Gamma radiation detection system and method based on perovskite scintillator

Abstract

The invention relates to the technical field of nuclear radiation detection, in particular to a gamma radiation detection system and method based on a perovskite scintillator, and the system comprises a perovskite scintillator module which employs a Cs3Cu2I5 perovskite scintillation crystal; the SiPM photoelectric conversion module is optically coupled with the perovskite scintillator module and is used for converting a fluorescence signal generated by the perovskite scintillator module into an electric signal; the signal processing module is used for amplifying and filtering the electric signal; and the data acquisition module is in communication connection with the signal processing module and is used for acquiring the energy spectrum data processed by the signal processing module and finishing energy calibration by matching with a multi-energy standard gamma radiation source so as to establish a linear relation between a channel address and gamma ray energy. The scheme has the advantages that the energy resolution and the detection efficiency of gamma radiation detection are remarkably improved, and the energy calibration process is simplified at the same time.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of nuclear radiation detection, in particular to a gamma radiation detection system and method based on perovskite scintillator. BACKGROUND

[0002] As a core technical means in the fields of nuclear radiation monitoring, nuclear safety and environmental monitoring, the performance of gamma spectrum measurement directly determines the energy resolution and detection accuracy of gamma rays. Energy resolution and detection efficiency are key indicators for evaluating the performance of a measurement system.

[0003] Current mainstream gamma spectrum measurement systems mainly use traditional scintillator detectors, such as cesium iodide thallium (CsI:Tl) or bismuth germanate (BGO) scintillators coupled with photomultiplier tubes or silicon photomultipliers (SiPMs). However, these traditional scintillator materials have significant inherent defects: CsI:Tl scintillators generally have poor energy resolution under characteristic gamma ray excitation, making it difficult to achieve high-precision energy resolution; BGO scintillators have low light yield, resulting in insufficient detection efficiency and inability to accurately collect complete spectrum data. In addition, the calibration process of traditional measurement methods is often complex and tedious, relying on a single energy standard source for calibration, which is difficult to cover the measurement requirements of a wide energy range. Moreover, traditional scintillators have long decay times, which can cause signal pile-up under high count rate conditions, resulting in broadening of the energy spectrum peak shape and further deterioration of energy resolution. SUMMARY

[0004] To solve the problems in the related art, the present disclosure provides a gamma radiation detection system and method based on perovskite scintillator.

[0005] In a first aspect, the present disclosure provides a gamma radiation detection system based on perovskite scintillator, comprising: a perovskite scintillator module, the perovskite scintillator module adopts a Cs3Cu2I5 perovskite scintillation crystal; a SiPM photoelectric conversion module, the SiPM photoelectric conversion module is optically coupled with the perovskite scintillator module, and is configured to convert the fluorescent signal generated by the perovskite scintillator module into an electrical signal; a signal processing module, the signal processing module is electrically connected with the SiPM photoelectric conversion module, and is configured to amplify and filter the electrical signal; a data acquisition module, the data acquisition module is communicatively connected with the signal processing module, and is configured to acquire the energy spectrum data processed by the signal processing module, and complete energy calibration in cooperation with a multi-energy standard gamma radiation source to establish a linear relationship between channel address and gamma ray energy.

[0006] According to an embodiment of the present disclosure, the signal processing module comprises a preamplification circuit, a shaping filter circuit and a main amplification circuit connected in sequence, the shaping filter circuit adopts a Gaussian filter algorithm, and filter parameters are set according to output signal characteristics of the SiPM photoelectric conversion module.

[0007] According to an embodiment of the present disclosure, the data acquisition module is a multi-channel analyzer, the number of channels is configured as 2048 or 4096, and the data acquisition module is in communication connection with the signal processing module through a USB interface.

[0008] In a second aspect, the present disclosure provides a gamma energy spectrum measurement method based on the system of any one of the first aspect, comprising the following steps: An energy calibration step: at least three different energy standard gamma radiation sources are used to calibrate the energy of the system, and a linear regression equation of channel address and gamma ray energy is established; A parameter setting step: the bias of the SiPM photoelectric conversion module and the acquisition parameters of the data acquisition module are set according to the test scene; An energy spectrum acquisition step: the perovskite scintillator module is placed in a test environment, the SiPM photoelectric conversion module converts the fluorescence signal generated by the scintillator into an electrical signal, and the energy spectrum data is acquired by the data acquisition module after being processed by the signal processing module; A data processing step: based on the linear regression equation, the acquired energy spectrum data is energy calibrated, the channel address is converted into the corresponding gamma ray energy, the energy resolution and the detection efficiency are calculated, the G(E) function of the system is obtained, and the dose rate is calculated based on the energy spectrum data and the G(E) function, wherein the G(E) function is the dose response coefficient of the system to different energy gamma rays; A performance evaluation step: the gamma energy spectrum measurement performance of the system is evaluated according to the energy resolution, the detection efficiency and the dose rate measurement accuracy.

[0009] According to an embodiment of the present disclosure, the calculation method of the energy resolution is: , Wherein, is the energy resolution, is the energy value corresponding to the full width at half maximum of the full energy peak, is the energy value of the gamma ray corresponding to the full energy peak.

[0010] According to an embodiment of the present disclosure, the calculation method of the detection efficiency is: , Wherein, is the detection efficiency, is the net count of the full energy peak, which is obtained by subtracting the background count from the total count of the full energy peak; The number of incident photons at the detector for a standard gamma radiation source is calculated according to the activity, emission rate and distance of the standard source.

[0011] According to an embodiment of the present disclosure, the dose rate calculation method is: , wherein, is the dose rate, is the count rate at energy E, obtained by dividing the count corresponding to energy E in the energy spectrum data by the acquisition time, and ΔE is the energy interval, and the summation range covers the measured gamma ray energy interval.

