X-ray photon counting detection system and method

Abstract

This disclosure provides an X-ray photon counting and detection system and method. A fluorescence conversion component converts incident X-rays into fluorescence pulses of a target duration. A time detection component receives the fluorescence pulses, treating each pulse as an independent X-ray photon event, recording the arrival time of each event, and mapping X-ray photon events arriving at different times to different spatial locations to output an optical image. An event recognition module analyzes the optical image, identifies independent X-ray photon events, and counts X-ray photons based on the recognition results. This transforms the traditional electronic counting mode into a fluorescence, time-encoded, and event-recognition-based counting mode, enabling the mapping of X-ray photon events arriving at different times to different spatial locations. This spatially separates the X-ray photon events, avoids photon accumulation, and improves the accuracy of X-ray photon counting.

Description

Technical Field

[0001] This disclosure relates to the field of optical technology, and in particular to an X-ray photon counting detection system and method. Background Technology

[0002] In recent years, with the rapid development of fields such as medical imaging, synchrotron radiation imaging, high-energy physics experiments, industrial non-destructive testing, and security inspection imaging, increasingly higher requirements have been placed on the spatial resolution, temporal resolution, energy resolution, and detection efficiency of X-ray detectors. Traditional integrating X-ray detectors obtain image signals by integrating the total energy of all incident photons within a certain time period. Although they have advantages such as simple structure and large detection area, they cannot distinguish individual photon events and their energy information, and suffer from problems such as large electronic noise, limited low-dose imaging performance, and lack of energy spectrum information.

[0003] Photon counting detectors (PCDs) can detect each incident X-ray photon as an independent event and record the number of times the photon arrives and its energy information. Therefore, they have the characteristics of low electronic noise, high dynamic range, strong energy spectral resolution and excellent low-dose imaging performance, and have become an important development direction for next-generation medical CT, energy spectral CT and high-performance X-ray detectors.

[0004] Currently, mainstream X-ray photon counting detectors primarily use semiconductor materials such as CdTe, CdZnTe (CZT), and Si as direct conversion media. When X-ray photons enter the detector, electron-hole pairs are generated within the semiconductor material. Charge carriers drift to the pixel electrode under the influence of a bias electric field, and single-photon counting is completed via a front-end amplifier, shaping circuit, and high-speed ASIC. Energy discrimination is then based on the charge pulse amplitude. Therefore, existing photon counting detectors essentially belong to a photon counting technology route based on electronic readout.

[0005] In recent years, to further improve photon counting capabilities, researchers have continuously optimized semiconductor material performance, reduced detector pixel size, and increased ASIC readout speed. They have also proposed various compensation methods, such as charge-sharing correction, pile-up correction, and multi-threshold energy discrimination, to improve counting performance under high-throughput conditions. However, these methods are all based on traditional electronic counting architectures, and their core still relies on the generation, transport, and collection of electron-hole pairs and the electronic counting process. Therefore, the overall system performance is still limited by factors such as carrier drift velocity, electronic dead time, and high-speed readout circuitry.

[0006] As applications such as medical CT increasingly demand higher X-ray flux, the probability of multiple X-ray photons consecutively incident on the same detector unit within a very short time has significantly increased. When the arrival time of subsequent photons is less than the detector's electronic recovery time, multiple photon events are prone to overlap, forming a photon pile-up phenomenon, which leads to a decrease in the accuracy of X-ray photon counting. Summary of the Invention

[0007] The main objective of this disclosure is to provide an X-ray photon counting detection system and method to solve the above-mentioned problems.

[0008] To achieve the above objectives, a first aspect of this disclosure provides an X-ray photon counting and detection system, comprising: A fluorescence conversion component is used to convert incident X-rays into fluorescence pulses of a target duration, wherein the target duration is less than or equal to a preset time threshold. A time-detection component is used to receive the fluorescence pulse, treat the fluorescence pulse as an independent X-ray photon event, record the arrival time of the X-ray photon event, and map the X-ray photon events arriving at different times to different spatial locations to output an optical image; The event recognition module is used to analyze the optical image, identify independent X-ray photon events, and count X-ray photons based on the recognition results.

[0009] In some embodiments, the fluorescence conversion component includes: Supporting base; A perovskite fluorescent layer is disposed on the side of the supporting substrate facing the X-rays, for absorbing the incident X-rays and generating the fluorescence pulses; A protective layer is disposed on the outside of the perovskite fluorescent layer to protect the perovskite fluorescent layer; A fixing mechanism is used to fix the supporting substrate, the perovskite fluorescent layer, and the protective layer.

