A ray spectrum monitoring system and spectrum correction method

Abstract

The present invention provides a ray spectrum monitoring system and a spectrum correction method. The ray spectrometer includes three parts: a detector, a signal processing electronics system and a back-end data acquisition system, and also includes a spectrum monitoring system. The spectrum monitoring system generates one or more reference signals with a pulse shape similar to that of a signal to be measured and with adjustable amplitude and frequency. By changing the parameters of the reference signal, the characteristic drift matrix of the entire ray spectrometer is calibrated, and then used for monitoring and correction of the spectrum data. The spectrum monitoring system and correction method proposed in the present invention can solve the problems of unknown error degree and error correction of ray spectrum data. Especially in complex ray spectrum measurement conditions such as high counting rate and strong magnetic field, the ray spectrum monitoring and correction method proposed in the present invention can monitor the quality of spectrum data in real time and greatly reduce the error of spectrum data, which is of great significance and value.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear radiation detection, and relates to a ray energy spectrum monitoring system and an energy spectrum correction method. Background Art

[0002] X-ray spectrometers are important instruments for measuring the energy distribution of nuclear radiation (X-rays, gamma rays, etc.) and its evolution over time. The most common situation we see and use is the measurement of the radiation energy spectrum by the X-ray spectrometer in a laboratory or other good measurement environment. At this time, the measurement environment is almost in an ideal state, and the X-ray spectrometer can easily give relatively good measurement results. However, in specific applications, the measurement environment cannot always be ideal. The X-ray spectrometer is likely to be in a harsh and extreme measurement environment during specific work. For example: the measurement energy range may be very wide, the counting rate of the radiation in the measurement environment may be very high, the spectrometer may need to work in a strong magnetic field or an environment with drastic temperature changes, and so on. These harsh measurement environments will seriously affect the quality of the measured X-ray energy spectrum.

[0003] When the X-ray spectrometer is operated at a high count rate, it will cause serious accumulation of pulse signals, and the pulse signals will have a large drift at a high count rate, resulting in the provision of X-ray energy spectrum data with extremely high errors. Even if it is barely operated in a high dead time environment, the error of the energy spectrum cannot be monitored in real time, and it is not known whether the energy spectrum error is changing over time and how much it has changed. In environments such as strong magnetic fields, the electronic components used in the X-ray spectrometer will also produce energy spectrum errors, and these errors can easily be as large as ΔE / E~20%. Therefore, these X-ray spectrometers cannot know and control the possible errors in the energy spectrum data. At present, X-ray spectrometers at home and abroad generally cannot meet the requirements of energy spectrum monitoring or correction. Such X-ray spectrometers can only measure weak X-ray radiation in the laboratory and are not suitable for applications in harsh measurement environments. Therefore, how to enable the X-ray spectrometer to still provide high-quality energy spectrum data in harsh measurement environments has a very clear practical significance and demand, and the energy spectrum monitoring system and correction method can play a vital role at this time. Summary of the invention

[0004] Aiming at the harsh measurement environment of wide energy range and high counting rate, based on the energy spectrum monitoring and correction system, the present invention provides a ray energy spectrum monitoring system and an energy spectrum correction method, which have very important significance and broad application prospects.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A ray energy spectrum monitoring system is combined with a ray spectrometer, comprising three parts: a detector, a signal processing electronics system and a back-end data acquisition system; wherein the detector is composed of a scintillator and a light detection device; the ray energy spectrum monitoring system drives a light source through a voltage pulse signal to generate a light pulse signal, which is input into the scintillator and the light detection device of the detector to generate a reference signal; the signal processing electronics system acquires the detector signal, wherein the detector signal includes both the real signal to be measured and the reference signal; the back-end data acquisition performs back-end data processing on the signal output by the signal processing electronics system to obtain energy spectrum data; the ray energy spectrum monitoring system calculates a one-dimensional matrix of drift degree according to the drift degree of the reference signal; the energy spectrum data is corrected according to the original energy spectrum data and the one-dimensional matrix of drift degree to obtain the corrected energy spectrum data; and the error of the energy spectrum data before and after correction is calculated.

