A Synchronous Neutron and Gamma Spectrum Acquisition and Detection System and Method Based on SiPM and CLYC Combined Detectors

Abstract

This invention discloses a neutron-gamma spectrum synchronous discrimination and acquisition system and method based on a SiPM and CLYC combined detector. In this system, the combined detection module converts incident neutrons or gamma rays into electrical pulse signals; the temperature compensation module adjusts the bias voltage according to the real-time temperature change of the SiPM array to reduce the impact of temperature drift on the detector gain; the front-end amplification and filtering module amplifies and suppresses noise in the electrical pulse signals; the ADC sampling module converts analog pulses into digital waveform data; the FPGA data processing module performs digital filtering, effective pulse judgment, long-gate integration, short-gate integration, and PSD parameter calculation on the digital waveform data, and binds the event address information, PSD parameters, and energy spectrum integral values ​​corresponding to the same particle event; and the host computer module completes data parsing, storage, and spectrum display. This invention enables the synchronous acquisition of neutron-gamma discrimination information and energy spectrum information, improving the stability and accuracy of neutron-gamma discrimination in mixed radiation fields.

Description

Technical Field

[0001] This invention belongs to the field of nuclear radiation detection and nuclear electronics technology, specifically relating to a neutron and gamma spectrum synchronous discrimination and acquisition system and method based on a SiPM and CLYC combined detector. In particular, it relates to an electronic system and its data processing method capable of amplifying and filtering, temperature compensation, waveform integration, PSD discrimination calculation, and synchronous acquisition of energy spectrum information for particle pulse signals in a mixed neutron and gamma radiation field. Background Technology

[0002] Neutron detection technology has significant applications in nuclear safety monitoring, nuclear material identification, public safety inspection, space radiation detection, medical treatment, and nuclear physics experiments. Since neutrons are uncharged, they cannot be detected directly through conventional ionization methods. They typically require detection media such as scintillators, semiconductor detectors, or gas detectors to convert the secondary particles or scintillation signals generated by the interaction of neutrons with matter into collectable electrical signals.

[0003] In practical neutron detection scenarios, gamma-ray background often coexists with the neutron field. Since both neutrons and gamma rays are uncharged, and some neutron detectors also have a certain sensitivity to gamma rays, the detector output signal is easily mixed with gamma background signals, thus affecting the accuracy of neutron energy spectrum measurements and particle type identification. Therefore, effectively distinguishing between neutron events and gamma events in a mixed radiation field is one of the key issues in the design of neutron detection systems.

[0004] CLYC scintillators are scintillating materials capable of responding to both neutrons and gamma rays. When neutrons and gamma rays interact with CLYC scintillators, their energy deposition mechanisms differ, resulting in different scintillator attenuation characteristics. This difference, after SiPM photoelectric conversion, manifests as variations in the rise, fall, and tail characteristics of the output electrical pulse waveform. Therefore, neutrons and gamma rays can be distinguished using pulse shape discrimination methods. Among these, the charge comparison method calculates the integral value of the pulse waveform within different time windows and constructs a position-sensitive detector (PSD) parameter for particle discrimination. This method offers advantages such as relatively simple structure, good real-time performance, and suitability for implementation on digital logic platforms such as FPGAs.

[0005] However, existing neutron-gamma discrimination systems based on SiPM and scintillator combined detectors still have the following problems: First, the pulse signals output by the CLYC and SiPM combined detectors usually have a certain tailing characteristic, which is easily affected by noise, baseline fluctuations and integration threshold settings when performing falling edge integration or long and short gate integration, resulting in unstable PSD parameter calculations; Second, the output gain of SiPM is significantly affected by ambient temperature. Temperature changes can cause changes in breakdown voltage and overvoltage, which in turn leads to output pulse amplitude drift, affecting the stability of energy spectrum peak positions and neutron-gamma discrimination effect; Third, some acquisition systems only acquire energy spectrum or PSD parameters separately, making it difficult to ensure that the energy information and discrimination information of the same particle event strictly correspond, which can easily introduce repeated measurement errors or data matching errors; Fourth, traditional acquisition methods lack a synchronous binding mechanism for particle events in terms of data buffering, serial port transmission and host computer storage and display, which is not conducive to subsequent three-dimensional spectrum analysis and particle distribution judgment in mixed radiation fields.

