CN-120428346-B - X & gamma ray real-time screening system based on energy spectrum-space-time fusion

CN120428346BCN 120428346 BCN120428346 BCN 120428346BCN-120428346-B

Abstract

The invention belongs to the technical field of radiation detection and analysis, in particular to an X & gamma ray real-time screening system based on energy spectrum-space fusion, which comprises a double-layer detector, a detection module and a detection module, wherein the double-layer detector comprises an upper layer filtering layer and a lower layer full spectrum layer and is used for receiving and screening X rays and gamma rays; the data acquisition module synchronously acquires energy spectrum, time sequence pulse and space distribution data, the time sequence analysis and LSTM network takes LSTM as a special cyclic neural network, has remarkable advantages in the aspects of processing long-sequence data and capturing long-term dependency, can make up for the defects of a traditional time sequence analysis method, and the characteristic extraction module is a bridge connecting original data and a prediction model in the time sequence analysis and is used for calculating the peak area occupation ratio of K-edge and judging effective pulse according to the output of the LSTM network, and realizes 300ms real-time response by adopting the combination of a double-layer detector and the LSTM network, so that the distinguishing capability of X-rays and gamma-rays is improved, and the accuracy and reliability of integral detection are also enhanced.

Inventors

YANG BIN
HAO JIAYU
Xuan Taijie
LIU GUANGHAO
ZHAO HONGTAO
LI YAN
GAO WA
Gou yan
LI GANG
GAO WEICHEN
Yang Dazhan
ZHOU DONGLIANG

Assignees

黑龙江省原子能研究院

Dates

Publication Date: 20260512
Application Date: 20250422

Claims (4)

1. An energy spectrum-space-time fusion-based real-time X & gamma ray screening system, comprising: the double-layer detector comprises an upper layer filtering layer and a lower layer full spectrum layer and is used for receiving and screening X-rays and gamma-rays; the upper filter layer adopts a copper foil with the thickness of 0.2mm, and shields X rays with the energy of less than 20keV, retains the characteristic peak of K-edge at 20-80keV, and reduces low-energy gamma ray interference; The lower full spectrum layer is SiPM array coupling NaI crystal size 50Mm multiplied by 50mm, realizing coverage of an energy region of 1-300keV, and inverting the leakage X-ray energy spectrum formula as follows: ; In the above formula: is a full-energy spectrum of the product, The energy spectrum E is E [20,80] keV for the filtering layer; The data acquisition module synchronously acquires energy spectrum, time sequence pulse and space distribution data, and ensures the data synchronization through a time stamp technology; the timing analysis and LSTM network comprises: signal synchronization, namely collecting high-voltage power supply signal of X-ray machine as The detector pulse is Constructing a cross-correlation function: ; Wherein, the The number of the sampling points is calculated; for sampling index, representing the first of the signal sequence Sampling points; for a time offset, the time delay or offset between two signals is represented; for the pulse signal output by the detector, in this case The whole is shifted on the time axis Sequences obtained after sampling points; LSTM network with input layer of 100 point time window Sequence, hidden layer 32 node, output sequence matching degree Capturing the causal relationship between the X-ray pulse and the on-off state of the equipment; LSTM output Threshold value Judging as a valid pulse; The characteristic extraction module is a bridge connecting the original data with the prediction model in time sequence analysis, and is used for calculating the K-edge peak area occupation ratio and judging effective pulses according to LSTM network output; The fusion decision module is used for comprehensively judging based on a dynamic weighting fusion model by combining the energy spectrum weight, the peak area occupation ratio, the time sequence weight and the time sequence matching degree and triggering the X-ray leakage alarm; The dynamic weighting fusion model is used for carrying out comprehensive calculation according to the energy spectrum weight, the peak area occupation ratio, the time sequence weight and the time sequence matching degree to obtain a discrimination result, establishing a weight self-adaptive rule, dynamically adjusting the weight according to the environment background gamma dose rate and the equipment working frequency, and ensuring that the energy spectrum weight is improved in a high background environment and the time sequence weight is improved in a pulse dense scene; The criterion formula of the dynamic weighting fusion model is as follows: ; In the above Energy spectrum weight; Peak area ratio; is a time sequence weight; The time sequence matching degree; Dynamically compensating gain drift of the detector based on a temperature sensor to ensure that the error is less than 3% under the working condition of-30 ℃ to 60 ℃; And establishing the following weight self-adaptive rule according to the model: High background environment, gamma dosage rate >1 mu Sv/h, and improved energy spectrum weight Suppressing time interference; Pulse dense scene, equipment frequency >100Hz, lifting time sequence weight Short pulse recognition is enhanced.
2. The energy spectrum-space time fusion-based X & gamma ray real-time screening system according to claim 1, wherein the data acquisition module acquires original data from the double-layer detector in real time according to a set acquisition frequency, ensures the synchronism of the data through a time stamping technology, and performs preliminary processing on the acquired data to improve the data quality.
3. The energy spectrum-space time fusion-based real-time X & gamma ray screening system according to claim 1, wherein the calculation formula of the K-edge peak area ratio is as follows: ; Wherein, the Inverting the leakage X-ray energy spectrum; Is a full spectrum.
4. The energy spectrum-space time fusion-based real-time X & gamma ray screening system according to claim 1, wherein the threshold value of the criterion formula of the dynamic weighted fusion model Triggering an X-ray leakage alarm.

