CN-121978738-A - SiPM test and calibration method and system for particle detection application

CN121978738ACN 121978738 ACN121978738 ACN 121978738ACN-121978738-A

Abstract

The invention relates to the technical field of particle detection, in particular to an SiPM test and calibration method and system for particle detection application, which comprises the following steps of extracting a slope secondary differential set to determine a current change inflection point so as to calculate a local slope change proportion set to obtain a breakdown turning voltage point, analyzing the output pulse trigger probability, combining the photon number extraction probability increase interval, constructing a reference ratio of the extraction detection efficiency of the thinned pulse, screening high-density trigger data, calculating a spatial deviation extremum, and thus adjusting the offset compensation voltage of the system. According to the invention, the breakdown turning voltage point is positioned, so that measurement interference caused by basic background noise is avoided, the trigger probability sequence is established by counting the attenuation quantity, the detection efficiency reference ratio is extracted by combining a preset maximum likelihood estimation model, the channel deviation extremum is calculated to directly correct parameter fluctuation, and the array global dynamic balance is established, so that the long-term stability of the whole detection working state is maintained.

Inventors

ZHONG XIN
LU PEIZHI
ZHANG HUIXIA
QIU HUIYE
LIN FUZHONG
SHEN XIUQIU

Assignees

龙岩学院

Dates

Publication Date: 20260505
Application Date: 20260401

Claims (10)