[0012] According to an embodiment of the present disclosure, the function is obtained through Monte Carlo simulation or standard radiation field calibration, and at least five standard gamma radiation sources of different energies are used in the calibration process to establish the correspondence between the count rate and the known dose rate, and the function value at different energies is fitted.

[0013] According to an embodiment of the present disclosure, the performance evaluation step further comprises: stability evaluation: calculating the energy resolution change rate after a set time of continuous measurement wherein, is the initial energy resolution, is the energy resolution after the set time; repeatability evaluation: calculating the energy resolution standard deviation and the dose rate standard deviation of multiple measurements; linearity evaluation: calculating the linearity wherein, is the gamma ray energy value measured by the system, is the true energy value of the gamma ray.

[0014] According to an embodiment of the present disclosure, in the parameter setting step: the bias of the SiPM photoelectric conversion module is set to 27-30V; the acquisition time of the data acquisition module is set to 1200-6400 seconds; the Gaussian filter shaping time of the signal processing module is set to 0.5-6us.

[0015] The technical effects provided by the embodiments of the present disclosure can include the following beneficial effects: According to the technical scheme provided by the embodiments of the present disclosure, by using Cs3Cu2I5 perovskite scintillation crystal, combined with SiPM photoelectric conversion module, signal processing module and data acquisition module, high-precision gamma radiation detection is realized, which has the advantages of significantly improving the energy resolution and detection efficiency of gamma radiation detection, and simplifying the energy calibration process. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A structural schematic diagram of a gamma radiation detection system based on a perovskite scintillator according to an embodiment of the present disclosure is shown.

[0017] Figure 2 A gamma spectrum curve diagram according to an embodiment of the present disclosure is shown, with a Cs3Cu2I5 perovskite scintillation crystal size of 5mmx5mmx5mm.

[0018] Figure 3 A gamma spectrum curve diagram according to an embodiment of the present disclosure is shown, with a Cs3Cu2I5 perovskite scintillation crystal size of 10mmx10mmx5mm. DETAILED DESCRIPTION

[0019] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so as to be easily implemented by those skilled in the art. Also, parts irrelevant to the description of the exemplary embodiments are omitted in the accompanying drawings for the sake of clarity.

[0020] In the present disclosure, it should be understood that terms such as "include" or "have" are intended to indicate that there are features, numbers, steps, actions, components, parts or combinations thereof disclosed in the specification, and do not exclude the possibility that one or more other features, numbers, steps, actions, components, parts or combinations thereof exist or are added.

[0021] It should also be noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict. The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0022] The conventional gamma spectrum measurement method is widely used in the fields of nuclear radiation monitoring, nuclide identification and radiation dose evaluation, but the scintillators such as CsI:Tl and BGO used in the prior art have limitations such as poor energy resolution, low light yield leading to insufficient detection efficiency, complex calibration process and difficulty in covering a wide energy range, signal pile-up leading to broadening of the energy spectrum peak shape, etc.

[0023] Figure 1 A structural schematic diagram of a gamma radiation detection system based on a perovskite scintillator according to an embodiment of the present disclosure is shown.

[0024] As Figure 1 shown, the present disclosure proposes a gamma radiation detection system based on a perovskite scintillator, comprising: a perovskite scintillator module, which adopts a Cs3Cu2I5 perovskite scintillation crystal; a SiPM photoelectric conversion module, which is optically coupled with the perovskite scintillator module and is used for converting the fluorescent signal generated by the perovskite scintillator module into an electric signal; a signal processing module electrically connected with the SiPM photoelectric conversion module, configured to amplify and filter the electrical signal; a data acquisition module communicatively connected with the signal processing module, configured to acquire the energy spectrum data processed by the signal processing module, and complete energy calibration with a multi-energy standard gamma radiation source to establish a linear relationship between channel address and gamma ray energy.

[0025] For ease of understanding, some key terms in this embodiment are explained as follows: Perovskite scintillator module: This module is the core part of the detection system, which contains Cs3Cu2I5 perovskite scintillation crystal inside. When gamma rays are incident on the crystal, the crystal material absorbs the gamma ray energy and generates a fluorescence signal, the intensity of which is related to the energy of the incident gamma rays. Cs3Cu2I5 perovskite scintillation crystal is selected for its high light yield and fast decay time to improve detection performance.

[0026] SiPM photoelectric conversion module: This module is an array of silicon photomultipliers, which converts the weak fluorescence signal generated by the perovskite scintillator module into a measurable electrical signal. The module usually has high gain, low noise and compact features, suitable for converting scintillation light into electrical pulses.

[0027] Signal processing module: This module receives the electrical signal output by the SiPM photoelectric conversion module and pre-processes it. Its main functions include amplifying the electrical signal to improve the signal-to-noise ratio, and filtering to remove noise and shaping the pulse, thereby providing high-quality signals for subsequent data acquisition.

[0028] Data acquisition module: This module is responsible for receiving and digitizing the processed electrical signal output by the signal processing module, converting it into energy spectrum data. The module also performs energy calibration, establishing a correspondence between the energy spectrum channel address and the actual gamma ray energy by cooperating with a standard gamma radiation source of known energy.

[0029] Optical coupling: refers to the tight connection between the perovskite scintillator module and the SiPM photoelectric conversion module through an optically transparent medium, to ensure that the fluorescence signal emitted by the scintillator can be efficiently transmitted to the light-sensitive surface of the SiPM photoelectric conversion module, minimizing light signal loss.

[0030] Energy calibration: refers to measuring the energy spectrum of a standard gamma radiation source of known energy to determine the response of the detection system to different energy gamma rays, thereby establishing a quantitative relationship between the channel address in the energy spectrum and the actual gamma ray energy.

