillator subunit further from the detection substrate 20.

[0078] As shown in Figure 1-1, after passing through the detection target, the radiation can illuminate the scintillator layer 10 and sequentially pass through each stacked scintillator subunit SCU. The radiation travels in the following order: from the scintillator subunit SCU furthest from the detection substrate 20 to the scintillator subunit SCU closest to the detection substrate 20. During this transmission, the scintillator material in each scintillator subunit SCU absorbs part of the radiation and converts the absorbed radiation into visible light. Thus, the radiation intensity received by the scintillator material gradually decreases from the scintillator subunit SCU furthest from the detection substrate 20 to the scintillator subunit SCU closest to the detection substrate 20.

[0079] In the radiation detection panel provided in this embodiment, the farther the scintillator subunits (SCUs) in the scintillator unit 100 are from the detection substrate 20, the better the radiation resistance of the corresponding scintillator material. This avoids the scintillator material far from the detection substrate 20 being easily damaged by radiation, thus preventing the impact on the performance and lifespan of the radiation detection panel. Simultaneously, to avoid reducing the light conversion efficiency due to using only scintillator materials with good radiation resistance, the scintillator subunits (SCUs) closer to the detection substrate can use materials with high light conversion efficiency but low radiation resistance. Thus, through the combination of multiple scintillator subunits (SCUs), both the stability and resolution of the radiation detection panel are improved, enabling low-dose radiation and high-resolution radiation imaging, expanding the application scenarios of the radiation detection panel.

[0080] This disclosure also provides a method for fabricating the aforementioned radiation detection panel. The method includes fabricating a scintillator layer 10 located on one side of a detection substrate 20, the scintillator layer 10 having an array of scintillator units 100. The method includes sequentially forming at least two scintillator sublayers on the substrate layer, each scintillator sublayer containing scintillator subunits (SCUs) corresponding to each scintillator unit 100. Specifically, in any two adjacent scintillator subunits (SCUs), the luminous efficiency (light conversion efficiency to radiation) of the scintillator subunit (SCU) closer to the detection substrate 20 is greater than that of the scintillator subunit (SCU) farther from the detection substrate 20, and the radiation tolerance of the scintillator subunit (SCU) closer to the detection substrate 20 is less than that of the scintillator subunit (SCU) farther from the detection substrate 20.

[0081] In one embodiment of this disclosure, the scintillator unit includes at least a second scintillator subunit SCU2 on the side closest to the detection substrate 20 and a first scintillator subunit SCU1 on the side furthest from the detection substrate 20.

[0082] In one example, the scintillator unit 100 includes a first scintillator subunit SCU1 and a second scintillator subunit SCU2. Exemplarily, the first scintillator subunit SCU1 is a gadolinium oxysulfate subunit, and the second scintillator subunit SCU2 is a cesium iodide subunit. The gadolinium oxysulfate subunit contains gadolinium oxysulfate in its material; for example, the gadolinium oxysulfate subunit is a gadolinium oxysulfate scintillator. The cesium iodide subunit contains cesium iodide in its material; for example, the cesium iodide subunit is a cesium iodide scintillator. Radiation first irradiates the gadolinium oxysulfate subunit, which receives a portion of the radiation and converts the received radiation into visible light. The radiation intensity decreases after passing through the gadolinium oxysulfate subunit, and the reduced-intensity radiation is then transmitted to the cesium iodide subunit. Thus, the radiation is reduced by the gadolinium oxysulfate subunit before reaching the cesium iodide subunit, which lowers the intensity of the radiation reaching the cesium iodide subunit, thereby reducing the damage caused by radiation and improving its stability. The cesium iodide scintillator has a high light conversion efficiency, and the cesium iodide subunit can more efficiently convert the transmitted radiation source into visible light, improving the conversion efficiency of the scintillator unit 100. Therefore, on the one hand, placing the gadolinium oxysulfate subunit away from the detection substrate 20 avoids direct radiation from the radiation source onto the cesium iodide subunit, improving its stability. On the other hand, placing the cesium iodide subunit closer to the detection substrate 20 allows the cesium iodide scintillator to convert part of the radiation source, improving the conversion efficiency and thus increasing the visible light emission intensity of the scintillator layer 10.

