Digital adaptive passive peak stabilizing method for gamma-ray energy spectrum measurement and analysis

Abstract

The invention discloses a digital self-adaptive passive peak stabilizing method for gamma-ray energy spectrum measurement and analysis. The method comprises the following steps: 1, measuring gamma-ray energy spectrum scales of a radiation detection instrument; 2, electrifying the radiation detection instrument; 3, preheating the radiation detection instrument and performing initial energy spectrum drift correction; and 4, self-adaptive peak stabilization of the radiation detection instrument. According to the method, the peak drift is accurately identified and corrected in a digital passive mode, and the energy spectrum is stabilized through an adaptive method, so that normal work can be ensured when an interference source exists, and the energy peak can be adaptively selected for stabilization.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear energy spectrum processing, and in particular relates to a digital adaptive passive peak stabilization method for gamma-ray energy spectrum measurement and analysis. Background Art

[0002] In the gamma-ray measurement and analysis system, due to the influence of environmental heat and device heat dissipation, the performance of passive devices such as amplifiers, photoelectric converters, resistors and capacitors will change significantly, causing the peak position of the measured energy spectrum to drift with temperature changes, affecting the accuracy of the measurement.

[0003] At present, the gamma spectrum stabilization is mainly divided into two steps, namely, identifying peak drift and correcting peak drift. Among them, the identification of peak drift is divided into two methods: active and passive. The active method uses a reference energy peak formed by a known energy LED light source or a radioactive source in the gamma ray measurement and analysis system as a reference peak, and uses the deviation between the measured energy and the scale energy as the basis for peak drift judgment. This method has strong anti-interference ability, but due to the introduction of an additional incident source, it will cause a certain degree of interference to normal measurement, which is particularly obvious when using an LED light source, and the use of a radioactive source will increase the cost of the measurement system and management costs. Relatively speaking, the passive method not only does not introduce interference, but also does not have to bear high manufacturing and maintenance costs. It is an economical method, but its stability and accuracy are poor.

[0004] In addition, there are two methods to correct peak drift: analog and digital. The analog method is achieved by adjusting the high voltage and amplifier gain, but this method has no feedback mechanism and is highly dependent on the working performance of analog devices in unknown environments, and even has the risk of increased drift. The digital method is more flexible, has low maintenance costs, and is more precise to operate. It is a method with great potential for correcting energy spectrum drift, but it has higher requirements for the correction algorithm. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a digital adaptive passive peak stabilization method for gamma-ray energy spectrum measurement and analysis in view of the deficiencies in the above-mentioned prior art.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a digital adaptive passive peak stabilization method for gamma-ray energy spectrum measurement and analysis, characterized in that the method comprises the following steps:

[0007] Step 1: Calibrate the gamma-ray energy spectrum of the radiation detection instrument: Calibrate the gamma-ray energy spectrum of the radiation detection instrument at a standard temperature using a standard radiation source known to emit gamma-rays of a specific energy;

[0008] Step 2: Power on the radiation detection instrument;

[0009] Step 3: Preheat the radiation detection instrument and perform initial spectrum drift correction. The process is as follows:

[0010] Step 301: When the preheating environment has background environment conditions, or the preheating environment does not have background environment conditions but the gamma ray energy of the interfering nuclide in the preheating environment is less than the full energy peak position of the standard radioactive source reference peak, step 302 is executed; when the preheating environment does not have background environment conditions and the gamma ray energy of the interfering nuclide in the preheating environment is not less than the full energy peak position of the standard radioactive source reference peak, step 303 is executed;

[0011] Step 302: quickly record the initial energy spectrum drift L0 caused by the change in ambient temperature after the radiation detection instrument is powered on, and then enter the fast preheating mode. When the fast preheating mode achieves spectrum stabilization within the running measurement time of 1000s, the radiation detection instrument preheating ends and the initial energy spectrum drift correction is completed; when the fast preheating mode does not achieve spectrum stabilization within the running measurement time of 1000s, the slow preheating mode is turned on, and the slow preheating mode is only run once. After the slow preheating mode ends, the initial energy spectrum drift correction is completed;