[0031] Linear relationship between channel and gamma ray energy: refers to the process of energy calibration, which establishes a mathematical linear mapping relationship between the energy spectrum channel recorded by the data acquisition module and the corresponding gamma ray energy, so that the energy of the incident gamma ray can be accurately calculated through the measured channel.

[0032] The gamma radiation detection system of the embodiment is characterized by the high performance of the perovskite scintillator and the optimized signal processing and data acquisition mechanism.

[0033] Firstly, the system includes a perovskite scintillator module. The module is loaded with Cs3Cu2I5 perovskite scintillator crystal inside. The crystal material can generate high light yield fluorescent signal when excited by gamma rays, and has a relatively fast decay time. As an implementation, the crystal can be cut into regular geometric shapes such as cubes or cylinders and polished to optimize light collection efficiency. The crystal can also be wrapped with reflective material on the side to further improve the output of the fluorescent signal through encapsulation technology.

[0034] Secondly, the system is configured with a SiPM photoelectric conversion module. The module is optically coupled with the perovskite scintillator module, which converts the fluorescent signal generated by the scintillator into an electrical signal. Optical coupling can be achieved in various ways, such as coating a layer of optical silicone between the scintillator crystal and the SiPM photosensitive surface to fill the air gap between them and reduce light reflection loss; or using transparent optical glue to directly bond the two, forming a compact detection unit. The SiPM photoelectric conversion module can be composed of a single SiPM device or an array of multiple SiPM devices to accommodate different sizes of scintillator crystals or improve light collection area.

[0035] Further, the system is provided with a signal processing module. The module is electrically connected with the SiPM photoelectric conversion module, which is used for amplifying and filtering the converted electrical signal. The amplification of the electrical signal can be realized by an operational amplifier circuit to improve the signal amplitude, making it easy to process subsequently. Filtering can use various analog or digital filters, such as RC filter, Butterworth filter, etc., to remove high-frequency noise or low-frequency drift, and to shape the pulse signal, making it more suitable for digital acquisition. The circuit design of the module can be adjusted according to the output characteristics of SiPM to optimize the signal quality.

[0036] Finally, the system is integrated with a data acquisition module. The module is in communication connection with the signal processing module, and is used to collect the processed energy spectrum data. The data acquisition module can be a separate digitizer, responsible for converting analog signals into digital signals and storing them. The module also undertakes the function of energy calibration, through the use of multiple energy standard gamma radiation sources, for example, Cs-137, Co-60, Am-241 and other gamma radiation sources with different characteristic energies can be used in sequence to measure the system, and record the corresponding energy spectrum peak position. Based on these measurement results, the data acquisition module can establish a linear relationship between the energy spectrum channel address and the gamma ray energy, for example, through least squares fitting to obtain a straight line equation, thereby realizing accurate measurement of unknown gamma ray energy.

[0037] The gamma radiation detection system of the embodiments of the present disclosure effectively solves the problems of poor energy resolution, insufficient detection efficiency, complex calibration and mismatched signal processing of traditional detectors by using Cs3Cu2I5 perovskite scintillation crystal, combining SiPM photoelectric conversion, signal amplification and filtering, and multi-energy standard source calibration data acquisition mechanism. The system can provide high-quality energy spectrum data, realize accurate linear relationship establishment of channel address and gamma ray energy, and provide high-precision and high-adaptability measurement basis for nuclear radiation monitoring, nuclide identification and radiation dose evaluation.

[0038] According to the embodiments of the present disclosure, the signal processing module comprises a preamplification circuit, a shaping filter circuit and a main amplification circuit connected in sequence, the shaping filter circuit adopts a Gaussian filter algorithm, and the filter parameters are set according to the output signal characteristics of the SiPM photoelectric conversion module.

[0039] Specifically, the preamplification circuit is used to preliminarily amplify the weak current pulse output by the SiPM photoelectric conversion module, convert it into a voltage signal, and reduce noise introduction as much as possible. The preamplification circuit adopts a low-noise operational amplifier, which can preliminarily amplify the weak electrical signal output by the SiPM and reduce noise introduction.

[0040] The shaping filter circuit then performs pulse shaping and noise suppression on the signal after preamplification. In order to optimize the signal-to-noise ratio and reduce the pulse pile-up effect, the shaping filter circuit adopts a Gaussian filter algorithm. Gaussian filtering can convert the step-shaped or long-decay pulse output by the preamplifier into a symmetrical bell-shaped pulse, which is crucial for subsequent amplitude analysis. The implementation of Gaussian filtering can be realized through an analog circuit composed of multiple RC filters and operational amplifiers, or through a digital signal processing method after digitization.

[0041] In addition, in order to ensure the best effect of signal processing, the filter parameters, such as the shaping time of Gaussian filtering, are set according to the output signal characteristics of the SiPM photoelectric conversion module. This means that the system will dynamically or pre-set the parameters of the filter according to the parameters such as the rise time, decay time, dark count rate, gain and noise characteristics of the SiPM, so as to achieve the best signal-to-noise ratio and pulse shape.

[0042] The main amplification circuit further adjusts the gain of the signal after the shaping filter, so that the amplitude reaches the input range required by the data acquisition module, so as to perform accurate analog-to-digital conversion.