[0083] Thus, by using gadolinium oxysulfide subunits and cesium iodide subunits to form a composite scintillator unit 100, the problems of low resolution and low sensitivity when using only gadolinium oxysulfide as a scintillator material are solved, as are the problems of high afterglow and low radiation resistance when using only cesium iodide as a scintillator material. This gives the scintillator unit 100 the advantages of high light yield, high resolution, high quantum efficiency, high radiation resistance, low decay lifetime, and low afterglow.

[0084] In other examples, the first scintillator subunit SCU1 and the second scintillator subunit SCU2 may also be a combination of other scintillator materials.

[0085] In other embodiments of this disclosure, other scintillator subunits may also be included on the side of the second scintillator subunit SCU2 away from the first scintillator subunit SCU1, such as a third scintillator subunit SCU3, a fourth scintillator subunit SCU4, etc., located between the second scintillator subunit SCU2 and the detection substrate.

[0086] In one embodiment of this disclosure, as shown in FIG4, the radiation detection panel further includes a reflective layer REL, the reflective layer REL having a back side facing the detection substrate 20 and a front side facing away from the detection substrate 20. The back side of the reflective layer REL has a plurality of grooves IND corresponding one-to-one with the plurality of scintillator units 100, the grooves IND opening on the back side; the first scintillator subunit SCU1 of the scintillator unit 100 is located in the corresponding groove IND. That is, the scintillator material corresponding to the first scintillator subunit SCU1 fills the corresponding groove to form a scintillator material layer.

[0087] For example, the first scintillator subunit SCU1 is a gadolinium oxysulfate subunit. In the gadolinium oxysulfate scintillator, gadolinium oxysulfate is a particulate material. After X-rays are converted into visible light, the visible light scatters in multiple directions, preventing some of the formed visible light from propagating along the predetermined emission direction, thus affecting the final imaging resolution. By setting a groove IND on the reflective layer REL and placing the gadolinium oxysulfate subunit within the groove IND, the visible light emission range is limited to a certain range, allowing more visible light to propagate along the predetermined emission direction. This reduces the light scattering caused by the visible light converted from the gadolinium oxysulfate scintillator, improving the luminous intensity of the scintillator layer 10 and the final imaging resolution.

[0088] In this embodiment, the substrate layer is a reflective layer REL; the reflective layer REL has a back side facing the detection substrate 20 and a front side facing away from the detection substrate 20. The method for fabricating the scintillator layer 10 further includes: providing the reflective layer REL, forming a plurality of grooves IND on the back side of the reflective layer REL, the plurality of grooves IND corresponding one-to-one with a plurality of scintillator units 100; the grooves IND open on the back side. The step of sequentially forming at least two scintillator sublayers on the substrate layer includes: forming a first scintillator sublayer, the first scintillator sublayer including a first scintillator subunit SCU1 of each scintillator unit 100, the first scintillator subunit SCU1 of each scintillator unit 100 being located in the corresponding groove IND; forming a second scintillator sublayer, the second scintillator sublayer including a second scintillator subunit SCU2 of each scintillator unit.

[0089] For example, the first scintillator subunit SCU1 is a gadolinium oxysulfate subunit, and the second scintillator subunit SCU2 is a cesium iodide subunit. Forming the first scintillator sublayer includes: mixing gadolinium oxysulfate particles with an organic matrix to form a gadolinium oxysulfate precursor; filling the gadolinium oxysulfate precursor into a groove IND, and curing it to form the gadolinium oxysulfate subunit. For example, the gadolinium oxysulfate precursor can be filled into the groove IND by inkjet printing; the organic matrix in the gadolinium oxysulfate precursor can then be cured to form the gadolinium oxysulfate subunit. For example, the gadolinium oxysulfate particles can be praseodymium-doped gadolinium oxysulfate; the organic matrix can be a resin.

