Three-dimensional position sensitive scintillation detector and scintillation imaging detector

Abstract

The application provides a three-dimensional position sensitive scintillation detector and a scintillation imaging detector, each unit element comprising a scintillation crystal and two one-dimensional position sensitive silicon photomultipliers coupled to opposite ends of the scintillation crystal, and the light receiving surfaces of the two one-dimensional position sensitive silicon photomultipliers are oppositely arranged and connected to the two ends of the scintillation crystal respectively; each light receiving surface is provided with an electrode structure, and each electrode structure comprises a plurality of front electrodes parallel to each other; and the electrode structures on the light receiving surfaces of the two one-dimensional position sensitive silicon photomultipliers are perpendicular to each other. The application can reduce the number of readout channels of the three-dimensional position sensitive scintillation detector and the cost of readout electronics while manufacturing a large-area array scintillation imaging detector, and can ensure that the spatial resolution of each position is uniform, thereby improving the imaging effect.

Description

Technical Field

[0001] This invention relates to the field of detector technology, and more particularly to three-dimensional position-sensitive scintillation detectors and scintillation imaging detectors. Background Technology

[0002] Scintillation imaging detectors, composed of scintillation crystal arrays and photoelectric conversion elements, are widely used in various applications due to their excellent performance in terms of time response, position resolution, and detection efficiency. Currently, the conventional design involves coupling a scintillation crystal array with a silicon photomultiplier (SiPM) array to create a large-area scintillation imaging detector. For example, the paper "Development of ultrahigh resolution Si-PM-based PET system using 0.32mm pixel scintillators" published by Seiichi Yamamoto et al. in 2013 in *Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment*. However, the size of the SiPM limits the spatial resolution of the scintillation imaging depth detector, and the large number of readout channels increases the cost of readout electronics and reduces reliability.

[0003] To address the issue of multiple readout channels, some researchers have proposed using optical guides and encoding circuits to achieve position resolution. For example, the paper "Depth of interaction measurement in gamma ray imaging detectors with continuous scintillation crystals" presented by Ch.W. Lerche et al. in the 2003 Nuclear Science Symposium proceedings illustrates this. While achieving the design goal, it resulted in reduced position resolution, increased decoding difficulty, and deteriorated temporal characteristics. In practical applications, to effectively prevent rays from penetrating the crystal and improve sensitivity, the scintillation crystal needs a certain thickness, which introduces drawbacks. Furthermore, positron emission tomography (PET) imaging introduces a parallax effect, leading to reduced image resolution and resolution inhomogeneity. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a three-dimensional position-sensitive scintillation detector and a scintillation imaging detector to eliminate or improve one or more defects existing in the prior art.

[0005] One aspect of the present invention provides a three-dimensional position-sensitive scintillation detector, comprising: a unit element;

[0006] Each of the unit elements includes: a scintillation crystal and two one-dimensional position-sensitive silicon photomultipliers respectively coupled to opposite ends of the scintillation crystal, wherein the light-receiving surfaces of the two one-dimensional position-sensitive silicon photomultipliers are arranged opposite each other and respectively connected to the two ends of the scintillation crystal; each light-receiving surface is provided with an electrode structure, and each electrode structure includes a plurality of mutually parallel front electrodes; the electrode structures on the light-receiving surfaces of the two one-dimensional position-sensitive silicon photomultipliers are perpendicular to each other.

[0007] In some embodiments of the present invention, there are multiple unit elements, and the unit elements are arranged sequentially to form a three-dimensional position-sensitive scintillation detector array.

[0008] In some embodiments of the present invention, the electrode structures on the one-dimensional position-sensitive silicon photomultiplier at the same end of each of the unit elements are arranged in parallel sequentially.

[0009] In some embodiments of the present invention, the front electrodes on the one-dimensional position-sensitive silicon photomultiplier at the same end of each of the unit elements have the same arrangement structure; and each row of unit elements is spliced ​​side by side according to the front electrodes on the one-dimensional position-sensitive silicon photomultiplier at the same end.

[0010] In some embodiments of the present invention, the front electrodes of the one-dimensional position-sensitive silicon photomultiplier at the same end of each row of unit elements are connected in parallel, and introduced into the same readout channel of the three-dimensional position-sensitive scintillation detector array.