[0006] Therefore, it is necessary to provide a neutron-gamma energy spectrum synchronous discrimination and acquisition system and method, which can stably condition and digitally acquire the pulse signal output by the SiPM and CLYC combined detector, and synchronously obtain the energy spectrum integral value and PSD discrimination parameters under the same particle event. At the same time, temperature compensation can reduce the influence of SiPM temperature drift on the detection results, thereby improving the stability, accuracy and data acquisition efficiency of neutron-gamma discrimination. Summary of the Invention

[0007] To address the problems existing in current neutron-gamma mixed radiation field detection, such as gamma background interference, SiPM detector temperature drift, susceptibility of pulse waveforms to noise, and difficulty in synchronously binding energy spectrum information with PSD discrimination information, this invention provides a neutron and gamma energy spectrum synchronous discrimination and acquisition system and method based on a SiPM and CLYC combined detector. This invention aims to achieve synchronous acquisition of energy information and neutron and gamma discrimination information for the same particle event through temperature compensation, front-end amplification and filtering, digital waveform acquisition, long and short gate integration, PSD parameter calculation, and synchronous storage and display on a host computer. This improves the accuracy, stability, and data acquisition efficiency of neutron and gamma discrimination in mixed radiation fields.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A neutron and gamma spectrum synchronous discrimination and acquisition system based on a SiPM and CLYC combined detector includes a combined detection module, a temperature compensation module, a power supply module, a front-end amplification and filtering module, an ADC sampling module, an FPGA data processing module, a data buffer and transmission module, and a host computer module.

[0009] The combined detection module is used to convert incident neutrons or gamma rays into electrical pulse signals; the combined detection module includes a CLYC scintillator and a SiPM array, the CLYC scintillator is used to convert neutrons or gamma rays into scintillation light signals, and the SiPM array is used to convert scintillation light signals into electrical pulse signals.

[0010] The combined detection module is also equipped with a temperature sensor, which is placed close to the SiPM array to collect the real-time temperature near the SiPM array and output the real-time temperature equivalent voltage.

[0011] The temperature compensation module adjusts the bias voltage of the SiPM array based on its real-time temperature changes to reduce SiPM gain drift caused by temperature variations. The temperature compensation module includes a reference temperature voltage input unit, a differential circuit, a compensation coefficient amplifier circuit, and a voltage coupling circuit. The reference temperature voltage input unit provides a reference temperature voltage corresponding to a reference temperature. The differential circuit subtracts the real-time temperature equivalent voltage from the reference temperature equivalent voltage to obtain the difference voltage corresponding to the temperature change. The compensation coefficient amplifier circuit amplifies the difference voltage proportionally based on the SiPM's temperature dependence coefficient. The voltage coupling circuit adds the amplified compensation voltage to the initial SiPM bias voltage to obtain the compensated SiPM bias voltage.

[0012] The front-end amplification and filtering module amplifies and filters the electrical pulse signal output by the combined detection module to increase the effective signal amplitude and suppress high-frequency noise. The front-end amplification and filtering module may include a passive low-pass filter circuit, a first-stage amplification unit, a second-stage amplification unit, and an active low-pass filter circuit. The passive low-pass filter unit performs preliminary high-frequency noise suppression on the original electrical pulse signal output by the combined detection module; the first-stage and second-stage amplification units perform multi-stage amplification of the electrical pulse signal; and the active low-pass filter unit performs low-pass filtering on the amplified electrical pulse signal to suppress high-frequency noise introduced during the amplification process.

[0013] The ADC sampling module performs analog-to-digital conversion on the amplified and filtered electrical pulse signal to obtain digitized waveform data. The FPGA data processing module performs digital filtering, pulse trigger detection, long-gate integration, short-gate integration, and PSD parameter calculation on the digitized waveform data, and binds the energy spectrum integral value corresponding to the same particle event with the PSD parameter. The FPGA data processing module includes a high-speed data receiving unit, a digital filtering unit, a pulse trigger judgment unit, a long-gate integration unit, a short-gate integration unit, a PSD calculation unit, a RAM storage unit, a FIFO buffer unit, and a transmission control unit. The high-speed data receiving unit receives digitized waveform data output from the ADC sampling module. The digital filtering unit performs low-pass filtering on the digitized waveform data. The pulse trigger judgment unit determines valid pulses based on a preset amplitude threshold. The long-gate integration unit calculates the integral value of the valid pulse within a long time window. The short-gate integration unit calculates the integral value of the valid pulse within a short time window. The PSD calculation unit calculates PSD parameters based on the short-gate and long-gate integral values. The RAM storage unit stores event address information, PSD parameters, and energy spectrum integral values ​​corresponding to the same particle event. The FIFO buffer unit performs data buffering and cross-clock domain processing. The transmission control unit outputs the buffered data to the host computer module.

