Scintillator light output measurement method based on time discrimination

Abstract

The invention discloses a scintillator light output measurement method based on time discrimination. The method comprises the following steps: converting scintillation light generated by a scintillator sample to be measured under excitation of a radioactive source into an electric signal; after the electric signal is amplified by an amplifier, discriminating, collecting and storing rise time and pulse height of a digital waveform, or obtaining a long gate integral value Qlong and a short gate integral value Qshort, and obtaining a pulse discriminating value PSD according to the long gate integral value Qlong and the short gate integral value Qshort; generating a two-dimensional distribution histogram of the low-light output scintillator by taking the Qlong value as an abscissa and the PSD value as an ordinate; performing corresponding processing on the obtained two-dimensional distribution histogram, and performing projection in the X-axis direction to obtain a scintillator energy spectrogram; gaussian fitting is carried out on a full-energy peak in the energy spectrum diagram to obtain a central value and a half-peak width, and then light output and energy resolution of the scintillator are obtained through calculation. According to the invention, scintillator signals with low light output can be accurately detected and calibrated, the data acquisition speed is fast, and the output result precision is high.

Description

Technical Field

[0001] The present invention relates to a method for measuring scintillator light output, and more particularly to a method for measuring scintillator light output based on time discrimination. Background Art

[0002] Scintillators, key materials in the field of radiation detection, are capable of efficiently detecting a variety of high-energy particles, including X-rays, gamma rays, and neutrons. They are widely used in fields such as nuclear physics research, medical imaging diagnostics, industrial non-destructive testing, and safety inspections, playing an irreplaceable and important role. With the continuous expansion of their application scenarios, scintillator performance is facing higher requirements. In the scintillator performance evaluation system, light output (or light yield) and energy resolution are two critical performance indicators that directly determine the detection efficiency and energy spectrum analysis accuracy of radiation detectors. However, due to factors such as differences in crystal growth processes, intrinsic defects, and doping inhomogeneities, the light output performance and energy resolution of different scintillator samples vary significantly, making it difficult for some materials to achieve ideal performance. For example, some scintillators often have low light output due to their specific composition and structural characteristics. Insufficient light output directly weakens the output signal strength, thereby reducing the signal-to-noise ratio between the signal and background noise such as electronic noise and dark current, severely limiting the sensitivity and measurement accuracy of the detection system. In actual testing, in addition to the electronics noise floor and dark current noise, there are also unavoidable intrinsic noise (originating from internal material defects or the randomness of thermal excitation processes) and transmission noise in the communication link (such as crosstalk and quantization error introduced by analog signals over long distances). The combined effect of these multiple noise sources further degrades the signal-to-noise ratio, posing a challenge to accurately capturing weak signals. Therefore, one of our research focuses is to improve the signal-to-noise ratio during testing and enhance the system's responsiveness to low-light output signals, while minimizing changes to the material structure. This problem is particularly prominent in applications such as low-dose radiation measurement and rapid event detection. Furthermore, the loose structure and low atomic number density of some low-density samples result in insufficient energy deposition of the radiation particles, resulting in a weak scintillation signal. This also complicates signal acquisition and quantitative analysis, ultimately affecting the accuracy of radiation dose measurements. Furthermore, existing scintillators have limitations in energy resolution, making it difficult to effectively distinguish radiation signals of similar energy. This can easily lead to overlapping energy spectrum signals, compromising the accuracy of radiation source identification and analysis, especially in complex radiation fields. This problem is particularly pronounced in applications requiring high energy resolution, such as nuclear medicine PET imaging and high-energy physics experiments. Energy resolution is one of the core metrics for evaluating scintillator performance. Given a certain light output, the smaller the value, the greater the energy resolution and the more accurate the measurement results. Therefore, while ensuring light output, improving energy resolution is equally crucial. Scintillator performance optimization has long targeted high light output, fast decay times, and excellent energy resolution. While continuously improving crystal growth processes, how to more accurately detect the low-light output signals of existing scintillators and how to increase the peak-to-comparison ratio of test signals, thereby improving energy resolution, have become key issues that urgently need to be addressed.

