Radiation imaging device and method based on solid Fries gate detector

Abstract

The invention belongs to the technical field of radiation imaging, and particularly relates to a radiation imaging device and method based on a solid Fries gate detector, and the device comprises a radiation source, the solid Fries gate detector, a pre-amplification module, and an upper computer. According to the solid Fries gate detector, a semiconductor detection material interacts with rays to generate current carriers, the current carriers are driven to drift under the action of an electric field formed by an anode and a cathode, and when the current carriers penetrate through a gap between two adjacent gate wires in a gate, the adjacent gate wires generate gate induction signals; the pre-amplification module is used for amplifying an induction signal output by the solid-state Fries gate detector; and the upper computer obtains the drift time and position information of a carrier based on the time and amplitude information of the amplified induction signal, so as to obtain the energy deposition position and time of the ray. According to the scheme, extra amplitude and time information is provided by utilizing the grid electrode of the solid-state Fry gate detector, so that the ray deposition position, the carrier drift path and the carrier drift time are deduced.

Description

Technical Field

[0001] The present invention relates to the field of radiation imaging technology, and in particular to a radiation imaging device and method based on a solid-state Frisch grating detector. Background Art

[0002] Semiconductor detectors utilize the photoelectric effect of semiconductor materials on high-energy radiation, converting it into electrical signals, thereby enabling the detection of information such as the timing and energy of radiation events. In photon counting radiation imaging applications, semiconductor detectors offer significant advantages over traditional scintillator detectors in both energy and spatial resolution.

[0003] At present, radiation imaging technology based on semiconductor detectors mainly relies on strip detectors and pixel detectors. Figure 1 The figure shows the structure of the strip detector. Figure 2 The following is a schematic diagram of the pixel-type detector structure. Taking a semiconductor material with holes as the primary charge carrier as an example, its cathode uses multiple discrete strip electrodes or multiple pixel electrodes arranged in an array. Each discrete electrode collects carriers generated by the interaction of high-energy radiation with the semiconductor material and outputs a cathode sensing signal containing carrier information. Based on the cathode sensing signal output by each electrode, the drift position information of the carriers and, therefore, the radiation deposition information can be obtained. However, both types of detectors have the following problems: in the gap region between the electrodes, due to the presence of surface conductivity, the electric field lines terminate there, preventing the collection of carriers drifting into this region, resulting in charge loss and affecting imaging accuracy. Furthermore, when adjacent electrodes are too close, carriers can be collected by multiple electrodes simultaneously, leading to charge sharing and signal crosstalk, which also affects the detector's position resolution and, consequently, imaging accuracy. To address the above-mentioned issues, the existing technology can only suppress charge loss by reducing the electrode size and electrode spacing. However, at the same time, this will also aggravate the charge sharing and signal crosstalk problems. Therefore, in order to avoid the charge sharing and signal crosstalk problems, the electrode size in the existing technology is 200 μm and above, and the electrode spacing is 50 μm and above, which cannot be further reduced. This also limits the detector's detection accuracy of the carrier drift position, resulting in low imaging resolution.

[0004] In summary, existing radiation imaging devices based on semiconductor detectors have the problem of low imaging resolution. Summary of the Invention

[0005] To this end, the technical problem to be solved by the present invention is to overcome the problems of charge loss, charge sharing, signal crosstalk and low imaging resolution in radiation imaging devices based on semiconductor detectors in the prior art.

[0006] To solve the above technical problems, the present invention provides a radiation imaging device based on a solid-state Frisch grating detector, comprising: A ray source, used for generating rays; A solid-state Frisch grid detector comprises an anode, a cathode, and a grid disposed between the anode and the cathode. It is used to generate carriers by the interaction between a semiconductor detection material and radiation. The electric field formed by the anode and cathode causes the carriers to drift. When a carrier passes between two adjacent grid wires in the grid, both adjacent grid wires generate a grid sensing signal. A preamplifier module is connected to the output end of the solid-state Frisch grating detector and is used to amplify the anode sensing signal, cathode sensing signal and grid sensing signal output by the solid-state Frisch grating detector; The host computer is connected to the output end of the preamplifier module and is used to obtain the drift time and position information of the carriers based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal and gate sensing signal, thereby obtaining the deposition time and position information of the rays.

[0007] Preferably, the preamplifier module includes: an anode preamplifier connected to the anode voltage module of the solid-state Frisch grid detector and used to amplify the anode sensing signal; a cathode preamplifier connected to the cathode voltage module of the solid-state Frisch grid detector and used for amplifying the cathode sensing signal; A plurality of grid preamplifiers are respectively connected to the grid voltage modules of the grid wires of the solid-state Frisch grid detector and are used for amplifying the grid induction signals generated by the grid wires.

[0008] Preferably, a multi-channel acquisition system is further included, which is connected to the anode preamplifier, the cathode preamplifier, multiple grid preamplifiers and the host computer, and is used to transmit the amplified anode sensing signal, cathode sensing signal and grid sensing signal to the host computer.

[0009] Preferably, the gate comprises at least one gate unit, wherein the gate unit comprises a plurality of grid wires arranged separately on the same horizontal line, and the extension direction of each grid wire is perpendicular to the carrier drift direction; When the number of gate units is greater than 1, the multiple gate units are separately arranged in sequence from bottom to top or from top to bottom along the carrier drift direction, and the angle between the extension directions of the grid wires in each gate unit is 0°~180°.