[0012] The fast preheating mode: peak search once per fast peak search cycle, channel address CH i The peak search results are compared with the calibration peak address CH0 result of the full energy peak of the standard radioactive source reference peak. i When the difference between the address CH0 and the address CH1 is less than the first threshold, the address CH2 is i The result is the actual measured peak of the full energy peak of the standard radioactive source reference peak, and the drift L1 in the fast preheating mode is recorded. Each channel of the measured energy spectrum is subtracted from the L1 value in turn to complete the initial energy spectrum drift correction, where i is the channel address number and i=1,2,...,n, and n is the total number of channels;

[0013] The slow preheating mode: set the second threshold and search for peaks, and the channel address CH within the second threshold i The peak search result is the actual measured peak of the full energy peak of the standard radioactive source reference peak, the drift amount L2 in the slow preheating mode is recorded, and each channel of the measured energy spectrum is sequentially subtracted from the L2 value to complete the initial energy spectrum drift correction, wherein the second threshold is greater than the first threshold;

[0014] Step 303: Query the address CHO corresponding to the energy of a specific nuclide in the nuclide library i , peak search is performed once in each fast peak search cycle, channel address CH i The peak search results are in the same directory as the address CHO iCompare the results. Only when the channel address difference is less than the first threshold value, match the peak search result with the energy. Only when the corresponding energy number N1 is consistent with the current nuclide energy number N0, the current nuclide is considered to be matched successfully. Calculate the difference L3 between the peak with the maximum energy currently matched and the corresponding nuclide ray energy. Subtract the L3 value from each channel of the measured energy spectrum in turn to complete the initial energy spectrum drift correction.

[0015] Step 4: Radiation detection instrument adaptive peak stabilization, the process is as follows:

[0016] Step 401: After the radiation detection instrument is preheated, it enters the adaptive peak stabilization state. At this time, the radiation detection instrument can enter any radiation field to start measurement, and record the first peak search result and the corresponding channel address. extract The peak with the highest energy

[0017] Step 402: Use the radiation detection instrument to perform real-time measurement, search for peaks once per rapid peak search cycle, and obtain the current peak search result and the corresponding channel address. extract The peak with the highest energy Wherein, X is a positive integer not less than 1;

[0018] Step 403: and When the difference is less than the first threshold, it is considered that the peak positions before and after the peak search correspond to the same γ-ray, and the forward drift amount L is obtained. Each channel of the measured energy spectrum is subtracted from the L value in turn to complete the energy spectrum drift correction, and the peak search result is not retained;

[0019] when and When the difference is not less than the first threshold, it indicates that the detected nuclide has changed, the current peak search result will be retained, and step 402 will be repeated until the measurement is completed, so as to realize adaptive selection of energy peak stable spectrum according to the change of the γ radiation field.

[0020] The above-mentioned digital adaptive passive peak stabilization method for gamma-ray energy spectrum measurement and analysis is characterized in that: the radiation detection instrument includes a NaI radiation detection instrument and a LaBr3 radiation detection instrument;

[0021] When the radiation detection instrument adopts NaI radiation detection instrument, natural 40 The K peak is used as the reference peak for peak stabilization;

[0022] When the radiation detection instrument adopts LaBr3 radiation detection instrument, the lanthanum peak is used as the reference peak for peak stabilization.

[0023] The above-mentioned digital adaptive passive peak stabilization method for gamma-ray energy spectrum measurement and analysis is characterized in that the rapid peak search period is 30s to 100s.

[0024] The above-mentioned digital adaptive passive peak stabilization method for gamma-ray energy spectrum measurement and analysis is characterized in that: the first threshold is 5 to 15 channels; the second threshold is 30 to 50 channels.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. The present invention accurately identifies and corrects peak drift in a digital passive manner, and stabilizes the energy spectrum through an adaptive method. It can not only ensure normal operation when interference sources exist, but also adaptively select energy peaks for stabilization, which is convenient for promotion and use.

[0027] 2. The present invention can not only identify drift in passive conditions and when the temperature difference is large, but also automatically identify the interference radiation field in the environment, correctly identify the drift amount, and can adaptively identify the changes in the nuclides in the external radiation field under normal working conditions to perform adaptive peak stabilization, thereby ensuring that the detector is stable and reliable in various environments and has good use effect.