[0007] Furthermore, the light detection device includes a photomultiplier tube, a photodiode, an avalanche photomultiplier tube or a silicon photomultiplier tube.

[0008] Furthermore, the reference signal has a shape similar to that of a signal pulse of the X-ray spectrometer, and has an adjustable amplitude and frequency.

[0009] Furthermore, by changing the parameters of the reference signal, the characteristic drift matrix R of the entire X-ray spectrometer is calibrated. mn , where R represents the feature matrix, m represents the calibration number of amplitude, and n represents the calibration number of frequency.

[0010] The present invention also provides a method for correcting energy spectrum data based on the ray energy spectrum monitoring system, the steps of which include:

[0011] (1) The X-ray spectrometer measures the energy spectrum data S of the signal to be measured Original ;

[0012] (2) Calculate the drift degree D of the reference signal Ri =P Ri / P RRi , where P Ri is the position of the reference signal, P RRi is the drift matrix R mn The position corresponding to the reference signal in ;

[0013] (3) According to the drift degree D of the reference signal Ri , interpolation calculation drift degree one-dimensional matrix D R , the interpolation method is linear or least squares;

[0014] (4) According to the original energy spectrum data S Original And the one-dimensional matrix D of drift degree R, perform energy spectrum data correction to obtain the corrected energy spectrum data: S Correction =S Original / D R ;

[0015] (5) Compare the original energy spectrum data S Original and corrected energy spectrum data S Correction , according to the characteristic drift matrix R mn , calculate the errors of the energy spectrum data before and after correction, respectively: E Original =(S Original -R mn (:,n)) / R mn (:,n) and E Correction =(S Correction -R mn (:,n)) / R mn (:,n), where n represents the nominal number of frequencies.

[0016] Beneficial effects:

[0017] The ray energy spectrum monitoring and correction method proposed in the present invention can give the error of the energy spectrum data measured by the ray spectrometer, and can correct the energy spectrum data to reduce the error of the energy spectrum data to below ΔE / E~1%. The present invention solves the problem of unknown error degree and error correction of ray energy spectrum data, so that the ray spectrometer can still provide high-quality energy spectrum data in harsh measurement environments such as high counting rate and strong magnetic field, thereby ensuring the accuracy of the energy spectrum data. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of the X-ray spectrometer of the present invention;

[0019] Figure 2 It is a typical principle schematic diagram of the radiation energy spectrum monitoring system of the present invention;

[0020] Figure 3 It is typical schematic data of the monitoring signal generated by the ray energy spectrum monitoring system of the present invention on the energy spectrum data;

[0021] Figure 4 for Figure 3 The ordinate of the typical schematic data is changed to a logarithmic coordinate diagram;

[0022] Figure 5 It is a typical schematic diagram of the evolution of the energy spectrum of rays over time without energy spectrum data correction;

[0023] Figure 6 This is a typical schematic data diagram of the evolution of the ray energy spectrum over time after energy spectrum data correction. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be described more clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0025] like Figure 1 As shown, the radiation spectrum monitoring system of the present invention includes three parts: a detector, a signal processing electronics system, and a back-end data acquisition system. Among them, the detector involved in the present invention is mainly composed of a scintillator and a photodetector, and the photodetector includes a photomultiplier tube, a photodiode, an avalanche photomultiplier tube, a silicon photomultiplier tube, etc. The radiation spectrometer is affected by external environments such as magnetic fields or counting rates, and the peak position of the radiation measured by it will drift and change accordingly, which leads to the occurrence of measurement errors. For example, when the counting rate changes, the drift of its peak position increases greatly with the increase of the counting rate, and may be as high as ΔE / E~10%-20%. Moreover, for a fixed counting rate, the degree of peak drift of radiation with different energies is also different. The relationship between multiple factors is nonlinearly coupled together, and it is difficult to simply eliminate it. The original energy spectrum monitoring method can be to place the radiation source in the working environment of the radiation spectrometer to give a reference energy point, but it has great limitations. The radiation source itself is an ionizing radiation hazard, with limited application scenarios, and its intensity is generally very low in the laboratory, and there are only one or a few energy points.