[0010] Preferably, the anode or cathode comprises a plurality of discretely arranged strip electrodes, each strip electrode extending in a direction perpendicular to the carrier drift direction, for collecting carriers and generating an anode sensing signal or a cathode sensing signal; or, The anode or cathode includes a plurality of pixel electrodes arranged in an array on the same horizontal line, and is used to collect carriers and generate an anode sensing signal or a cathode sensing signal.

[0011] Preferably, the grid wire is composed of a gate metal and an insulating layer wrapping the gate metal, and the thickness of the insulating layer is 0-1 mm; and / or, The cross-sectional shape of the grid wire is circular, rectangular or irregular polygonal; and / or, The semiconductor detection material of the solid-state Frisch gate detector is a halide perovskite semiconductor, a halide semiconductor, a sulfide semiconductor or a sulfur halide semiconductor; Among them, halide perovskite semiconductors include three-dimensional perovskite, two-dimensional perovskite, one-dimensional perovskite, zero-dimensional perovskite and double perovskite, and the three-dimensional perovskite is A1B1X13, wherein A1 is one or more of Na, K, Rb, Cs, Cu, Tl and H3O, B1 is one or more of Pb, Si, Ge, Sn, Mg, Ca, Sr, Ba, Zn, Cd and Hg, and X1 is F, Cl, Br, I, BF4, HCOO, OH, One or more of CN, SCN, NCS, SH, NO3 and H2POO; two-dimensional perovskite is A23B22X29, wherein A2 is one or both of Cs and Rb, B2 is one or both of Sb and Bi, and X2 is one or more of F, Cl, Br and I; zero-dimensional perovskite is Cs3Bi2I9, Cs2TeI6, Cs2TeBr6 or Cs2TeCl6; double perovskite is Cs2AgBiBr6; The halide semiconductor is HgI2 or TlBr; Sulfide semiconductor is M1 x Q y , wherein M1 is one or more of Zn, Cd, and Hg, and Q is one or more of S, Se, and Te; Sulfur halide semiconductor is M2 x Q y X2 z , wherein M2 is one or more of Zn, Cd, Hg, Pb, Bi, Tl, Q is one or more of S, Se, Te, and X2 is one or more of F, Cl, Br, and I.

[0012] Preferably, the host computer obtains the drift time and position information of the carriers based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal and gate sensing signal using a center of gravity method, a difference method or a fitting method.

[0013] Preferably, obtaining the drift time and position information of the carriers based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal and gate sensing signal using the center of gravity method includes: Based on the anode sensing signal and the cathode sensing signal, obtaining the start time, end time and amplitude of the gate sensing signal; Based on the gate sensing signal generated by each of the adjacent grid wires, a first amplitude difference of the carrier drifting on the anode side, a second amplitude difference of the carrier drifting on the cathode side, and a carrier gate-crossing time are calculated; The anode side coordinate and cathode side coordinate of the carrier are calculated based on the first amplitude difference and the second amplitude difference of the two gate sensing signals; wherein the anode side coordinate calculation formula of the carrier is: , in, represents the anode-side coordinate of the carrier; Indicates the first amplitude difference of the gate sensing signal generated by the first grid wire among the adjacent grid wires; represents the first amplitude difference of the gate sensing signal generated by the second grid wire among the adjacent grid wires; The calculation formula for the cathode side coordinate of the carrier is: , in, represents the cathode-side coordinate of the carrier; A second amplitude difference representing a gate sensing signal generated by a first grid wire among adjacent grid wires; It represents the second amplitude difference of the gate sensing signal generated by the second grid wire among the adjacent grid wires.

[0014] Preferably, a shielding box is further included, in which the solid-state Frisch grid detector and the preamplifier module are placed, so that the shielding box is used to reduce electromagnetic interference during radiation imaging.

[0015] The present invention further provides a radiation imaging method based on a solid-state Frisch grating detector, which is applied to the above-mentioned radiation imaging device based on a solid-state Frisch grating detector, comprising: A ray source is used to generate rays and act on a solid-state Frisch grid detector; The semiconductor detection material in the solid-state Frisch grid detector interacts with the radiation to generate carriers, and the electric field formed by the anode and cathode causes the carriers to drift. When the carriers pass between two adjacent grid wires in the grid, the two adjacent grid wires generate a grid sensing signal. A preamplifier module is used to amplify the anode sensing signal, cathode sensing signal and grid sensing signal output by the solid-state Frisch grid detector; The host computer obtains the drift time and position information of the carriers based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal and gate sensing signal, thereby obtaining the deposition time and position information of the rays.