1. A SiPM testing and calibration method for particle detection applications, comprising the steps of: S1, acquiring steady-state dark current data corresponding to a silicon photomultiplier under a bias voltage sequence, calculating a current change slope sequence, extracting a slope secondary differential set, judging a value corresponding position exceeding a differential cutoff threshold in the slope secondary differential set, and extracting a current change inflection point set; S2, screening a local scanning voltage interval based on the current change inflection point set, acquiring secondary dark current data in the local scanning voltage interval, calculating a local slope change proportion set, analyzing numerical distribution in the local slope change proportion set, and determining breakdown turning voltage points; S3, based on the breakdown turning voltage point, obtaining an output pulse signal corresponding to the silicon photomultiplier under the light pulse excitation sequence, calculating and obtaining a trigger probability sequence, comparing the trigger probability sequence with the number of light pulse photons in the corresponding light pulse excitation sequence, and extracting a probability increase interval; S4, calculating a local trigger probability sequence based on the probability increase interval and the fine tuning photon step length, inputting the ratio parameter of the photon number of the light pulse to the local trigger probability sequence into a maximum likelihood estimation model for calculation, and extracting the reference ratio of the detection efficiency; S5, based on the detection efficiency reference ratio, acquiring pulse time intervals output by the silicon photomultiplier in a plurality of detection channels, judging a numerical value with the time interval smaller than a preset time threshold value as high-density trigger data, calculating a spatial deviation extremum, and adjusting bias compensation voltage based on the spatial deviation extremum.
2. The SiPM test and calibration method for particle detection applications of claim 1, wherein the set of current change inflection points comprises critical abrupt coordinates, a response inflection index, and a differential transition node, the breakdown inflection voltage point comprises a turn-on decay threshold, a steady-state level parameter, and a breakdown edge potential, the probability increase interval comprises a response onset lower bound, a sensitivity ramp-up band, and a linear response upper bound, the detection efficiency reference ratio comprises a quantum conversion coefficient, an absolute calibration constant, and a photo-electric gain factor, and the bias compensation voltage comprises a dark noise stabilizing bias voltage, an array equalization difference, and a leakage current correction.
3. The SiPM test and calibration method for particle detection applications of claim 1, wherein the step of obtaining the current change inflection point set is specifically: S101, collecting steady-state dark current data of a silicon photomultiplier in a bias voltage sequence, extracting voltage differential variables aiming at adjacent nodes in the bias voltage sequence, extracting current differential variables at corresponding positions in the steady-state dark current data, performing algebraic division operation on the current differential variables and the voltage differential variables to obtain node slope variables, and performing array splicing according to a scanning sequence on all the node slope variables to obtain a current change slope sequence; s102, performing offset alignment on adjacent numerical items in the current change slope sequence, extracting a post index value and subtracting a pre index value to obtain a primary differential variable, performing adjacent item subtraction operation again on all the primary differential variables to obtain a secondary differential variable, and arranging all the secondary differential variables according to an original numerical index to generate a slope secondary differential set; And S103, extracting a preset differential cutoff threshold, comparing the distributed numerical value in the slope secondary differential set with the differential cutoff threshold, screening sequence target index marks corresponding to the numerical value exceeding the differential cutoff threshold in the slope secondary differential set, extracting voltage parameters matched with the sequence target index marks in the bias voltage sequence, and obtaining a current change inflection point set.
4. The SiPM test and calibration method for particle detection applications according to claim 3, wherein the obtaining manner of the differential cut-off threshold is specifically that a background reference sequence is built by extracting a plurality of secondary differential variables located at initial arrangement positions in the slope secondary differential set, a sequence mean value parameter and a background standard deviation parameter are calculated based on all secondary differential variables in the background reference sequence, a fluctuation confidence coefficient is extracted, the setting manner of the fluctuation confidence coefficient is that a distribution boundary multiple of a static dark level of the silicon photomultiplier is collected under a non-shielding state, a margin offset is obtained by multiplying the background standard deviation parameter and the fluctuation confidence coefficient, and a differential cut-off threshold is generated by adding the sequence mean value parameter and the margin offset.
5. The SiPM testing and calibration method for particle detection applications of claim 1, wherein the step of obtaining the breakdown breakover voltage point specifically comprises: S201, calling the current change inflection point set and the current change slope sequence, extracting voltage parameters for distributed nodes in the current change inflection point set, comparing corresponding position values of each node in the current change slope sequence, extracting a corresponding sequence value maximum value node as a candidate target, calculating a candidate target adjacent node voltage difference value, selecting a voltage difference value minimum value attribution node as a central coordinate, extending preset voltage step sizes along two sides of the central coordinate, and establishing a neighborhood offset scanning interval; S202, collecting secondary dark current data corresponding to each level of voltage node in the neighborhood bias scanning interval, performing difference calculation on adjacent voltage nodes in the neighborhood bias scanning interval, obtaining local voltage increment, performing differential operation on adjacent numerical values in the secondary dark current data, obtaining local current increment, performing division operation on the local current increment and the local voltage increment to obtain secondary slope parameters, extracting adjacent secondary slope parameters, performing ratio calculation, and generating a local slope ratio sequence; S203, arranging distributed numerical values in the local slope ratio sequence to form a contrast gradient, extracting minimum value items in the contrast gradient, mapping the minimum value items to corresponding voltage parameter nodes in the neighborhood offset scanning interval, and extracting the points of the corresponding voltage parameter nodes to digital records to obtain breakdown turning voltage points.