[0011] In some embodiments of the present invention, adjacent front electrodes in the one-dimensional position-sensitive silicon photomultiplier at the same end of two adjacent rows of unit elements are introduced into the same readout channel of the three-dimensional position-sensitive scintillation detector array.

[0012] In some embodiments of the present invention, the front electrode includes a metal block lead-out electrode and a metal strip connected to the metal block lead-out electrode.

[0013] In some embodiments of the present invention, the scintillation crystal is a strip scintillation crystal, a sheet scintillation crystal, or a block scintillation crystal.

[0014] In some embodiments of the present invention, the three-dimensional position of the unit element includes: a position perpendicular to the direction of the one-dimensional position-sensitive silicon photomultiplier; and a position in a plane parallel to the one-dimensional position-sensitive silicon photomultiplier, respectively perpendicular to the direction of the electrode structure in the two one-dimensional position-sensitive silicon photomultipliers.

[0015] Another aspect of the present invention provides a scintillation imaging detector, including the above-mentioned three-dimensional position-sensitive scintillation detector and an imaging unit connected to the one-dimensional position-sensitive silicon photomultiplier; the imaging unit is used to perform imaging based on the three-dimensional position information measured by the three-dimensional position-sensitive scintillation detector.

[0016] The three-dimensional position-sensitive scintillation detector and scintillation imaging detector of the present invention, through a one-dimensional position-sensitive silicon photomultiplier coupled to the front electrodes arranged in parallel at opposite ends of the scintillation crystal, can significantly reduce the number of readout channels of the three-dimensional position-sensitive scintillation detector and reduce the cost of readout electronics while manufacturing a large-area array of scintillation imaging detectors; and can ensure uniform spatial resolution at each position, thereby improving the imaging effect.

[0017] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows, and will also become apparent in part to those skilled in the art upon studying the description, or may be learned by practice of the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures specifically pointed out in the description and drawings.

[0018] Those skilled in the art will understand that the objectives and advantages achievable with the present invention are not limited to those specifically described above, and that the above and other objectives achievable with the present invention will become clearer from the following detailed description. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, are not intended to limit the scope of the invention. The components in the drawings are not drawn to scale but are merely illustrative of the principles of the invention. For ease of illustration and description of certain parts of the invention, corresponding portions in the drawings may be enlarged, i.e., may appear larger relative to other components in an exemplary device actually manufactured according to the invention. In the drawings:

[0020] Figure 1 This is a structural diagram of a three-dimensional position-sensitive scintillation detector.

[0021] Figure 2 This is a structural diagram of a one-dimensional position-sensitive silicon photomultiplier detector with two parallel front electrodes in one embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of position measurement for a one-dimensional position-sensitive silicon photomultiplier detector with two parallel front electrodes in one embodiment of the present invention.

[0023] Figure 4 This is a structural diagram of a unit element using a bulk scintillation crystal in one embodiment of the present invention.

[0024] Figure 5 This is a structural diagram of a unit element using a sheet-like scintillation crystal in another embodiment of the present invention.

[0025] Figure 6 This is a structural diagram of a unit element using a strip-shaped scintillation crystal in another embodiment of the present invention.

[0026] Figure 7 This is a schematic diagram of the splicing of a one-dimensional positional silicon photomultiplier detector array in one embodiment of the present invention.

[0027] Figure 8 This is a schematic diagram of the splicing of a one-dimensional position silicon photomultiplier detector array according to another embodiment of the present invention.

[0028] Figure 9This is a cross-sectional view of a one-dimensional position-sensitive silicon photomultiplier detector element in one embodiment of the present invention.

[0029] In the figure, 1-scintillation crystal, 2-one-dimensional position-sensitive silicon photomultiplier, 21-metal block lead-out electrode, 22-metal strip, 23-antireflective coating, 24-silicon dioxide, 25-P-type heavily doped region, 26-N-type heavily doped region (high electric field region), 27-N-type epitaxial layer, 28-N-type low-resistivity substrate material, 29-back electrode. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments and accompanying drawings. Here, the illustrative embodiments and descriptions of this invention are used to explain the invention, but are not intended to limit the invention.

[0031] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0032] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, element, or component, but does not exclude the presence or addition of one or more other features, elements, or components.

[0033] It should also be noted that, unless otherwise specified, the term "connection" in this article can refer not only to a direct connection, but also to an indirect connection involving an intermediary.

