A calculation method for determining total gamma concentration based on gamma spectrum

Abstract

The present application belongs to the technical field of radioactivity monitoring, and particularly relates to a calculation method for determining total gamma concentration based on gamma spectrum, which comprises the following steps: step 1, obtaining an energy calibration file, an efficiency calibration file and a spectrum file; step 2, obtaining net count rate of each channel address; step 3, establishing an energy-channel address formula; step 4, establishing a detection efficiency-energy formula; and step 5, integrating to calculate total gamma concentration. According to the present application, the relationship among channel address, energy and detection efficiency is established, so that the matching between each channel count and detection efficiency is realized, and the gamma ray emission rate corresponding to each channel address is calculated, and finally the total gamma concentration is obtained through integration. The total gamma concentration of a sample can be accurately calculated through the precise matching between the measured count and detection efficiency.

Description

Technical Field

[0001] This invention belongs to the field of radioactive monitoring technology, specifically relating to a calculation method for total gamma concentration based on gamma energy spectrum determination. Background Technology

[0002] To quickly detect radiation anomalies in the liquid media of process systems, nuclear power plants have installed online radiation monitoring instruments to measure the total gamma concentration of the liquid media. Some process systems also manually sample the samples, which are then sent to the laboratory for total gamma concentration measurement. Online monitoring and laboratory measurements typically use scintillator detectors or high-purity germanium detectors to obtain gamma energy spectrum counts. Then, the total gamma concentration of the liquid media is obtained by dividing the integrated net count rate within a specific energy range (usually 50 keV to 2000 keV) by the detection efficiency at 661.657 keV and the sample volume.

[0003] Since detectors have different detection efficiencies for gamma rays of different energies, using the detection efficiency of a single energy to represent the detection efficiency of the entire energy range has limitations. In particular, when the gamma ray energy of radionuclides contained in liquid media differs significantly from 661.657 keV, the measurement results will not accurately reflect the actual level of total gamma ray concentration in the liquid medium.

[0004] Therefore, there is an urgent need to develop a method for calculating total γ concentration that can accurately reflect the actual level of total γ concentration in liquid media. Summary of the Invention

[0005] The purpose of this invention is to provide a method for calculating the total γ concentration based on γ-ray spectroscopy. This method accurately calculates the total γ concentration of a sample by precisely matching the measurement count and detection efficiency.

[0006] Technical solution to achieve the purpose of this invention: A method for calculating total gamma concentration based on gamma spectroscopy, comprising: Step 1: Obtain the energy scale file, efficiency scale file, and spectrum file; Step 2: Obtain the net count rate for each address; Step 3: Establish the energy-pathway formula; Step 4: Establish the detection efficiency-energy formula; Step 5: Integrate and calculate the total γ concentration.

[0007] Further, step 1 includes: measuring the energy calibration source using a gamma spectrometer, and automatically generating an energy calibration file using gamma spectroscopy software according to the energy calibration steps; measuring the efficiency calibration source using a gamma spectrometer, and automatically generating an efficiency calibration file using gamma spectroscopy software according to the efficiency calibration steps; and measuring the sample using a gamma spectrometer, and automatically generating a spectral file using gamma spectroscopy software.

[0008] Furthermore, the formula for calculating the net count rate of each road address in step 2 is as follows: In the formula: —Net count rate at a given address, cps; —A count of a specific address; —Sample measurement live time, s; —Counting blank samples at a specific track location; — Blank sample measurement time, s.

[0009] Furthermore, the energy-address fitting formula in step 3 is: In the formula: —The location of the All-Powerful Peak. P 1 The first power represents the location of the road. P 2 Represents the square of the path address; ， — Fitting parameters, the parameter values ​​are generated directly from the energy scale file.

[0010] Furthermore, the fitting formula for the detection efficiency-energy in step 4 is: In the formula: — γ-ray full-energy peak detection efficiency; —Gamma ray energy, MeV; —Fitting constant, parameter values ​​are directly generated from the efficiency scale file; i This represents the index, starting from 1 and ending at 6.

[0011] Furthermore, the formula for calculating the total γ concentration in step 5 is as follows: In the formula: —Total γ concentration in the liquid medium, s -1 / m 3 ; —Net count rate at a given address, cps; — γ-ray full-energy peak detection efficiency; Sample volume, m 3 ; b These are the starting address and the ending address, respectively.