6. The SiPM test and calibration method for particle detection applications of claim 1, wherein the step of obtaining the probability increase interval is specifically: S301, detecting an initial pulse signal fed back during the period that an optical pulse excitation sequence acts on a silicon photomultiplier based on the breakdown turning voltage point, extracting pulse amplitude characteristic data carried in the initial pulse signal, comparing the pulse amplitude characteristic data with a preset attenuation judgment threshold value, screening out a background waveform lower than the preset attenuation judgment threshold value, reserving a node exceeding the preset attenuation judgment threshold value as an attenuation signal, counting attenuation signal accumulated values in a set triggering period, and generating an effective attenuation pulse quantity set sequence; S302, calling the effective attenuation pulse quantity set sequence and the unit triggering frequency parameter, performing traversal reading on each numerical value in the effective attenuation pulse quantity set sequence, performing algebraic division operation on each numerical value and the unit triggering frequency parameter to obtain a single-point triggering proportion, performing array splicing on all the single-point triggering proportions according to an original scanning time sequence, and establishing a triggering probability sequence; S303, acquiring the photon number of the light pulse corresponding to the light pulse excitation sequence, executing differential operation on adjacent nodes in the trigger probability sequence, solving the probability change increment, executing comparison operation on the probability change increment and a preset judgment reference value, selecting a coherent node set with the probability change increment exceeding the preset judgment reference value, mapping two ends of the coherent node set to the photon number distribution dimension of the light pulse, intercepting a section boundary number field limited by start-stop coordinates, and acquiring a probability increase section.
7. The SiPM test and calibration method for particle detection application of claim 6, wherein the setting process of the attenuation decision threshold is specifically to collect a dark noise signal set in a dark environment state, extract an amplitude distribution maximum value in the dark noise signal set, obtain a single photon amplitude reference value in a calibration state, perform an addition operation on the amplitude distribution maximum value and the single photon amplitude reference value to obtain an amplitude reference sum, perform a division operation by two on the amplitude reference sum to obtain a centering level parameter, and establish the centering level parameter as a preset attenuation decision threshold; The setting mode of the preset judging reference value is specifically that a background probability fluctuation peak value under the no-illumination triggering environment is extracted, a standard triggering slope constant of the silicon photomultiplier under a fixed working state is obtained, algebraic summation operation is carried out on the standard triggering slope constant and the background probability fluctuation peak value, and a numerical value result generated by the algebraic summation operation is set as the preset judging reference value.
8. The SiPM test and calibration method for particle detection applications of claim 1, wherein the step of obtaining the detection efficiency reference ratio is specifically: S401, invoking the probability increase interval and locally extracting a fine tuning photon step length, extracting a start-stop boundary value of the probability increase interval, performing equidistant discrete division on the start-stop boundary value according to the fine tuning photon step length to obtain the number of associated photons of each discrete node, and performing sequential combination operation on all photon numbers according to node positions to construct a fine tuning light pulse signal; S402, acquiring an associated detection response waveform based on the thinned optical pulse signal, counting the accumulated attenuation total number of the detection response waveform in unit triggering times, performing algebraic division on the accumulated attenuation total number and the unit triggering times to obtain single-point triggering variables, performing corresponding mapping and splicing on all the single-point triggering variables according to the thinned optical pulse signal index, and generating a local triggering probability sequence; S403, according to the local trigger probability sequence and the number of light pulse photons, executing sequence alignment on each node of the local trigger probability sequence and the number of light pulse photons, extracting an alignment value, dividing to obtain a probability photon proportion set, inputting the probability photon proportion set into a preset maximum likelihood estimation model, calling the maximum likelihood estimation model to execute iterative fitting on the probability photon proportion set to obtain a convergence extremum, and extracting a detection efficiency reference ratio.
9. The SiPM test and calibration method for particle detection applications of claim 1, wherein the step of obtaining the bias compensation voltage is specifically: S501, based on the detection efficiency reference ratio, acquiring corresponding time stamps of a plurality of detection channel output pulses, performing subtraction on adjacent pulse time stamps to obtain a single-point time difference value, combining the single-point time difference values according to channel types to establish a time interval change sequence, calling a preset time cutoff threshold, performing numerical comparison on internal distribution numerical values of the time interval change sequence and the preset time cutoff threshold, screening associated numerical value items lower than the preset time cutoff threshold, and obtaining high-density trigger data; S502, counting accumulated pulse quantity in the high-density trigger data, acquiring a detection channel to match with the sampled total pulse quantity, dividing the accumulated pulse quantity by the sampled total pulse quantity to obtain channel duty ratio variables, and performing sequence merging and assembly on the channel duty ratio variables to generate a high-density trigger proportion; And S503, calculating an average reference term of each numerical value in the high-density trigger proportion, performing subtraction operation on each numerical value and the average reference term to extract deviation absolute parameters, searching the maximum term in all the deviation absolute parameters to extract a spatial deviation extremum, performing addition operation on the device reference bias and the spatial deviation extremum to obtain an array balance correction amount, and establishing bias compensation voltage.
10. A SiPM test and calibration system for particle detection applications, characterized in that the system is adapted to implement the SiPM test and calibration method for particle detection applications of any of claims 1-9, the system comprising: The dark current characteristic analysis module is used for acquiring steady-state dark current data corresponding to the silicon photomultiplier under the bias voltage sequence, calculating a current change slope sequence, extracting a slope secondary differential set, judging a value corresponding position exceeding a differential cutoff threshold in the slope secondary differential set, and extracting a current change inflection point set; The breakdown voltage analysis module screens a local scanning voltage interval based on the current change inflection point set, acquires secondary dark current data in the local scanning voltage interval, calculates a local slope change proportion set, analyzes numerical distribution in the local slope change proportion set, and determines breakdown turning voltage points; The trigger probability analysis module is used for acquiring an output pulse signal corresponding to the silicon photomultiplier under the light pulse excitation sequence based on the breakdown turning voltage point, calculating and acquiring a trigger probability sequence, comparing the trigger probability sequence with the number of light pulse photons in the corresponding light pulse excitation sequence, and extracting a probability increase interval; The detection efficiency reference extraction module is used for calculating a local trigger probability sequence based on the probability increase interval and the fine-tuning photon step length, inputting the ratio parameter of the light pulse photon number and the local trigger probability sequence into the maximum likelihood estimation model for calculation, and extracting the detection efficiency reference ratio; and the space deviation compensation module is used for acquiring pulse time intervals output by the silicon photomultiplier in a plurality of detection channels based on the detection efficiency reference ratio, judging a numerical value with the time interval smaller than a preset time threshold value as high-density trigger data, calculating a space deviation extremum, and adjusting bias compensation voltage based on the space deviation extremum.