[0034] In the following description, embodiments of the invention will be illustrated with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or similar parts, or the same or similar steps.

[0035] Existing technologies employ a dual-end readout method to measure reflection depth. Optical sensors are coupled to both ends of a scintillation crystal to receive fluorescence emitted by the crystal. The visible light photons generated by the fluorescence propagate is isotropic. During their propagation within the crystal, photons are either absorbed by the scintillation crystal or escape from its sides. The reflection depth of the photons within the crystal is determined by the signal difference detected by the optical sensors at both ends. Simultaneously, photoelectric sensors coupled to both ends of the scintillation crystal measure the X and Y coordinates, thereby achieving three-dimensional position information imaging. The photoelectric sensors can be selected from silicon photomultiplier tube (SiPM) arrays or two-dimensional position-sensitive silicon photomultiplier tubes (2D-PS-SiPM) with intrinsic position resolution.

[0036] When using a SiPM array as a photoelectric sensor, and employing a SiPM and a scintillation crystal in a one-to-one coupling manner as a single position detection device, each device is treated as a pixel. When pursuing high resolution, pixel size becomes a limiting factor. When fabricating large-area detectors, smaller pixels, excessive readout channels, and numerous back-end readout circuits reduce the overall system reliability and increase costs, thus limiting the fabrication of large-area detectors. According to the paper "Performance comparison of depth-encoding detectors based on dual-ended readout and different SiPMs for high-resolution PET applications" published by Du J et al. in "Physics in Medicine and Biology" in 2019, while the resistor network encoding readout method solves the problem of multiple readout channels, the resolution limiting factor changes from pixel size to the complexity of the encoding circuit. When using a simple circuit, the crystal resolution becomes uneven, and the resolution capability of the edge crystals decreases. When using a complex circuit, although the above phenomena are improved, the difficulty of subsequent decoding processing increases. Due to the addition of resistors or capacitors, the time characteristics of the detector also deteriorate, as well as crosstalk between channels, thus affecting the resolution.

[0037] When using 2D-PS-SiPM as the photoelectric sensor, for a small-area, double-ended readout detector, the total number of readout channels (8) is still within an acceptable range. However, if a large-area detector is required, an N*N array can be used, resulting in 8N readout channels for the double-ended readout. 2When using a single-channel independent output method, the problem of too many readout channels and excessive electronic costs arises. While using a capacitor network to multiplex channels for readout, existing research, such as Du J et al.'s 2019 paper "ASimpleCapacitive Charge-Division Readout for Position-Sensitive Solid-State Photomultiplier Arrays" published in *IEEE Transactions on Nuclear Science*, uses smaller capacitors to decrease the pulse height, reducing pulse stacking in high-count mode and also shortening the rise and fall times, but requiring a high-gain amplifier circuit. Using larger capacitors increases the pulse height but causes pulse stacking, affecting position resolution. This readout method is currently only implemented in small arrays; there is no relevant research on large arrays.

[0038] Based on the above analysis of existing technologies, this invention addresses the following problems: in the one-to-one coupling method between the photoelectric sensor and the scintillation crystal, the resolution of the photoelectric sensor array is limited by pixel size, there are multiple readout channels, and the readout electronics are complex; in the resistive network encoding readout method, the resolution is affected by the complexity of the encoding circuit, the decoding method is complex, and channel crosstalk causes a decrease in resolution; and two-dimensional position-sensitive silicon photomultipliers are not suitable for fabricating large-area detectors. This invention provides a three-dimensional position-sensitive scintillation detector, comprising a unit element, such as... Figure 1 As shown; each of the unit elements includes: a scintillation crystal 1 and two one-dimensional position-sensitive silicon photomultipliers 2 respectively coupled to opposite ends of the scintillation crystal, and the light-receiving surfaces of the two one-dimensional position-sensitive silicon photomultipliers 2 are arranged opposite each other and respectively connected to the two ends of the scintillation crystal 1; each of the light-receiving surfaces is provided with an electrode structure, and each of the electrode structures includes mutually parallel front electrodes; the electrode structures on the light-receiving surfaces of the two one-dimensional position-sensitive silicon photomultipliers 2 are perpendicular to each other.

[0039] The three-dimensional position of the unit element in the above-mentioned three-dimensional position-sensitive scintillation detector includes: a position perpendicular to the direction of the one-dimensional position-sensitive silicon photomultiplier; and a position in a plane parallel to the one-dimensional position-sensitive silicon photomultiplier, perpendicular to the direction of the electrode structure in each of the two one-dimensional position-sensitive silicon photomultipliers.