[0003] Therefore, existing radiation detection technology still has certain limitations in many aspects, including low light output of some scintillators, difficulty in achieving effective measurement, insufficient energy resolution, and limited radiation energy deposition in low-density samples.

[0004] Currently, three main methods are used to test scintillator light output: 1) Traditional multi-channel spectrometers based on analog signal processing. This method is the most widely used and works by converting scintillation light into a pulsed current through a photomultiplier tube (PMT), converting it into a voltage pulse through a preamplifier, and then performing amplitude sampling after shaping through a main amplifier, ultimately forming an energy spectrum. Although this method is mature in structure and simple to implement, it can only obtain energy spectrum information corresponding to the light output, cannot provide time-related decay characteristics, and has limited ability to detect weak signals from low-light-output samples. 2) Another type of multi-channel spectrometer based on analog signal acquisition and processing uses a splitter to separate part of the signal for identification and logical judgment, and then uses a charge-to-digital converter to perform charge integration within a set gate width. This method can achieve a certain degree of time control in combination with logic triggering, but its integration window is fixed and the gate width is limited, making it difficult to cover scintillators with long decay times. 3) A multi-channel spectrometer based on digital sampling technology uses a fast analog-to-digital conversion module to acquire the pulse waveform output by the photomultiplier tube. The collected waveform data is then processed using a field-programmable gate array (FPGA) to obtain information such as the pulse's integrated intensity, trigger time, and pulse amplitude at different sampling times. By processing a large amount of pulse data, a multi-channel energy spectrum can be obtained. However, this method has difficulty accurately capturing the complete attenuation process and low-signal characteristics when measuring low-light-output scintillators. It also has disadvantages such as large data volumes and complex development. Furthermore, its real-time performance and energy resolution may be limited.

[0005] In the field of nuclear detection, testing technologies are constantly evolving to improve the accuracy and efficiency of scintillator performance measurements. Some research focuses on improvements in signal processing and data acquisition, resulting in the proposal of various testing systems. Chinese Patent 1 (Publication No. CN108983281B) discloses a detection system and method for measuring the relative light yield of a scintillator under test. This method uses an electron beam to excite the scintillator to produce luminescence, and uses this to measure its relative light yield. The system architecture includes an electron beam control device, a scintillator sample chamber, and a signal acquisition circuit, and can be used to quantitatively evaluate the luminescence properties of different materials. However, this solution primarily relies on an electron beam device, which places high demands on the test environment and introduces significant system complexity. Furthermore, signal resolution is limited at extremely low light output, making it difficult to meet the demands of more sensitive testing. Chinese Patent 2 (Publication No. CN106997058A) discloses a scintillator performance testing device and its consistency correction method. This device utilizes a multi-channel independent acquisition architecture, enabling simultaneous testing of multiple samples while effectively eliminating optical crosstalk between channels, improving data consistency and repeatability. The system also includes a temperature control module to support long-term testing in a stable environment. However, when the signal intensity is weak or the sample density is low, there may still be unstable measurements, which cannot meet the needs of detecting extremely low doses or low-energy events. Chinese Patent 3 (Publication No. CN109507716B) discloses a method for obtaining energy information of a scintillator detector, the principle of which is to measure the time difference between the high and low thresholds of the output pulse signal at the leading edge to infer the energy information. This method relies on the leading edge time characteristics, has a simple circuit structure, fast processing speed, and can achieve real-time performance evaluation. However, if the signal amplitude is small or the light output is insufficient, the accuracy of the leading edge signal discrimination will decrease, resulting in limited accuracy of the energy information. In summary, although there are many technologies dedicated to improving the accuracy and efficiency of scintillator performance testing, there are still obvious deficiencies in dealing with problems such as low light output, insufficient energy deposition of low-density samples, and poor energy resolution. Therefore, in order to achieve rapid, stable, low-signal detection and performance evaluation of large-scale scintillators, it is necessary to develop a new testing technology with higher signal-to-noise ratio and stronger adaptability. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a scintillator light output measurement method based on time discrimination that can overcome the problems of low light output, difficult energy deposition and high test signal-to-noise ratio caused by poor energy resolution of existing scintillators, thereby improving the accuracy and stability of radiation detection.