[0090] In one embodiment of this disclosure, the reflective layer REL is a non-transparent substrate capable of reflecting visible light. A groove IND is formed on the non-transparent reflective layer REL that reflects visible light. Part of the visible light generated by the first scintillator subunit SCU1 within the groove IND is transmitted to the inner wall of the groove IND due to light scattering. The opaque nature of the reflective layer REL prevents the scattered visible light from passing through the reflective layer REL and affecting the visible light intensity in adjacent groove INDs, thereby avoiding crosstalk in visible light transmission between adjacent groove INDs and improving imaging accuracy. The reflective layer REL can reflect visible light, allowing the light emitted by the first scintillator subunit SCU1 to be transmitted within the groove IND by reflection. This reduces the light intensity reduction caused by light absorption by the reflective layer REL, minimizing the loss of visible light generated by the first scintillator subunit SCU1; furthermore, it allows the visible light to be focused and emitted from the groove IND opening, enabling the light generated by the first scintillator subunit SCU1 to be focused onto the corresponding detection unit 200; this increases the light emission intensity of the scintillator layer 10.

[0091] In one example, the reflective layer REL can be a metal substrate. For instance, the reflective layer REL can be an aluminum plate, specifically a high-purity aluminum plate.

[0092] In another example, the reflective layer REL is an organic material. Reflective particles can be added to the organic material to prepare an organic reflective layer that is both reflective of visible light and opaque. For example, a resin can be melted, titanium dioxide can be added and stirred evenly, and then cured to form the reflective layer REL. The resin can be, but is not limited to, polyethylene terephthalate (PET) or polyimide (PI). Thus, the reflective layer REL is an organic reflective layer with dispersed reflective particles. Furthermore, the reflective layer REL is a flexible reflective layer.

[0093] In another example, the reflective layer REL may include a main substrate and a coating material layer. The main substrate may be made of a light-transmitting organic material. An array of recesses IND may be formed on the main substrate using an etching method, with the openings of the recesses IND located on the back side of the reflective layer REL. A coating material layer, such as a metal layer, is then formed on the bottom and sidewalls of the recesses IND. Thus, the metal layer deposited within the recesses IND has high reflectivity while being opaque to visible light, avoiding crosstalk between adjacent scintillator units 100 caused by visible light scattering. Simultaneously, it also allows the reflective layer REL to have a certain degree of flexibility. For example, the organic material may be a resin material; the coating material may be metallic aluminum or metallic silver.

[0094] In one embodiment of this disclosure, plasma etching can be used to etch the reflective layer REL to form the groove IND. Of course, depending on the material of the reflective layer REL, other feasible methods can also be used to form the groove IND.

[0095] In one embodiment of this disclosure, the orthographic projection of the groove IND onto the reflective layer REL can be a square, a circle, a regular polygon, etc. Of course, the groove IND can also be set to other shapes as needed.

[0096] In one embodiment of this disclosure, the aspect ratio of the groove IND is between 5 and 10. It is understood that a larger aspect ratio of the groove IND results in better constraint on the emission direction of visible light, allowing visible light to propagate along a predetermined direction and improving the resolution of the scintillator panel. As shown in Figure 5, the reflective layer REL has an array of grooves IND, the depth dimension of which is Z, where Z is the distance from the groove opening to the deepest point at the bottom of the groove. The width dimension of the groove IND is X, where Z:X = (5-10):1. Within this range, the emission direction of visible light within the groove IND can be guaranteed while avoiding an increase in the thickness of the reflective layer REL and increased processing difficulty caused by an excessively large groove IND depth. It is understood that an increase in the overall thickness of the scintillator panel is detrimental to the miniaturization / thinning requirements of radiation detection equipment.

[0097] In one example, the orthographic projection of the groove IND onto the backplate RP is a rectangle, and the width X of the groove IND is the dimension of its longer side. In another example, the orthographic projection of the groove IND onto the backplate RP is a circle, and the width X of the groove IND is the diameter of the circle. In still other examples, the orthographic projection of the groove IND onto the backplate RP is a regular polygon, and the width X of the groove IND is the diameter of the circle containing each vertex of the regular polygon.