[0040] The working principle of the unit element in the above-mentioned three-dimensional position-sensitive scintillation detector is as follows: X-rays or gamma rays are directed at positions in the scintillation crystal 1 other than those coupled with one-dimensional position-sensitive silicon photomultipliers 2; using the one-dimensional position-sensitive silicon photomultipliers 2 coupled to opposite ends of the scintillation crystal 1, the position information of the X-rays or gamma rays in the scintillation crystal 1 in the direction perpendicular to the one-dimensional position-sensitive silicon photomultipliers 2 is obtained through the principle of double-ended readout (hereinafter, the direction perpendicular to the one-dimensional position-sensitive silicon photomultipliers is referred to as the Z direction); using two one-dimensional position-sensitive silicon photomultipliers 2 with mutually perpendicular electrode structures, the position information in the direction perpendicular to the electrode structure in their respective one-dimensional position-sensitive silicon photomultipliers 2 is measured (hereinafter, the directions perpendicular to the electrode structure in their respective one-dimensional position-sensitive silicon photomultipliers are referred to as the X direction and the Y direction, respectively).

[0041] In one or more embodiments of this application, the front electrode structure of the unit element in the three-dimensional position-sensitive scintillation detector is as follows: Figure 2 As shown, the photoelectric converter has two parallel front electrodes on its light-receiving surface. A schematic diagram illustrating the principle of X-direction position information calculation during the operation of this unit is shown below. Figure 3 As shown, the point with coordinates (x, y) represents the position of the incident photon. The one-dimensional position-sensitive silicon photomultiplier 2 operates at its breakdown voltage. The avalanche charge triggered by the incident photon is distributed between cathode 1 and cathode 2 through a continuous P++ resistor layer. Taking the center of photosensitive device 2 as the origin, the centroid position of the triggered photosensitive device 2 or the centroid position of the incident photon in the X direction is obtained. In one embodiment, the centroid position of the incident photon in the X direction is calculated according to the principle formula of resistor shunting. The principle formula of resistor shunting is:

[0042]

[0043] Where L is the distance between the two front electrodes in the one-dimensional position-sensitive silicon photomultiplier, Q1 and Q2 are the height or area of ​​the output pulses of cathode 1 and cathode 2, respectively, and K is the optimization coefficient, which is used to reflect the influence of the load and the square metal electrode, and its value can be obtained by calibration.

[0044] In another embodiment, the center position of the incident photon in the X direction is calculated using a method similar to time-of-flight: Based on the known conditions: the distance L between the two front electrodes in the one-dimensional position-sensitive silicon photomultiplier 2, the generation time T0 of the incident photon, and the time points T1 and T2 when the pulse signal generated by the incident photon arrives at cathode 1 and cathode 2, the centroid position of the incident photon in the X direction can be calculated.

[0045]

[0046]

[0047]

[0048] Wherein, V represents the effective transmission speed of the pulse signal, which is obtained by measuring the incident points T1 and T2 with different known x coordinates and then performing linear fitting.

[0049] The centroid position of the incident photon in the Y direction is obtained using the same calculation method as in the X direction by a one-dimensional position-sensitive silicon photomultiplier at the other end of the scintillation crystal 1.

[0050] The centroid position of the incident photon in the Z direction can be calculated using the total pulse amplitude or total area output by the two one-dimensional position-sensitive silicon photomultipliers 2:

[0051]

[0052] Wherein, S1 represents the total pulse amplitude or total area output by the one-dimensional position-sensitive silicon photomultiplier at one end of the scintillation crystal; S2 represents the total pulse amplitude or total area output by the one-dimensional position-sensitive silicon photomultiplier at the other end of the scintillation crystal.

[0053] The centroid position of the incident photon in the Z-direction can also be determined using the time-of-flight method. When the incident photon strikes a point on the scintillation crystal 1, that point generates a luminescence center. The Z-axis coordinate is determined by the time difference (T2-T1) between the pulse signals generated by the one-dimensional position-sensitive silicon photomultiplier 2 at both ends of the scintillation crystal 1 and the cathodes 1 and 2.

[0054]

[0055] Where c is the speed of light and n is the refractive index of the scintillator.