[0014] The data caching and transmission module is used to cache, frame, and transmit the energy spectrum integral value, PSD parameters, and event address information. The host computer module receives data frames, parses, stores, and displays them, and generates neutron and gamma discrimination spectra based on the energy spectrum integral value and PSD parameters. The host computer module includes a data parsing unit, a data storage unit, and a spectrum display unit; the data parsing unit verifies and deframes the received data frames based on the frame header and frame trailer; the data storage unit stores the parsed event address information, PSD parameters, and energy spectrum integral value; and the spectrum display unit generates neutron and gamma discrimination spectra based on the PSD parameters and energy spectrum integral value.

[0015] Furthermore, the PSD parameter can be calculated based on the short-gate integral value and the long-gate integral value, and the calculation method is: PSD = Qshor / Qlong. Where, Qshort is the integral value of the pulse waveform within a preset short time window, and Qlong is the integral value of the pulse waveform within a preset long time window.

[0016] Furthermore, the data caching and transmission module concatenates the event address information, PSD parameters, and energy spectrum integral values ​​into the same data frame, so that the energy spectrum information of each particle event has a one-to-one correspondence with the neutron-γ discrimination information.

[0017] Furthermore, the method for simultaneous discrimination and acquisition of neutron and gamma spectra by the SiPM and CLYC combined detector is characterized by comprising the following steps: S1. The CLYC scintillator receives incident neutrons or gamma rays and generates corresponding scintillating light signals. S2. The scintillation signal is converted into an electrical pulse signal using a SiPM array; S3. Acquire the real-time temperature near the SiPM array and compensate the bias voltage of the SiPM array according to the real-time temperature change; acquire the real-time temperature near the SiPM array and convert it into a real-time temperature equivalent voltage; calculate the difference between the real-time temperature equivalent voltage and the reference temperature voltage to obtain the difference voltage; amplify the difference voltage proportionally according to the temperature dependence coefficient of the SiPM array to obtain the compensation voltage; superimpose the compensation voltage with the initial bias voltage of the SiPM to obtain the compensated SiPM bias voltage. S4. Amplify and filter the electrical pulse signal output by the SiPM array; S5. Perform AD sampling on the amplified and filtered electrical pulse signal to obtain digital waveform data; S6. Perform digital filtering and valid pulse determination on the digitized waveform data; S7. When the digitized waveform data meets the valid pulse judgment condition, perform long-gate integration and short-gate integration on the valid pulse; long-gate integration starts after the start of the valid pulse and stops at the end of the valid pulse; short-gate integration is performed within the preset time window of the valid pulse. S8. Calculate the PSD parameters based on the short gate integral value and the long gate integral value, and use the long gate integral value as the energy spectrum integral value; S9. Bind, cache, and frame the event address information, PSD parameters, and energy spectrum integral value corresponding to the same particle event; the event address information, PSD parameters, and energy spectrum integral value are spliced ​​into the same data frame so that the neutron-γ discrimination information and energy spectrum information of the same particle event correspond one-to-one. S10. The spliced ​​data is sent to the host computer module, which then performs data parsing, storage, and spectrum display.

[0018] Compared with the prior art, the present invention has the following advantages: 1. This invention detects neutrons and gamma rays by combining a CLYC scintillator with a SiPM array, and uses the difference in pulse waveform attenuation characteristics between neutron events and gamma events to distinguish PSD parameters, thereby enabling the differentiation of particle types under mixed neutron and gamma radiation fields.

[0019] 2. The present invention incorporates a temperature compensation module that adjusts the bias voltage of the SiPM array according to the real-time temperature changes of the SiPM array. This reduces the SiPM output gain drift caused by temperature changes and improves the stability of the energy spectrum peak position and the system's environmental adaptability.

[0020] 3. This invention amplifies and suppresses noise in the weak pulse signal output by the detector through a front-end amplification and filtering module, making the signal more suitable for back-end ADC sampling and FPGA digital processing, thereby improving the reliability of waveform acquisition.

[0021] 4. This invention uses an FPGA data processing module to perform long-gate integration, short-gate integration, and PSD parameter calculation on the same pulse waveform, thereby achieving synchronous acquisition of energy spectrum information and neutron-γ discrimination information.

[0022] 5. This invention binds and transmits the event address information, PSD parameters, and energy spectrum integral value of the same particle event, avoiding data correspondence errors and repeated measurement errors caused by the separation of energy spectrum measurement and PSD measurement.