[0098] In one embodiment of this disclosure, the second scintillator subunit SCU2 is at least partially located within the groove IND. In other words, the first scintillator subunit SCU1 does not completely fill the groove IND, resulting in a certain distance between the top surface of the first scintillator subunit SCU1 and the opening of the groove IND. This reduces the scattering of the visible light generated by the first scintillator subunit SCU1. Since the first scintillator subunit SCU1 does not completely fill the groove IND, the portion of the groove IND not filled by the first scintillator subunit SCU1 is filled by the second scintillator subunit SCU2, thus partially placing the second scintillator subunit SCU2 within the groove IND. It is understood that if the first scintillator subunit SCU1 were filled to the opening of the groove IND, the visible light generated by the scintillator material at the opening end of the groove IND would be emitted in all directions, forming scattered light, thereby interfering with adjacent detection units 200.

[0099] In one embodiment of this disclosure, referring to FIG4, the second scintillator subunit SCU2 includes a regular crystal layer RL close to the detection substrate and an irregular crystal layer IRL away from the detection substrate; the irregular crystal layer IRL is at least partially located within the groove IND.

[0100] In one example, the second scintillator subunit SCU2 is a cesium iodide subunit. When preparing the cesium iodide subunit using vacuum thermal evaporation or electron beam evaporation, the initial stage of evaporation involves fragmenting cesium iodide crystals, forming an irregular crystal layer IRL, before the formation of a columnar, regular crystal layer RL. The extension direction of the cesium iodide crystal pillars in the regular crystal layer RL is the visible light emission direction of the scintillator layer 10. In this embodiment, at least a portion of the irregular cesium iodide crystal layer IRL fills the groove IND, which confines the visible light converted from the cesium iodide fragments within the groove IND, preventing visible light scattering and interference with adjacent detection units 200, and increasing the intensity of visible light transmitted along the emission direction.

[0101] In another example, the irregular crystal layer IRL is located within the groove IND, and at least a portion of the regular crystal layer is also located within the groove IND. That is, the irregular crystal layer IRL of the second scintillator subunit SCU2 is completely located within the groove IND, while a portion of the regular crystal layer is also located within the groove IND. In this way, the visible light converted from the first scintillator subunit SCU1 and the irregular crystal layer IRL can be confined within the groove IND. Simultaneously, more visible light is transmitted along the regular crystal layer located within the groove IND, further increasing the intensity of visible light along the emission direction.

[0102] For example, the orthographic projection of the first scintillator subunit SCU1 on the detection substrate 20 is located within the range of the orthographic projection of the regular crystal layer RL on the detection substrate 20. It can be understood that the first scintillator subunit SCU1 is located within the groove IND, and a portion of the regular crystal layer RL is located within the groove IND, while a portion is located on the surface of the reflective layer near the detection substrate. For example, the orthographic projection of the irregular crystal layer on the detection substrate can coincide with the orthographic projection of the regular crystal layer on the detection substrate. The irregular crystal layer and the regular crystal layer represent different morphologies at different growth stages of the second scintillator subunit SCU2.

[0103] In one embodiment of this disclosure, the groove IND includes a first space IND1 and a second space IND2, with the second space IND2 located on the side of the first space IND1 near the opening of the groove IND. The first space IND1 of the groove IND is filled with the first scintillator subunit SCU1; the second space IND2 is filled with at least a portion of the irregular crystal layer. Thus, the visible light converted from the irregular crystal layer IRL of the second scintillator subunit SCU2 is confined within the groove, thereby avoiding visible light scattering loss.

[0104] In this embodiment, the method for fabricating the radiation detection panel is as follows: forming the first scintillator sublayer includes forming a corresponding first scintillator subunit SCU1 within the first space IND1 of each of the grooves IND. Forming the second scintillator sublayer includes forming a second scintillator sublayer covering the first scintillator sublayer, such that the irregular crystal layer of the second scintillator subunit SCU2 is at least partially located within the second space of the groove IND. Thus, the first scintillator subunit SCU1 is formed in the first space, and the irregular crystal layer IRL is formed in the second space.

[0105] In another embodiment of this disclosure, the irregular crystal layer IRL of the second scintillator subunit SCU2 is located within the groove IND, and at least a portion of the regular crystal layer is located within the groove IND. That is, the scintillator portions that are prone to light scattering (the irregular crystal layers IRL of the first scintillator subunit SCU1 and the second scintillator subunit SCU2) are confined within the groove. The groove IND ensures that visible light is emitted in the correct direction, preventing loss of visible light due to scattering.