[0016] The radiation imaging device based on the solid-state Frisch grating detector provided in this application has the following beneficial effects: The solid-state Frisch grid detector includes an anode, a cathode, and a gate, and the gate inside it is composed of multiple grid wires arranged separately to form a grid; when the radiation interacts with the semiconductor detection material to generate carriers, the carriers drift toward the cathode and anode under the action of the electric field formed by the anode and cathode. The present application found that when the carrier passes between any two grid wires in the gate, only these two grid wires will generate an induction signal, and the induction amplitude of the remaining grid wires is relatively low. Based on this discovery, the present application uses the solid-state Frisch grid detector for radiation imaging for the first time, utilizing the characteristic that the grid wires in the gate do not collect carriers but generate induction signals when the carriers pass through, thereby avoiding the problems of charge loss, charge sharing, and signal crosstalk in the prior art; at the same time, the gate induction signal generated by the gate can provide independent amplitude and time information, which can not only further correct the amplitude and time of the anode induction signal and the cathode reflection signal, but also provide more carrier position and drift information, thereby calculating the drift time and drift path of the carrier between the grid wires, and then obtaining the time and position of the radiation deposition, effectively improving the spatial resolution of radiation imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 Schematic diagram of the strip detector structure provided for this application; Figure 2 A schematic diagram of the pixel detector structure provided in this application; Figure 3 A structural diagram of a radiation imaging device based on a solid-state Frisch grating detector provided in this application; Figure 4 Schematic diagram of the radiation imaging principle of the solid-state Frisch grating detector provided in this application; Figure 5 Schematic diagram of various solid-state Frisch grid detector structures provided in this application; wherein, Figure 5 (a) is a schematic diagram of the structure of a mesh-type solid-state Frisch grating detector. Figure 5 (b) is a schematic diagram of the three-dimensional orthogonal solid-state Frisch grating detector structure. Figure 5 (c) is a schematic diagram of the structure of a solid-state Frisch grid detector with parallel grid wires and strip electrodes orthogonal to each other. Figure 5 (d) is a schematic diagram of the structure of a solid-state Frisch grid detector with parallel grid wires and pixel electrodes orthogonal to each other; Figure 6 A diagram of a solid-state Frisch grating detector device provided in an embodiment of the present application; Figure 7A waveform diagram of the sensing signal output by the solid-state Frisch grating detector provided in an embodiment of the present application during radiation imaging; Figure 8 for Figure 7 The schematic diagram of the induction signal analysis shown in FIG. Figure 8 (a) is the second and third grid wires 137 Cs induced waveform, Figure 8 (b) is a schematic diagram of the carrier migration path between the second and third grid wires; Figure 9 This is a schematic diagram of imaging position analysis provided in an embodiment of the present application; wherein, Figure 9 (a) is a schematic diagram of the linear response of the initial carrier coordinates and the laser position calculated in this application. Figure 9 (b) is a schematic diagram of the imaging position resolution of the solid-state Frisch grating detector provided by this application; Explanation of the reference numerals in the specification: 1. X-ray source; 2. Solid-state Frisch grid detector; 21. Anode; 211. Anode voltage module; 22. Cathode; 221. Cathode voltage module; 23. Gate; 231. Grid wire; 232. Gate voltage module; 31. Anode preamplifier; 32. Cathode preamplifier; 33. Gate preamplifier; 4. Host computer; 5. Multi-channel signal acquisition system; 6. Shielding box. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0019] Patent publication number CN118943233A discloses a solid-state Frisch gate detector device based on perovskite materials. Specifically, the solid-state Frisch gate detector comprises a crystal and a gate embedded within the crystal. The anode and cathode are arranged at opposite ends of the crystal, and the gate, anode, and cathode are arranged in parallel. The gate is composed of multiple grid wires. It is worth noting that the solid-state Frisch gate detector is used in this patent to optimize radiation detection performance and achieve high energy spectrum resolution, but is not used for radiation imaging.

[0020] See also Figure 3 , Figure 3 This is a structural diagram of a radiation imaging device based on a solid-state Frisch grating detector provided in this application. The device specifically includes a radiation source 1, a solid-state Frisch grating detector 2, a preamplifier module (31, 32, 33) and a host computer 4.

[0021] The radiation source 1 is used to generate radiation.

[0022] Specifically, rays include photons (X-rays, gamma rays, visible light, etc.) and high-energy particles (alpha particles, beta particles, protons, neutrons, etc.).

[0023] The solid-state Frisch grid detector 2 includes an anode 21, a cathode 22, and a gate 23 disposed between the anode 21 and the cathode 22. Carriers are generated by the interaction between the semiconductor detection material and the radiation. The electric field formed by the anode 21 and the cathode 22 drives the carriers to drift. When the carriers pass between two adjacent grid wires 231 in the gate 23, the two adjacent grid wires 231 generate a gate sensing signal.

[0024] Specifically, a plurality of grid wires 231 separately arranged on the same horizontal plane can be regarded as a grid unit.

[0025] The preamplifier module is connected to the output end of the solid-state Frisch grating detector 2 and is used to amplify the anode induction signal, cathode induction signal and grid induction signal output by the solid-state Frisch grating detector 2 .

[0026] The host computer 4 is connected to the output end of the preamplifier module, and is used to obtain the drift time and position information of the carriers based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal and gate sensing signal, thereby obtaining the deposition time and position information of the rays.

[0027] Furthermore, the grid 231 is composed of a gate metal and an insulating layer wrapping the gate metal, and the thickness of the insulating layer is 0-1 mm.

[0028] Furthermore, the cross-sectional shape of the grid wire 231 may be circular, rectangular, or irregular polygonal.