[0010] In some embodiments, the perovskite fluorescent layer is at least one of CsPbBr3, CsPbCl3, MAPbBr3 or FAPbBr3; The thickness of the perovskite fluorescent layer is 100–500 μm; The supporting substrate is made of quartz glass, fused silica, or sapphire, with a thickness of 0.2–2 mm; The protective layer is made of quartz glass, sapphire, optical glass or transparent polymer film, with a thickness of 100 to 500 μm.

[0011] In some embodiments, the supporting substrate, the perovskite fluorescent layer, and the protective layer form a sandwich structure, and the layers are encapsulated by optically transparent adhesive bonding, vacuum lamination, or thermoforming.

[0012] In some embodiments, the fluorescence conversion component is installed at the slit entrance of the time detection component, the distance between the perovskite fluorescent layer and the slit entrance is no greater than 1 mm, and the width of the slit entrance is set to 20–100 μm.

[0013] In some embodiments, the time sensing component employs a stripe camera, the stripe camera comprising: A photocathode is used to receive the fluorescence pulses and convert the light signal into an electron beam; An electron acceleration and focusing unit is used to accelerate and focus the electron beam; The time scanning unit is used to perform time-spreading of the accelerated and focused electron beam under the action of a high-speed scanning electric field; A fluorescent screen is used to convert the time-spread electron beam back into an optical image; An image acquisition unit is used to record the optical image and transmit it to the event recognition module.

[0014] To achieve the above objectives, a second aspect of this disclosure also provides an X-ray photon counting and detection method, applied to an X-ray photon counting and detection system, the X-ray photon counting and detection method comprising: The incident X-rays are converted into fluorescence pulses of a target duration, wherein the target duration is less than or equal to a preset time threshold. The fluorescence pulse is received, and the fluorescence pulse is treated as an independent X-ray photon event. The arrival time of the X-ray photon event is recorded, and the X-ray photon events arriving at different times are mapped to different spatial locations to output an optical image. The optical image is analyzed to identify individual X-ray photon events, and X-ray photon counting is performed based on the identification results.

[0015] In some embodiments, the optical image is a stripe image unfolding along a time direction, and mapping the X-ray photon events arriving at different times to different spatial locations to output the optical image includes: The fluorescence pulse is treated as an independent X-ray photon event. A one-to-one correspondence between the arrival time of the fluorescence pulse and the electron deflection position is established using a high-speed scanning electric field, so that the X-ray photon events arriving at different times form light spots at different positions in the image, thereby outputting the striped image. Specifically, when the time interval between adjacent X-ray photon events is greater than the system time resolution, the corresponding X-ray photon events are effectively separated in the space of the stripe image.

[0016] In some embodiments, the X-ray photon counting detection method further includes: The X-ray photon counting and detection system is irradiated with two or more standard materials having known K-edge absorption energies, and the corresponding optical images are acquired and the X-ray photon events are recovered. The number of X-ray photon events under different fluorescence response parameters was counted to obtain the fluorescence response distribution curves; Based on the abrupt change characteristics of the absorption coefficient of each standard material at the K-edge energy, the mapping relationship between the fluorescence response parameters and the X-ray photon energy is determined to establish an energy calibration function; Based on the energy calibration function, the corresponding X-ray photon energy is calculated according to the fluorescence response parameters of the identified X-ray photon event.

[0017] In some embodiments, the optical image is a two-dimensional photon counting image, and the X-ray photon counting detection system includes a time-detection component that receives the fluorescence pulses through a slit. The process of treating the fluorescence pulses as independent X-ray photon events, recording the arrival time of the X-ray photon events, and mapping X-ray photon events arriving at different times to different spatial locations to output an optical image includes: The object under test is controlled to move relative to the X-ray photon counting detection system along a slit direction perpendicular to the time detection component, and the scanning step size is set to the effective width of the slit; The fluorescence pulse is treated as an independent X-ray photon event. One X-ray photon event is completed at each scanning position to obtain the spatial location, arrival time and photon energy of all X-ray photon events in the corresponding slit region. The X-ray photon events obtained at each scanning position are spatially corrected and stitched together according to the displacement coordinates of the object under test to form the two-dimensional photon counting image of the entire area under test.