[0043] Through the above technical solutions, the present disclosure can perform hierarchical and fine processing on the weak electrical signals output by the SiPM photoelectric conversion module. The preamplifier circuit first amplifies the weak signal with low noise to provide a suitable input signal for the main amplifier circuit and effectively suppress the noise introduced by the subsequent circuit. The shaping filter circuit uses Gaussian filtering algorithm, which can convert the pulse signal with fast rising edge and long decay time output by the SiPM into a symmetrical and narrow pulse, thereby effectively suppressing noise, improving signal-to-noise ratio, and reducing pulse pile-up effect. At the same time, the filter parameters are set according to the output signal characteristics of the SiPM photoelectric conversion module, which ensures that the filtering process is highly matched with the characteristics of the detector, so that the signal processing can be optimized in a targeted manner, the energy information of the signal is maximized, and the energy spectrum is widened or the energy resolution is reduced due to the mismatched filter parameters. The main amplification circuit further amplifies the signal after the shaping filter to the amplitude range required by the data acquisition module. This hierarchical processing and optimized filtering strategy significantly improves the accuracy of γ-ray energy measurement and the clarity of the energy spectrum of the system, thereby improving the overall performance of the γ radiation detection system.

[0044] According to an embodiment of the present disclosure, the data acquisition module is a multichannel analyzer with 2048 or 4096 channels, which is in communication connection with the signal processing module through a USB interface.

[0045] Specifically, the data acquisition module is designed as a multichannel analyzer. The multichannel analyzer is a device specially used in the field of nuclear electronics, and its core function is to accurately classify and count the amplitude of the input electrical pulse signal, thereby constructing a detailed energy spectrum. In the γ radiation detection system, the multichannel analyzer can distribute the analog pulse signal output by the SiPM photoelectric conversion module and the signal processing module to the preset discrete "channels" according to the pulse amplitude after digitization by an analog-to-digital converter (ADC), and accumulate the count in each channel. This design enables the system to accurately record the electrical pulse amplitude corresponding to the fluorescent signal generated by different energy γ rays in the perovskite scintillator module, thereby forming a high-resolution γ spectrum, which provides basic data for subsequent energy calibration and nuclide identification.

[0046] Further, the number of channels of the multi-channel analyzer is configured as 2048 channels or 4096 channels. The number of channels refers to the number of discrete intervals that the multi-channel analyzer can divide the input pulse amplitude range into. The more the number of channels, the higher the degree of detail of the energy spectrum, and the better the energy resolution in theory. For example, for a typical gamma spectrum measurement range, a configuration of 2048 channels or 4096 channels is a commonly used high-resolution configuration in nuclear spectrum measurement. Such a high number of channel configuration can more accurately distinguish gamma rays with similar energies, and is crucial for identifying complex nuclide compositions, accurately measuring the full width at half maximum (FWHM) of energy peaks, and performing fine energy spectrum analysis. By increasing the number of channels, the system can provide more detailed energy resolution, thereby improving the accuracy and reliability of energy spectrum analysis.

[0047] In some embodiments of the present disclosure described above, a gamma radiation detection system based on a perovskite scintillator is proposed, which can convert the scintillation signal caused by gamma rays into an electrical signal and perform preliminary processing and collection. However, in order to ensure that the system can accurately and reliably perform gamma spectrum measurement, and to comprehensively evaluate its measurement performance, a systematic measurement method is needed to guide the operation and data analysis.

[0048] To this end, the present application further proposes a gamma spectrum measurement method based on the above system, which comprises the following steps: An energy calibration step: at least three standard gamma radiation sources with different energies are used to calibrate the energy of the system, and a linear regression equation of channel address and gamma ray energy is established; A parameter setting step: the bias of the SiPM photoelectric conversion module and the acquisition parameters of the data acquisition module are set according to the test scenario; A spectrum acquisition step: the perovskite scintillator module is placed in a test environment, the SiPM photoelectric conversion module converts the fluorescence signal generated by the scintillator into an electrical signal, which is processed by the signal processing module and then collected by the data acquisition module to obtain the energy spectrum data; A data processing step: based on the linear regression equation, the energy of the collected energy spectrum data is calibrated, the channel address is converted into the corresponding gamma ray energy, the energy resolution and the detection efficiency are calculated, the G(E) function of the system is obtained, and the dose rate is calculated based on the energy spectrum data and the G(E) function, wherein the G(E) function is the dose response coefficient of the system to gamma rays with different energies; A performance evaluation step: the gamma spectrum measurement performance of the system is evaluated according to the energy resolution, detection efficiency and dose rate measurement accuracy results.

[0049] Specifically, the energy calibration step aims to establish a linear relationship between the system channel address and the gamma ray energy, which is crucial for converting the raw count data into physically meaningful energy spectra. At least three different energy standard gamma radiation sources can be used to calibrate the system. For example, radioactive sources with known energies (such as Am-241, Cs-137, Co-60, etc.) can be used for measurements, and the channel addresses corresponding to their full energy peaks are recorded. By performing linear regression analysis on these known energies and corresponding channel addresses, a linear regression equation of channel address versus gamma ray energy can be established. This equation will serve as the basis for energy calibration in subsequent data processing.

[0050] The parameter setting step sets the working parameters of the system according to the specific test scenario to optimize the measurement effect. For example, the bias voltage of the SiPM photoelectric conversion module can be set, which directly affects the gain and noise level of the SiPM, and usually needs to be adjusted according to the specific model of the SiPM and the desired performance indicators. At the same time, the acquisition parameters of the data acquisition module also need to be set, such as the acquisition time, which helps to improve the statistical accuracy but also increases the measurement period. In addition, the Gaussian filter shaping time of the signal processing module also needs to be set, which affects the shaping speed and signal-to-noise ratio of the signal, and needs to be balanced according to the output signal characteristics of the SiPM and the desired energy resolution. Reasonable setting of these parameters is crucial for obtaining high-quality energy spectrum data.