[0029] Furthermore, the semiconductor detection material of the solid-state Frisch gate detector 2 is a halide perovskite semiconductor, a halide semiconductor, a sulfide semiconductor or a sulfur halide semiconductor; Among them, halide perovskite semiconductors include three-dimensional perovskite, two-dimensional perovskite, one-dimensional perovskite, zero-dimensional perovskite and double perovskite, and the three-dimensional perovskite is A1B1X13, wherein A1 is one or more of Na, K, Rb, Cs, Cu, Tl and H3O, B1 is one or more of Pb, Si, Ge, Sn, Mg, Ca, Sr, Ba, Zn, Cd and Hg, and X1 is F, Cl, Br, I, BF4, HCOO, OH, One or more of CN, SCN, NCS, SH, NO3 and H2POO; two-dimensional perovskite is A23B22X29, wherein A2 is one or both of Cs and Rb, B2 is one or both of Sb and Bi, and X2 is one or more of F, Cl, Br and I; zero-dimensional perovskite is Cs3Bi2I9, Cs2TeI6, Cs2TeBr6 or Cs2TeCl6; double perovskite is Cs2AgBiBr6; The halide semiconductor is HgI2 or TlBr; Sulfide semiconductor is M1 x Q y , wherein M1 is one or more of Zn, Cd, and Hg, and Q is one or more of S, Se, and Te; Sulfur halide semiconductor is M2 x Q y X2 z , wherein M2 is one or more of Zn, Cd, Hg, Pb, Bi, Tl, Q is one or more of S, Se, Te, and X2 is one or more of F, Cl, Br, and I.

[0030] Specifically, see Figure 4 , Figure 4 Figure 3 is a schematic diagram of the radiation imaging principle of a solid-state Frisch grating detector. The grid of this solid-state Frisch grating detector includes x grid wires. When gamma rays act between the second and third grid wires, only the second and third grid wires will generate significant induction signals, while the induction amplitudes of the first and fourth grid wires are relatively low. Therefore, by analyzing the induction signal strength of each grid wire, the ray deposition position can be accurately located, thereby improving the position sensitivity of radiographic imaging.

[0031] Specifically, if Figure 3 As shown, the preamplifier module includes an anode preamplifier 31 , a cathode preamplifier 32 and a grid preamplifier 33 .

[0032] The anode preamplifier 31 is connected to the anode voltage module 211 of the solid-state Frisch grid detector 2 and is used to amplify the anode sensing signal; The cathode preamplifier 32 is connected to the cathode voltage module 221 of the solid-state Frisch grid detector 2 and is used to amplify the cathode sensing signal; The plurality of gate preamplifiers 33 are respectively connected to the gate voltage modules 232 of the respective grid wires 231 of the solid-state Frisch grid detector 2 , and are used to amplify the gate sensing signals generated by the grid wires 231 .

[0033] Furthermore, the device also includes a multi-channel signal acquisition system 5 , and the signals amplified by each preamplifier are transmitted to the multi-channel signal acquisition system 5 , and then transmitted to the host computer 4 by the multi-channel signal acquisition system 5 .

[0034] Furthermore, since the solid-state Frisch grating detector 2 in the prior art is not used for radiation imaging, that is, there is no need to obtain the specific coordinate information of carrier deposition, its gate only needs to be formed by multiple grid wires 231 arranged horizontally and discretely to form a grid. When this application uses it for radiation imaging, it is necessary to accurately obtain the coordinate information of the carrier deposition position, so as to obtain the ray deposition position information. Therefore, this application proposes the following structures of solid-state Frisch grating detectors 2 to further increase the resolution during radiation imaging.

[0035] Figure 5 Schematic diagram of various solid-state Frisch grid detector structures provided in this application; wherein, Figure 5 (a) is a schematic diagram of the structure of a mesh-type solid-state Frisch grating detector. Figure 5 (b) is a schematic diagram of the three-dimensional orthogonal solid-state Frisch grating detector structure. Figure 5 (c) is a schematic diagram of the structure of a solid-state Frisch grid detector with parallel grid wires and strip electrodes orthogonal to each other. Figure 5 (d) is a schematic diagram of the structure of a solid-state Frisch grid detector with parallel grid wires and pixel electrodes orthogonal to each other.

[0036] Optionally, the gate 23 includes at least one gate unit, and the gate unit includes a plurality of grid wires 231 separately arranged on the same horizontal line, and the extension direction of each grid wire 231 is perpendicular to the carrier drift direction.

[0037] Specifically, when the number of gate units is greater than 1, the multiple gate units are sequentially arranged from bottom to top or from top to bottom along the carrier drift direction, and the angle between the extension directions of the grid wires 231 in each gate unit is 0° to 180°. Figure 5 As shown in (a) and (b) in FIG, when the number of gate units is 2, the multiple grid wires 231 in the first gate unit and the multiple grid wires 231 in the second gate unit may be arranged orthogonally.