[0026] The ray spectrum monitoring system and spectrum correction method proposed in the present invention are a monitoring system with multiple monitoring energy points and multiple monitoring frequencies based on a variable multi-energy point and multi-frequency external signal source. The drift characteristics of the entire set of ray spectrometers are calibrated, the peak position drift of the ray spectrum caused by changes in the measurement environment (such as counting rate, radiation field, magnetic field, temperature, etc.) is measured, and the error of the spectrum data is monitored; then, the optimal spectrum data correction algorithm is developed according to different measurement environments to correct the spectrum data error. This can solve the problem of unknown error degree and error correction of ray spectrum data, especially in the case of high counting rate, strong magnetic field, etc., spectrum monitoring and correction are very important.

[0027] Specifically, the energy spectrum correction method of the present invention comprises the following steps:

[0028] First, build an energy spectrum monitoring system, whose function is to generate an optical reference signal with a similar shape to the signal pulse of the X-ray spectrometer and adjustable width and amplitude, and generate one or more reference signals; introduce the reference signal into the front end of the detector so that the reference signal can enter the optical detection device; the signal processing electronics system collects the detector signal, wherein the detector signal includes both the real signal to be measured and the reference signal generated by the X-ray energy spectrum monitoring system; perform back-end data processing on the signal output by the signal processing electronics system to obtain energy spectrum data; change the parameters of the reference signal, such as its amplitude and frequency, and perform parameter scanning to obtain the energy spectrum changes measured by the entire set of X-ray spectrometers, and calibrate the characteristic drift matrix of the entire set of X-ray spectrometers; use the X-ray spectrometer in specific applications to measure energy spectrum data; calculate the drift degree of the reference signal, and then calculate the one-dimensional matrix of the drift degree based on the drift degree of the reference signal; perform energy spectrum data correction based on the original energy spectrum data and the one-dimensional matrix of the drift degree to obtain the corrected energy spectrum data; calculate the error of the energy spectrum data before and after correction.

[0029] The present invention is described in detail below with a specific embodiment. Assuming that the reference signals of the above-mentioned radiation spectrum monitoring system are 2, the specific implementation of the present invention can be:

[0030] Typical principles of the X-ray spectrum monitoring system are as follows: Figure 2 As shown. First, use a signal generator to generate two voltage pulse signals. The shape of the pulse signal needs to be similar to the shape of the original output signal of the detector. Depending on the type of detector, the matching pulse shape may be different. The frequency is set to 1kHz and the amplitude is set to 1V.

[0031] The two voltage pulse signals generated are connected to the two LED input terminals respectively, and a current limiting resistor of 1.2KΩ is added to each of them. Then, the two optical pulse signals generated are coupled together and output using a Y-type optical fiber to form a set of pulse optical reference signals.

[0032] The pulse light reference signal is connected to the detector so that the pulse light reference signal can be incident on the optical detection device and generate a reference signal on the final energy spectrum data. The typical results of the monitoring reference signal generated by the X-ray energy spectrum monitoring system on the energy spectrum data are as follows: Figure 3 and Figure 4 shown.

[0033] Adjust the frequency of the voltage pulse signal, observe the counting rate of the reference signal on the energy spectrum, change its counting rate from low (1kHz) to high (1MHz), and record the position of the reference signal on the energy spectrum;

[0034] Adjust the amplitude of the voltage pulse signal, observe the position of the reference signal on the energy spectrum, and change its position from low (channel 1) to high (channel 4096) on the energy spectrum. Repeat the above frequency change for each amplitude.

[0035] After the above frequency and amplitude adjustments, the characteristic drift matrix R of the entire spectrometer is recorded. mn , where R represents the feature matrix, m represents the number of amplitudes, and n represents the number of frequencies.

[0036] After obtaining the drift matrix of the X-ray spectrometer, the frequencies and amplitudes of the two reference signals are fixed so that their positions are offset from the positions of the signals to be measured.