[0106] In this embodiment, the method for fabricating the radiation detection panel is as follows: forming the first scintillator sublayer includes forming a corresponding first scintillator subunit SCU1 within the first space IND1 of each of the grooves IND. Forming the second scintillator sublayer includes forming a second scintillator sublayer covering the first scintillator sublayer, such that the irregular crystal layer IRL of the second scintillator subunit SCU2 is located within the second space IND2 of the groove IND, and that the regular crystal layer RL of the second scintillator subunit is at least partially located within the second space IND2. Thus, the first scintillator subunit SCU1 is formed in the first space, and the irregular crystal layer IRL and the partially regular crystal layer RL are formed in the second space.

[0107] For example, the first scintillator subunit SCU1 is a gadolinium oxysulfate subunit, and the second scintillator subunit SCU2 is a cesium iodide subunit. The irregular crystal layer IRL of the cesium iodide subunit completely fills the second space IND2 of the groove IND, while the regular crystal layer RL of the cesium iodide subunit can be partially filled into the groove IND or completely located outside the groove IND. It is understood that visible light generated by the gadolinium oxysulfate subunit and visible light generated by the irregular crystal layer IRL of the cesium iodide subunit can be transmitted along the regular crystal layer RL. The regular crystal layer RL of the cesium iodide subunit can reduce the scattering of visible light, achieving efficient transmission of visible light. Thus, the visible light generated by the irregular crystal layer IRL of the cesium iodide subunit is confined within the groove IND and transmitted along the emission direction; simultaneously, the visible light emitted from the groove IND can be effectively transmitted along the regular crystal layer RL of the cesium iodide subunit, further avoiding the loss of visible light.

[0108] In one example, the depth of the second space IND2 is between 100 and 200 micrometers. Within this depth range, the irregular crystal layer IRL of the second scintillator subunit SCU2 can be completely located within the groove IND, allowing visible light to propagate along the emission direction and improving the light intensity resolution of the scintillator panel.

[0109] In one embodiment of this disclosure, referring to Figures 6 and 7, a transparent protective layer TRL is provided on the side of the scintillator layer 10 away from the reflective layer REL, and the transparent protective layer TRL at least completely covers the scintillator layer 10. The orthographic projection of each scintillator unit 100 onto the reflective layer REL lies within the orthographic projection range of the transparent protective layer TRL onto the reflective layer REL. That is, the transparent protective layer TRL at least completely covers the scintillator material of the scintillator unit. For example, as shown in Figure 6, the side or front of the reflective layer REL can also be covered by the transparent protective layer TRL.

[0110] Optionally, the thickness of the transparent protective layer TRL can be 1–50 μm.

[0111] Optionally, the visible light transmittance of the transparent protective layer TRL is greater than 90% to reduce losses during visible light transmission. For example, the transparent protective layer TRL is made of an organic material, such as phenelzine or polyurea.

[0112] In one embodiment of this disclosure, the method for preparing the scintillator layer 10 further includes: forming a transparent protective layer TRL that at least covers the scintillator layer 10. For example, a waterproof film, such as a polyurea or a paraben, can be formed on the side of the second scintillator subunit SCU2 away from the reflective layer REL by spraying or other methods, serving as the transparent protective layer TRL to protect the scintillator unit 100. In addition to its water-blocking function, the transparent protective layer TRL also provides a certain buffer against temperature cycling, which can greatly improve the temperature shock reliability of the scintillator panel.

[0113] In one embodiment of this disclosure, taking the fabrication of a two-layer scintillator subunit SCU as an example, referring to Figure 8, the fabrication method of the scintillator layer 10 in the above-mentioned radiation detection panel includes the following steps:

[0114] S100, a reflective layer REL is provided; the reflective layer REL has a back side facing the detection substrate 20 and a front side facing away from the detection substrate 20. A plurality of grooves IND are formed in an array on the back side of the reflective layer REL.

