High-energy particle position sensitive detector based on scintillator strips

Abstract

The invention discloses a high-energy particle position sensitive detector based on scintillator strips, and the detector is characterized in that the detector comprises a housing which is internally provided with a photoelectric device circuit board, a signal amplifier circuit board, and a scintillator strip array; the scintillator strip array comprises a plurality of cuboid scintillator strips with square end surfaces; the scintillator strips are arranged in four layers, and the scintillator strips in each layer are sequentially and adjacently arranged in parallel at an inclined angle of 45 degrees, so that the square end surfaces of the scintillator strips in the layer form a zigzag plane; two of the four layers are stacked up and down to form a first array unit, the other two layers are stacked up and down to form a second array unit, the square detection planes of the first array unit and the second array unit are parallel, and the length direction of the scintillator strips in the first array unit is perpendicular to the length direction of the scintillator strips in the second array unit; one end of each scintillator strip is connected with a photoelectric device on the photoelectric device circuit board; and the signal amplifier circuit board is connected with the photoelectric device circuit board.

Description

Technical Field

[0001] This invention belongs to the field of high-energy charged particle detection and relates to equipment for detecting high-energy charged particles and its design process. This invention has certain application prospects in nuclear technology, nuclear energy, particle physics, medical imaging and other fields. Background Art

[0002] Since the early 20th century, nuclear radiation detection technology and nuclear energy application technology have gradually become an indispensable part of modern science. Through the study of nuclear radiation, people have achieved explosive leaps in many fields of knowledge—from astronomy and cosmology to medicine, biology, and microscopic particles. It can be said that nuclear science has become the cornerstone and forefront of science in all aspects and from all angles. The development of nuclear detection technology has also achieved breakthroughs in recent decades. Initially, nuclear technology detectors were only able to detect radioactivity. Later, they gradually achieved the measurement of radioactive ray intensity, and later the measurement of individual radioactive particles. Currently, representative high-energy particle detectors include ionization chambers, multi-wire proportional chambers, scintillator detectors, semiconductor detectors, and other types. The present invention is a scintillator detector with a special structure and thus special functions.

[0003] Traditionally, the main body of a scintillation detector consists of a single scintillator, one end face of which is tightly fitted to a photoelectric amplifier device (such as a SiPM) and is completely shielded from light. The main material of the scintillator is usually polystyrene, which is doped with a fluorescent agent. Part of its surface is polished or otherwise treated. The hydrocarbon molecules of polystyrene form a stable structure by sharing π electrons, which is the basis for the scintillator to function effectively. When a charged particle or gamma ray passes through the scintillator, energy is lost through electromagnetic interaction, causing the π electrons of the molecules in the scintillator to jump from the ground state to the excited state. These electrons then release energy and return to the ground state through different pathways. In most cases, when the π electrons return from the excited state to the ground state, they emit fluorescence lasting 1 to 10 nanoseconds. The generated fluorescence indicates that a charged particle has passed through the scintillator.

[0004] After the scintillation light is generated internally, the fluorescent photons are emitted in random directions at random emission angles. Generally speaking, the refractive index of the scintillator is high, approximately 1.60. Therefore, if the surface of the scintillator is smooth, a considerable portion of the photons will be totally reflected at the interface between the scintillator and the air. A portion of the scintillator is reserved for bonding the optoelectronic device. When a material with a refractive index close to that of the scintillator is bonded to the scintillator, this portion of the light can be effectively transmitted to the optoelectronic device. Optoelectronic devices traditionally use photomultiplier tubes (PMTs), and in recent years, silicon photomultiplier tube (SiPM) technology has also been developed. This type of device can collect photons and trigger a larger electron avalanche internally, thereby converting the signal of a tiny photon into a significant electrical signal. The electrical signal needs to be further amplified and ultimately read using nuclear electronics devices.