[0018] The beneficial effects of the embodiments disclosed herein include: By setting up a fluorescence conversion component, a time detection component, and an event recognition module, the fluorescence conversion component converts incident X-rays into fluorescence pulses of target duration, achieving efficient conversion of X-ray photons into optical signals. The time detection component receives the fluorescence pulses, treats them as independent X-ray photon events, records the arrival time of the X-ray photon events, and maps X-ray photon events arriving at different times to different spatial locations to output an optical image. The event recognition module analyzes the optical image, identifies independent X-ray photon events, and counts X-ray photons based on the identification results. This transforms the traditional electronic counting mode into a counting mode based on fluorescence, time encoding, and event recognition, enabling the mapping of X-ray photon events arriving at different times to different spatial locations. This spatially separates the X-ray photon events, avoids photon accumulation, and improves the accuracy of X-ray photon counting. Attached Figure Description

[0019] Figure 1 This is an architectural diagram of an X-ray photon counting and detection system provided in an embodiment of the present disclosure; Figure 2 A detailed structural diagram of the X-ray photon counting and detection system provided in the embodiments of this disclosure; Figure 3 A flowchart of the X-ray photon counting detection method provided in the embodiments of this disclosure; Figure 4 This is a schematic diagram of the X-ray photon counting process provided in an embodiment of the present disclosure; Figure 5 This is a schematic diagram illustrating the process of scanning a large-area object according to an embodiment of the present disclosure. Detailed Implementation

[0020] The accompanying drawings in the embodiments clearly and completely describe the technical solutions in the embodiments of this disclosure. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0021] It is understood that when the above embodiments of this disclosure are applied to specific products or technologies, permission or consent from the subject is required, and the collection, use and processing of related data must comply with relevant laws, regulations and standards.

[0022] Furthermore, when this embodiment of the disclosure needs to retrieve relevant data, it will obtain separate permission or separate consent for the relevant data through pop-up windows or redirection to a confirmation page. After clearly obtaining separate permission or separate consent for the relevant data, it will then obtain the necessary relevant data for enabling this embodiment of the disclosure to operate normally.

[0023] In this disclosure, the terms "module" or "unit" refer to a computer program or part of a computer program that has a predetermined function and works with other related parts to achieve a predetermined goal, and can be implemented wholly or partially using software, hardware (such as processing circuitry or memory), or a combination thereof. Similarly, a processor (or multiple processors or memory) can be used to implement one or more modules or units. Furthermore, each module or unit can be part of an overall module or unit that includes the functionality of that module or unit.

[0024] Reference Figure 1 , Figure 1 This is an architectural diagram of an X-ray photon counting and detection system provided in an embodiment of this disclosure. The X-ray photon counting and detection system includes a fluorescence conversion component, a time detection component, and an event recognition module.

[0025] The fluorescence conversion component converts incident X-rays into fluorescence pulses of a target duration, wherein the target duration is less than or equal to a preset time threshold. The time detection component receives the fluorescence pulses, treats them as independent X-ray photon events, records the arrival time of the X-ray photon events, and maps X-ray photon events arriving at different times to different spatial locations to output an optical image. The event recognition module analyzes the optical image, identifies independent X-ray photon events, and counts X-ray photons based on the recognition results.

[0026] Specifically, the fluorescence conversion component enables efficient and rapid conversion of X-ray photons into optical signals. When X-ray photons are incident on the fluorescence conversion component, high-energy electrons are generated through the photoelectric effect. These high-energy electrons then excite a large number of visible light photons, forming fluorescence pulses. For example, perovskite materials can be used for this conversion, exhibiting a short fluorescence decay time. The fluorescence pulse generated after each X-ray photon incident has an extremely short duration, and the fluorescence pulses generated by different photons are temporally independent.

[0027] The preset time threshold is an upper limit set according to the overall time resolution requirements of the system to ensure that the duration of the fluorescence pulse is short enough to avoid temporal overlap between fluorescence pulses generated by adjacent photon events. In this embodiment, the preset time threshold can be determined comprehensively based on factors such as the fluorescence decay time of the perovskite material, the time resolution of the time detection component, and the target X-ray flux.

[0028] The time detection component can use time-expansion technology to detect fluorescence pulses. Unlike traditional photon counting detectors that integrate and distinguish charge pulses through electronic circuits, the time detection component of this disclosure uses a high-speed scanning electric field to convert the arrival time information of the fluorescence pulse into spatial position information.

[0029] The event recognition module identifies light spots representing independent X-ray photon events by performing image processing and analysis on optical images. The module can employ image processing techniques based on algorithms such as threshold segmentation, connected component analysis, Gaussian fitting, or machine learning to extract the position, intensity, and morphological information of each independent light spot from the optical image. For example, the event recognition module can be implemented using statistical circuits.

[0030] By setting up a fluorescence conversion component, a time detection component, and an event recognition module, the fluorescence conversion component converts incident X-rays into fluorescence pulses of target duration, achieving efficient conversion of X-ray photons into optical signals. The time detection component receives the fluorescence pulses, treats them as independent X-ray photon events, records the arrival time of the X-ray photon events, and maps X-ray photon events arriving at different times to different spatial locations to output an optical image. The event recognition module analyzes the optical image, identifies independent X-ray photon events, and counts X-ray photons based on the identification results. This transforms the traditional electronic counting mode into a counting mode based on fluorescence, time encoding, and event recognition, enabling the mapping of X-ray photon events arriving at different times to different spatial locations. This spatially separates the X-ray photon events, avoids photon accumulation, and improves the accuracy of X-ray photon counting.