[0056] In one or more embodiments of this application, two front electrodes of a 2D PS-SiPM in one direction are connected in series to be used as a one-dimensional position-sensitive silicon photomultiplier detector with intrinsic position resolution capability.

[0057] In one or more embodiments of this application, the scintillation crystal 1 may be a strip-shaped scintillation crystal, a sheet-shaped scintillation crystal, or a block-shaped scintillation crystal. When a block-shaped scintillation crystal is selected as the scintillation crystal 1, the structure of the unit element is as follows: Figure 4 As shown, the light-receiving surface of the one-dimensional position-sensitive silicon photomultiplier has the same area and shape as one end of the blocky scintillation crystal connected to it. When a sheet-like scintillation crystal is selected as the scintillation crystal 1, the structure of the unit element is as follows. Figure 5As shown, the device comprises multiple sheet-like scintillation crystals arranged side-by-side, such that the light-receiving surface of the one-dimensional position-sensitive silicon photomultiplier has the same area and shape as one end of the adjacent sheet-like scintillation crystals. When a strip-shaped scintillation crystal is selected as scintillation crystal 1, the structure of the unit element is as follows. Figure 6 As shown, it includes multiple strip-shaped scintillation crystals connected side by side. The light-receiving surface of the one-dimensional position-sensitive silicon photomultiplier has the same area and shape as one end of the side-by-side strip-shaped scintillation crystals connected to it.

[0058] In one or more embodiments of this application, each of the electrode structures includes a plurality of parallel front electrodes according to the resolution requirements in practical applications; the resolution of the three-dimensional position-sensitive scintillation detector is improved by increasing the number of front electrodes in each electrode structure.

[0059] In one or more embodiments of this application, the one-dimensional position-sensitive silicon photomultiplier is packaged in a packaging substrate, and the front electrode and back electrode of the photoelectric converter are both led out from the packaging substrate on the back surface of the one-dimensional position-sensitive silicon photomultiplier. The packaging method includes various packaging methods such as through-silicon via (TSV) packaging technology, wire bonding technology, flip-chip technology, or narrow dead-edge technology. When manufacturing a large-area array of three-dimensional position-sensitive scintillation detectors using the above-mentioned three-dimensional position-sensitive scintillation detector, in one or more embodiments of this application, there are multiple unit elements, and each of the unit elements is arranged sequentially to form a three-dimensional position-sensitive scintillation detector array. In the three-dimensional position-sensitive scintillation detector array, the electrode structures on the one-dimensional position-sensitive silicon photomultiplier 2 at the same end of each unit element are arranged in parallel, such that the front electrode directions of the one-dimensional position-sensitive silicon photomultiplier 2 at the same end of the three-dimensional position-sensitive scintillation detector array are the same; and each row of unit elements is spliced ​​side by side according to the front electrodes on the one-dimensional position-sensitive silicon photomultiplier 2 at the same end; the arrangement structure of the front electrodes on the one-dimensional position-sensitive silicon photomultiplier 2 at the same end of each unit element is the same, the number of front electrodes on each one-dimensional position-sensitive silicon photomultiplier 2 at the same end of the three-dimensional position-sensitive scintillation detector array, and the arrangement position of each front electrode on each one-dimensional position-sensitive silicon photomultiplier 2 are all the same.

[0060] In one or more embodiments of this application, the readout channel in the three-dimensional position-sensitive scintillation detector array is led out as follows: the front electrodes of the one-dimensional position-sensitive silicon photomultiplier 2, which are spliced ​​side by side at the same end of each row of unit elements, are connected in parallel and introduced into the same readout channel of the three-dimensional position-sensitive scintillation detector array. For example... Figure 7As shown, each one-dimensional position-sensitive silicon photomultiplier 2 in the unit element of this three-dimensional position-sensitive scintillation detector array has two parallel front electrodes, and the front electrodes are located at the edge positions on opposite sides of the one-dimensional position-sensitive silicon photomultiplier 2. In the three-dimensional position-sensitive scintillation detector array composed of these unit elements, the front electrodes of the one-dimensional position-sensitive silicon photomultiplier 2 at the same end of each row of unit elements are connected in parallel and introduced into the same readout channel. Two readout channels are led out from the same end of each row of unit elements in this three-dimensional position-sensitive scintillation detector array; when the above readout channel leadout method is applied to a three-dimensional position-sensitive scintillation detector array with N rows of unit elements arranged side by side, there are a total of 4N readout channels at both ends of the three-dimensional position-sensitive scintillation detector array.