Description

X & gamma ray real-time screening system based on energy spectrum-space-time fusion Technical Field The invention belongs to the technical field of radiation detection and analysis, and particularly relates to an X & gamma ray real-time screening system based on energy spectrum-space-time fusion. Background The energy range (1-150 keV) of the X-ray security inspection equipment is obviously overlapped with gamma rays (10 keV-3 MeV) released by natural radioactive substances (such as 137Cs and 226 Ra) in the environment due to shielding failure or mechanical abrasion when the X-ray security inspection equipment works, the traditional method depends on single energy threshold or pulse width detection, the misjudgment rate is as high as 30% -40%, and the radiation security monitoring system is caused to frequently give out false alarms, so that the normal operation of the equipment is affected. In addition, the X-ray leakage has the characteristics of directivity and pulse, the gamma rays are isotropic continuous radiation, the two are difficult to distinguish through a single parameter in a mixed radiation field, the existing detection technology can be used for distinguishing X & gamma rays by setting a fixed energy threshold (such as 50 keV), but the low-energy gamma rays (such as 59.5 keV of 241 Am) are overlapped with K-edge characteristic peaks (20-80 keV) of the X rays, so that misjudgment is caused, and if the difference between the pulse width (10-100 mu s) of the X-rays and the continuous radiation of the gamma rays is adopted for distinguishing by adopting a time filtering method, the difference is difficult to distinguish in an extremely short time due to the fact that the response time of a common scintillator detector is more than 100 ns. Therefore, an X & gamma ray real-time screening system based on energy spectrum-space-time fusion is provided for the problems. Disclosure of Invention (One) solving the technical problems Aiming at the defects of the prior art, the invention provides an X & gamma ray real-time screening system based on energy spectrum-space-time fusion, which is used for solving the problems in the background art. (II) technical scheme In order to achieve the purpose, the invention provides the following technical scheme that the X & gamma ray real-time screening system based on energy spectrum-space-time fusion comprises: the double-layer detector comprises an upper layer filtering layer and a lower layer full spectrum layer and is used for receiving and screening X-rays and gamma-rays; The data acquisition module synchronously acquires energy spectrum, time sequence pulse and space distribution data, and ensures the data synchronization through a time stamp technology; The LSTM is used as a special cyclic neural network, has remarkable advantages in the aspects of processing long-sequence data and capturing long-term dependency, and can make up for the defects of the traditional time sequence analysis method; The characteristic extraction module is a bridge connecting the original data with the prediction model in time sequence analysis, and is used for calculating the K-edge peak area occupation ratio and judging effective pulses according to LSTM network output; and the fusion decision module is used for comprehensively judging based on the dynamic weighted fusion model by combining the energy spectrum weight, the peak area occupation ratio, the time sequence weight and the time sequence matching degree and triggering the X-ray leakage alarm. Preferably, the upper filter layer adopts 0.2mm copper foil, shields X rays with energy less than 20keV, retains the characteristic peak of K-edge at 20-80keV, and reduces low-energy gamma ray interference; The lower full spectrum layer is SiPM array coupling NaI crystal size 50-Mm multiplied by 50mm, realizing coverage of an energy region of 1-300keV, and inverting the leakage X-ray energy spectrum formula: ; In the above formula: is a full-energy spectrum of the product, For the filter layer, the energy spectrum E is [20,80] keV. The upper filter layer directly influences the energy resolution capability and imaging quality of the detector, realizes synchronous acquisition of full energy spectrum information through unique materials and structural design, provides multi-dimensional material quantitative analysis capability for clinical diagnosis, and enhances detection resolution. Preferably, the data acquisition module acquires original data from the double-layer detector in real time according to a set acquisition frequency, ensures the synchronism of the data through a time stamping technology, and performs preliminary processing on the acquired data to improve the data quality. Preferably, the calculation formula of the K-edge peak area ratio is as follows: ; Wherein, the Inverting the leakage X-ray energy spectrum; Is a full spectrum. Preferably, the timing analysis and LSTM network includes: signal synchronization, namely col