[0031] In some embodiments, refer to Figure 2 , Figure 2 This is a detailed structural diagram of the X-ray photon counting and detection system provided in the embodiments of this disclosure. The fluorescence conversion component includes a supporting substrate, a perovskite fluorescent layer, a protective layer, and a fixing mechanism. The perovskite fluorescent layer is disposed on the side of the supporting substrate facing the X-rays, and is used to absorb incident X-rays and generate fluorescence pulses; the protective layer is disposed on the outside of the perovskite fluorescent layer, and is used to protect the perovskite fluorescent layer; the fixing mechanism is used to fix the supporting substrate, the perovskite fluorescent layer and the protective layer.

[0032] Specifically, the support substrate is used to support the perovskite phosphor layer and ensure that the entire phosphor conversion module has good mechanical stability and optical flatness. The support substrate is made of quartz glass, fused silica, sapphire, or other transparent materials with high transmittance to visible light and stable mechanical properties, and its thickness is 0.2 to 2 mm to balance mechanical strength and optical transmittance.

[0033] The perovskite materials used in the embodiments of this disclosure are not limited to a specific composition. Inorganic or organic-inorganic hybrid perovskite materials with high X-ray absorption efficiency, high light yield and fast fluorescence response characteristics are used, such as CsPbBr3, CsPbCl3, MAPbBr3, FAPbBr3, etc. Other perovskite scintillation materials with similar fluorescence response properties can also be used.

[0034] To balance X-ray absorption efficiency and fluorescence propagation characteristics, the thickness of the perovskite fluorescent layer in this embodiment is set to 100–500 μm, thus achieving a good balance between X-ray absorption efficiency and time response performance. To improve environmental stability, a transparent protective layer is provided outside the perovskite fluorescent layer. This protective layer can be made of materials such as quartz glass, sapphire, optical glass, or a transparent polymer film. Its function is to reduce the impact of air, water vapor, and mechanical impacts on the perovskite material while ensuring visible light transmittance, thereby improving the long-term stability of the device. The protective layer thickness is 100–500 μm.

[0035] The entire fluorescence conversion module forms a sandwich structure consisting of a supporting substrate, a perovskite fluorescent layer, and a transparent protective layer. The layers are bonded together with optically transparent adhesive or encapsulated using methods such as vacuum lamination or thermoforming to reduce interface reflection, improve fluorescence collection efficiency, and enhance the mechanical strength of the entire module.

[0036] In some embodiments, the supporting substrate, the perovskite fluorescent layer, and the protective layer form a sandwich structure, and the layers are encapsulated by optically transparent adhesive bonding, vacuum lamination, or thermoforming to reduce interface reflection, improve fluorescence collection efficiency, and enhance the mechanical strength of the entire component.

[0037] In some embodiments, the time-detection component can be a streak camera. To reduce spatial divergence during fluorescence propagation, the fluorescence conversion component is installed at the slit entrance of the time-detection component, bringing the perovskite fluorescent layer as close as possible to the photocathode of the time-detection component. The distance between the perovskite fluorescent layer and the slit entrance is no more than 1 mm. Placing the X-ray conversion component as close as possible to the streak camera's time-unfolding entrance minimizes the fluorescence propagation path, reduces optical loss and spatial diffusion, and ensures that the fluorescence pulse generated by each X-ray photon can enter the streak camera for time unfolding with high temporal accuracy. This enables accurate identification and counting of X-ray single-photon events under high-throughput conditions.

[0038] In some embodiments, refer again Figure 2 The stripe camera includes a photocathode, an electronic acceleration focusing unit, a time scanning unit, a fluorescent screen, and an image acquisition unit.

[0039] The photocathode receives fluorescence pulses and converts the light signal into an electron beam; the electron acceleration and focusing unit accelerates and focuses the electron beam; the time scanning unit performs time-spreading on the accelerated and focused electron beam under the action of a high-speed scanning electric field; the fluorescent screen converts the time-spread electron beam back into an optical image; and the image acquisition unit records the optical image and transmits it to the event recognition module.

[0040] For example, the electron acceleration focusing unit can be implemented using accelerating electrodes and focusing electrodes. The focusing electrodes are divided into focusing electrodes corresponding to the time axis and focusing electrodes corresponding to the spatial axis. The time scanning unit can be implemented using a scanning circuit. The optical image can be a fringe image unfolding along the time direction, where the horizontal and vertical axes of the fringe image represent space and time.