[0007] The technical solution adopted by the present invention is: a scintillator light output measurement method based on time discrimination, comprising the following steps:

[0008] 1) The scintillation light generated by the scintillator sample to be tested under the excitation of the radiation source is converted into an electrical signal through a photomultiplier tube;

[0009] 2) After the electric signal is amplified by an amplifier, the rising time and pulse height of the digitized waveform are discriminated, collected and stored by a high sampling rate oscilloscope, or the long gate integral value Qlong and the short gate integral value Qshort are obtained by using a multi-channel spectrometer test system with a built-in CoMPASS software, and the pulse discrimination value PSD is obtained according to the long gate integral value Qlong and the short gate integral value Qshort;

[0010] 3) According to the test requirement of the light output of the low light output scintillator, the long gate integral value Qlong and the short gate integral value Qshort data are generated into a two-dimensional distribution histogram of the low light output scintillator with the Qlong value as the horizontal coordinate and the PSD value as the vertical coordinate by using the Matlab software, and the two-dimensional distribution histogram specifically includes a two-dimensional distribution histogram of the low light output scintillator and a radioactive source and a two-dimensional distribution histogram of a single radioactive source;

[0011] According to the test requirement of the light output of the low-density scintillator, the rising time and pulse height data of the low-density scintillator and the radioactive source collected by the oscilloscope are generated into a two-dimensional distribution histogram of the low-density scintillator with the pulse height as the horizontal coordinate and the rising time as the vertical coordinate by using the Origin software, and the two-dimensional distribution histogram specifically includes a two-dimensional distribution histogram of the low-density scintillator and the radioactive source, a two-dimensional distribution histogram of a single radioactive source and a two-dimensional distribution histogram of a standard sample;

[0012] According to the test requirement of the light output of the scintillator with improved energy resolution, the long gate integral value Qlong and the short gate integral value Qshort data are generated into a two-dimensional distribution histogram of the scintillator with improved energy resolution with the Qlong value as the horizontal coordinate and the PSD value as the vertical coordinate by using the Matlab software;

[0013] 4) The obtained two-dimensional distribution histogram is processed accordingly, and projection is performed in the X-axis direction to obtain a scintillator energy spectrum;

[0014] 5) The full energy peak in the energy spectrum is subjected to Gaussian fitting to obtain a center value and a half-peak width, and then the light output and the energy resolution of the scintillator are obtained through calculation.

[0015] The scintillator light output measurement method based on time discrimination has the following beneficial effects:

[0016] 1) The method provided by the application can effectively distinguish the low light output (light yield less than 600 photons / MeV) scintillator signal from background noise, so that the scintillator signal with low light output can also be accurately detected and calibrated.

[0017] 2) The method provided by the application can solve the problem of low-density (density less than 3 g / cm 3The technical means solves the problem of insufficient energy deposition of the scintillator, and provides a feasible path for radiation detection of such materials.

[0018] 3. The application provides a method for optimizing the energy resolution of a scintillator, which is of great significance for the application of samples that need to improve the energy resolution (any sample that wants to improve the energy resolution) in radiation detection.

[0019] 4. The application has the advantages of fast data acquisition speed and high output result accuracy by combining the individual processing of single scintillation pulses with the statistical analysis of a large number of pulses, and can be used as a fast and accurate scintillator light output measurement method to meet the actual needs of material quality evaluation in industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The figure is a structural schematic diagram of the light output measurement system for measuring low light output scintillators according to the application;

[0021] Figure 2 The figure is a structural schematic diagram of the light output measurement system for measuring low density scintillators according to the application;

[0022] Figure 3 The figure is a structural schematic diagram of the light output measurement system for measuring scintillators that need to improve the energy resolution according to the application;

[0023] Figure 4 The figure is a two-dimensional distribution histogram of PSD and Qlong of a single Na-22 radioactive source obtained in the light output test of the YAG:Yb crystal in Example 1;