[0028] 3. The method of the present invention has simple steps, lower investment time, funds and management costs, has very good application prospects, and is easy to promote and use.

[0029] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a flowchart of the method of the present invention. DETAILED DESCRIPTION

[0031] like Figure 1 As shown, a digital adaptive passive peak stabilization method for gamma-ray energy spectrum measurement and analysis of the present invention comprises the following steps:

[0032] Step 1: Calibrate the gamma-ray energy spectrum of the radiation detection instrument: Calibrate the gamma-ray energy spectrum of the radiation detection instrument at a standard temperature using a standard radiation source known to emit gamma-rays of a specific energy;

[0033] It should be noted that gamma spectrum energy calibration is the process of calibrating the gamma spectrometer in fields such as nuclear physics, radioactivity detection and environmental monitoring to ensure that the instrument can accurately measure the energy of gamma rays. Place a standard radiation source in front of the detector of the gamma spectrometer, ensure that the position of the radiation source is fixed so that the gamma rays can be incident on the detector vertically, start the gamma spectrometer, and let the detector collect the gamma-ray energy spectrum for a certain period of time. During this process, the gamma rays will generate electron-hole pairs in the detector, which will be processed by the electronics system to form an energy spectrum diagram; on the energy spectrum diagram, gamma rays of different energies will form different peaks, and the energy peaks corresponding to each standard radiation source can be identified through the energy spectrum diagram; calculate the energy calibration coefficient, and use the energy of multiple standard radiation sources and the peak positions measured by the instrument to draw an energy calibration curve, which is usually a straight line, and the best fitting straight line is obtained by least squares fitting; use standard radiation sources that are not involved in the establishment of the calibration curve to verify the accuracy of the calibration. If the values ​​of the gamma-ray energy of these radiation sources obtained through the calibration curve are consistent with the actual values, it means that the calibration is accurate. When actually measuring unknown radiation sources, use the established energy calibration curve to correct the energy value measured by the instrument to obtain accurate gamma-ray energy.

[0034] Step 2: Power on the radiation detection instrument;

[0035] Step 3: Preheat the radiation detection instrument and perform initial spectrum drift correction. The process is as follows:

[0036] Step 301: When the preheating environment has background environment conditions, or the preheating environment does not have background environment conditions but the gamma ray energy of the interfering nuclide in the preheating environment is less than the full energy peak position of the standard radioactive source reference peak, step 302 is executed; when the preheating environment does not have background environment conditions and the gamma ray energy of the interfering nuclide in the preheating environment is not less than the full energy peak position of the standard radioactive source reference peak, step 303 is executed;

[0037] Step 302: quickly record the initial energy spectrum drift L0 caused by the change in ambient temperature after the radiation detection instrument is powered on, and then enter the fast preheating mode. When the fast preheating mode achieves spectrum stabilization within the running measurement time of 1000s, the radiation detection instrument preheating ends and the initial energy spectrum drift correction is completed; when the fast preheating mode does not achieve spectrum stabilization within the running measurement time of 1000s, the slow preheating mode is turned on, and the slow preheating mode is only run once. After the slow preheating mode ends, the initial energy spectrum drift correction is completed;

[0038] The fast preheating mode: peak search once per fast peak search cycle, channel address CH i The peak search results are compared with the calibration peak address CH0 result of the full energy peak of the standard radioactive source reference peak. i When the difference between the address CH0 and the address CH1 is less than the first threshold, the address CH2 is iThe result is the actual measured peak of the full energy peak of the standard radioactive source reference peak, and the drift L1 in the fast preheating mode is recorded. Each channel of the measured energy spectrum is subtracted from the L1 value in turn to complete the initial energy spectrum drift correction, where i is the channel address number and i=1,2,...,n, and n is the total number of channels;