[0012] The beneficial technical effects of this invention are as follows: 1. The present invention provides a calculation method for total γ concentration based on γ energy spectrum determination, which can accurately reflect the actual level of total γ concentration in liquid media.

[0013] 2. The present invention provides a method for calculating total γ concentration based on γ energy spectrum determination, which improves the operability of total γ concentration calculation.

[0014] 3. The method for calculating total gamma concentration based on gamma energy spectrum provided by this invention can be embedded into radiation monitoring instrument software, facilitating its widespread application. Attached Figure Description

[0015] Figure 1 The flowchart illustrates a calculation method for determining total gamma concentration based on gamma energy spectroscopy, provided by this invention. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0017] like Figure 1 As shown, this invention provides a method for calculating total gamma concentration based on gamma energy spectroscopy. By establishing a channel address-energy-detection efficiency relationship, the count and detection efficiency of each channel are matched, thereby calculating the gamma-ray emissivity corresponding to each channel address. Finally, the total gamma concentration is obtained by integration. The specific steps are as follows: Step 1: Obtain the energy scale file, efficiency scale file, and spectrum file. The energy calibration source is measured using a gamma spectrometer, and the energy calibration file is automatically generated by the gamma spectroscopy software following the energy calibration procedure. The efficiency calibration source is measured using a gamma spectrometer, and the efficiency calibration file is automatically generated by the gamma spectroscopy software following the efficiency calibration procedure. The sample is measured using a gamma spectrometer, and the spectral file is automatically generated by the gamma spectroscopy software.

[0018] Step 2: Obtain the net count rate for each address. The spectral file generated by the gamma-ray spectroscopy software contains counts for each channel (typically 8192 or 16384 channels). The count rate for each channel is calculated by dividing the count by the measurement time. The blank sample count is calculated by dividing the blank sample count by the blank sample measurement time. Subtracting the blank sample count rate from the sample count rate yields the net count rate for each channel. The calculation formula is as follows: In the formula: —Net count rate at a given address, cps ； —A count of a specific address; —Sample measurement live time, s; —Counting blank samples at a specific track location; — Blank sample measurement time, s.

[0019] Step 3: Establish the energy-pathway formula The energy calibration file generated by the gamma-ray spectroscopy software contains the energy-channel address fitting formula and fitting parameters. The fitting formula is as follows: In the formula: —The location of the All-Powerful Peak. P 1 The first power represents the location of the road. P 2 Represents the square of the path address; ， — Fitting parameters, the parameter values ​​are generated directly from the energy scale file.

[0020] Step 4: Establish the detection efficiency-energy formula; The efficiency calibration file generated by the gamma-ray spectroscopy software includes the fitting formula and fitting constants for the detection efficiency versus energy. The fitting formula is as follows: In the formula: — γ-ray full-energy peak detection efficiency; —Gamma ray energy, MeV; —Fitting constant, parameter values ​​are directly generated from the efficiency scale file; i This represents the index, starting from 1 and ending at 6.

[0021] Step 5: Integrate and calculate the total γ concentration In Excel, using the net count rate and detection efficiency obtained in steps 2-4, the gamma-ray emissivity corresponding to a given channel is calculated by dividing the net count rate by the detection efficiency. The total gamma-ray concentration of the liquid medium is then obtained by integrating the gamma-ray emissivity of all channels and dividing by the sample volume. The calculation formula is as follows: In the formula: —Total γ concentration in the liquid medium, s -1 / m 3 ; —Net count rate at a given address, cps; — γ-ray full-energy peak detection efficiency; Sample volume, m 3 ; b These are the starting address and the ending address, respectively.

[0022] Example 1 Taking a liquid sample with a volume of 1 L as an example, after measuring with a gamma spectrometer for 3600 s, the gamma spectroscopy file of the sample is generated using gamma spectroscopy software. The specific steps for calculating the total gamma concentration in this embodiment are as follows: Step 1: Obtain the energy scale file, efficiency scale file, and spectrum file. The energy calibration source is measured using a gamma spectrometer, and the energy calibration file is automatically generated by the gamma spectroscopy software following the energy calibration procedure. The efficiency calibration source is measured using a gamma spectrometer, and the efficiency calibration file is automatically generated by the gamma spectroscopy software following the efficiency calibration procedure. The sample is measured using a gamma spectrometer, and the spectral file is automatically generated by the gamma spectroscopy software.