[0038] For example, Figure 5As shown in (a) and (b), when the carrier passes between any two grid wires 231 in the first gate unit, the y coordinate of the carrier can be obtained based on the gate sensing signal generated by the two grid wires 231. When the carrier continues to drift and passes between any two grid wires 231 in the second gate unit, the x coordinate of the carrier can be obtained based on the gate sensing signal generated by the two grid wires 231. At the same time, the three-dimensional coordinate information of the carrier can be obtained based on the z coordinates of the first grid wire unit and the second grid wire unit, thereby obtaining the three-dimensional coordinate information of the ray deposition position.

[0039] Furthermore, solid-state Frisch grating detectors can be combined with traditional strip detectors and pixel detectors to improve the resolution of radiation imaging.

[0040] Optionally, in some embodiments of the present application, the anode 21 or the cathode 22 includes a plurality of discretely arranged strip electrodes, each strip electrode extending in a direction perpendicular to the carrier drift direction, and is used to collect carriers and generate an anode sensing signal or a cathode sensing signal, so that the host computer 4 obtains the drift time and position information of the carriers on the plane of the anode 21 or the cathode 22 based on the anode sensing signal or the cathode sensing signal.

[0041] For example, Figure 5 As shown in (c), the x-coordinate range of the carrier can be obtained by collecting the carrier information of each strip electrode. At the same time, the y-coordinate of the carrier can be obtained by combining the amplitude of the gate sensing signal generated by the grid wire 231 in the gate 23. Finally, the three-dimensional coordinate information of the carrier can be obtained by combining the z-coordinate of the gate 23, thereby obtaining the three-dimensional coordinate information of the ray deposition position.

[0042] Optionally, in other embodiments of the present application, the anode 21 or the cathode 22 includes a plurality of pixel electrodes arranged in an array on the same horizontal line, which are used to collect carriers and generate an anode sensing signal or a cathode sensing signal, so that the host computer 4 obtains the drift time and position information of the carriers on the plane of the anode 21 or the cathode 22 based on the anode sensing signal or the cathode sensing signal.

[0043] For example, Figure 5 As shown in (d), the carrier information collected by the pixel electrode can be used to obtain the x-coordinate range and y-coordinate range of the carrier. At the same time, the y-coordinate of the carrier can be obtained by combining the amplitude and time of the gate sensing signal generated by the gate wire 231 in the gate 23. Finally, combined with the z-coordinate of the gate 23, the three-dimensional coordinate information of the carrier can be obtained.

[0044] Optionally, the host computer 4 can use a centroid method, a differential method, or a fitting method to obtain the drift time and position information of the carriers based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal, and gate sensing signal. Specifically, the centroid method calculates the carrier position between two grid wires by directly comparing the amplitude difference; the differential method calculates the carrier position between three or more grid wires by comparing the gate sensing signals generated by each grid wire; and the fitting method calculates the carrier position between three or more grid wires by fitting the changing trend of the gate sensing signal amplitude difference generated by each grid wire using a Gaussian function, a Poisson distribution function, or the like.

[0045] It should be noted that when the grid spacing is wide, only two grid wires can generate gate sensing signals. If the grid density is further increased and the grid spacing is too close, multiple grid wires may generate gate sensing. At this time, the host computer can use the differential method or fitting method to infer the specific position of the carrier based on the gate sensing signals generated by multiple grid wires.

[0046] Specifically, the center of gravity method is used to obtain the drift time and position information of the carriers based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal and gate sensing signal, including: Based on the anode sensing signal and the cathode sensing signal, obtaining the start time, end time and amplitude of the gate sensing signal; Based on the gate sensing signal generated by each of the adjacent grid wires, a first amplitude difference of the carrier drifting on the anode side, a second amplitude difference of the carrier drifting on the cathode side, and a carrier gate-crossing time are calculated; The anode side coordinate and cathode side coordinate of the carrier are calculated based on the first amplitude difference and the second amplitude difference of the two gate sensing signals; wherein the anode side coordinate calculation formula of the carrier is: , in, represents the anode-side coordinate of the carrier; Indicates the first amplitude difference of the gate sensing signal generated by the first grid wire among the adjacent grid wires; represents the first amplitude difference of the gate sensing signal generated by the second grid wire among the adjacent grid wires; The calculation formula for the cathode side coordinate of the carrier is: , in, represents the cathode-side coordinate of the carrier; Indicates a second amplitude difference of the gate sensing signal generated by the first grid wire among the adjacent grid wires; It represents the second amplitude difference of the gate sensing signal generated by the second grid wire among the adjacent grid wires.

[0047] Optionally, using a differential method based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal, and gate sensing signal to obtain the drift time and position information of the carriers includes: Based on the anode sensing signal and the cathode sensing signal, obtaining the start time, end time and amplitude of the gate sensing signal; Based on the amplitude of the gate sensing signal generated by each sensing grid, the carrier position is calculated using a differential method based on the center position of the sensing grid and the distance between the carrier and the center position of the sensing grid; The calculation formula for the carrier position is: , in, represents the carrier position; Indicates the center position of n sensing grid wires; Indicates the number of inductive grids; Indicates the distance between the carrier and the center of the sensing grid; The calculation formula of the distance between the carrier and the center of the sensing grid is: , in, Indicates the The first differential parameter of the sensing grid; Indicates the A second differential parameter of a sensing grid; Indicates the The amplitude of the gate sensing signal generated by the sensing grid wire.