[0023] 6. This invention enables the host computer to analyze, store, and display the collected data, facilitating the formation of two-dimensional or three-dimensional energy-PSD spectra, thereby intuitively reflecting the distribution of neutrons and gamma events in the mixed radiation field. Attached Figure Description

[0024] Figure 1 This is a block diagram of the overall structure of a neutron-gamma spectrum synchronous discrimination and acquisition system based on a SiPM and CLYC combined detector according to the present invention. Figure 2 This is a schematic diagram of the combined detection module in this invention; Figure 3 This is a structural block diagram of the temperature compensation module in this invention; Figure 4 This is a structural block diagram of the front-end amplification and filtering module in this invention; Figure 5 This is a structural block diagram of the FPGA data processing module in this invention; Figure 6 This is a flowchart of the neutron-gamma spectrum synchronous discrimination and acquisition method in this invention; Figure 7 This is a schematic diagram of the data frame format in this invention.

[0025] Figure Label Explanation: 1. Combined Detection Module; 1.1. CLYC Scintillator; 1.2. SiPM Array; 1.3. Temperature Sensor; 2. Temperature Compensation Module; 2.1. Reference Temperature Voltage Input Unit; 2.2. Differential Circuit; 2.3. Compensation Coefficient Amplifier Circuit; 2.4. Voltage Coupling Circuit; 3. Power Supply Module; 3.1. SiPM Bias Power Supply Unit; 3.2. Temperature Compensation Power Supply Unit; 4. Front-End Amplification and Filtering Module; 4.1. Passive Low-Pass Filter Unit; 4.2. First-Stage Amplifier Unit; 4.3. Second-Stage Amplifier Unit; 4.4. Active Low-Pass Filter Unit; 5. ADC Sampling Module; 6. FPGA Data Processing Module; 6.1. JESD204B High-Speed ​​Data Receiving Unit; 6.2. Digital Filter Unit; 6.3. Pulse Trigger Judgment Unit; 6.4. Long-Gate Integrator Unit; 6.5. Short-Gate Integrator Unit; 6.6. PSD Calculation Unit; 6.7. RAM Storage Unit; 6.8. FIFO 6.9 Buffer unit; 7. Data buffer and transmission module; 8. Host computer module; 8.1 Data parsing unit; 8.2 Data storage unit; 8.3 Spectrum display unit. Detailed Implementation

[0026] The specific embodiments of the present invention will now be described with reference to the accompanying drawings. It should be understood that the following embodiments are only for illustrating the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent substitutions or improvements made by those skilled in the art to the device models, connection methods, parameter ranges, or data transmission methods of each module without departing from the concept of the present invention should fall within the scope of protection of the present invention.

[0027] like Figure 1 As shown, the present invention provides a neutron and gamma spectrum synchronous discrimination and acquisition system based on a SiPM and CLYC combined detector, including a combined detection module 1, a temperature compensation module 2, a power supply module 3, a front-end amplification and filtering module 4, an ADC sampling module 5, an FPGA data processing module 6, a data buffer and transmission module 7, and a host computer module 8.

[0028] like Figure 2As shown, the combined detection module 1 is used to receive incident neutrons or gamma rays and output corresponding electrical pulse signals. The combined detection module 1 includes a CLYC scintillator 1.1 and a SiPM array 1.2. The CLYC scintillator 1.1 converts incident neutrons or gamma rays into scintillation signals, and the SiPM array 1.2 converts the scintillation signals into electrical pulse signals. Because neutrons and gamma rays have different energy deposition mechanisms in the CLYC scintillator 1.1, the resulting scintillation light has different attenuation characteristics. Therefore, the electrical pulse waveforms obtained after conversion by the SiPM array 1.2 differ in attenuation time, tailing characteristics, and integration ratio. The system utilizes this difference to distinguish the shapes of neutron and gamma pulses.

[0029] In one embodiment, the CLYC scintillator 1.1 may be a cylindrical CLYC scintillator, and the SiPM array 1.2 may consist of an array structure composed of multiple SiPM units. Multiple SiPM units are arranged in parallel or in an array to improve the light collection area and output signal strength. The SiPM array 1.2 may be equipped with a standard output terminal and a fast output terminal, wherein the standard output terminal is used for energy spectrum integration and PSD parameter discrimination, and the fast output terminal can be used for trigger or backup signal output.