[0115] S200, Forming a first scintillator sublayer: Each first scintillator subunit SCU1 is formed in each groove IND, and the first scintillator sublayer includes each first scintillator subunit SCU1.

[0116] S300: Forming a second scintillator sublayer: A second scintillator subunit SCU2 is formed on the side of the first scintillator sublayer near the detection substrate 20, covering the first scintillator sublayer. The second scintillator sublayer includes the second scintillator subunit SCU2. Thus, the scintillator unit 100 corresponding to the groove IND is obtained through steps S200 and S300.

[0117] S400, a transparent protective layer TRL covering at least the second scintillator sublayer is formed on the side of the second scintillator sublayer near the detection substrate 20.

[0118] In one example, the first scintillator subunit SCU1 is a gadolinium oxysulfate subunit. In step S200, forming the first scintillator sublayer constitutes forming a gadolinium oxysulfate layer. This includes mixing gadolinium oxysulfate particles with an organic matrix to form a gadolinium oxysulfate precursor, thereby preparing the gadolinium oxysulfate layer. Thus, the gadolinium oxysulfate layer comprises an organic matrix and gadolinium oxysulfate particles dispersed within the organic matrix. Exemplarily, the gadolinium oxysulfate can be doped gadolinium oxysulfate, for example, praseodymium-doped gadolinium oxysulfate.

[0119] For example, praseodymium-doped gadolinium oxide (GOS:Pr) can be used. 3+ The powder is mixed with resin to obtain a gadolinium oxysulfate precursor; then, the gadolinium oxysulfate precursor layer is formed by inkjet printing, and the gadolinium oxysulfate precursor layer is cured to form a gadolinium oxysulfate layer.

[0120] In one example, the second scintillator subunit SCU2 is a cesium iodide subunit. In step S300, forming the second scintillator sublayer involves forming a cesium iodide layer; the cesium iodide layer includes an irregular crystal layer IRL and a regular crystal layer RL. Exemplarily, the irregular crystal layer IRL and the regular crystal layer RL can be formed on the side of the gadolinium oxysulfate layer near the detection substrate, and at least a portion of the irregular crystal layer IRL is located within the groove IND. In another example, the irregular crystal layer IRL and the regular crystal layer RL can also be formed on the side of the gadolinium oxysulfate layer near the detection substrate, with the irregular crystal layer IRL completely located within the groove IND, and at least a portion of the regular crystal layer RL located within the groove IND.

[0121] Optionally, the cesium iodide layer can be prepared by vacuum thermal evaporation or electron beam evaporation.

[0122] Optionally, the cesium iodide in the cesium iodide layer can be doped cesium iodide, such as, but not limited to, thallium-doped cesium iodide (CsI:Tl), sodium-doped cesium iodide (CsI:Na), or other doped columnar cesium iodide crystals.

[0123] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A radiation detection panel, characterized in that, It includes a detection substrate and a scintillator layer located on one side of the detection substrate; The detection substrate has an array of detection units; the scintillator layer has an array of scintillator units, and the scintillator units are correspondingly arranged with one or more detection units. The scintillator unit comprises at least two stacked scintillator subunits; In any two adjacent scintillator subunits, the luminous efficiency of the scintillator subunit closer to the detection substrate is greater than that of the scintillator subunit farther from the detection substrate, and the scintillator subunit closer to the detection substrate has less tolerance to radiation than the scintillator subunit farther from the detection substrate.

2. The radiation detection panel according to claim 1, characterized in that, The scintillator unit includes at least a second scintillator subunit on the side closest to the detection substrate and a first scintillator subunit on the side furthest from the detection substrate.

3. The radiation detection panel according to claim 2, characterized in that, It also includes a reflective layer having a back side facing the detection substrate and a front side facing away from the detection substrate; The reflective layer is provided with a plurality of grooves corresponding one-to-one with the scintillator unit, and the grooves open on the back side; The first scintillator subunit is located within the corresponding groove.

4. The radiation detection panel according to claim 3, characterized in that, The depth-to-width ratio of the groove is between 5 and 10.

5. The radiation detection panel according to claim 3, characterized in that, At least a portion of the second scintillator subunit is located within the groove.