[0024] Figure 5 The figure is a two-dimensional distribution histogram of PSD and Qlong of the scintillator and Na-22 radioactive source obtained in the light output test of the YAG:Yb crystal in Example 1;

[0025] Figure 6 The figure is a two-dimensional distribution histogram of PSD and Qlong of the scintillator obtained in the light output test of the YAG:Yb crystal in Example 1 after PSD interception and background subtraction;

[0026] Figure 7 The figure is the energy spectrum and fitting result obtained in the light output test of the YAG:Yb crystal in Example 1;

[0027] Figure 8 The figure is a two-dimensional distribution histogram of rise time and pulse height of a single Am-241 radioactive source obtained in the light output test of the MOF material in Example 2;

[0028] Figure 92D distribution histogram of rise time and pulse height of the Am-241 radiation source and scintillator obtained when performing light output testing on the MOF material in Example 2;

[0029] Figure 10 The two-dimensional distribution histogram of rise time and pulse height of a single scintillator obtained by deleting pulse signals with rise times less than 1000 ns when performing a light output test on the MOF material in Example 2;

[0030] Figure 11 This is the energy spectrum of the scintillator obtained in the light output test of MOF in Example 2;

[0031] Figure 12 2D distribution histogram of rise time and pulse height of the Am-241 radiation source and scintillator obtained in the light output test of BGO in Example 2;

[0032] Figure 13 This is the energy spectrum of BGO obtained in the light output test of BGO in Example 2;

[0033] Figure 14 2D distribution histogram of PSD and Qlong of the scintillator obtained in the light output test of LaBr3:Ce in Example 3;

[0034] Figure 15 2D distribution histogram of PSD and Qlong of the optimized scintillator obtained in the light output test of LaBr3:Ce in Example 3;

[0035] Figure 16 This is the comparison result of the energy spectrum before and after optimization extracted from the two-dimensional distribution histogram and the energy spectrum and energy resolution directly obtained by the test software when the light output test of the LaBr3:Ce scintillator is performed in Example 3. DETAILED DESCRIPTION

[0036] The following describes in detail a scintillator light output measurement method based on time discrimination according to the present invention in conjunction with the embodiments and drawings.

[0037] The present invention is a method for measuring the light output of a scintillator based on time discrimination. First, the sample is placed in a metal shielding box that can isolate external interference signals. The excitation source is selected according to different test requirements. For the light output test of a low light output scintillator, a Na-22 standard source is used. The test system structure is as follows: Figure 1 As shown; For the light output test of low-density scintillator, 59.5keV energy X-rays from Am-241 standard source are used, and the test system structure is as follows Figure 2 As shown; for the scintillator light output test that requires improved energy resolution, the Eu-152 standard source is used, and the test system structure is as followsFigure 3 As shown; the radioactive source used above can be changed according to specific circumstances, including the following steps:

[0038] 1) A photomultiplier tube (PMT) converts the scintillation light generated by the scintillator sample under test into an electrical signal when excited by a radioactive source. The PMT type is determined by the scintillator's characteristics: the Hamamatsu R2059 is used for testing low-light-output scintillators; the Hamamatsu R2257 is used for testing low-density scintillators; and the R2059 is also used for testing scintillators requiring improved energy resolution. The PMT model is selected based on the location of the scintillator's emission peak, with the highest quantum efficiency in that wavelength band being preferred. The R2059 has a wide spectral response range of 160–650 nm and a rise time of approximately 1.3 ns, offering high acquisition efficiency and gain. The R2257 has a wide spectral response range of 300–900 nm and a rise time of approximately 2.6 ns, also offering high acquisition efficiency and gain. In terms of setting the test voltage, when testing low-light-output scintillator samples (using R2059), the recommended voltage range is -1800V to -2400V; when testing low-density scintillator samples (using R2257), the recommended voltage range is also -1800V to -2400V; when testing scintillator samples that require improved energy resolution (using R2059), the recommended voltage range is -1600V to -2400V. The specific voltage can be adjusted appropriately according to the strength of the light signal.