[0023] Step 2: Obtain the net count rate for each address. The generated spectrum file was converted into an ASCII SPE format file to obtain the count for each channel. The count was then divided by the measurement time to obtain the count rate for each channel. The net count rate for each channel was obtained by subtracting the count rate of the blank spectrum from the count rate of the sample spectrum. Specific data are shown in Table 1.

[0024] Step 3: Establish the energy-pathway formula The energy calibration file generated by the gamma-ray spectroscopy software provides the energy-channel address fitting formula and parameters: in, —Gamma ray energy, keV; —The location of the All-Powerful Peak.

[0025] Step 4: Establish the detection efficiency-energy formula The efficiency calibration file generated by the gamma-ray spectroscopy software provides the fitting formula and parameters for the detection efficiency versus energy: In the formula: — γ-ray full-energy peak detection efficiency; —Gamma ray energy, MeV.

[0026] Step 5: Integrate and calculate the total γ concentration In EXCEL, the net count rate within each address is divided by the detection efficiency at the corresponding energy level to obtain the gamma-ray emissivity at that energy. The total gamma-ray concentration in the liquid medium is obtained by integrating the gamma-ray emissivity within the energy range and dividing it by the sample volume. Specific data are shown in Table 1.

[0027] Table 1. Total γ concentration calculation data in Excel The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. All contents not described in detail in the present invention can be derived from existing technologies.

Claims

1. A method for calculating total γ concentration based on γ-ray energy dispersive spectroscopy, characterized in that, include: Step 1: Obtain the energy scale file, efficiency scale file, and spectrum file; Step 2: Obtain the net count rate for each address; Step 3: Establish the energy-pathway formula; Step 4: Establish the detection efficiency-energy formula; Step 5: Integrate and calculate the total γ concentration.

2. The method for calculating total γ concentration based on γ-ray energy dispersive spectroscopy according to claim 1, characterized in that, Step 1 includes: measuring the energy calibration source using a gamma spectrometer, and automatically generating an energy calibration file using gamma spectroscopy software according to the energy calibration steps; measuring the efficiency calibration source using a gamma spectrometer, and automatically generating an efficiency calibration file using gamma spectroscopy software according to the efficiency calibration steps; and measuring the sample using a gamma spectrometer, and automatically generating a spectral file using gamma spectroscopy software.

3. The method for calculating total γ concentration based on γ-ray energy dispersive spectroscopy according to claim 2, characterized in that, The formula for calculating the net count rate of each road address in step 2 is as follows: In the formula: —Net count rate at a given address, cps; —A count of a specific address; —Sample measurement live time, s; —Counting blank samples at a specific track location; — Blank sample measurement time, s.

4. The method for calculating total γ concentration based on γ-ray energy dispersive spectroscopy according to claim 3, characterized in that, The energy-address fitting formula in step 3 is as follows: In the formula: —The location of the All-Powerful Peak. P 1 The first power represents the location of the road. P 2 Represents the square of the path address; ， — Fitting parameters, the parameter values ​​are generated directly from the energy scale file.

5. The method for calculating total γ concentration based on γ-ray energy dispersive spectroscopy according to claim 4, characterized in that, The fitting formula for detection efficiency versus energy in step 4 is as follows: In the formula: — γ-ray full-energy peak detection efficiency; —Gamma ray energy, MeV; —Fitting constant, parameter values ​​are directly generated from the efficiency scale file; i This represents the index, starting from 1 and ending at 6.

6. The method for calculating total γ concentration based on γ-ray energy dispersive spectroscopy according to claim 5, characterized in that, The formula for calculating the total γ concentration in step 5 is as follows: In the formula: —Total γ concentration in the liquid medium, s -1 / m 3 ; —Net count rate at a given address, cps; — γ-ray full-energy peak detection efficiency; Sample volume, m 3 ; b These are the starting address and the ending address, respectively.

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