[0041] Specifically, in order to ensure that fluorescence can enter the streak camera efficiently, the embodiments of this disclosure install the fluorescence conversion component at the slit entrance of the streak camera and keep the perovskite fluorescence layer coaxially aligned with the optical axis of the streak camera.

[0042] The slit width of the streak camera is set to 20–100 μm. A narrower slit can effectively limit the spatial diffusion of the incident beam in the non-time-spreading direction, improving the time-spreading accuracy; at the same time, it can ensure that sufficient fluorescence enters the streak camera, improving the detection sensitivity.

[0043] To further improve the light signal collection efficiency, the fluorescence conversion component and the streak camera are connected by direct optical coupling, that is, the fluorescence layer is set directly towards the slit of the streak camera, reducing the number of intermediate optical elements and reducing interface reflection and light energy loss.

[0044] In other embodiments, optical coupling structures such as quartz windows, fiber optic couplers, cylindrical lenses, or microscope objectives can be used to guide the fluorescence generated by the fluorescence conversion component to the slit of the streak camera.

[0045] When fluorescence enters the streak camera, fluorescence pulses generated at different times sequentially enter the time-scanning region. Under the influence of the scanning electric field, different arrival times correspond to different electron deflection positions, ultimately forming a two-dimensional streak image unfolding along the time direction on the fluorescent screen. Since the position of each spot in the streak image corresponds one-to-one with the fluorescence arrival time, each spot can be considered an independent photon event. By extracting and analyzing the independent spots in the streak image, the spatial position, arrival time, and energy information of each X-ray photon can be recovered, enabling single-photon counting of X-ray photons.

[0046] In some embodiments, refer to Figure 3 , Figure 3This is a flowchart of an X-ray photon counting and detection method provided in an embodiment of the present disclosure. The X-ray photon counting and detection method can be applied to the aforementioned X-ray photon counting and detection system. The X-ray photon counting and detection method includes the following steps S301 to S303.

[0047] S301 converts incident X-rays into fluorescent pulses of target duration; S302 receives fluorescence pulses, treats the fluorescence pulses as independent X-ray photon events, records the arrival time of the X-ray photon events, and maps X-ray photon events arriving at different times to different spatial locations to output optical images; S303 analyzes optical images, identifies independent X-ray photon events, and counts X-ray photons based on the identification results.

[0048] Among them, the target duration is less than or equal to a preset time threshold.

[0049] Traditional X-ray photon counting detectors use electron-hole pair generation, carrier drift, and electronic readout to count photons. Their counting speed is limited by carrier collection time and electronic recovery time. When multiple X-ray photons arrive at the same detection unit consecutively within the electronic recovery time, these different photon events overlap, leading to a pile-up phenomenon and reducing the accuracy of photon counting.

[0050] To address the aforementioned issues, the X-ray photon counting and detection method based on ultrafast time coding provided in this disclosure converts each incident X-ray photon into an X-ray photon event with a unique time tag, and then uses time-resolved detection technology to complete the X-ray photon event identification, thereby avoiding event overlap caused by traditional electronic integration.

[0051] In some embodiments, X-ray photon events arriving at different times are mapped to different spatial locations to output an optical image. Specifically, fluorescence pulses can be treated as independent X-ray photon events, and a one-to-one correspondence between the arrival time of the fluorescence pulse and the electron deflection position can be established using a high-speed scanning electric field, so that X-ray photon events arriving at different times form light spots at different positions in the image, thereby outputting a striped image that unfolds along the time direction.

[0052] Specifically, when the time interval between adjacent X-ray photon events is greater than the system's time resolution, the corresponding X-ray photon events are effectively separated in the spatial representation of the stripe image.

[0053] Reference Figure 4 , Figure 4This is a schematic diagram of the X-ray photon counting process provided in an embodiment of the present disclosure. When an X-ray photon is incident on the fluorescent layer, the scintillation layer absorbs the X-ray energy and generates a transient fluorescence pulse. Since the scintillation layer has a short fluorescence response time, each incident X-ray photon corresponds to an independent optical pulse. Therefore, each optical pulse can be regarded as an independent X-ray photon event. Figure 4 The fluorescent layer in the solution can be the aforementioned perovskite fluorescent layer.

[0054] Subsequently, the optical pulse enters the time-detection component. The time-detection component uses a high-speed scanning electric field to convert optical signals arriving at different times into electronic images at different spatial locations, thus establishing a one-to-one correspondence between time and spatial location. Since X-ray photon events arriving at different times will form light spots at different locations on the detection surface, even if multiple X-ray photons arrive at the detection system consecutively within a very short time, as long as the time interval between adjacent X-ray photon events is greater than the system's time resolution, each X-ray photon event can still be effectively separated spatially.