[0030] like Figure 2 As shown, the combined detection module 1 can also be equipped with a temperature sensor 1.3. The temperature sensor 1.3 is arranged close to the SiPM array 1.2 to collect the real-time temperature near the SiPM array 1.2. The temperature equivalent voltage output by the temperature sensor 1.3 is sent to the temperature compensation module 2 for subsequent bias voltage compensation.

[0031] like Figure 3 As shown, the temperature compensation module 2 includes a reference temperature voltage input unit 2.1, a differential circuit 2.2, a compensation coefficient amplifier circuit 2.3, and a voltage coupling circuit 2.4. The reference temperature voltage input unit 2.1 provides a reference voltage corresponding to the reference temperature. The differential circuit 2.2 receives the real-time temperature equivalent voltage output from the temperature sensor 1.3 and the reference temperature voltage, and outputs the voltage difference between the two. The compensation coefficient amplifier circuit 2.3 amplifies the voltage difference proportionally according to the temperature dependence coefficient of the SiPM array 1.2 to obtain the compensation voltage. The voltage coupling circuit 2.4 superimposes the compensation voltage with the initial bias voltage of the SiPM to obtain the compensated SiPM bias voltage.

[0032] The power supply module 3 includes a SiPM bias power supply unit 3.1 and a temperature compensation power supply unit 3.2. The SiPM bias power supply unit 3.1 provides a stable bias voltage to the SiPM array 1.2. The temperature compensation power supply unit 3.2 provides an operating voltage to the temperature compensation module 2. In one embodiment, the power supply module 3 may include a boost circuit and a voltage regulator circuit. The boost circuit converts an external low-voltage power supply into the required high voltage, and the voltage regulator circuit reduces output voltage ripple and improves power supply stability.

[0033] like Figure 4 As shown, the front-end amplification and filtering module 4 includes a passive low-pass filter unit 4.1, a first-stage amplification unit 4.2, a second-stage amplification unit 4.3, and an active low-pass filter unit 4.4. The passive low-pass filter unit 4.1 is connected to the output of the combined detection module 1 and is used to initially suppress high-frequency noise in the original electrical pulse signal. The first-stage amplification unit 4.2 and the second-stage amplification unit 4.3 are used to amplify the weak pulse signal through multiple stages, bringing it within the effective input range of the ADC sampling module 5. The active low-pass filter unit 4.4 is used to further suppress high-frequency noise introduced during the amplification process and improve the signal-to-noise ratio of the back-end sampling.

[0034] The ADC sampling module 5 is used to perform analog-to-digital conversion on the analog pulse signal output by the front-end amplification and filtering module 4 to obtain digital waveform data. In one embodiment, the ADC sampling module 5 can be a high-speed, high-resolution analog-to-digital converter, and the sampled digital waveform data is transmitted to the FPGA data processing module 6 through a high-speed serial interface. The high-speed serial interface can be a JESD204B interface, or it can be replaced with other high-speed data interfaces as needed.

[0035] like Figure 5 As shown, the FPGA data processing module 6 includes a JESD204B high-speed data receiving unit 6.1, a digital filtering unit 6.2, a pulse trigger judgment unit 6.3, a long gate integration unit 6.4, a short gate integration unit 6.5, a PSD calculation unit 6.6, a RAM storage unit 6.7, a FIFO buffer unit 6.8, and a UART transmission control unit 6.9.

[0036] The JESD204B high-speed data receiving unit 6.1 receives high-speed digital waveform data output from the ADC sampling module 5 and converts it into parallel data that can be processed internally by the FPGA. The digital filtering unit 6.2 performs low-pass filtering on the digital waveform data to reduce high-frequency noise during the digital sampling process. The digital filtering unit 6.2 can employ an FIR digital filter, an IIR digital filter, or other filtering structures suitable for pulse signal processing.

[0037] The pulse trigger judgment unit 6.3 is used to determine whether the digitized waveform data exceeds a preset amplitude threshold. When the waveform data exceeds the preset amplitude threshold, the system determines that a valid pulse has started and initiates the long gate integrator unit 6.4 to perform integration calculation. When the waveform data is below the preset amplitude threshold or meets the preset termination condition, the system determines that the valid pulse has ended.

[0038] The long-gate integration unit 6.4 calculates the integral value Qlong of the effective pulse within a long time window. This long-gate integral value is related to the energy deposited by the particle in the detector and can be used as energy spectrum information. The short-gate integration unit 6.5 calculates the integral value Qshort of the effective pulse within a preset short time window. The short time window can be set according to the difference in the falling edge of the neutron and gamma-ray pulse waveforms. The PSD calculation unit 6.6 calculates the PSD parameters based on the short-gate integral value Qshort and the long-gate integral value Qlong. To facilitate integer operations and data transmission in the FPGA, the PSD parameters can also be scaled up or fixed-point processed.