[0061] In one or more embodiments of this application, the readout channel in the three-dimensional position-sensitive scintillation detector array is led out as follows: the front electrodes of the one-dimensional position-sensitive silicon photomultipliers 2 at the same end of each row of unit elements are connected in parallel to lead out the same readout channel of the three-dimensional position-sensitive scintillation detector array; simultaneously, the adjacent front electrodes of the one-dimensional position-sensitive silicon photomultipliers 2 at the same end of two adjacent rows of unit elements are jointly introduced into the same readout channel of the three-dimensional position-sensitive scintillation detector array. For example... Figure 8 As shown, each one-dimensional position-sensitive silicon photomultiplier 2 in the unit element of this three-dimensional position-sensitive scintillation detector array has two parallel front electrodes, and the front electrodes are located at the edge positions on opposite sides of the one-dimensional position-sensitive silicon photomultiplier 2. In the three-dimensional position-sensitive scintillation detector array composed of these unit elements, the front electrodes of the one-dimensional position-sensitive silicon photomultiplier 2 at the same end of each row of unit elements are connected in parallel and introduced into the same readout channel; at the same time, the adjacent front electrodes of the one-dimensional position-sensitive silicon photomultiplier 2 at the same end of two adjacent rows of unit elements are introduced into the same readout channel. When the above readout channel lead-out method is applied to a three-dimensional position-sensitive scintillation detector array with N rows of unit elements arranged side by side, there are a total of (2N+1) readout channels at both ends of the three-dimensional position-sensitive scintillation detector array.

[0062] In one or more embodiments of this application, the lead-out structure of the readout channel in the above-mentioned three-dimensional position-sensitive scintillation detector array is as follows: a PCB (printed circuit board) base plate for splicing the three-dimensional position-sensitive scintillation detector array is prepared according to actual needs, and the packaged one-dimensional position-sensitive silicon photomultiplier is soldered into the PCB base plate. The connection between the front electrode and the back electrode in the corresponding photoelectric sensor is realized through the traces in the PCB base plate, thereby forming the readout channel of the three-dimensional position-sensitive scintillation detector array.

[0063] In one or more embodiments of this application, each one-dimensional position-sensitive silicon photomultiplier 2 in the unit element of the three-dimensional position-sensitive scintillation detector array is provided with three mutually parallel front electrodes. Two of the mutually parallel front electrodes are located at the edge positions on opposite sides of the one-dimensional position-sensitive silicon photomultiplier 2, and the other front electrode is located between the two edge front electrodes. The distance between the front electrode located in the middle position of each one-dimensional position-sensitive silicon photomultiplier 2 and its two edge front electrodes is the same. In the three-dimensional position-sensitive scintillation detector array composed of these unit elements, the way the front electrodes at the edge positions are led out to the readout channel is the same as in the above embodiments, and therefore will not be repeated here. The front electrodes at the middle positions of the one-dimensional position-sensitive silicon photomultiplier 2 at the same end of the same row of unit elements are connected in parallel and led out to the same readout channel of the three-dimensional position-sensitive scintillation detector array. When applied to a three-dimensional position-sensitive scintillation detector array with N rows of unit elements arranged side-by-side, the three-dimensional position-sensitive scintillation detector array has a total of 6N or (4N+2) readout channels at both ends.

[0064] It should be noted that the number of mutually parallel front electrodes in each of the one-dimensional position-sensitive silicon photomultipliers in the three-dimensional position-sensitive scintillation detector array of this application is not limited to the range in the above embodiments. The number of mutually parallel front electrodes in each of the one-dimensional position-sensitive silicon photomultipliers can also be set according to the resolution requirements of actual applications. The more front electrodes in each of the one-dimensional position-sensitive silicon photomultipliers in the three-dimensional position-sensitive scintillation detector, the higher the resolution of the corresponding three-dimensional position-sensitive scintillation detector. By setting the arrangement of unit elements in the three-dimensional position-sensitive scintillation detector array and the number and structure of front electrodes in the one-dimensional position-sensitive silicon photomultipliers of each unit element, this application enables the three-dimensional position-sensitive scintillation detector array to achieve sub-millimeter level spatial resolution.