[0039] The slow preheating mode: set the second threshold and search for peaks, and the channel address CH within the second threshold i The peak search result is the actual measured peak of the full energy peak of the standard radioactive source reference peak, the drift amount L2 in the slow preheating mode is recorded, and each channel of the measured energy spectrum is sequentially subtracted from the L2 value to complete the initial energy spectrum drift correction, wherein the second threshold is greater than the first threshold;

[0040] Step 303: Query the address CHO corresponding to the energy of a specific nuclide in the nuclide library i , peak search is performed once in each fast peak search cycle, channel address CH i The peak search results are in the same directory as the address CHO i Compare the results. Only when the channel address difference is less than the first threshold value, match the peak search result with the energy. Only when the corresponding energy number N1 is consistent with the current nuclide energy number N0, the current nuclide is considered to be matched successfully. Calculate the difference L3 between the peak with the maximum energy currently matched and the corresponding nuclide ray energy. Subtract the L3 value from each channel of the measured energy spectrum in turn to complete the initial energy spectrum drift correction.

[0041] Step 4: Radiation detection instrument adaptive peak stabilization, the process is as follows:

[0042] Step 401: After the radiation detection instrument is preheated, it enters the adaptive peak stabilization state. At this time, the radiation detection instrument can enter any radiation field to start measurement, and record the first peak search result and the corresponding channel address. extract The peak with the highest energy

[0043] Step 402: Use the radiation detection instrument to perform real-time measurement, search for peaks once per rapid peak search cycle, and obtain the current peak search result and the corresponding channel address. extract The peak with the highest energy Wherein, X is a positive integer not less than 1;

[0044] Step 403: and When the difference is less than the first threshold, it is considered that the peak positions before and after the peak search correspond to the same γ-ray, and the forward drift amount L is obtained. Each channel of the measured energy spectrum is subtracted from the L value in turn to complete the energy spectrum drift correction, and the peak search result is not retained;

[0045] when and When the difference is not less than the first threshold, it indicates that the detected nuclide has changed, the current peak search result will be retained, and step 402 will be repeated until the measurement is completed, so as to realize adaptive selection of energy peak stable spectrum according to the change of the γ radiation field.

[0046] In this embodiment, the radiation detection instrument includes a NaI radiation detection instrument and a LaBr3 radiation detection instrument;

[0047] When the radiation detection instrument adopts NaI radiation detection instrument, natural 40 The K peak is used as the reference peak for peak stabilization;

[0048] When the radiation detection instrument adopts LaBr3 radiation detection instrument, the lanthanum peak is used as the reference peak for peak stabilization.

[0049] In this embodiment, the fast peak-finding period is 30s to 100s.

[0050] In this embodiment, the first threshold is 5 to 15 tracks; the second threshold is 30 to 50 tracks.

[0051] When the present invention is used, the peak drift is accurately identified and corrected in a digital passive manner, and the energy spectrum is stabilized by an adaptive method, which can not only ensure normal operation when an interference source exists, but also adaptively select energy peaks for stabilization; not only can the drift be identified in a passive state and when the temperature difference is large, but also the interference radiation field in the environment can be automatically identified, the drift amount can be correctly identified, and under normal working conditions, the external radiation field nuclide changes can be adaptively identified for adaptive peak stabilization, thereby ensuring that the detector is stable and reliable in various environments; the time, capital and management costs are lower, and it has very good application prospects.