[0055] Unlike traditional photon counting detectors that distinguish different photon events through electronic recovery time, the embodiments of this disclosure utilize time unfolding to achieve counting separation. The limitation on the photon counting rate is shifted from electronic dead time to time resolution. Therefore, the embodiments of this disclosure overcome the technical limitations of traditional electronic counting methods that are restricted by carrier collection speed, and achieve single-photon event identification based on the time dimension.

[0056] In this embodiment, the streak camera first converts fluorescent photons into an electron beam using a photocathode. The electron beam is then accelerated and focused before entering a scanning deflection region. Under the influence of the scanning deflection electric field, electron beams entering the streak tube at different times acquire different deflection displacements, ultimately forming a streak image that unfolds along the time direction on the fluorescent screen. Since different positions in the streak image correspond to different arrival times, time encoding of photon events can be achieved.

[0057] For each detected light spot, its position and intensity correspond to the arrival time and fluorescence intensity of the X-ray photon event, respectively. The event recognition module identifies the corresponding photon event by analyzing the position and distribution information of each independent light spot in the stripe image, and completes the counting of X-ray photons.

[0058] Therefore, the embodiments of this disclosure transform the traditional electronic counting mode into a photon counting mode based on fluorescence, time coding, and event recognition, so that the X-ray photon counting is determined by time resolution instead of electronic recovery time, thereby significantly improving the photon event resolution and counting accuracy under high light flux conditions.

[0059] In some embodiments, the X-ray photon counting and detection system can be irradiated with two or more standard materials having known K-edge absorption energies to acquire corresponding stripe images and recover X-ray photon events; the number of X-ray photon events under different fluorescence response parameters can be counted to obtain fluorescence response distribution curves; based on the abrupt change characteristics of the absorption coefficient of each standard material at the K-edge energy, the mapping relationship between fluorescence response parameters and X-ray photon energy can be determined to establish an energy calibration function; based on the energy calibration function, the corresponding X-ray photon energy can be calculated according to the fluorescence response parameters of the identified X-ray photon events.

[0060] Specifically, to achieve X-ray photon energy measurement, after X-ray photon event identification, it is necessary to establish a correspondence between the fluorescence response signal and the incident X-ray photon energy. Therefore, this embodiment further calibrates the system's energy. This embodiment utilizes the physical property that different materials exhibit abrupt absorption characteristics near the K-edge, establishing a mapping relationship between the fluorescence response and X-ray photon energy using the known K-edge energy, thus achieving energy calibration of the entire detection system.

[0061] After system installation, the detection system was irradiated with standard materials possessing known K-edge absorption energies, and corresponding time-distributed images were acquired. Let the fluorescence response parameter corresponding to a single X-ray photon event be... The corresponding X-ray photon energy is Since there is a definite correspondence between the luminescence response of the scintillation material and the incident X-ray energy, the following energy calibration function can be established: (1) The energy calibration function can be established using linear, polynomial, exponential, or lookup table methods, and its specific form can be determined according to different scintillation materials and detection systems.

[0062] This disclosure uses two or more standard materials with known K-edge absorption energies as calibration samples. For example, iodine (K-edge: 33.2 keV) and gold (K-edge: 80.7 keV) can be selected as calibration samples to demonstrate the method. This disclosure is not limited to the above materials; any standard material with known K-edge absorption energies, such as gadolinium (Gd), erbium (Er), ytterbium (Yb), and tungsten (W), can also be used. Each standard material is irradiated with its corresponding tube voltage, and stripe images are acquired using the aforementioned X-ray photon counting detection system to recover all X-ray photon events. Subsequently, the number of X-ray photon events under different fluorescence responses is counted to obtain fluorescence response distribution curves. Since the absorption coefficient of the standard material undergoes a sudden change near the K-edge, a significant increase in response point will appear in the corresponding fluorescence response curve; this increase point corresponds to the known K-edge energy.

[0063] Based on the K-edge energies and response positions of multiple standard materials, a system energy calibration curve can be established. Formula (1) can be fitted using the least squares method. Alternatively, a nonlinear response relationship can be established using piecewise interpolation, spline fitting, or lookup table methods. After calibration, for any identified X-ray photon event, the corresponding X-ray photon energy can be calculated based on its fluorescence response parameters, thus achieving single X-ray photon energy recovery.