[0065] In one or more embodiments of this application, the front electrode includes a metal block lead-out electrode 21 and a metal strip 22 connected to the metal block lead-out electrode 21. Correspondingly, in one or more embodiments of this application, the structure of the one-dimensional position-sensitive silicon photomultiplier detector is as follows: Figure 9As shown, an N-type epitaxial layer 27 (or epitaxial wafer) is formed on an N-type low-resistivity silicon substrate material 28 (such as a single-sided polished, crystal-oriented silicon substrate 9) through epitaxial growth. Multiple N-type heavily doped regions 26 (high electric field regions) arrays are formed on the N-type epitaxial layer 27 through a doping process. A P-type heavily doped layer 25 is formed above the N-type heavily doped region 26 array. The P-type heavily doped layer 25 serves as a uniform and continuous heavily doped silicon resistive layer connecting the surfaces of all avalanche photodiodes. This uniform and continuous heavily doped silicon resistive layer can be used as a shunt resistor for a one-dimensional position-sensitive silicon photomultiplier detector. The N-type heavily doped region 26 array and the P-type heavily doped layer 25 are adjacent to form a PN junction array, corresponding to the formation of multiple avalanche photodiodes. Each avalanche photodiode is isolated from the deeper depletion region of the surrounding PN junction. An antireflective coating 23 is formed on the upper surface of the P-type heavily doped layer 25 in the region corresponding to the avalanche photodiode array, which serves to protect and enhance the light transmission. A front electrode is formed around the antireflective coating 23 on the surface of the edge portion of the P-type heavily doped layer 25, which is in contact with the P-type heavily doped layer 25. The front electrode includes a metal block lead-out electrode 21 and a metal strip 22 connected to the metal block lead-out electrode 21. The metal strip 22 has metal lead-out electrodes 21 at multiple predetermined positions, and the metal strip 22 is in contact with the P-type heavily doped layer 25. A silicon dioxide layer 24 is used for isolation between the front electrode and the N-type epitaxial layer 27. The back electrode 29 is located on the outer surface of the back silicon substrate of the one-dimensional position-sensitive silicon photomultiplier detector body. The front electrode can be used to electrically connect to the lead-out electrodes of a preamplifier or analog-to-digital converter (ADC) chip, while the back electrode 29 serves as the common voltage bias terminal for all avalanche photodiodes and the lead-out terminal for the total output signal current.

[0066] In the above embodiments, when a three-dimensional position-sensitive scintillation detector array is composed of multiple unit elements, the corresponding front electrodes are led out to the same output channel through the metal segment lead-out electrodes. The method for selecting the front electrodes led out to the same output channel has been given in the above embodiments and will not be repeated here.

[0067] The principle of generating the three-dimensional position of the three-dimensional position sensitive scintillation detector array comprising multiple unit elements in this application is as follows: the three-dimensional positions of each unit element are arranged according to the lead-out structure of the readout channel in the three-dimensional position sensitive scintillation detector array to obtain the three-dimensional position of the three-dimensional position sensitive scintillation detector array.

[0068] Current methods exist for generating the three-dimensional position of three-dimensional position-sensitive scintillation detector arrays composed of multiple unit elements. Although the three-dimensional position-sensitive scintillation detector array composed of unit elements described in this application has a larger area and scale than the existing three-dimensional position-sensitive scintillation detector arrays, the calculation principles and methods are the same. Since the technical focus of this application is on the structure of the three-dimensional position-sensitive scintillation detector, the specific calculation method can be derived from the existing technology combined with the structure of this application. Therefore, the three-dimensional position calculation process of the three-dimensional position-sensitive scintillation detector array in this application will not be described in detail here.

[0069] In summary, the three-dimensional position-sensitive scintillation detector described in this application, through a one-dimensional position-sensitive silicon photomultiplier coupled to the front electrodes at opposite ends of the scintillation crystal and arranged in parallel, can significantly reduce the number of readout channels in the three-dimensional position-sensitive scintillation detector while manufacturing a large-area array of scintillation imaging detectors, thus lowering the cost of readout electronics; and it can also ensure uniform spatial resolution at each position, thereby improving the imaging effect. It solves the problem of the position resolution limitation of pixel-type detectors due to the size of the photodetector, effectively reduces the impact of parallax effects on the spatial resolution of long crystal detectors, and ensures uniform spatial resolution at each position, effectively improving the imaging effect.