[0005] Scintillators and optoelectronic devices have been widely used in nuclear radiation detection and high-energy particle detection. Scintillation detectors offer high sensitivity, fast response, and excellent energy resolution, enabling them to effectively capture and analyze radiation signals. Furthermore, their portability, ease of use, and low cost make them highly practical in scientific research, industry, and medicine.

[0006] However, scintillation detectors still have shortcomings compared to other detector technologies in terms of position detection. If a complete scintillator is used as the detection medium, regardless of where the high-energy particle-induced ionization occurs in the scintillator, the photons will propagate randomly throughout the scintillator, making it impossible to accurately identify the location of the initial high-energy particle ionization in the photodetector. To enable scintillation detectors to have position resolution capabilities, one approach is to treat the scintillator as individual blocks or particles and attach a photodetector to each block or particle. In this usage, scintillators are inferior to semiconductors and crystals with higher light yields and are very expensive. A second approach is to treat the scintillator as long strips, cylinders, or fibers, assembling these into an array or module, with a row of photodetectors attached to the ends of the module.

[0007] In summary, scintillator-based particle position-sensitive detection technology is highly challenging due to physical mechanisms and various constraints. The development of low-cost, high-precision scintillation detector technology remains a research challenge. Summary of the Invention

[0008] Taking into account the current difficulties in using scintillator detectors for position detection, the present invention integrates a variety of feasible technical solutions, conducts principle research, solution demonstration and system design, and thus realizes a high-energy particle position sensitive detector based on scintillator strips, which is mainly used in situations where particle position measurement is required. By optimizing the shape, arrangement and external structure of the detector, by properly arranging the position of the scintillator strips, and in conjunction with a reasonable readout method, the present invention can use plastic scintillators to achieve higher position resolution and improve its spatial resolution. In the system design, a double-layer detector configuration is introduced to realize signal output in the X and Y planes, and signal readout electronics are used to ensure the accuracy and efficiency of position detection. This high-precision scintillator detector is not only suitable for the detection of cosmic ray muons, but also provides more detailed images in medical imaging.

[0009] The technical solution of the present invention is:

[0010] A high-energy particle position sensitive detector based on scintillator strips, characterized by comprising a housing 5, wherein a photoelectric device circuit board 2, a signal amplifier circuit board 3 and a scintillator strip array 1 are arranged in the housing 5;

[0011] The scintillator strip array 1 includes a plurality of rectangular parallelepiped scintillator strips with square end faces; the scintillator strips are arranged into four layers, wherein the scintillator strips in each layer are sequentially placed adjacent to each other in parallel at an angle of 45 degrees, so that the square end faces of the scintillator strips in the layer form a serrated plane; two of the four layers are stacked up and down to form a first array unit, and the other two of the four layers are stacked up and down to form a second array unit, and the first array unit and the second array unit both have square detection planes of the same size; the first array unit and the second array unit are stacked, the square detection planes of the first array unit and the second array unit are parallel, and the length direction of the scintillator strips in the first array unit is perpendicular to the length direction of the scintillator strips in the second array unit;

[0012] One end of each of the scintillator strips is connected to a photoelectric device on the photoelectric device circuit board 2, and is used to convert the incident particle signal into a light signal and transmit it to the connected photoelectric device;

[0013] The signal amplifier circuit board 3 is connected to the photoelectric device circuit board 2 and is used to amplify the signal output by each photoelectric device; wherein, the signal output by the photoelectric device connected to each scintillator bar in the first array unit is used to calculate one coordinate value of the incident position coordinate (x, y) of the incident particle, and the signal output by the photoelectric device connected to each scintillator bar in the second array unit is used to calculate another coordinate value of the incident position coordinate (x, y) of the incident particle.

[0014] Furthermore, a heat sink 4 is provided in the housing 5 , and the heat sink 4 is arranged between the first array unit and the second array unit.

[0015] Furthermore, the heat sink 4 is a full copper heat sink; the heat sink 4 is isolated from the signal amplifier circuit board 3 and the optoelectronic device circuit board 2 by a thermally conductive insulating silicone sheet, and the top of the heat sink 4 is connected to an external water cooling component.