[0048] Alternatively, as Figure 3 As shown, in some embodiments, the device further includes a shielding box 6. By placing the solid-state Frisch grid detector 2 and the preamplifier module in the shielding box, the shielding box 6 is used to reduce external electromagnetic interference during radiation imaging.

[0049] The radiation imaging device based on the solid-state Frisch grating detector is further explained below through multiple embodiments: This embodiment 1 provides a high-resolution imaging device based on a solid-state Frisch gate detector of CsPbBr3 perovskite.

[0050] The prepared multi-filament solid-state Frisch grating detector is as follows Figure 6 As shown, the crystal size of the detector is 3.4×3.0×2.2 mm 3 , the distance between the gate and the bottom cathode is 1.0 mm, the grid wire spacing is 0.6 mm, and the grid wire radius is 0.025 mm.

[0051] The detector is used to detect gamma ray signals. The signals sensed by each electrode are sequentially passed through the preamplifier, multi-channel signal acquisition system and host computer. The obtained signals are as follows: Figure 7 As shown in the figure, the anode and cathode show positive and negative signals respectively, and only the second and third grid wires generate corresponding gate sensing signals for this event, while the first and fourth grid wires do not show obvious responses, which indicates that in this event, the carriers are located in the area between the second and third grid wires.

[0052] Furthermore, the center of gravity method is used to analyze the specific action position of the γ-ray, such as Figure 8 As shown, Figure 8 (a) is the second and third grid wires 137 Cs induced waveform, Figure 8 (b) is a schematic diagram of the carrier migration path between the second and third grid wires; the starting time of the waveform ( t A ) and end time ( t D ) are the times corresponding to 10% of the anode signal and 90% of the cathode signal, respectively. The turning point of the gate sensing signal (in the second grid wire is t B , in the third grid wire t C ), which indicates that the carriers have passed through the corresponding gate at this moment.

[0053] Based on this, the abscissa of the anode drift side is defined as , the abscissa of the cathode drift side is defined as The positions of these two points can be determined by the amplitude difference ( Amp ) is calculated using the following formula: , in, represents the anode-side coordinate of the carrier; Indicates the difference between the amplitude at the beginning and the amplitude at the turning point of the waveform of the gate sensing signal generated by the second grid wire; Indicates the difference between the amplitude at the beginning and the amplitude at the turning point of the waveform of the gate sensing signal generated by the third grid wire; The calculation formula for the cathode side coordinate of the carrier is: , in, represents the end point coordinates of the carrier; The difference between the amplitude at the end of the waveform of the gate sensing signal generated by the second grid wire and the amplitude at the turning point; It represents the difference between the amplitude at the end of the waveform of the gate sensing signal generated by the third grid wire and the amplitude at the turning point.

[0054] Furthermore, the calculation results are expressed in Figure 8 In (b), the dotted line in the figure is the possible migration path of the carrier.

[0055] To further verify the position resolution capability of the multi-wire solid-state Frisch grating detector provided by this embodiment, this embodiment also uses a pulsed laser source to excite the crystal to simulate the process of radiation acting on the surface. In the test, the laser starts from the position of the second grid wire and gradually drifts to the third grid wire. The test results are as follows: Figure 9 As shown, Figure 9 (a) is a schematic diagram of the linear response of the initial carrier coordinates and the laser position calculated in this application. Figure 9 (b) is a schematic diagram of the imaging position resolution of the solid-state Frisch grating detector provided in this application.

[0056] from Figure 9 As can be seen from (a) in the figure, the carrier endpoint coordinates calculated by the present application show a good linear relationship with the laser position, indicating that the detector can accurately reflect the position of the ray action. Furthermore, based on this linear relationship, this embodiment further analyzes the deviation of the carrier endpoint coordinates from the fitting straight line in the detector range of 0~600μm, as shown in FIG. Figure 9 In (b), it can be seen that its distribution shows a half-peak width of 40.0 μm.

[0057] Example 2 of the present application provides a radiation imaging device based on a multi-filament solid-state Frisch grating detector prepared by Cs3Bi2Br9, wherein the crystal size of the detector is 5×5×6 mm 3 .

[0058] The detector features a planar anode on top and a planar cathode below, providing depth information (Z direction). A gate composed of multiple discrete filaments within the crystal provides carrier information in the Y direction. By applying a positive voltage to the anode, a negative voltage to the cathode, and grounding the gate, the device's pulse waveform response and energy spectrum are measured. The gate-induced signal generated by the gate is used to infer the locations of carrier deposition and carrier drift using a differential method.

[0059] Example 3 of the present application provides a radiation imaging device based on a mesh-type solid-state Frisch grating detector prepared by Cs2TeI6, wherein the crystal size of the detector is 4×4×5 mm 3 .

[0060] The detector has a planar anode on top and a planar cathode on the bottom, providing depth information (Z direction). The crystal contains two gate units, with orthogonal grid filaments in each unit providing carrier information in the X and Y directions, respectively. By applying a positive voltage to the anode and a negative voltage to the cathode, with the gate grounded, the device's pulse waveform response and energy spectrum are measured. The gate-induced signal generated by the gate is then used to infer the locations of carrier deposition and carrier drift using a fitting method.