[0051] In the energy spectrum acquisition step, the perovskite scintillator module is placed in the environment to be tested, ensuring that the module surface is perpendicular to the radiation incident direction. When gamma rays interact with the perovskite scintillator module, fluorescence signals are generated. The SiPM photoelectric conversion module converts these fluorescence signals into electrical signals, which are then amplified and filtered by the signal processing module to remove noise and optimize signal quality. Finally, the data acquisition module acquires these processed electrical signals to form raw energy spectrum data, with channel address as the horizontal coordinate and count as the vertical coordinate.

[0052] The data processing step is an in-depth analysis and conversion of the acquired energy spectrum data. First, based on the linear regression equation established in the energy calibration step, the acquired energy spectrum data is energy-calibrated to convert the original channel address to the corresponding gamma ray energy value, thereby obtaining the energy spectrum. On this basis, the energy resolution and detection efficiency of the system can be calculated. Energy resolution is usually measured by the ratio of the full width at half maximum to the peak energy, reflecting the system's ability to distinguish different energy gamma rays. The detection efficiency represents the proportion of incident gamma rays detected by the system, which is an important indicator of the system's sensitivity. In addition, the G(E) function of the system needs to be obtained, which represents the dose response coefficient of the system to different energy gamma rays. Based on the acquired energy spectrum data and G(E) function, the dose rate of the environment to be tested can be further calculated.

[0053] Finally, the performance evaluation step. This step comprehensively evaluates the performance of the system in gamma spectrum measurement according to the results of energy resolution, detection efficiency and dose rate measurement accuracy, etc. This helps to verify the accuracy, stability and reliability of the system, and ensures that it meets the needs of practical applications. When the energy resolution is ≤5%, the detection efficiency is ≥30% and the dose rate measurement accuracy is ≤±5%, it is determined that the system meets the requirements of gamma spectrum measurement; if not, return to the parameter adjustment step or the rescaling step until the requirements are met.

[0054] Through the above technical solutions, the present disclosure provides a systematic gamma spectrum measurement method, effectively solving the problem of how to use a gamma radiation detection system based on a perovskite scintillator to accurately and reliably measure and comprehensively evaluate its performance. The energy scaling step ensures accurate conversion of energy information, the parameter setting step optimizes the working state of the system in different scenarios, the energy spectrum acquisition step ensures effective data acquisition, and the data processing step converts the original data into physical quantities with practical significance. Finally, the performance evaluation step provides a verification basis for reliable operation of the system. This method enables the above-mentioned gamma radiation detection system to efficiently and accurately complete the gamma spectrum measurement task, providing strong technical support for the fields of radiation monitoring and nuclear safety, etc.

[0055] According to an embodiment of the present disclosure, the calculation method of the energy resolution is: , wherein, is the energy resolution, is the energy value corresponding to the full width at half maximum of the full energy peak, is the energy value of the gamma ray corresponding to the full energy peak.

[0056] The above calculation method is based on the full width at half maximum and peak position energy of the full energy peak, which can intuitively reflect the discrimination ability of the detection system for different energy gamma rays. Through the standardized calculation formula, the objectivity and comparability of the energy resolution evaluation results are ensured, so that the evaluation of system performance is more accurate and reliable.

[0057] According to an embodiment of the present disclosure, the calculation method of the detection efficiency is: , wherein, is the detection efficiency, is the net count of the full energy peak, obtained by subtracting the background count from the total count of the full energy peak; is the number of incident photons of the standard gamma radiation source at the detector, calculated according to the activity, emission rate and distance of the standard source.

[0058] The above calculation method clearly defines the calculation formula of the detection efficiency, and obtains the detection efficiency by deducting the background count from the total count of the full-energy peak , effectively eliminates the interference of environmental noise on the measurement results, so that the efficiency evaluation more truly reflects the response ability of the detector to the source signal. At the same time, The calculation is based on the activity, emission rate and distance of the standard source, which provides traceable incident photon number and avoids errors caused by subjective estimation. The activity refers to the number of nuclei decaying per unit time of the radioactive source, the emission rate refers to the average number of γ photons emitted per decay of a specific energy, and the distance affects the proportion of photons reaching the detector through the geometric factor (such as solid angle).

[0059] According to an embodiment of the present disclosure, the calculation method of the dose rate is: , wherein, is the dose rate, is the count rate at energy E, which is obtained by dividing the count corresponding to energy E in the energy spectrum data by the total acquisition time, ΔE is the energy interval, and the summation range covers the measured γ ray energy interval.

[0060] Specifically, the count rate at energy E refers to the number of γ ray events recorded by the detector per unit time at a specific energy E. This count rate is obtained by dividing the count corresponding to energy E in the energy spectrum data by the total acquisition time, and directly reflects the relative intensity of γ rays at this energy point. The function is the dose response coefficient of the system to γ rays of different energies, which converts the count rate N(E) measured by the detector at a specific energy E into the contribution of the dose rate at that energy. The function considers the detection efficiency, energy deposition characteristics and conversion factor from absorbed energy to dose rate of the detector for γ rays of different energies, and is the key to accurate dose rate calculation. The energy interval ΔE represents the width of each energy channel or energy interval in the energy spectrum data. In discrete energy spectrum data, the calculation of the dose rate is realized by accumulating and summing the count rate in each energy interval multiplied by the corresponding dose response coefficient. The summation range covers the measured γ ray energy interval, which means that when calculating the total dose rate, the term needs to be accumulated to ensure the comprehensiveness and accuracy of the calculation result.

[0061] According to an embodiment of the present disclosure, the function is obtained by Monte Carlo simulation or standard radiation field experiment calibration. At least five standard γ radiation sources of different energies are used in the calibration process to establish the correspondence between the count rate and the known dose rate, and the function value. The function value is obtained by Monte Carlo simulation or standard radiation field experiment calibration. The function reflects the conversion relationship between the output signal (e.g. count rate) of the system and the actual dose rate when receiving γ-rays of a specific energy. An accurate function is the key to achieving accurate dose rate measurement, as it can correct the response differences of the detector to γ-rays of different energies, thereby converting the detected energy spectrum data into dose rate values with physical meaning.