[0039] Furthermore, to improve the accuracy of effective pulse selection, the pulse trigger judgment unit 6.3 can also set pulse width threshold, amplitude threshold, and debouncing judgment conditions. When the pulse width is less than the preset minimum width or greater than the preset maximum width, the system can determine that the pulse is a noise pulse, a piling pulse, or an invalid pulse, and will not store it further. This can reduce the impact of noise, baseline fluctuations, and abnormal pulses on the PSD calculation results.

[0040] RAM storage unit 6.7 is used to store the PSD parameters, long-gate integral value, and event address information corresponding to the same particle event. FIFO buffer unit 6.8 is used to buffer the data output from RAM storage unit 6.7 and perform cross-clock domain processing to match the rate difference between the high-speed processing clock inside the FPGA and the external low-speed transmission interface. UART transmission control unit 6.9 is used to concatenate the event address information, PSD parameters, and long-gate integral value according to a preset frame format and send them to the host computer module 8.

[0041] The data caching and transmission module 7 is used to perform event data framing, verification, and output. In one embodiment, the data frame includes a frame header, event address information, PSD parameters, energy spectrum integral value, and frame trailer. The frame header and frame trailer are used by the host computer module 8 for frame synchronization and data integrity verification. The event address information is used to identify the order of particle events. The PSD parameters are used for neutron and gamma discrimination. The energy spectrum integral value is used for energy spectrum analysis. Since the event address information, PSD parameters, and energy spectrum integral value are transmitted in the same data frame, it can be ensured that the discrimination information and energy information of the same particle event correspond one-to-one.

[0042] like Figure 7As shown, in one embodiment, the data frame may include a two-byte frame header, a two-byte event address, a two-byte PSD parameter, a two-byte energy spectrum integral value, and a two-byte frame trailer. It should be understood that the data frame length, the frame header and trailer values, and the bit width of each field can be adjusted according to the actual sampling accuracy, communication method, and the host computer's parsing requirements, and are not limited to the above format. The event address information, PSD parameter, and energy spectrum integral value are located in the same data frame to ensure a one-to-one correspondence between the discrimination information and the energy spectrum information for the same particle time.

[0043] The host computer module 8 includes a data parsing unit 8.1, a data storage unit 8.2, and a spectrum display unit 8.3. The data parsing unit 8.1 receives data frames sent by the data buffer and transmission module 7 and performs data verification and frame de-framing based on the frame header and trailer. The data storage unit 8.2 stores the parsed event address information, PSD parameters, and energy spectrum integral values ​​as data files. The spectrum display unit 8.3 generates two-dimensional scatter plots, two-dimensional count spectra, three-dimensional count spectra, or three-dimensional contour plots based on the PSD parameters and energy spectrum integral values ​​to visually display the distribution of neutron and gamma events.

[0044] like Figure 6 As shown, this invention also provides a method for simultaneous discrimination and acquisition of neutron and gamma spectra based on a SiPM and CLYC combined detector, comprising the following steps: S1. An incident neutron or gamma ray enters the CLYC scintillator 1.1, and the CLYC scintillator 1.1 generates a corresponding scintillating light signal according to the interaction process of the incident particles; S2 and SiPM array 1.2 receive the scintillation light signal and convert it into an electrical pulse signal; S3, temperature sensor 1.3 acquires the real-time temperature near SiPM array 1.2 and outputs the real-time temperature equivalent voltage; Temperature compensation module 2 compares the real-time temperature equivalent voltage with the reference temperature voltage and generates a compensation voltage based on the comparison result. Temperature compensation module 2 superimposes the compensation voltage with the initial bias voltage of SiPM to obtain the compensated bias voltage of SiPM, so as to reduce the gain drift of SiPM array 1.2 caused by temperature changes. S4, the front-end amplification and filtering module 4 performs low-pass filtering, multi-stage amplification, and further low-pass filtering on the electrical pulse signal output by the SiPM array 1.2; S5 and ADC sampling module 5 perform digital sampling on the processed analog pulse signal to obtain digital waveform data; S6, FPGA data processing module 6 receives digitized waveform data and performs digital filtering through digital filtering unit 6.2; The pulse trigger judgment unit 6.3 judges the valid pulse according to the preset amplitude threshold. When the digitized waveform data exceeds the preset amplitude threshold, long gate integration is started. S7, Long Gate Integrator 6.4 integrates the pulse waveform during the effective pulse duration to obtain the long gate integral value Qlong; The short-gate integration unit 6.5 integrates the pulse waveform within a preset short-gate integration time window to obtain the short-gate integration value Qshort; S8, PSD Calculation Unit 6.6 calculates the PSD parameters based on the short-gate integral value Qshort and the long-gate integral value Qlong; S9. The system binds and stores the event address information, PSD parameters, and long-door integral value corresponding to the same particle event; The data caching and transmission module 7 caches, frames, and sends the bound event data; S10, the host computer module 8 receives data frames and completes data parsing, storage and spectrum display.