[0016] Furthermore, the optoelectronic device and the scintillator strip adopt the same numbering system, and the optoelectronic device and the scintillator strip to which it is connected have the same number.

[0017] Furthermore, according to the fact that the signal intensity output by the photoelectric device is proportional to the incident position of the incident particle, the incident position coordinates (x, y) of the incident particle are calculated.

[0018] Furthermore, both ends of each scintillator strip are respectively connected to a photoelectric device on the photoelectric device circuit board 2 ; the sum of the signals output by the photoelectric devices connected to both ends of the same scintillator strip is used as the detection signal of the scintillator strip.

[0019] Furthermore, the optoelectronic device of the optoelectronic device circuit board 2 is a silicon photomultiplier tube.

[0020] Furthermore, a light reflecting layer is added to the outer side of the scintillator strip after polishing to maximize signal collection.

[0021] Furthermore, the light reflecting layer is aluminum foil or an organic reflective material coating.

[0022] In the present invention, a unique scintillator arrangement method is adopted: using plastic scintillator strips with a square cross-section, each plastic scintillator strip is placed at 45° and placed next to each other in sequence to form a jagged plane, that is, the cross-section of each scintillator strip is diamond-shaped, and is arranged at a 45° angle upward / downward, and continuously superimposed in one direction. If SiPMs are attached to both sides, the signals of the two SiPMs are added when used, and the rest is the same as when using single-ended SiPMs. Silicon photomultipliers and scintillators use the same numbering system, and the numbering starts from one direction of the array to the other direction and ends in the other direction, such as Figure 1 shown.

[0023] For an incident particle perpendicular to the detector or with a small angle to the vertical direction, the particle has a greater probability of passing through the two scintillators. When the particle passes through the two scintillators, the position of the particle between the two adjacent scintillators is correlated with the charge collected between the two scintillators, such as Figure 2As shown. The charge center of gravity method is a widely used readout method for signal readout, assuming a linear relationship between the amplitude and position of the incident signal. The charge center of gravity method is a widely known and applied calculation method, and the structure of the present invention is designed to adapt to the charge center of gravity method. Therefore, for the arrangement described in the present invention, using the charge center of gravity method to calculate the incident position can achieve a high position resolution.

[0024] The advantages of the present invention are as follows:

[0025] Traditionally, using scintillators for position resolution has been extremely challenging, primarily because the scintillators themselves lack the ability to detect particle positions. The present invention proposes a design that has a high position resolution capability and is comparable to traditional scintillation detectors in other respects. The present invention optimizes the spatial arrangement of scintillators, thereby enabling the position resolution capability of scintillation detectors to exceed the limitations of their particle size. The present invention possesses high detection accuracy, a high particle recognition rate, and relatively low cost, and can become a fundamental device for particle detection technology, with potential applications in a wide range of fields, including cosmology, physics, and medicine. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the arrangement of scintillator strips of the present invention.

[0027] Figure 2 Schematic diagram of the relationship between the particle incident position and the distance of the particle in the scintillator when the particle passes through the detector group.

[0028] Figure 3 It is a schematic diagram of the overall structure of the present invention.

[0029] Reference numerals: 1 - scintillator strip array, 2 - optoelectronic device circuit board, 3 - signal amplifier circuit board, 4 - all-copper heat sink, 5 - housing. DETAILED DESCRIPTION

[0030] The present invention will be described in further detail below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0031] The key component of the present invention is a structure formed by overlapping two layers of plastic scintillator strips, such as Figure 1 As shown in the figure, each scintillator strip has a square cross-section and is arranged in parallel at a 45-degree angle, with the sides closely adjacent. These strips are arranged in a square array with a specific number and length, one in each of the X and Y directions. The scintillator strip width can be as small as 3 mm, with no maximum limit, depending on the scintillator model and manufacturing process, to meet various practical needs. In actual use, light signals are collected on one or both sides of the scintillator strip.