[0039] 2) After the electrical signal is amplified by an amplifier, the rise time and pulse height of the digitized waveform are identified, collected, and stored using a high-sampling-rate oscilloscope. Alternatively, a multi-channel energy spectrometer test system (model CAEN-DT5751) with built-in CoMPASS software is used to obtain the long gate integral value Qlong and the short gate integral value Qshort. The pulse discrimination value PSD is obtained based on the long gate integral value Qlong and the short gate integral value Qshort.

[0040] The method of identifying, collecting and storing the rise time and pulse height of the digitized waveform by using a high-sampling rate oscilloscope includes: selecting a self-triggering mode, and using an electrical signal with a signal amplitude higher than a preset amplitude as a target electrical signal; setting a trigger threshold and a waveform display window during testing to ensure that each trigger signal is fully displayed and that the rise time and pulse amplitude can be effectively extracted. Under the self-triggering mode, the oscilloscope collects the rise time and pulse height of 100,000 electrical pulse signals that have been amplified and shaped by a preamplifier.

[0041] The pulse discrimination value PSD is obtained according to the long gate integral value Qlong and the short gate integral value Qshort, according to the formula: Calculate the pulse discrimination value PSD.

[0042] When testing low-light-output scintillators, using a multi-channel spectrometer with built-in CoMPASS software to obtain the long-gate integral value, Qlong, and the short-gate integral value, Qshort, the test environment and parameter settings remain the same, differing only with the presence or absence of the scintillator. When testing low-light-output scintillators and those requiring improved energy resolution, the long-gate width set in the multi-channel spectrometer with built-in CoMPASS software should encompass all pulse signals from the scintillator sample under test. The short-gate and pre-gate settings should ensure that the PSD value remains within the 0-1 range, based on the long-gate width.

[0043] 3) According to the test requirements of the light output of the low light output scintillator, Matlab software is used to generate a two-dimensional distribution histogram of the low light output scintillator with the long gate integral value Qlong and the short gate integral value Qshort data, with the Qlong value as the horizontal axis and the PSD value as the vertical axis. Specifically, it includes: a two-dimensional distribution histogram of the low light output scintillator and the radioactive source, and a two-dimensional distribution histogram of the radioactive source alone. Figure 4 2D distribution histogram of a single Na-22 radiation source obtained in the light output test of the YAG:Yb crystal in Example 1; Figure 5 This is a two-dimensional distribution histogram of the scintillator and Na-22 radiation source obtained in the light output test of the YAG:Yb crystal in Example 1.

[0044] According to the test requirements of the light output of the low-density scintillator, the rise time and pulse height data of the low-density scintillator and the radioactive source acquired by the oscilloscope are used to generate a two-dimensional distribution histogram of the low-density scintillator with pulse height as the horizontal axis and rise time as the vertical axis using Origin software. Specifically, the two-dimensional distribution histogram includes: a two-dimensional distribution histogram of the low-density scintillator and the radioactive source, a two-dimensional distribution histogram of the radioactive source alone, and a two-dimensional distribution histogram of the standard sample; Figure 8 This is a two-dimensional distribution histogram of the rise time and pulse height of a single Am-241 radiation source obtained during the light output test of the MOF material in Example 2; Figure 9 The two-dimensional distribution histogram of the rise time and pulse height of the Am-241 radiation source and the scintillator obtained during the light output test of the MOF material in Example 2; Figure 12 2D distribution histogram of the Am-241 radiation source and scintillator obtained in the light output test of BGO in Example 2;

[0045] According to the test requirements of the light output of the scintillator whose energy resolution needs to be improved, Matlab software is used to generate a two-dimensional distribution histogram of the scintillator whose energy resolution needs to be improved with Qlong value as the horizontal axis and PSD value as the vertical axis from the long gate integral value Qlong and short gate integral value Qshort data, specifically including: a two-dimensional distribution histogram of the scintillator whose energy resolution needs to be improved and the radiation source; Figure 14 This is a two-dimensional distribution histogram of the scintillator requiring improved energy resolution obtained in the light output test of LaBr3:Ce in Example 3;

[0046] 4) Processing the obtained two-dimensional distribution histogram accordingly and projecting it in the X-axis direction to obtain a scintillator energy spectrum;