[0064] In some embodiments, the optical image can also be a two-dimensional photon counting image. The X-ray photon counting detection system includes a time-detection component that receives fluorescence pulses through a slit. The fluorescence pulses are treated as independent X-ray photon events, and the arrival time of the X-ray photon events is recorded. X-ray photon events arriving at different times are mapped to different spatial positions to output an optical image. Specifically, the relative movement between the object under test and the X-ray photon counting detection system can be controlled along the slit direction perpendicular to the time-detection component. The scanning step size is set to the effective width of the slit. The fluorescence pulses are treated as independent X-ray photon events, and one X-ray photon event is completed at each scanning position to obtain the spatial position, arrival time, and photon energy of all X-ray photon events in the corresponding slit area. The X-ray photon events obtained at each scanning position are spatially corrected and stitched according to the displacement coordinates of the object under test to form a two-dimensional photon counting image of the entire area under test.

[0065] Specifically, streak cameras receive light signals through slits, so a single exposure can only acquire photon event information within the corresponding area of ​​the slit, making it impossible to complete a large-area two-dimensional detection in one go. To achieve large-field-of-view X-ray photon counting imaging, the relative motion between the scanning object and the detection system can be controlled to allow the slits to sequentially cover the entire area to be measured, and photon events can be detected at each scanning position. Finally, a complete two-dimensional photon counting image can be reconstructed, with the horizontal and vertical axes of the two-dimensional photon counting image representing spatial positions.

[0066] Reference Figure 5 , Figure 5 This is a schematic diagram illustrating the large-area object scanning process provided in this embodiment. During the scanning process, the X-ray source and the X-ray photon counting and detection system remain fixed, while the object under test is mounted on a high-precision linear motion platform and moves gradually along a direction perpendicular to the slit of the streak camera. At each scanning position, the X-ray photon counting and detection system completes a full X-ray photon event acquisition, obtaining information on all X-ray photon events within the corresponding slit region, including photon spatial location, arrival time, and photon energy. Subsequently, the motion platform is controlled to move to the next scanning position according to a preset step size, and the X-ray photon event acquisition is repeated. When the entire scanning area is completed, the X-ray photon events obtained from each scanning position are stitched together according to the position coordinates of the motion platform to finally form a two-dimensional photon counting image of the entire object under test.

[0067] Specifically, let the axial length of the object to be scanned be... The effective width of the slit in the striped camera is To ensure that adjacent scanning areas completely cover the entire area under test, the scanning step size is set to: (2) The total number of scans satisfies: (3) In formula (3), Number of scans; This is the scan step size.

[0068] Since each scan captures all X-ray photon events within the corresponding region, the system first establishes a unified spatial coordinate system for each scan position based on the current position of the motion platform. Then, the X-ray photon events recovered from each scan position are transformed into the unified coordinate system.

[0069] (4) in, For X-ray photon events, Let t be the spatial coordinates, t be the arrival time, and E be the photon energy.

[0070] set up The displacement of the platform during the first scan is... The corresponding photon event space coordinates are then corrected to... (5) in, These are the local coordinates of the current scan position. These are global coordinates.

[0071] The embodiments described in this disclosure are for the purpose of more clearly illustrating the technical solutions of this disclosure and do not constitute a limitation on the technical solutions provided by this disclosure. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by this disclosure are also applicable to similar technical problems.

[0072] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this disclosure, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0073] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0074] Those skilled in the art will understand that all or some of the steps, apparatuses, or functional modules / units in the methods disclosed above can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0075] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in this disclosure and the foregoing drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this disclosure described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0076] It should be understood that in this disclosure, "at least one item" means one or more, and "more than one" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0077] In the several embodiments provided in this disclosure, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0078] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0079] Furthermore, the functional units in the various embodiments of this disclosure can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0080] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this disclosure, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this disclosure. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0081] The preferred embodiments of the present disclosure have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present disclosure. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and spirit of the present disclosure shall be within the scope of the claims of the present disclosure.

Claims

1. An X-ray photon counting and detection system, characterized in that, include: A fluorescence conversion component is used to convert incident X-rays into fluorescence pulses of a target duration, wherein the target duration is less than or equal to a preset time threshold. A time-detection component is used to receive the fluorescence pulse, treat the fluorescence pulse as an independent X-ray photon event, record the arrival time of the X-ray photon event, and map the X-ray photon events arriving at different times to different spatial locations to output an optical image; The event recognition module is used to analyze the optical image, identify independent X-ray photon events, and count X-ray photons based on the recognition results.

2. The X-ray photon counting and detection system according to claim 1, characterized in that, The fluorescence conversion component includes: Supporting base; A perovskite fluorescent layer is disposed on the side of the supporting substrate facing the X-rays, for absorbing the incident X-rays and generating the fluorescence pulses; A protective layer is disposed on the outside of the perovskite fluorescent layer to protect the perovskite fluorescent layer; A fixing mechanism is used to fix the supporting substrate, the perovskite fluorescent layer, and the protective layer.

