A liquid scintillation measurement deconvolution method for two different energy beta emitters

Abstract

This invention relates to a liquid scintillation measurement and interpretation method for samples containing two different energy β nuclides, comprising the following steps: (1) preparing a background sample by using a blank sample according to the system and preparation method of the sample to be tested; (2) preparing a double-labeled sample and measuring it, determining the counting windows of nuclides A and B based on the energy of β particles emitted by nuclides A and B and the sample measurement results; (3) preparing an A-efficiency calibration sample and measuring it, calculating and determining the counting efficiency of nuclide A in the A counting window; (4) preparing a B-efficiency calibration sample and measuring it, calculating and determining the counting efficiency of nuclide B in the A and B counting windows; (5) preparing a sample and measuring it, calculating the results of nuclide A and nuclide B in the sample. Using the method of this invention to measure the liquid scintillation of a sample containing two different energy β nuclides, the radioactivity of different energy β nuclides in the sample can be obtained separately.

Description

Technical Field

[0001] This invention belongs to the field of radiation environment monitoring technology, specifically relating to a method for measuring and interpreting the spectroscopic properties of a liquid scintillation sample containing two different energies of β nuclides. Background Technology

[0002] Beta nuclides are radioactive isotopes that release high-speed electron beams (beta particles) rather than alpha particles. While beta particles are generally considered to have stronger penetrating power than alpha particles, factors such as energy level and matter density must be considered in practical applications. Beta nuclides typically originate from the beta decay process of atomic nuclei. During this decay, a neutron transforms into a proton, releasing a high-speed electron (a beta particle) and an antineutrino. Common beta nuclides include hydrogen-3 (tritium), carbon-14, and strontium-90. These nuclides have wide applications in medicine, industry, agriculture, and environmental protection. For example, carbon-14 can be used for compound labeling and dating.

[0003] Beta rays are beams of beta particles released during nuclear decay. Beta particles are a collective term for electrons and positrons. The beta rays emitted during decay have a continuously distributed energy spectrum, and their kinetic energy can take any value from 0 to a certain maximum energy. This maximum energy value is different for beta decay of different atomic nuclei.

[0004] A liquid scintillation spectrometer is a nuclear instrument used to measure radioactive decay, primarily β and α radionuclides, and has wide applications in nuclear medicine, nuclear physics, and radiochemistry. A liquid scintillation spectrometer typically consists of a scintillator, a photomultiplier tube, and signal processing circuitry. In a liquid scintillation spectrometer, the scintillator is the material used to capture and convert X-ray energy. When X-rays enter the scintillator, they excite the atoms or molecules within it, causing them to fluoresce. This fluorescence is converted into an electrical signal by the photomultiplier tube, and further amplified and processed by the signal processing circuitry to ultimately obtain the energy and quantity of the X-rays.

[0005] For the measurement of β-nuclides in samples, although radiochemistry can be used to completely separate the analyte for measurement in most cases, it is inevitable that the analyte will contain two β-nuclides. When the sample contains more than one β-nuclide, although liquid scintillation spectrometry can provide an energy spectrum distribution, the energy spectra of different β-nuclides will overlap because the β-rays emitted by the atomic nucleus are a continuous spectrum. Using the energy spectrum distribution of a single nuclide to calculate the result may introduce calculation errors. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a liquid scintillation measurement and spectral interpretation method for samples containing two different energies of β nuclides. This method can obtain the radioactivity of different energies of β nuclides in the sample separately, providing a reliable method for calculating the results.

[0007] To achieve the above objectives, the technical solution adopted in this invention is: a scintillation measurement and interpretation method for a sample containing two β-nuclides with different energies, wherein the sample contains two β-nuclides A and B with different energies, and the maximum energy of the β-particle of nuclide A is much smaller than that of nuclide B. The method for determining the radioactivity of nuclides A and B in the sample liquid includes the following steps:

[0008] (1) The blank sample was prepared according to the system and preparation method of the sample to be tested to obtain the background sample;

[0009] (2) Prepare and measure the double-labeled sample, and determine the counting window of nuclide A and nuclide B based on the energy of β particles emitted by nuclides A and B and the sample measurement results;

[0010] (3) Prepare A efficiency calibration samples and measure them, and calculate and determine the counting efficiency of A nuclide in the A counting window;

[0011] (4) Prepare and measure the B efficiency calibration sample, and calculate and determine the counting efficiency of the B nuclide in the A counting window and the B counting window;

[0012] (5) Prepare the sample and measure it, and calculate the measurement results of nuclide A and nuclide B in the sample.

[0013] Furthermore, in step (2), known amounts of standard solutions of nuclide A and nuclide B are added to the blank sample, and a double-labeled sample is obtained according to the system and preparation method of the sample to be tested.