[0061] Example 4 of the present application provides a radiation imaging device based on a three-dimensional orthogonal solid-state Frisch grating detector prepared by Cs2AgBiBr6, wherein the crystal size of the detector is 5×4×3 mm 3 .

[0062] The detector features a planar anode on top and a planar cathode below, providing depth information (Z direction). Two sets of orthogonally spaced gates, separated by 1 mm, provide carrier information in the X, Y, and Z directions. By applying a positive voltage to the anode and a negative voltage to the cathode, with the gates grounded, the device's pulse waveform response and energy spectrum are measured. The gate-induced signals generated by the gates are used to infer the locations of carrier deposition and drift using the center of gravity method.

[0063] Example 5 of the present application provides a radiation imaging device based on a solid-state Frisch grating detector with parallel grid wires and strip electrodes orthogonal to each other, prepared by CdTe, wherein the crystal size of the detector is 6×4×3 mm. 3 .

[0064] The detector features a planar anode on top and a strip-shaped cathode array below. The anode and cathode provide depth information (Z direction), while the cathode provides X-direction information. The gate and cathode are arranged orthogonally within the crystal, with a 1 mm spacing between them, providing carrier information in the X, Y, and Z directions. By applying a positive voltage to the anode, a negative voltage to the cathode, and grounding the gate, the device's pulse waveform response and energy spectrum are measured. The gate-induced signal generated by the gate is used to infer the locations of carrier deposition and carrier drift using the center of gravity method.

[0065] Example 6 of the present application provides a radiation imaging device based on a solid-state Frisch grating detector coupled with parallel wires prepared from Hg3Se2I2 and pixel electrodes, wherein the crystal size of the detector is 6×4×2 mm 3 .

[0066] The detector features a planar anode on top and a pixel electrode array on the cathode below. The anode and cathode provide depth information (Z direction), while the cathode provides information in the X and Y directions. A parallel wire grid within the crystal is parallel to the pixel array in the cathode in the Y direction, with a 1 mm gap between the grid and cathode. This provides carrier information in the Y and Z directions, as well as additional time and Z direction information. By applying a positive voltage to the anode, a negative voltage to the cathode, and grounding the gate, the device's pulse waveform response and energy spectrum are measured. The gate-induced signal generated by the gate is then used to infer the locations of carrier deposition and carrier drift using a fitting method.

[0067] Based on the radiation imaging device based on the solid-state Frisch grating detector provided in the above embodiment, the embodiment of the present application further provides a radiation imaging method based on the solid-state Frisch grating detector, which specifically includes: S10: A ray source is used to generate rays and act on a solid-state Frisch grid detector.

[0068] S20: The semiconductor detection material in the solid-state Frisch gate detector interacts with the radiation to generate carriers, and the electric field formed by the anode and cathode is used to make the carriers drift. When the carriers pass between two adjacent grid wires in the gate, the two adjacent grid wires generate gate sensing signals.

[0069] S30: A preamplifier module is used to amplify the anode sensing signal, the cathode sensing signal, and the grid sensing signal output by the solid-state Frisch grid detector.

[0070] S40: The host computer obtains the drift time and position information of the carriers based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal and gate sensing signal, thereby obtaining the deposition time and position information of the radiation.

[0071] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0072] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0073] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0074] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0075] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A radiation imaging device based on a solid-state Frisch grating detector, characterized in that: include: A ray source, used for generating rays; A solid-state Frisch grid detector comprises an anode, a cathode, and a grid disposed between the anode and the cathode. It is used to generate carriers by the interaction between a semiconductor detection material and radiation. The electric field formed by the anode and cathode causes the carriers to drift. When a carrier passes between two adjacent grid wires in the grid, both adjacent grid wires generate a grid sensing signal. A preamplifier module is connected to the output end of the solid-state Frisch grating detector and is used to amplify the anode sensing signal, cathode sensing signal and grid sensing signal output by the solid-state Frisch grating detector; The host computer is connected to the output end of the preamplifier module and is used to obtain the drift time and position information of the carriers based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal and gate sensing signal, thereby obtaining the deposition time and position information of the rays.

2. The radiation imaging device based on a solid-state Frisch grating detector according to claim 1, characterized in that: The preamplifier module includes: an anode preamplifier connected to the anode voltage module of the solid-state Frisch grid detector and used to amplify the anode sensing signal; a cathode preamplifier connected to the cathode voltage module of the solid-state Frisch grid detector and used for amplifying the cathode sensing signal; A plurality of grid preamplifiers are respectively connected to the grid voltage modules of the grid wires of the solid-state Frisch grid detector and are used for amplifying the grid induction signals generated by the grid wires.

3. The radiation imaging device based on a solid-state Frisch grating detector according to claim 2, characterized in that: It also includes a multi-channel acquisition system connected to the anode preamplifier, the cathode preamplifier, multiple grid preamplifiers and the host computer, and is used to transmit the amplified anode sensing signal, cathode sensing signal and grid sensing signal to the host computer.

4. The radiation imaging device based on a solid-state Frisch grating detector according to claim 1, characterized in that: The gate includes at least one gate unit, and the gate unit includes a plurality of grid wires arranged separately on the same horizontal line, and the extension direction of each grid wire is perpendicular to the carrier drift direction; When the number of gate units is greater than 1, the multiple gate units are separately arranged in sequence from bottom to top or from top to bottom along the carrier drift direction, and the angle between the extension directions of the grid wires in each gate unit is 0°~180°.