[0032] The overall structure of the present invention is as follows Figure 3 As shown, the scintillator bar array 1 converts particle signals into optical signals as particles pass through it. The optoelectronic device circuit board 2 is tightly connected to the scintillator bar, where the optoelectronic device converts the optical signal into a pulsed electrical signal. The signal amplifier circuit board 3 is connected to the optoelectronic device 2 and amplifies the pulsed signal so that it can be received by the back-end electronics. A full copper heat sink 4 is located between the optoelectronic device circuit board 2 and the signal amplifier circuit board 3 to remove excess heat generated by the optoelectronic device circuit board 2 and the signal amplifier circuit board 3. A housing 5 covers all of the above components to ensure light protection and mechanical strength. The optoelectronic device on the optoelectronic device circuit board 2 is a silicon photomultiplier tube.

[0033] Scintillator strips can be made from traditional polystyrene or other processes or materials. The outer surface of the strip is polished, and if necessary, a light-reflecting layer is added to maximize signal collection. The upper and lower portions of the strip are supported and encapsulated by a housing, primarily to shield the strip from light. After encapsulation, multiple strips form a square or rectangular detection surface. The outer surface of the strip can be covered with aluminum foil, organic reflective materials, or other materials to maximize light collection.

[0034] Silicon photomultiplier tubes (SPMTs) can be used to collect light outside the scintillator strips. These tubes are arranged at a 45-degree angle, mirroring the scintillator strips, and all are soldered to a single circuit board. Since the detector is already packaged, the SPMTs are located outside the detector, separate from the detector. A specialized optical fiber is used to connect the light collection components to the detector, ensuring system flexibility. The SPMTs are directly connected to the signal amplifier, where the signal is amplified after the SPMTs convert the optical signal into an electrical signal. The signal amplifier is located on a separate circuit board and connects to the PMT detector using a board-to-board connector to ensure smooth signal flow. A single wire transmits the amplified signal to external electronics and then to a computer for reading and processing. To facilitate signal transmission, a multi-channel readout connector socket is required on the amplifier circuit board, using a multi-channel signal interface with a pitch of 0.5 to 1 mm.

[0035] Both the silicon photomultiplier tube (SPMT) and the signal amplifier require an external low-voltage power supply. Therefore, a dedicated power supply channel is required in this system. The design employed in this invention utilizes a four-channel power supply connector, each containing two voltage sources and a corresponding ground line. The power supply enters from the outermost circuit board, passing through the signal amplifier circuit board and the circuit board housing the SPM tube.

[0036] Since the system generates heat during operation, an additional heat dissipation mechanism needs to be designed. The two circuit boards of the present invention have a relatively large number of components, and all need to dissipate heat, so it is not suitable to use an external cold source or internal air cooling. Therefore, a full copper heat sink 4 for heat conduction is designed between the two circuit boards and is located between the two circuit boards. A thermally conductive insulating silicone sheet is used to isolate the full copper heat sink 4 from the circuit boards. Finally, the top portion of the full copper heat sink 4 is connected to the external water-cooled components.

[0037] The above is a high position resolution particle detector invented by us based on the lateral coupling readout method of plastic scintillator. Since the present invention can collect light on both sides of the scintillator strip, single-end readout or double-end readout (double-end readout and summation as a single-end signal) can be adopted during design, so that the present invention can be adjusted according to specific application requirements. The present invention is a compact, flexible and low-cost particle position readout solution. The present invention realizes a compact and low-cost particle position readout solution by optimizing material usage and structural design. The focus of the design is to improve the position accuracy while still maintaining high performance in other aspects, and at the same time improve the adaptability of the detector in different environments to expand its scope of use. This solution provides a new option for the field of particle detection and has application prospects in many fields.