[0062] Specifically, the function value is obtained by Monte Carlo simulation or standard radiation field experiment calibration. The function value is obtained by Monte Carlo simulation or standard radiation field experiment calibration. In obtaining the function value, a geometric model and material composition of the detection system can be established, γ-rays of different energies can be simulated to be incident into the detector, the response of the detector to these γ-rays (such as energy deposition, count rate, etc.) can be calculated, and the dose rate information of the known radiation field can be combined to derive the function value under different energies. This method has the advantages of low cost and the ability to simulate complex geometric structures and radiation fields. Alternatively, the function value can also be obtained by standard radiation field experiment calibration. The function value is obtained by Monte Carlo simulation or standard radiation field experiment calibration. The function value is obtained by Monte Carlo simulation or standard radiation field experiment calibration. The function value is obtained by Monte Carlo simulation or standard radiation field experiment calibration.

[0063] In the calibration process, at least five standard γ radiation sources of different energies are used. At least five standard γ radiation sources of different energies are used to ensure that the function has good accuracy and continuity in a wide energy range. The interaction mechanisms of γ-rays of different energies with the detector material are different, resulting in changes in the response characteristics of the detector with energy. By using enough energy points for calibration, the trend of the function value with energy can be more finely described, avoiding interpolation errors or inaccurate extrapolation due to insufficient sampling points, thereby improving the accuracy of dose rate measurement in the entire energy range.

[0064] On this basis, the correspondence between the count rate and the known dose rate is established. In Monte Carlo simulation or standard radiation field experiment, for each specific energy of the γ radiation source, the system will generate a corresponding count rate ​Meanwhile, the radiation source produces a known dose rate at the detector position . By recording these pairs of data, i.e. , a basis for subsequent function fitting can be provided.

[0065] Subsequently, the function values at different energies are fitted. After obtaining the correspondence between the count rate and the known dose rate at a series of different energy points, a continuous function needs to be obtained through fitting methods. The fitting process usually involves selecting a suitable mathematical model (such as polynomial fitting, exponential fitting, piecewise linear fitting, etc.) to describe the trend of the function with energy E. Through least squares method or other optimization algorithms, the experimental or simulation data points are fitted with the selected model, thus obtaining a function expression applicable in the entire measurement energy interval or a set of discrete function values. This fitting method can smooth the data, reduce the influence of random errors, and allow the estimation of the function at energy points that are not directly calibrated.

[0066] In some embodiments of the present disclosure described above, a gamma spectrum measurement method is proposed, which includes an energy calibration step, a parameter setting step, a spectrum acquisition step, a data processing step, and a performance evaluation step. However, in actual application, if the long-term stability of the system, the repeatability of the measurement results, and the linearity of the energy response are not explicitly and quantitatively evaluated, it is difficult to fully grasp the reliability and accuracy of the system, which may lead to insufficient confidence in the measurement results, limiting the application of the system in scenarios with high precision requirements.

[0067] To this end, the present disclosure further refines the above-mentioned performance evaluation step, which also includes stability evaluation, repeatability evaluation, and linearity evaluation.

[0068] Specifically, the stability evaluation is used to measure the change of the energy resolution of the system after a continuous measurement setting time. This evaluation is completed by calculating the energy resolution change rate after the continuous measurement setting time; where is the initial energy resolution, is the energy resolution after the setting time. To ensure the long-term stability of the system, it is required that ≤ 5%. This means that the drift of the energy resolution of the system after a long time of operation should be controlled within 5%, thereby ensuring the performance consistency of the system in continuous working state.

[0069] ​​The repeatability evaluation is used to measure the consistency of the measurement results of the system when measuring multiple times under the same conditions. The evaluation is completed by calculating the energy resolution standard deviation and the dose rate standard deviation . Among them, , is the energy resolution of the ith measurement, is the average value of n measurements, n≥5; , is the dose rate of the ith measurement, is the average value of n measurements, n≥5. In order to ensure the reliability of the measurement results, the energy resolution standard deviation ≤0.3%, and the dose rate standard deviation ≤±2%. These strict indicators ensure that the system can provide highly consistent and reliable data when repeatedly measuring, effectively reducing the influence of random errors on the measurement results, and improving the confidence of the measurement results.

[0070] The linearity evaluation is used to measure whether the response of the system to different energy gamma rays is linearly related to its true energy. The evaluation is completed by calculating the linearity , wherein, , is the energy value of the gamma ray measured by the system, is the true energy value of the gamma ray. In order to ensure the accuracy of the energy response of the system, ≤2%. This indicates that the system has good energy response linearity in a wide energy range, and can accurately measure gamma rays of different energies, thereby improving the accuracy of energy calibration.

[0071] The above evaluation methods work together to make the gamma spectrum measurement system not only provide spectrum data, but also strictly control the quality of its performance, thereby improving the scientificity and practicality of the entire measurement method, making it more suitable for application scenarios with high requirements for measurement accuracy and reliability.

[0072] According to the embodiments of the present disclosure, in the parameter setting step: the bias of the SiPM photoelectric conversion module is set to 27-30V; the acquisition time of the data acquisition module is set to 1200-6400 seconds; the Gaussian filter shaping time of the signal processing module is set to 0.5-6μs.