3. The X-ray photon counting and detection system according to claim 2, characterized in that, The perovskite fluorescent layer is made of at least one of CsPbBr3, CsPbCl3, MAPbBr3 or FAPbBr3. The thickness of the perovskite fluorescent layer is 100–500 μm; The supporting substrate is made of quartz glass, fused silica, or sapphire, with a thickness of 0.2–2 mm; The protective layer is made of quartz glass, sapphire, optical glass or transparent polymer film, with a thickness of 100 to 500 μm.

4. The X-ray photon counting and detection system according to claim 2, characterized in that, The supporting substrate, the perovskite fluorescent layer, and the protective layer form a sandwich structure, and the layers are encapsulated by optically transparent adhesive bonding, vacuum lamination, or thermoforming.

5. The X-ray photon counting and detection system according to claim 2, characterized in that, The fluorescence conversion component is installed at the slit entrance of the time detection component. The distance between the perovskite fluorescent layer and the slit entrance is no greater than 1 mm, and the width of the slit entrance is set to 20–100 μm.

6. The X-ray photon counting and detection system according to claim 1, characterized in that, The time detection component employs a stripe camera, which includes: A photocathode is used to receive the fluorescence pulses and convert the light signal into an electron beam; An electron acceleration and focusing unit is used to accelerate and focus the electron beam; The time scanning unit is used to perform time-spreading of the accelerated and focused electron beam under the action of a high-speed scanning electric field; A fluorescent screen is used to convert the time-spread electron beam back into an optical image; An image acquisition unit is used to record the optical image and transmit it to the event recognition module.

7. A method for X-ray photon counting detection, characterized in that, The X-ray photon counting and detection method is applied to an X-ray photon counting and detection system and includes: The incident X-rays are converted into fluorescence pulses of a target duration, wherein the target duration is less than or equal to a preset time threshold. The fluorescence pulse is received, and the fluorescence pulse is treated as an independent X-ray photon event. The arrival time of the X-ray photon event is recorded, and the X-ray photon events arriving at different times are mapped to different spatial locations to output an optical image. The optical image is analyzed to identify individual X-ray photon events, and X-ray photon counting is performed based on the identification results.

8. The X-ray photon counting detection method according to claim 7, characterized in that, The optical image is a striped image unfolded along the time direction. Mapping X-ray photon events arriving at different times to different spatial locations to output the optical image includes: The fluorescence pulse is treated as an independent X-ray photon event. A one-to-one correspondence between the arrival time of the fluorescence pulse and the electron deflection position is established using a high-speed scanning electric field, so that the X-ray photon events arriving at different times form light spots at different positions in the image, thereby outputting the striped image. Specifically, when the time interval between adjacent X-ray photon events is greater than the system time resolution, the corresponding X-ray photon events are effectively separated in the space of the stripe image.

9. The X-ray photon counting detection method according to claim 7, characterized in that, The X-ray photon counting detection method also includes: The X-ray photon counting and detection system is irradiated with two or more standard materials having known K-edge absorption energies, and the corresponding optical images are acquired and the X-ray photon events are recovered. The number of X-ray photon events under different fluorescence response parameters was counted to obtain the fluorescence response distribution curves; Based on the abrupt change characteristics of the absorption coefficient of each standard material at the K-edge energy, the mapping relationship between the fluorescence response parameters and the X-ray photon energy is determined to establish an energy calibration function; Based on the energy calibration function, the corresponding X-ray photon energy is calculated according to the fluorescence response parameters of the identified X-ray photon event.

10. The X-ray photon counting detection method according to claim 7, characterized in that, The optical image is a two-dimensional photon counting image. The X-ray photon counting detection system includes a time-detection component that receives the fluorescence pulses through a slit. The system treats the fluorescence pulses as independent X-ray photon events, records the arrival time of each X-ray photon event, and maps X-ray photon events arriving at different times to different spatial locations to output an optical image. This includes: The object under test is controlled to move relative to the X-ray photon counting detection system along a slit direction perpendicular to the time detection component, and the scanning step size is set to the effective width of the slit; The fluorescence pulse is treated as an independent X-ray photon event. One X-ray photon event is completed at each scanning position to obtain the spatial location, arrival time and photon energy of all X-ray photon events in the corresponding slit region. The X-ray photon events obtained at each scanning position are spatially corrected and stitched together according to the displacement coordinates of the object under test to form the two-dimensional photon counting image of the entire area under test.

Images