[0037] The X-ray spectrometer measures the energy spectrum data S of the signal to be tested Original , this energy spectrum data includes both the real signal to be measured and the reference signal generated by the energy spectrum monitoring system. The energy spectrum data can also evolve over time. At this time, the energy spectrum data is the energy spectrum of the ray that has not been corrected. The typical results of its evolution over time are as follows: Figure 5 shown.

[0038] In the energy spectrum data, the positions of the two reference signals are P R1 and P R2 ; In the drift matrix, the position corresponding to the two reference signals is P RR1 and P RR2 .

[0039] Calculate the drift degree D of the two reference signals R1 =P R1 / P RR1 ,D R2 =P R2 / P RR2 .

[0040] According to the drift degree D of the two reference signals R1 and D R2 , interpolate and calculate the one-dimensional matrix D of the drift degree at all positions R The interpolation method can be linear, least squares or other algorithms. The choice of algorithm depends on the specific characteristics of the spectrometer.

[0041] According to the original energy spectrum data S Original And the one-dimensional matrix D of drift degree R , perform energy spectrum data correction to obtain the corrected energy spectrum data: S Correction =S Original / D R For comparison, the typical results of the evolution of the corrected ray energy spectrum over time are as follows: Figure 6 shown.

[0042] Compare the original energy spectrum data S Original and corrected energy spectrum data S Correction , according to the characteristic drift matrix R mn , calculate the error of the energy spectrum data before and after correction, E Original =(SOriginal -R mn (:,n)) / R mn (:,n) and E Correction =(S Correction -R mn (:,n)) / R mn (:,n).

[0043] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A radiation spectrum monitoring system, characterized in that: Combined with a ray spectrometer, it includes three parts: a detector, a signal processing electronics system and a back-end data acquisition system; wherein the detector is composed of a scintillator and a light detection device; the ray energy spectrum monitoring system drives the light source through a voltage pulse signal to generate a light pulse signal, which is input into the scintillator and the light detection device of the detector to generate a reference signal; the signal processing electronics system acquires the detector signal, wherein the detector signal includes both the real signal to be measured and the reference signal; the back-end data acquisition performs back-end data processing on the signal output by the signal processing electronics system to obtain energy spectrum data; the ray energy spectrum monitoring system calculates a one-dimensional matrix of drift degree according to the drift degree of the reference signal; the energy spectrum data is corrected according to the original energy spectrum data and the one-dimensional matrix of drift degree to obtain the corrected energy spectrum data; the error of the energy spectrum data before and after correction is calculated; the reference signal is similar in shape to the signal pulse of the ray spectrometer, and the amplitude and frequency are adjustable.

2. The radiation spectrum monitoring system according to claim 1, characterized in that: The light detection device is a photomultiplier tube, a photodiode, an avalanche photomultiplier tube or a silicon photomultiplier tube.

3. The radiation spectrum monitoring system according to claim 1, characterized in that: By changing the parameters of the reference signal, the characteristic drift matrix R of the entire X-ray spectrometer is calibrated. mn , where R represents the feature matrix, m represents the calibration number of amplitudes, and n represents the calibration number of frequencies.

4. A method for correcting energy spectrum data of a radiation energy spectrum monitoring system according to any one of claims 1 to 3, characterized in that: The steps include: (1) The X-ray spectrometer measures the energy spectrum data S of the signal to be measured Original ; (2) Calculate the drift degree D of the reference signal Ri =P Ri / P RRi , where P Ri is the position of the reference signal, P RRi is the drift matrix R mn The position corresponding to the reference signal in ; (3) According to the drift degree D of the reference signal Ri , interpolation calculation drift degree one-dimensional matrix D R , the interpolation method is linear or least squares; (4) Based on the original energy spectrum data S Original And the one-dimensional matrix D of drift degree R , perform energy spectrum data correction to obtain the corrected energy spectrum data: S Correction =S Original / D R ; (5) Comparison of original energy spectrum data S Original and corrected energy spectrum data S Correction , according to the characteristic drift matrix R mn , calculate the errors of the energy spectrum data before and after correction, respectively: E Original =(S Original -R mn (:,n)) / R mn (:,n) and E Correction =(S Correction -R mn (:,n)) / R mn (:,n), where n represents the number of frequencies.

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