[0047] The two-dimensional distribution histogram of the low-light-output scintillator is processed as follows: using Matlab software, the two-dimensional distribution histogram of the scintillator and the radiation source is first subtracted from the two-dimensional distribution histogram of the radiation source alone to obtain the two-dimensional distribution histogram of the low-light-output scintillator alone; and then the two-dimensional distribution histogram of the low-light-output scintillator alone is projected onto the X-axis to obtain the low-light-output scintillator energy spectrum. Figure 6 This is a two-dimensional distribution histogram of the scintillator obtained in the light output test of the YAG:Yb crystal in Example 1 after PSD interception and background subtraction. Figure 7 The energy spectrum and fitting results obtained from the light output test of the YAG:Yb crystal in Example 1;

[0048] The processing of the two-dimensional distribution histogram of the low-density scintillator is as follows: using Origin software to draw the two-dimensional distribution histogram of the low-density scintillator and the radioactive source and the two-dimensional distribution histogram of the independent radioactive source, using Excel software to delete the data in the two-dimensional distribution histogram of the low-density scintillator and the radioactive source that overlaps with the two-dimensional distribution histogram of the independent radioactive source, and then using Origin software to draw the processed data to obtain the two-dimensional distribution histogram of the independent low-density scintillator; using Origin software to draw a distribution histogram of the pulse height data of the independent low-density scintillator after processing to obtain the energy spectrum of the independent low-density scintillator. Figure 10 The two-dimensional distribution histogram of rise time and pulse height of a single scintillator obtained by deleting pulse signals with rise times less than 1000ns during the MOF material light output test in Example 2; Figure 11 This is the energy spectrum of the scintillator obtained in the light output test of MOF in Example 2; Figure 13 This is the energy spectrum of BGO obtained in the light output test of BGO in Example 2;

[0049] The method for processing the two-dimensional distribution histogram of the scintillator whose energy resolution needs to be improved is as follows: using Matlab software to process the two-dimensional distribution histogram of the scintillator, deleting the data points with counts below 5% of the maximum count of the center value near the full energy peak, and obtaining a new two-dimensional distribution histogram; then projecting the processed two-dimensional distribution histogram in the X-axis direction to obtain the energy spectrum of the scintillator. Figure 15 is the optimized two-dimensional distribution histogram obtained in the light output test of LaBr3:Ce in Example 3; Figure 16 This is a comparison chart between the energy spectra before and after optimization and the energy spectra directly obtained in the test software when the light output test of the LaBr3:Ce scintillator is performed in Example 3.

[0050] 5) Gaussian fitting is performed on the full energy peak in the energy spectrum to obtain the center value and half-peak width, and then the light output and energy resolution of the scintillator are calculated; the light output and energy resolution of the scintillator obtained by calculation are obtained using the following formula, and the light yield value can be further calculated:

[0051] Where LO is the light output, ER is the energy resolution, LY is the light yield, xc is the center value of the full energy peak, E is the energy of the radiation source, SPE is the single photoelectron peak at the corresponding test voltage of the photomultiplier tube, FWHM is the half maximum width, QE is the quantum efficiency corresponding to the photomultiplier tube, and the light collection efficiency is assumed to be 100%.

[0052] For the low light output scintillator, such as Figure 7 The energy spectrum and fitting results obtained in the light output test of the YAG:Yb crystal in Example 1 are used to calculate the light output; for the low-density scintillator, Figure 11 This is the energy spectrum of the scintillator obtained in the light output test of MOF in Example 2, in which the central value is fitted and the energy resolution is calculated; for the scintillator whose energy resolution needs to be improved, Figure 16 This is a comparison diagram between the energy spectra before and after optimization and the energy spectra directly obtained in the test software when the light output test of the LaBr3:Ce scintillator is performed in Example 3, in which the energy resolution is calculated.