5. The radiation imaging device based on a solid-state Frisch grating detector according to claim 4, characterized in that: The anode or cathode includes a plurality of discretely arranged strip electrodes, each strip electrode extending in a direction perpendicular to the carrier drift direction, and is used to collect carriers and generate an anode sensing signal or a cathode sensing signal; or, The anode or cathode includes a plurality of pixel electrodes arranged in an array on the same horizontal line, and is used to collect carriers and generate an anode sensing signal or a cathode sensing signal.

6. The radiation imaging device based on a solid-state Frisch grating detector according to claim 1, characterized in that: The grid wire is composed of a gate metal and an insulating layer wrapping the gate metal, and the thickness of the insulating layer is 0-1 mm; and / or, The cross-sectional shape of the grid wire is circular, rectangular or irregular polygonal; and / or, The semiconductor detection material of the solid-state Frisch gate detector is a halide perovskite semiconductor, a halide semiconductor, a sulfide semiconductor or a sulfur halide semiconductor; Among them, halide perovskite semiconductors include three-dimensional perovskite, two-dimensional perovskite, one-dimensional perovskite, zero-dimensional perovskite and double perovskite, and the three-dimensional perovskite is A1B1X13, wherein A1 is one or more of Na, K, Rb, Cs, Cu, Tl and H3O, B1 is one or more of Pb, Si, Ge, Sn, Mg, Ca, Sr, Ba, Zn, Cd and Hg, and X1 is F, Cl, Br, I, BF4, HCOO, OH, One or more of CN, SCN, NCS, SH, NO3 and H2POO; two-dimensional perovskite is A23B22X29, wherein A2 is one or both of Cs and Rb, B2 is one or both of Sb and Bi, and X2 is one or more of F, Cl, Br and I; zero-dimensional perovskite is Cs3Bi2I9, Cs2TeI6, Cs2TeBr6 or Cs2TeCl6; double perovskite is Cs2AgBiBr6; The halide semiconductor is HgI2 or TlBr; Sulfide semiconductor is M1 x Q y , wherein M1 is one or more of Zn, Cd, and Hg, and Q is one or more of S, Se, and Te; Sulfur halide semiconductor is M2 x Q y X2 z , wherein M2 is one or more of Zn, Cd, Hg, Pb, Bi, Tl, Q is one or more of S, Se, Te, and X2 is one or more of F, Cl, Br, and I.

7. The radiation imaging device based on a solid-state Frisch grating detector according to claim 1, characterized in that: The host computer obtains the drift time and position information of the carriers based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal and gate sensing signal using the center of gravity method, difference method or fitting method.

8. The radiation imaging device based on a solid-state Frisch grating detector according to claim 7, characterized in that: The center of gravity method is used to obtain the drift time and position information of the carriers based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal, and gate sensing signal, including: Based on the anode sensing signal and the cathode sensing signal, obtaining the start time, end time and amplitude of the gate sensing signal; Based on the gate sensing signal generated by each of the adjacent grid wires, a first amplitude difference of the carrier drifting on the anode side, a second amplitude difference of the carrier drifting on the cathode side, and a carrier gate-crossing time are calculated; The anode side coordinate and cathode side coordinate of the carrier are calculated based on the first amplitude difference and the second amplitude difference of the two gate sensing signals; wherein the anode side coordinate calculation formula of the carrier is: ， in, represents the anode-side coordinate of the carrier; Indicates the first amplitude difference of the gate sensing signal generated by the first grid wire among the adjacent grid wires; represents the first amplitude difference of the gate sensing signal generated by the second grid wire among the adjacent grid wires; The calculation formula for the cathode side coordinate of the carrier is: ， in, represents the cathode-side coordinate of the carrier; Indicates a second amplitude difference of the gate sensing signal generated by the first grid wire among the adjacent grid wires; It represents the second amplitude difference of the gate sensing signal generated by the second grid wire among the adjacent grid wires.

9. The radiation imaging device based on a solid-state Frisch grating detector according to claim 1, characterized in that: The invention also includes a shielding box, in which a solid-state Frisch grid detector and a preamplifier module are placed, so that the shielding box is used to reduce electromagnetic interference during radiation imaging.

10. A radiation imaging method based on a solid-state Frisch grating detector, characterized in that: The method is applied to the radiation imaging device based on the solid-state Frisch grating detector according to any one of claims 1 to 9, comprising: A ray source is used to generate rays and act on a solid-state Frisch grid detector; The semiconductor detection material in the solid-state Frisch grid detector interacts with the radiation to generate carriers, and the electric field formed by the anode and cathode causes the carriers to drift. When the carriers pass between two adjacent grid wires in the grid, the two adjacent grid wires generate a grid sensing signal. A preamplifier module is used to amplify the anode sensing signal, cathode sensing signal and grid sensing signal output by the solid-state Frisch grid detector; The host computer obtains the drift time and position information of the carriers based on the time and amplitude of the amplified anode sensing signal, cathode sensing signal and gate sensing signal, thereby obtaining the deposition time and position information of the rays.

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