[0073] Specifically, the bias is set in a specific range of 27-30V, aiming to make the SiPM photoelectric conversion module work in the best state, ensure efficient conversion of weak fluorescent signals, and effectively suppress noise, thereby providing high-quality raw electrical signals for subsequent signal processing. The acquisition time is set in the range of 1200-6400 seconds to ensure that the full-energy peak count meets the statistical error requirement, and the statistical error is controlled within 1%. The Gaussian filter shaping time is set in the range of 0.5-6μs, which can optimize the output signal characteristics of the perovskite scintillator module and the SiPM photoelectric conversion module, effectively suppress noise, reduce pulse pile-up effect, and obtain clearer energy spectrum peak shape.

[0074] The gamma radiation detection system based on perovskite scintillator provided by the embodiments of the present disclosure at least achieves the following technical effects: 1. The multi-energy standard source calibration method is adopted to establish a precise channel address-energy linear relationship, fully utilize the high light yield advantage of perovskite scintillator, and improve the energy calibration accuracy.

[0075] 2. The signal processing module adopts the strategy of combining low-noise amplification and Gaussian filtering to match the fast decay characteristics of perovskite scintillator, reduce signal pile-up and noise interference, and improve the energy resolution to below 5%.

[0076] 3. A multi-dimensional performance evaluation system covering energy resolution, detection efficiency, stability, repeatability and linearity is established to comprehensively reflect the measurement performance of the system.

[0077] 4. The G(E) function is introduced and obtained through Monte Carlo simulation combined with experimental calibration, realizing accurate dose rate calculation based on energy spectrum data and solving the problem of large measurement error of traditional methods.

[0078] 5. The system adopts the architecture of perovskite scintillator coupled with SiPM, which is small in size and light in weight, and the perovskite scintillator has good environmental stability, which is suitable for on-site measurement in complex scenes such as nuclear emergency.

[0079] The technical solutions of the present disclosure are further illustrated by a specific embodiment as follows: The gamma energy spectrum measurement method of the gamma radiation detection system based on perovskite scintillator includes the following steps: Step one, energy calibration: complete the energy calibration of the system according to the set procedure to obtain the linear regression equation of channel address x and gamma ray energy E, E=kx+b, where k and b are parameters of the linear equation.

[0080] Step two, parameter setting: according to the characteristics of the test scene, the bias voltage of the SiPM photoelectric conversion module is set; the acquisition time and channel number configuration of the data acquisition module are set according to the requirements; the Gaussian filter shaping time and the gain of the amplification circuit of the signal processing module are set according to the adaptation requirements.

[0081] Step three, energy spectrum acquisition: place the perovskite scintillator module in the test environment, and ensure that the surface of the module is perpendicular to the radiation incident direction. The SiPM photoelectric conversion module converts the fluorescent signal generated by the scintillator into an electrical signal. After being amplified by the preamplification circuit, the electrical signal is filtered by the shaping filter circuit to remove noise, and then amplified by the main amplification circuit and transmitted to the data acquisition module. The data acquisition module acquires energy spectrum data according to the set acquisition parameters, and stores the energy spectrum curve with channel address as the horizontal coordinate and count as the vertical coordinate.

[0082] Figure 2 A gamma spectrum curve diagram according to an embodiment of the present disclosure is shown, and the size of the Cs3Cu2I5 perovskite scintillation crystal is 5mmx5mmx5mm. The red full energy peak in the figure corresponds to the characteristic gamma ray, and the following is recorded in the figure: The full energy peak energy value Peak: 690.95keV; the energy value corresponding to the full energy peak half width FWHM: 33.08keV; the width FW(1 / 5)M at 1 / 5 of the peak height: 51.10keV; the total peak area (integral count) Gross Area: 54004; the net peak area (signal count after background subtraction) Net Area: 51425±307; the total count rate and net count rate Gross / Net Count Rate: 45.27 / 43.11 cps.

[0083] Figure 3 A gamma spectrum curve diagram according to an embodiment of the present disclosure is shown, and the size of the Cs3Cu2I5 perovskite scintillation crystal is 10mmx10mmx5mm. The red full energy peak in the figure corresponds to the characteristic gamma ray, and the following is recorded in the figure: The full energy peak energy value Peak: 280.25keV; the energy value corresponding to the full energy peak half width FWHM: 13.91keV; the width FW(1 / 5)M at 1 / 5 of the peak height: 21.81keV; the total peak area (integral count) Gross Area: 39861; the net peak area (signal count after background subtraction) Net Area: 38258±228; the total count rate and net count rate Gross / Net Count Rate: 25.18 / 24.17 cps.

[0084] The 5mm×5mm×5mm small-size crystal focuses on optimizing energy resolution. Due to its small size and short photon transmission path, it can reduce signal accumulation and noise interference, making it suitable for scenarios with high radiation intensity and the need for accurate resolution of gamma-ray energy. The 10mm×10mm×5mm large-size crystal improves detection efficiency by increasing the gamma-ray interaction area, and can capture more incident photons, making it suitable for scenarios with low radiation intensity and the need for high-sensitivity acquisition of energy spectrum data.

[0085] Step four, data processing: Based on the linear regression equation E=kx+b established in step one, the collected energy spectrum data is calibrated to convert the channel address into the corresponding gamma-ray energy. The full-energy peak in the energy spectrum curve is identified, and the channel address range corresponding to the full-energy peak's half-width at half-maximum (FWHM) is measured. The energy value FWHM corresponding to the FWHM is calculated using the linear regression equation. The energy resolution is calculated using the energy resolution calculation formula. Simultaneously, the detection efficiency is calculated using the detection efficiency calculation formula.

[0086] During dose rate calculation, a pre-stored calibration value for the G(E) function is invoked. This G(E) function is calibrated through Monte Carlo simulation combined with experiments using five different energy standard sources. The calibrated energy spectrum data is divided into several energy intervals according to the energy range of 0-2000 keV, with each interval ΔE being 1 keV. The counts corresponding to each energy E are extracted, and the count rate N(E) = counts / acquisition time is calculated. Substituting this into the dose rate calculation formula, the summation covers the interval within 2000 keV to obtain the dose rate of the test environment.