[0053] The following is a specific implementation

[0054] Example 1 (Light Output Test of YAG:Yb Crystal)

[0055] The YAG:Yb sample crystal (15×15×2mm 3) was coupled to the PMT via silicone oil, covered with a reflective layer, and placed on a Na-22 standard source. The negative high voltage on the photomultiplier tube R2059 was -2300V. The test software parameters were set to: long gate time of 100ns, short gate time of 12ns, pre-gate time of 3ns, and gain coefficient of 20fC / LSB. Raw data including Qlong and Qshort values ​​were collected. Under the same experimental conditions, Qlong and Qshort data were further collected when only the Na-22 radioactive source was placed (without the scintillator sample). Finally, a computer program was used to uniformly process and analyze the large amount of collected data.

[0056] Example 2 (Light output test of MOF)

[0057] MOF powder was sprinkled onto a photomultiplier tube (PMT) coated with silicone oil, followed by an Am-241 radiation source and a reflective layer. A negative high voltage of -2300V was applied to the R2257 photomultiplier tube, and the preamplifier gain was set to 10. Signal acquisition was performed using a Lecroy WaveRUNNER HD04104A oscilloscope, with the following parameters: impedance matching to 50 ohms, sampling rate of 10 GS / s, trigger mode of self-triggering, trigger mode of edge-triggering, and trigger threshold of 90 mV. A computer program was used to process the rise time and pulse height data of 100,000 collected pulse signals to calculate the full-energy peak address of the MOF sample. Subsequently, a standard BGO crystal sample was measured under the same test conditions to obtain its full-energy peak address. By comparing the full-energy peaks of the MOF and BGO under the same conditions, the light output of the MOF sample can be calculated.

[0058] Example 3 (Light output test of LaBr3:Ce excited by Eu-152 source)

[0059] The single-pass type LaBr3:Ce (Φ1"×1"mm 3 The crystal was coupled to a photomultiplier tube (PMT) via silicone oil and excited by a Eu-152 standard source. A negative high voltage of -1600V was applied to the R2059 PMT. The test software parameters were set to: long gate 200ns, short gate 50ns, pre-gate 3ns, and gain 40fC / LSB. Raw data, including Qlong and Qshort, was collected and processed and analyzed using a computer program.

Claims

1. A scintillator light output measurement method based on time discrimination, characterized in that: The steps include: 1) The scintillation light generated by the scintillator sample to be tested under the excitation of the radiation source is converted into an electrical signal through a photomultiplier tube; 2) After the electrical signal is amplified by an amplifier, the rise time and pulse height of the digitized waveform are identified, collected, and stored using a high-sampling-rate oscilloscope, or a multi-channel spectrometer test system with built-in CoMPASS software is used to obtain the long gate integral value Qlong and the short gate integral value Qshort. The pulse discrimination value PSD is obtained based on the long gate integral value Qlong and the short gate integral value Qshort; 3) Based on the light output test requirements of the low-light-output scintillator, Matlab software was used to generate a two-dimensional distribution histogram of the low-light-output scintillator with Qlong as the horizontal axis and PSD as the vertical axis from the long-gate integral value Qlong and short-gate integral value Qshort data. Specifically, the two-dimensional distribution histogram includes: a two-dimensional distribution histogram of the low-light-output scintillator and the radioactive source, and a two-dimensional distribution histogram of the radioactive source alone; According to the test requirements of the light output of low-density scintillators, the rise time and pulse height data of the low-density scintillator and radioactive source acquired by the oscilloscope were used to generate a two-dimensional distribution histogram of the low-density scintillator using Origin software, with pulse height as the horizontal axis and rise time as the vertical axis. Specifically, the two-dimensional distribution histogram includes: a two-dimensional distribution histogram of the low-density scintillator and radioactive source, a two-dimensional distribution histogram of a single radioactive source, and a two-dimensional distribution histogram of a standard sample; According to the test requirements of the light output of the scintillator whose energy resolution needs to be improved, Matlab software is used to generate a two-dimensional distribution histogram of the scintillator whose energy resolution needs to be improved, with the Qlong value as the horizontal axis and the PSD value as the vertical axis, from the long gate integral value Qlong and short gate integral value Qshort data. 4) Processing the obtained two-dimensional distribution histogram accordingly and projecting it in the X-axis direction to obtain a scintillator energy spectrum; 5) Gaussian fitting is performed on the full energy peak in the energy spectrum to obtain the center value and half-peak width, and then the light output and energy resolution of the scintillator are calculated.