[0014] Furthermore, in step (2), the counting windows for nuclide A and nuclide B are determined as follows: the counting window for nuclide A is the counting address from the corresponding counting address after deducting interference to the counting address corresponding to the maximum energy of the β-particle emitted by nuclide A; and the counting window for nuclide B is the upper limit of the counting window for nuclide A to the counting address corresponding to the maximum energy of the β-particle emitted by nuclide B.

[0015] Further, in step (3), a known amount of A nuclide standard solution is added to the blank sample, and an A efficiency calibration sample is obtained according to the system and preparation method of the sample to be tested. The background sample and the A efficiency calibration sample are measured using a liquid scintillation spectrometer to obtain the counting efficiency of A nuclide in the A counting window.

[0016] Further, in step (4), a known amount of B nuclide standard solution is added to the blank sample, and a B efficiency calibration sample is obtained according to the system and preparation method of the sample to be tested. The B efficiency calibration sample is measured using a liquid scintillation spectrometer to obtain the counting efficiency of B nuclide in the A counting window and the B counting window.

[0017] Furthermore, in step (4), the formula for calculating the counting efficiency of nuclide A within the A counting window is as follows:

[0018]

[0019] In the formula, E AA n represents the counting efficiency of nuclide A within the A counting window. AS Let A be the count rate of the sample within the A counting window, representing the efficiency scale. -1 ;n BA The count rate of the background sample within the A counting window is min. -1 A A Bq represents the activity of nuclide A added to the A efficiency calibration sample.

[0020] Furthermore, in step (4), the calculation formulas for the counting efficiency of nuclide B in counting windows A and B are as follows:

[0021]

[0022]

[0023] In the formula, E BA The counting efficiency of nuclide B within the counting window of nuclide A; n BS,A The count rate of the sample within the counting window A is the efficiency scale of B. -1 ;n BA The min value represents the count rate of the background sample within the A counting window. -1 A B E represents the activity of B nuclide added to the B efficiency calibration sample, expressed as Bq. BB The counting efficiency of B nuclides within the B counting window; n BS,B The B-efficiency calibration sample count rate within the B-counting window, min -1 ;n BB The min value represents the count rate of the background sample within the B counting window. -1 .

[0024] Furthermore, in step (5), the formulas for calculating the results of nuclide A and nuclide B in the sample are as follows:

[0025]

[0026]

[0027] In the formula, C A Bq represents the activity of nuclide A in the sample; n A Let min be the count rate of the sample within the A counting window. -1 ;n B The min value represents the count rate of the sample within the B counting window. -1 E BA E represents the counting efficiency of nuclide B within the counting window of nuclide A.BB E represents the counting efficiency of B nuclides within the B counting window. AA The counting efficiency of nuclide A within the counting window of A; C B Let Bq represent the activity of nuclide B in the sample.

[0028] The technical effect of this invention is that by using the liquid scintillation measurement and spectral interpretation method for samples containing two different β nuclides provided by this invention, the radioactivity of different β nuclides in the sample can be obtained separately, providing a reliable method for determining the results. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the flow chart of a liquid scintillation measurement and spectral interpretation method for a sample containing two β nuclides with different energies, as described in this invention. Detailed Implementation

[0030] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In this invention, the sample to be tested contains two β nuclides, A and B, with different energies, wherein the maximum energy of the β particles of nuclide A is much smaller than that of the β particles of nuclide B.

[0032] like Figure 1 As shown, this embodiment takes the liquid scintillation measurement and spectral interpretation method of a sample containing tritium and carbon-14 as an example, including the following steps:

[0033] 1) Prepare the background sample by using the same system and preparation method as the test sample from the blank sample;

[0034] 2) Add known amounts of tritium and carbon-14 standard solutions to the blank sample to obtain a double-labeled sample;

[0035] 3) Use liquid scintillation spectrometry to determine the double-labeled samples;

[0036] 4) Determine the counting windows for tritium and carbon-14. The counting window for tritium is the counting address from the corresponding counting address after deducting interference to the counting address corresponding to the maximum energy of tritium emitted β particles. The counting window for carbon-14 is the upper limit of the tritium counting window to the counting address corresponding to the maximum energy of carbon-14 emitted β particles.

[0037] 5) Add a standard solution with known tritium activity to the blank sample, and obtain a tritium efficiency calibration sample according to the system and preparation method of the sample to be tested;

[0038] 6) Use a liquid scintillation spectrometer to measure the background sample and the tritium efficiency calibration sample to obtain the tritium counting efficiency in the tritium counting window;

[0039]

[0040] In the formula, E AA n represents the counting efficiency of tritium nuclides within the tritium counting window. AS The tritium efficiency calibration is used to measure the count rate of the sample within the tritium counting window, min. -1 ;n BA The min represents the count rate of the background sample within the tritium counting window. -1 A A Bq represents the activity of tritium nuclides added to the tritium efficiency calibration sample.