[0087] Step 5, Performance Evaluation: Energy resolution meets ≤5%, detection efficiency meets ≥30%, and dose rate measurement accuracy is obtained by comparison with a standard dosimeter, meeting ≤±5%. Further stability testing: Continuous measurement for a set time is performed to calculate the initial energy resolution. Energy resolution after a set time, such as 24 hours rate of change ,Require ≤5%; Calculate the initial dose rate Dose rate after set time rate of change ,Require ≤±3%. Repeatability test: Perform multiple measurements and calculate the standard deviation of energy resolution. ,Require ≤0.3%; calculate the standard deviation of dose rate ,Require ≤±2%. Linearity test: The linearity is calculated using standard sources with different energies. ,Require ≤2%.

[0088] The above description is merely that of the preferred embodiments of the present disclosure and a description of the technical principles of the present disclosure. It should be understood by those skilled in the art that the inventive scope involved in the present disclosure is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by the combinations of the above technical features or equivalent features without departing from the inventive concept. For example, the technical solutions formed by the mutual replacement of the above features and the technical features with similar functions disclosed in the present disclosure (but not limited to) can be used.

Claims

1. A gamma radiation detection system based on a perovskite scintillator, characterized in that, include: A perovskite scintillator module, wherein the perovskite scintillator module uses a Cs3Cu2I5 perovskite scintillator crystal; The SiPM photoelectric conversion module is optically coupled to the perovskite scintillator module and is used to convert the fluorescence signal generated by the perovskite scintillator module into an electrical signal. A signal processing module, which is electrically connected to the SiPM photoelectric conversion module, is used to amplify and filter the electrical signal; The data acquisition module is communicatively connected to the signal processing module. It is used to acquire the energy spectrum data processed by the signal processing module and to complete the energy calibration in conjunction with a multi-energy standard gamma radiation source to establish a linear relationship between channel address and gamma ray energy.

2. The system according to claim 1, characterized in that, The signal processing module includes a preamplifier circuit, a shaping filter circuit, and a main amplifier circuit connected in sequence. The shaping filter circuit adopts a Gaussian filtering algorithm, and the filtering parameters are set according to the output signal characteristics of the SiPM photoelectric conversion module.

3. The system according to claim 1 or 2, characterized in that, The data acquisition module is a multichannel analyzer, configured with 2048 or 4096 channels, and communicates with the signal processing module via a USB interface.

4. A method for measuring the gamma spectrum based on the system described in any one of claims 1 to 3, characterized in that, Includes the following steps: Energy calibration steps: The system is calibrated using at least three standard gamma radiation sources with different energies, and a linear regression equation between channel address and gamma ray energy is established. Parameter setting steps: Set the bias voltage of the SiPM photoelectric conversion module and the acquisition parameters of the data acquisition module according to the test scenario; Energy spectrum acquisition steps: The perovskite scintillator module is placed in the test environment. The SiPM photoelectric conversion module converts the fluorescence signal generated by the scintillator into an electrical signal. After being processed by the signal processing module, the energy spectrum data is acquired by the data acquisition module. Data processing steps: Based on the linear regression equation, the collected energy spectrum data is calibrated, the channel address is converted into the corresponding gamma-ray energy, and the energy resolution and detection efficiency are calculated; The system's G(E) function is obtained, and the dose rate is calculated based on the energy spectrum data and the G(E) function, where the G(E) function is the system's dose response coefficient to gamma rays of different energies; Performance evaluation steps: Evaluate the system's gamma spectroscopy measurement performance based on energy resolution, detection efficiency, and dose rate measurement accuracy results.

5. The method according to claim 4, characterized in that, The method for calculating the energy resolution is as follows: ， in, For energy resolution, This represents the energy value corresponding to the full-energy peak's half-width at half-maximum. This represents the energy value of the gamma rays corresponding to the full-energy peak.

6. The method according to claim 4, characterized in that, The method for calculating the detection efficiency is as follows: ， in, For detection efficiency, The net count of the total energy peaks is obtained by subtracting the background count from the total energy peak count. The number of incident photons from the standard gamma radiation source at the detector is calculated based on the activity, emissivity, and distance of the standard source.

7. The method according to claim 4, characterized in that, The dose rate is calculated as follows: ， in, For dose rate, ΔE represents the count rate at energy E, obtained by dividing the count corresponding to energy E in the energy spectrum data by the acquisition time. ΔE represents the energy interval, and the summation range covers the measured γ-ray energy range.

8. The method according to claim 4, characterized in that, The The function is obtained through Monte Carlo simulation or standard radiation field experiment calibration. During the calibration process, at least five standard gamma radiation sources with different energies are used to establish the correspondence between the count rate and the known dose rate, and the function is fitted to obtain the values ​​at different energies. Function value.

9. The method according to any one of claims 4 to 8, characterized in that, The performance evaluation steps also include: Stability assessment: Calculate the rate of change in energy resolution after continuous measurement for a set time. ,in, For the initial energy resolution, Energy resolution after setting time; Repeatability assessment: Calculate the standard deviation of energy resolution and dose rate over multiple measurements; Linearity evaluation: Calculate linearity ,in, The measured gamma-ray energy value is... This represents the actual energy value of the gamma rays.

10. The method according to claim 4, characterized in that, In the parameter setting steps: The bias voltage of the SiPM photoelectric conversion module is set to 27-30V; The data acquisition module's acquisition time is set to 1200-6400 seconds; The Gaussian filtering shaping time of the signal processing module is set to 0.5-6 μs.

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