6. The radiation detection panel according to claim 3, characterized in that, The second scintillator subunit includes a regular crystal layer close to the detection substrate and an irregular crystal layer away from the detection substrate; The irregular crystal layer is at least partially located within the groove.

7. The radiation detection panel according to claim 3, characterized in that, The second scintillator subunit includes a regular crystal layer close to the detection substrate and an irregular crystal layer away from the detection substrate; The irregular crystal layer is located within the groove, and at least a portion of the regular crystal layer is located within the groove.

8. The radiation detection panel according to claim 6 or 7, characterized in that, The orthographic projection of the first scintillator subunit on the detection substrate is within the range of the orthographic projection of the regular crystal layer on the detection substrate.

9. The radiation detection panel according to claim 3, characterized in that, The groove includes a first space and a second space, wherein the second space is located on the side of the first space near the opening of the groove; The first space of the groove is filled with the first scintillator subunit; the second space is filled with the second scintillator subunit; The depth of the second space is between 100 and 200 micrometers.

10. The radiation detection panel according to claim 1, characterized in that, It also includes a transparent protective layer that at least covers the scintillator layer.

11. The radiation detection panel according to claim 2, characterized in that, The first scintillator subunit is a gadolinium sulfide subunit, and the second scintillator subunit is a cesium iodide subunit.

12. A radiation detector, characterized in that, Includes the radiation detection panel as described in any one of claims 1-11.

13. A method for preparing a radiation detection panel, characterized in that, This includes fabricating a scintillator layer located on one side of a detection substrate, the scintillator layer having an array of scintillator units; The preparation of the scintillator layer includes: At least two scintillator sublayers are sequentially formed on the substrate layer, each scintillator sublayer containing scintillator subunits corresponding to each scintillator unit; wherein, in any two adjacent scintillator subunits, the luminous efficiency of the scintillator subunit closer to the detection substrate is greater than that of the scintillator subunit farther from the detection substrate, and the scintillator subunit closer to the detection substrate has less tolerance to radiation than the scintillator subunit farther from the detection substrate.

14. The method for preparing a radiation detection panel according to claim 13, characterized in that, The substrate layer is a reflective layer; the reflective layer has a back side facing the detection substrate and a front side facing away from the detection substrate; The preparation method further includes: Multiple grooves are formed on the back side of the reflective layer, and each of the multiple grooves corresponds to one of the multiple scintillator units; the grooves open on the back side. The step of sequentially forming at least two scintillator sublayers on the substrate layer includes: A first scintillator sublayer is formed, the first scintillator sublayer comprising a first scintillator subunit of each scintillator unit, the first scintillator subunit of each scintillator unit being located in a corresponding groove; A second scintillator sublayer is formed, the second scintillator sublayer comprising the second scintillator subunits of each scintillator unit.

15. The method for preparing a radiation detection panel according to claim 14, characterized in that, The second scintillator subunit includes an irregular crystal layer and a regular crystal layer; the groove includes a first space and a second space, the second space being located on the side of the first space near the opening of the groove; The formation of the first scintillator sublayer includes: A corresponding first scintillator subunit is formed within the first space of each of the grooves; The formation of the second scintillator sublayer includes: A second scintillator sublayer is formed covering the first scintillator sublayer, such that the irregular crystal layer of the second scintillator subunit is at least partially located within the second space of the groove.

16. The method for preparing a radiation detection panel according to claim 14, characterized in that, The second scintillator subunit includes an irregular crystal layer and a regular crystal layer; the groove includes a first space and a second space, the second space being located on the side of the first space near the opening of the groove; The formation of the first scintillator sublayer includes: A corresponding first scintillator subunit is formed within the first space of each of the grooves; The formation of the second scintillator sublayer includes: A second scintillator sublayer is formed covering the first scintillator sublayer, such that the irregular crystal layer of the second scintillator subunit is located within the second space of the groove, and the regular crystal layer of the second scintillator subunit is at least partially located within the second space.

17. The method for preparing a radiation detection panel according to any one of claims 13-16, characterized in that, The preparation method further includes: A transparent protective layer is formed that at least covers the scintillator layer.

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