2. The method for measuring scintillator light output based on time discrimination according to claim 1, characterized in that: Step 2) The method of using a high sampling rate oscilloscope to identify, collect and store the rise time and pulse height of the digitized waveform includes: selecting a self-triggering mode, and using an electrical signal with a signal amplitude higher than a preset amplitude as a target electrical signal; setting a trigger threshold and a waveform display window during the test to ensure that each trigger signal is fully displayed and that the rise time and pulse amplitude can be effectively extracted. Under the self-triggering mode, the oscilloscope collects the rise time and pulse height of 100,000 electrical pulse signals amplified and shaped by the preamplifier.

3. The method for measuring scintillator light output based on time discrimination according to claim 1, characterized in that: The pulse discrimination value PSD is obtained according to the long gate integral value Qlong and the short gate integral value Qshort in step 2) according to the formula: Calculate the pulse discrimination value PSD.

4. The method for measuring scintillator light output based on time discrimination according to claim 1, characterized in that: Step 2) When using a multi-channel spectrometer test system with built-in CoMPASS software to obtain the long gate integral value Qlong and the short gate integral value Qshort, the long gate width set in the multi-channel spectrometer test system with built-in CoMPASS software can include all pulse signals of the scintillator sample to be tested. The short gate and pre-gate settings are based on the long gate width to ensure that the PSD value is within the range of 0-1. For the test of the light output of low-light-output scintillators, the test environment and parameter settings remain consistent, with the only difference being the presence or absence of the scintillator.

5. The method for measuring scintillator light output based on time discrimination according to claim 1, characterized in that: In step 4), the two-dimensional distribution histogram of the low-light-output scintillator is processed as follows: using Matlab software, the two-dimensional distribution histogram of the scintillator and the radiation source is first subtracted from the two-dimensional distribution histogram of the radiation source alone to obtain the two-dimensional distribution histogram of the low-light-output scintillator alone; and then the two-dimensional distribution histogram of the low-light-output scintillator alone is projected onto the X-axis to obtain the low-light-output scintillator energy spectrum.

6. The method for measuring scintillator light output based on time discrimination according to claim 1, characterized in that: The processing of the two-dimensional distribution histogram of the low-density scintillator in step 4) is as follows: using Origin software to draw a two-dimensional distribution histogram of the low-density scintillator and the radioactive source and a two-dimensional distribution histogram of the single radioactive source, using Excel software to delete the data in the two-dimensional distribution histogram of the low-density scintillator and the radioactive source that overlaps with the two-dimensional distribution histogram of the single radioactive source, and then using Origin software to draw a graph of the processed data to obtain a two-dimensional distribution histogram of the single low-density scintillator; using Origin software to make a distribution histogram of the pulse height data of the processed single low-density scintillator to obtain an energy spectrum of the single low-density scintillator.

7. The method for measuring scintillator light output based on time discrimination according to claim 1, characterized in that: In step 4), the two-dimensional distribution histogram of the scintillator whose energy resolution needs to be improved is processed as follows: the two-dimensional distribution histogram of the scintillator is processed using Matlab software, and data points near the full-energy peak whose counts are less than 5% of the maximum count of the center value are deleted to obtain a new two-dimensional distribution histogram; then, the processed two-dimensional distribution histogram is projected in the X-axis direction to obtain an energy spectrum of the scintillator.

8. The method for measuring scintillator light output based on time discrimination according to claim 1, characterized in that: The light output and energy resolution of the scintillator obtained by calculation in step 5) are obtained using the following formula, and the light yield value can be further calculated: Where LO is the light output, ER is the energy resolution, LY is the light yield, xc is the center value of the full energy peak, E is the energy of the radiation source, SPE is the single photoelectron peak at the corresponding test voltage of the photomultiplier tube, FWHM is the half maximum width, QE is the quantum efficiency corresponding to the photomultiplier tube, and the light collection efficiency is assumed to be 100%.

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