[0038] The relationship between the particle incident position and the distance of the particle in the scintillator when the particle passes through the detector group is shown in the figure below: Figure 2 As shown, x1 / x2 is approximately equal to l2 / l1, and the ratio of l2 / l1 to the signal generated by the detector is approximately equal; therefore, since the signal intensity output by the silicon photomultiplier tube is proportional to the incident position of the incident particle, the incident position coordinates (x, y) of the incident particle can be calculated using the charge center of gravity method.

[0039] While specific embodiments of the present invention have been disclosed for illustrative purposes, intended to facilitate understanding and implementation of the present invention, those skilled in the art will appreciate that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the disclosure of the preferred embodiments, and the scope of protection claimed in the present invention shall be determined by the scope of the claims.

Claims

1. A high-energy particle position sensitive detector based on scintillator strips, characterized in that: It comprises a housing (5), wherein a photoelectric device circuit board (2), a signal amplifier circuit board (3) and a scintillator strip array (1) are arranged in the housing (5); The scintillator strip array (1) comprises a plurality of rectangular parallelepiped scintillator strips with square end faces; the scintillator strips are arranged into four layers, wherein the scintillator strips in each layer are sequentially placed adjacent to each other in parallel at an inclination of 45 degrees, so that the square end faces of the scintillator strips in the layer form a sawtooth plane; two of the four layers are stacked up and down to form a first array unit, and the other two of the four layers are stacked up and down to form a second array unit, and the first array unit and the second array unit both have square detection planes of the same size; the first array unit and the second array unit are stacked, the square detection planes of the first array unit and the second array unit are parallel, and the length direction of the scintillator strips in the first array unit is perpendicular to the length direction of the scintillator strips in the second array unit; One end of each scintillator strip is connected to a photoelectric device on the photoelectric device circuit board (2) and is used for converting an incident particle signal into a light signal and then transmitting the light signal to the connected photoelectric device; The signal amplifier circuit board (3) is connected to the photoelectric device circuit board (2) and is used to amplify the signal output by each photoelectric device; wherein the signal output by the photoelectric device connected to each scintillator bar in the first array unit is used to calculate one coordinate value of the incident position coordinate (x, y) of the incident particle, and the signal output by the photoelectric device connected to each scintillator bar in the second array unit is used to calculate the other coordinate value of the incident position coordinate (x, y) of the incident particle.

2. The high-energy particle position sensitive detector according to claim 1, characterized in that: A heat sink (4) is provided in the housing (5), and the heat sink (4) is arranged between the first array unit and the second array unit.

3. The high-energy particle position sensitive detector according to claim 2, characterized in that: The heat sink (4) is a full copper heat sink; the heat sink (4) is isolated from the signal amplifier circuit board (3) and the photoelectric device circuit board (2) by a thermally conductive insulating silicone sheet, and the top end of the heat sink (4) is connected to an external water-cooling component.

4. The high-energy particle position sensitive detector according to claim 1, 2 or 3, characterized in that: The optoelectronic device and the scintillator strip adopt the same numbering system, and the optoelectronic device and the scintillator strip connected thereto have the same number.

5. The high-energy particle position sensitive detector according to claim 1, 2 or 3, characterized in that: According to the signal intensity output by the photoelectric device being proportional to the incident position of the incident particle, the incident position coordinates (x, y)。 6. The high-energy particle position sensitive detector according to claim 1, 2 or 3, characterized in that: The two ends of each scintillator strip are respectively connected to a photoelectric device on the photoelectric device circuit board (2); the sum of the signals output by the photoelectric devices connected to the two ends of the same scintillator strip is used as the detection signal of the scintillator strip.

7. The high-energy particle position sensitive detector according to claim 1, 2 or 3, characterized in that: The photoelectric device of the photoelectric device circuit board (2) is a silicon photomultiplier tube.

8. The high-energy particle position sensitive detector according to claim 1, 2 or 3, characterized in that: The outer side of the scintillator strips is polished and then a light reflecting layer is added to maximize the signal collection.

9. The high-energy particle position sensitive detector according to claim 8, characterized in that: The light reflecting layer is aluminum foil or an organic reflective material coating.

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