[0070] Corresponding to the aforementioned three-dimensional position-sensitive scintillation detector, this application also provides a scintillation imaging detector, including the aforementioned three-dimensional position-sensitive scintillation detector and an imaging unit connected to the one-dimensional position-sensitive silicon photomultiplier. The imaging unit is used to perform imaging based on the three-dimensional position information measured by the three-dimensional position-sensitive scintillation detector. The imaging unit is respectively connected to the readout channel and the back electrode of the one-dimensional position-sensitive silicon photomultiplier 2 at each end of the three-dimensional position-sensitive scintillation detector, introducing the three-dimensional position information of the incident photons measured by the three-dimensional position-sensitive scintillation detector into the imaging unit, which then performs imaging based on the measured three-dimensional position information. Since the connection structure of the three-dimensional position-sensitive scintillation detector and the imaging unit in the scintillation imaging detector of this application is no different from that in the prior art, it will not be described in detail here.

[0071] It should be clarified that this invention is not limited to the specific configurations and structures described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. Those skilled in the art can make various changes, modifications, and additions after understanding the spirit of this invention.

[0072] In this invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or in place of features of other embodiments.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations of the embodiments of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-dimensional position-sensitive scintillation detector, characterized in that, include: Unit component; Each of the unit elements includes: a scintillation crystal and two one-dimensional position-sensitive silicon photomultipliers respectively coupled to opposite ends of the scintillation crystal, wherein the light-receiving surfaces of the two one-dimensional position-sensitive silicon photomultipliers are arranged opposite each other and respectively connected to the two ends of the scintillation crystal; Each of the light-receiving surfaces is provided with an electrode structure, and each of the electrode structures includes mutually parallel front electrodes; The electrode structures on the light-receiving surfaces of the two one-dimensional position-sensitive silicon photomultipliers are perpendicular to each other; The front electrodes of the one-dimensional position-sensitive silicon photomultiplier at the same end of each row of unit elements are connected in parallel, introducing the same readout channel into the three-dimensional position-sensitive scintillation detector array.

2. The three-dimensional position-sensitive scintillation detector according to claim 1, characterized in that, There are multiple unit elements, and the unit elements are arranged sequentially to form a three-dimensional position-sensitive scintillation detector array.

3. The three-dimensional position-sensitive scintillation detector according to claim 2, characterized in that, The electrode structures on the one-dimensional position-sensitive silicon photomultiplier at the same end of each of the unit elements are arranged in parallel sequentially.

4. The three-dimensional position-sensitive scintillation detector according to claim 2, characterized in that, The front electrodes on the one-dimensional position-sensitive silicon photomultiplier at the same end of each of the unit elements have the same arrangement structure; and each row of unit elements is spliced ​​side by side according to the front electrodes on the one-dimensional position-sensitive silicon photomultiplier at the same end.

5. The three-dimensional position-sensitive scintillation detector according to claim 1, characterized in that, The adjacent front electrodes of the one-dimensional position-sensitive silicon photomultiplier at the same end of the unit elements in two adjacent rows are introduced into the same readout channel of the three-dimensional position-sensitive scintillation detector array.

6. The three-dimensional position-sensitive scintillation detector according to claim 1, characterized in that, The front electrode includes a metal block lead-out electrode and a metal strip connected to the metal block lead-out electrode.

7. The three-dimensional position-sensitive scintillation detector according to claim 1, characterized in that, The scintillation crystal is a strip-shaped scintillation crystal, a sheet-shaped scintillation crystal, or a block-shaped scintillation crystal.

8. The three-dimensional position-sensitive scintillation detector according to claim 1, characterized in that, The three-dimensional position of the unit element includes: The position perpendicular to the direction of the one-dimensional position-sensitive silicon photomultiplier; And, in a plane parallel to the one-dimensional position-sensitive silicon photomultiplier, the positions are respectively perpendicular to the directions of the electrode structures in the two one-dimensional position-sensitive silicon photomultipliers.

9. A scintillation imaging detector, characterized in that, It includes a three-dimensional position-sensitive scintillation detector as described in any one of claims 1 to 8, and an imaging unit connected to the one-dimensional position-sensitive silicon photomultiplier; The imaging unit is used to create an image based on the three-dimensional position information measured by the three-dimensional position-sensitive scintillation detector.

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