[0045] Through the above system and method, the present invention can simultaneously obtain the energy spectrum integral value and PSD parameter under the same particle event, so that the energy information corresponds one-to-one with the neutron and gamma discrimination information; at the same time, SiPM gain drift is reduced by temperature compensation, and noise influence is reduced by front-end amplification filtering and digital filtering, thereby improving the detection stability and discrimination accuracy under the mixed radiation field of neutron and gamma.

Claims

1. A neutron and gamma spectrum synchronous discrimination and acquisition system based on a SiPM and CLYC combined detector, characterized in that, include: A combined detection module is used to convert incident neutrons or gamma rays into electrical pulse signals. The combined detection module includes a CLYC scintillator and a SiPM array. The CLYC scintillator converts incident neutrons or gamma rays into scintillation signals, and the SiPM array converts the scintillation signals into electrical pulse signals. A temperature compensation module is used to adjust the bias voltage of the SiPM array according to the real-time temperature change of the SiPM array in the combined detection module. A power supply module is used to provide operating voltage to the combined detection module and the temperature compensation module. A front-end amplification and filtering module is used to amplify and filter the electrical pulse signals output by the combined detection module. The ADC sampling module is used to perform analog-to-digital conversion on the electrical pulse signal processed by the front-end amplification and filtering module to obtain digital waveform data; the FPGA data processing module is used to perform digital filtering, effective pulse judgment, long gate integration, short gate integration and PSD parameter calculation on the digital waveform data, and bind the energy spectrum integral value corresponding to the same particle event with the PSD parameter; The data caching and transmission module is used to cache, frame, and transmit the event address information, PSD parameters, and energy spectrum integral values ​​corresponding to the same particle event; the host computer module is used to receive the data frames output by the data caching and transmission module, and to parse, store, and display the data frames in a spectrum.

2. The neutron and gamma spectrum synchronous discrimination and acquisition system according to claim 1, characterized in that, The SiPM array includes multiple SiPM units, which are arranged in an array and coupled to the CLYC scintillator to improve the scintillator light collection area and the electrical pulse signal output intensity. The combined detection module is also equipped with a temperature sensor, which is placed close to the SiPM array to collect the real-time temperature near the SiPM array and output the real-time temperature equivalent voltage.

3. The neutron and gamma spectrum synchronous discrimination and acquisition system according to claim 1, characterized in that, The temperature compensation module includes a reference temperature voltage input unit, a differential circuit, a compensation coefficient amplifier circuit, and a voltage coupling circuit. The reference temperature voltage input unit provides a reference temperature voltage corresponding to a reference temperature. The differential circuit calculates the difference between the real-time temperature equivalent voltage output by the temperature sensor and the reference temperature voltage to obtain a difference voltage corresponding to the temperature change. The compensation coefficient amplifier circuit amplifies the difference voltage proportionally according to the temperature dependence coefficient of the SiPM array to obtain a compensation voltage. The voltage coupling circuit superimposes the compensation voltage with the initial bias voltage of the SiPM to obtain the compensated SiPM bias voltage.

4. The neutron and gamma spectrum synchronous discrimination and acquisition system according to claim 1, characterized in that, The front-end amplification and filtering module includes a passive low-pass filter unit, a first-stage amplification unit, a second-stage amplification unit, and an active low-pass filter unit. The passive low-pass filter unit is used to perform preliminary high-frequency noise suppression on the original electrical pulse signal output by the combined detection module. The first-stage and second-stage amplification units are used to amplify the electrical pulse signal in multiple stages. The active low-pass filter unit is used to perform low-pass filtering on the amplified electrical pulse signal to suppress high-frequency noise introduced during the amplification process.

5. The neutron and gamma spectrum synchronous discrimination and acquisition system according to claim 4, characterized in that, The active low-pass filter unit adopts a Sallen-Key type low-pass filter structure.