Description

SiPM test and calibration method and system for particle detection application Technical Field The invention relates to the technical field of particle detection, in particular to an SiPM (SiPM) testing and calibrating method and system for particle detection application. Background The technical field of particle detection and nuclear detection relates to observation, measurement and analysis of high-energy particles, radiation particles and interaction processes thereof, and is widely applied to directions such as high-energy physical experiments, nuclear physical experiments, cosmic ray observation, medical imaging, radiation monitoring and the like. In the technical field, a particle detector is generally used as a core device, and an electric signal or an optical signal generated by the interaction of particles and substances is acquired and recorded through a detection material and readout electronic system, wherein common detector types include a scintillator detector, a gas detector, a semiconductor detector, a photomultiplier detector and the like. In modern particle detection systems, silicon photomultipliers are widely used in scintillator readout systems and particle detection arrays as solid-state photon detection devices, which have the characteristics of high gain, small volume, response to weak light signals, and the like. In the practical application process, in order to ensure the consistency and stability of the output signals of the detector array, systematic testing and calibration work needs to be carried out on the detector in the experimental device building or using process, the process generally involves such matters as bias voltage setting, dark count rate measurement, gain measurement, single photon response measurement, parameter change measurement under the temperature condition and the like, and the acquisition and arrangement of the performance parameters of the detector are completed through an electronic reading circuit and data recording equipment. The conventional SiPM test and calibration method for particle detection application refers to performance test and parameter calibration processes performed on a silicon photomultiplier before or during the use in a particle detection system, and mainly aims at measuring parameters such as device gain, dark count rate, photon detection efficiency, breakdown voltage and the like. The method is characterized in that an SiPM device is generally arranged on a test circuit board, an adjustable bias voltage is applied to the SiPM through a stable power supply, weak light pulses are generated by utilizing a pulse light source or a light emitting diode to irradiate the SiPM light-sensitive surface, meanwhile, output current signals of the SiPM are amplified through a pre-amplifying circuit, output pulse waveform amplitude and charge distribution are recorded through an oscilloscope or a multi-channel charge integration device, a single photon response peak position is determined through statistics of the pulse amplitude distribution to calculate device gain, the number of output pulses in unit time is recorded under the condition of no illumination so as to obtain dark count rate, bias voltage is generally adjusted step by step in the breakdown voltage measurement process, an output current change curve is recorded to determine a voltage point of rapid current rising, and under the array SiPM application scene, the gain and response parameters of all channels are obtained through connecting the test circuit one by one channel and repeating the illumination measurement step, and the bias voltage is adjusted channel by channel according to the measured parameters so as to complete calibration. The traditional calibration method relies on manual construction of a peripheral circuit board and steady-state power supply adjustment, pulse waveform and charge distribution static statistics are carried out through external test equipment, when breakdown voltage is measured, only monotonically stepping adjustment voltage is used, and absolute change amplitude of current is observed, so that characteristic point judgment deviation is easily caused by background noise interference in an execution process, parameters are obtained in a channel-by-channel repeated wiring and illumination test mode when an array detection architecture is faced, a calibration period is prolonged by a fussy flow, meanwhile, spatial deviation correlation analysis is carried out on abnormal fluctuation of time intervals under a multichannel concurrency state, and consistency of bias states of all channels in a device array is difficult to maintain. Disclosure of Invention The invention aims to solve the defects in the prior art, and provides a SiPM test and calibration method and system for particle detection application. In order to achieve the above object, the present invention adopts the following technical scheme, and an SiPM test and calibration method for particle