[0052] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A digital adaptive passive peak stabilization method for gamma-ray spectrum measurement and analysis, characterized in that: The method comprises the following steps: Step 1: Calibrate the gamma-ray energy spectrum of the radiation detection instrument: Calibrate the gamma-ray energy spectrum of the radiation detection instrument at a standard temperature using a standard radiation source known to emit gamma-rays of a specific energy; Step 2: Power on the radiation detection instrument; Step 3: Preheat the radiation detection instrument and perform initial spectrum drift correction. The process is as follows: Step 301: When the preheating environment has background environment conditions, or the preheating environment does not have background environment conditions but the gamma ray energy of the interfering nuclide in the preheating environment is less than the full energy peak position of the standard radioactive source reference peak, step 302 is executed; when the preheating environment does not have background environment conditions and the gamma ray energy of the interfering nuclide in the preheating environment is not less than the full energy peak position of the standard radioactive source reference peak, step 303 is executed; Step 302: quickly record the initial energy spectrum drift L0 caused by the change in ambient temperature after the radiation detection instrument is powered on, and then enter the fast preheating mode. When the fast preheating mode achieves spectrum stabilization within the running measurement time of 1000s, the radiation detection instrument preheating ends and the initial energy spectrum drift correction is completed; when the fast preheating mode does not achieve spectrum stabilization within the running measurement time of 1000s, the slow preheating mode is turned on, and the slow preheating mode is only run once. After the slow preheating mode ends, the initial energy spectrum drift correction is completed; The fast preheating mode: peak search once per fast peak search cycle, channel address CH i The peak search results are compared with the calibration peak address CH0 result of the full energy peak of the standard radioactive source reference peak. i When the difference between the address CH0 and the address CH1 is less than the first threshold, the address CH2 is i The result is the actual measured peak of the full energy peak of the standard radioactive source reference peak, and the drift L1 in the fast preheating mode is recorded. Each channel of the measured energy spectrum is subtracted from the L1 value in turn to complete the initial energy spectrum drift correction, where i is the channel address number and i=1,2,...,n, and n is the total number of channels; The slow preheating mode: set the second threshold and search for peaks, and the channel address CH within the second threshold i The peak search result is the actual measured peak of the full energy peak of the standard radioactive source reference peak, the drift amount L2 in the slow preheating mode is recorded, and each channel of the measured energy spectrum is sequentially subtracted from the L2 value to complete the initial energy spectrum drift correction, wherein the second threshold is greater than the first threshold; Step 303: Query the address CHO corresponding to the energy of a specific nuclide in the nuclide library i , peak search is performed once in each fast peak search cycle, channel address CH i The peak search results are related to the channel address CHO i Compare the results. Only when the channel address difference is less than the first threshold value, match the peak search result with the energy. Only when the corresponding energy number N1 is consistent with the current nuclide energy number N0, the current nuclide is considered to be matched successfully. Calculate the difference L3 between the peak with the maximum energy currently matched and the corresponding nuclide ray energy. Subtract the L3 value from each channel of the measured energy spectrum in turn to complete the initial energy spectrum drift correction. Step 4: Radiation detection instrument adaptive peak stabilization, the process is as follows: Step 401: After the radiation detection instrument is preheated, it enters the adaptive peak stabilization state. At this time, the radiation detection instrument can enter any radiation field to start measurement, and record the first peak search result and the corresponding channel address. extract The peak with the highest energy Step 402: Use the radiation detection instrument to perform real-time measurement, search for peaks once per rapid peak search cycle, and obtain the current peak search result and the corresponding channel address. extract The peak with the highest energy Wherein, X is a positive integer not less than 1; Step 403: and When the difference is less than the first threshold, it is considered that the peak positions before and after the peak search correspond to the same γ-ray, and the forward drift amount L is obtained. Each channel of the measured energy spectrum is subtracted from the L value in turn to complete the energy spectrum drift correction, and the peak search result is not retained; when and When the difference is not less than the first threshold, it indicates that the detected nuclide has changed, the current peak search result will be retained, and step 402 will be repeated until the measurement is completed, so as to realize adaptive selection of energy peak stable spectrum according to the change of the γ radiation field.

2. A digital adaptive passive peak stabilization method for gamma-ray spectrum measurement and analysis according to claim 1, characterized in that: The radiation detection instrument includes a NaI radiation detection instrument and a LaBr3 radiation detection instrument; When the radiation detection instrument adopts NaI radiation detection instrument, natural 40 The K peak is used as the reference peak for peak stabilization; When the radiation detection instrument adopts LaBr3 radiation detection instrument, the lanthanum peak is used as the reference peak for peak stabilization.

3. A digital adaptive passive peak stabilization method for gamma-ray spectrum measurement and analysis according to claim 1, characterized in that: The fast peak search period is 30s to 100s.

4. A digital adaptive passive peak stabilization method for gamma-ray spectrum measurement and analysis according to claim 1, characterized in that: The first threshold is 5 to 15 channels; the second threshold is 30 to 50 channels.

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