6. The neutron and gamma spectrum synchronous discrimination and acquisition system according to claim 1, characterized in that, The FPGA data processing module includes a high-speed data receiving unit, a digital filtering unit, a pulse trigger judgment unit, a long-gate integration unit, a short-gate integration unit, a PSD calculation unit, a RAM storage unit, a FIFO buffer unit, and a UART transmission control unit. The high-speed data receiving unit receives digitized waveform data output from the ADC sampling module. The digital filtering unit performs low-pass filtering on the digitized waveform data. The pulse trigger judgment unit determines valid pulses based on a preset amplitude threshold. The long-gate integration unit calculates the integral value of the valid pulse within a long time window. The short-gate integrator is used to calculate the integral value of the effective pulse within a short time window; The PSD calculation unit is used to calculate PSD parameters based on the short-gate integral value and the long-gate integral value; the RAM storage unit is used to store the event address information, PSD parameters, and energy spectrum integral value corresponding to the same particle event; the FIFO cache unit is used for data caching and cross-clock domain processing; The UART transmission control unit is used to output the buffered data to the host computer module; The pulse triggering judgment unit is also used to filter valid pulses according to a preset pulse width threshold; when the pulse width is less than the preset minimum width or greater than the preset maximum width, the pulse is determined to be an invalid pulse and the PSD parameters and energy spectrum integral values ​​are not stored.

7. The neutron and gamma spectrum synchronous discrimination and acquisition system according to claim 6, characterized in that, The PSD parameter is calculated as follows: PSD = Qshort / Qlong, where Qshort is the short-gate integral value and Qlong is the long-gate integral value.

8. The neutron and gamma spectrum synchronous discrimination and acquisition system according to claim 1, characterized in that, The data frame output by the data caching and transmission module includes a frame header, event address information, PSD parameters, energy spectrum integral value, and frame tail. The event address information, PSD parameters, and energy spectrum integral value correspond to the same particle event. The host computer module includes a data parsing unit, a data storage unit, and a spectrum display unit. The data parsing unit is used to verify and deframe the received data frames according to the frame header and frame tail. The data storage unit is used to store the parsed event address information, PSD parameters, and energy spectrum integral values. The spectrum display unit is used to generate neutron and gamma discrimination spectra according to the PSD parameters and energy spectrum integral values.

9. A method for simultaneous discrimination and acquisition of neutron and gamma spectra based on a SiPM and CLYC combined detector, characterized in that, The system implementation based on any one of claims 1 to 8 includes the following steps: S1. The CLYC scintillator receives incident neutrons or gamma rays and generates corresponding scintillating light signals. S2. The scintillation signal is converted into an electrical pulse signal using a SiPM array; S3. Collect the real-time temperature near the SiPM array and compensate the bias voltage of the SiPM array according to the real-time temperature change. S4. Amplify and filter the electrical pulse signal output by the SiPM array; S5. The amplified and filtered electrical pulse signal is sampled by an ADC to obtain digital waveform data; S6. Perform digital filtering and valid pulse determination on the digitized waveform data; S7. When the digitized waveform data meets the valid pulse judgment condition, perform long-gate integration and short-gate integration on the valid pulse; S8. Calculate the PSD parameters based on the short gate integral value and the long gate integral value, and use the long gate integral value as the energy spectrum integral value; S9. Bind, cache, and stitch together the event address information, PSD parameters, and energy spectrum integral value corresponding to the same particle event; S10. The spliced ​​data is sent to the host computer module, which then performs data parsing, storage, and spectrum display.

10. The method for simultaneous discrimination and acquisition of neutron and gamma spectra according to claim 9, characterized in that, Step S3 includes: acquiring the real-time temperature near the SiPM array and converting it into a real-time temperature equivalent voltage; subtracting the real-time temperature equivalent voltage from the reference temperature voltage to obtain a difference voltage; proportionally amplifying the difference voltage according to the temperature dependence coefficient of the SiPM array to obtain a compensation voltage; and superimposing the compensation voltage with the initial bias voltage of the SiPM to obtain the compensated SiPM bias voltage. In step S7, long-gate integration begins after the start of the effective pulse and stops at the end of the effective pulse; short-gate integration is performed within a preset time window of the effective pulse. In step S9, the event address information, PSD parameters, and energy spectrum integral value are concatenated into the same data frame, so that the neutron-γ discrimination information and energy spectrum information of the same particle event correspond one-to-one.

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