[0041] 7) Add a standard solution with known carbon-14 activity to the blank sample, and obtain a carbon-14 efficiency calibration sample according to the system and preparation method of the sample to be tested;

[0042] 8) The counting efficiencies of carbon-14 in the tritium counting window and the carbon-14 counting window were determined using a liquid scintillation spectrometer. The calculation formulas are as follows:

[0043]

[0044]

[0045] In the formula, E BA The counting efficiency of carbon-14 in the tritium counting window; n BS,A The count rate of the carbon-14 efficiency calibration sample within the tritium counting window, min -1 ;n BA The min is the count rate of the background sample within the tritium counting window. -1 A B E represents the activity of carbon-14 added to the carbon-14 efficiency calibration sample, in Bq. BB The counting efficiency of carbon-14 within the carbon-14 counting window; n BS,B The min is the count rate of the carbon-14 efficiency calibration sample within the carbon-14 counting window. -1 ;n BB The min represents the count rate of the background sample within the carbon-14 counting window. -1 .

[0046] 9) Calculation formulas for obtaining the results of tritium and carbon-14 in the sample;

[0047]

[0048]

[0049] In the formula, C A Let Bq be the activity of tritium in the sample; n A The min is the count rate of the sample within the tritium counting window. -1 ;n B The min value represents the count rate of the sample within the carbon-14 counting window. -1 C B Let Bq represent the activity of carbon-14 in the sample.

[0050] As can be seen from the above embodiments, the liquid scintillation measurement and spectral interpretation method for samples containing two β nuclides of the present invention can obtain the radioactivity of different β nuclides in the sample, providing a reliable method for determining the results.

[0051] Those skilled in the art should understand that the method described in this invention is not limited to the embodiments shown in the specific implementation details. The above detailed description is merely for illustrative purposes and is not intended to limit the invention. Other implementation methods derived by those skilled in the art based on the technical solution of this invention also fall within the scope of this invention's technical innovation. The scope of protection of this invention is defined by the claims and their equivalents.

Claims

1. A method for spectral analysis of a sample liquid containing two β-nuclides with different energies, wherein the sample contains two β-nuclides A and B with different energies, and the maximum energy of the β-particle of nuclide A is much smaller than that of nuclide B, the method comprising the following steps when determining the radioactivity of nuclide A and nuclide B in the sample liquid: (1) Prepare the background sample by using the blank sample according to the system and preparation method of the sample to be tested; (2) Prepare and measure the double-labeled sample, and determine the counting window of nuclide A and nuclide B based on the energy of β particles emitted by nuclides A and B and the sample measurement results; (3) Prepare A efficiency calibration samples and measure them, and calculate and determine the counting efficiency of A nuclide in the A counting window; (4) Prepare and measure the efficiency of B-type nuclide, and calculate and determine the counting efficiency of B-type nuclide in the A-counting window and the B-counting window; (5) Prepare the sample and measure it, and calculate the measurement results of nuclide A and nuclide B in the sample; In step (2), the counting windows of nuclide A and nuclide B are determined as follows: the counting window of A is the counting address from the corresponding counting address after deducting interference to the counting address corresponding to the maximum energy of the β particle emitted by nuclide A; the counting window of B is the upper limit of the counting window of nuclide A to the counting address corresponding to the maximum energy of the β particle emitted by nuclide B. In step (5), the formulas for calculating the results of nuclide A and nuclide B in the sample are as follows: In the formula, C A Bq represents the activity of nuclide A in the sample; n A Let min be the count rate of the sample within the A counting window. -1 ;n B The min value represents the count rate of the sample within the B counting window. -1 E BA E represents the counting efficiency of nuclide B within the counting window of nuclide A. BB E represents the counting efficiency of B nuclides within the B counting window. AA The counting efficiency of nuclide A within the counting window of A; C B Let Bq represent the activity of nuclide B in the sample.

2. The method for measuring and interpreting the liquid scintillation spectrum of a sample containing two β nuclides with different energies according to claim 1, characterized in that, In step (2), known amounts of standard solutions of nuclide A and nuclide B are added to the blank sample, and a double-labeled sample is obtained according to the system and preparation method of the sample to be tested.

3. The method for measuring and interpreting the liquid scintillation spectrum of a sample containing two β nuclides with different energies according to claim 1, characterized in that, In step (3), a known amount of A nuclide standard solution is added to the blank sample. According to the system and preparation method of the sample to be tested, an A efficiency calibration sample is obtained. The background sample and the A efficiency calibration sample are measured using a liquid scintillation spectrometer to obtain the counting efficiency of A nuclide in the A counting window.

4. The method for measuring and interpreting the liquid scintillation spectrum of a sample containing two β nuclides with different energies according to claim 3, characterized in that, In step (3), the formula for calculating the counting efficiency of nuclide A in the A counting window is as follows: In the formula, E AA n represents the counting efficiency of nuclide A within the A counting window. AS Let A be the count rate of the sample within the A counting window, representing the efficiency scale. -1 ;n BA The count rate of the background sample within the A counting window is min. -1 A A Bq represents the activity of nuclide A added to the A efficiency calibration sample.

5. The method for measuring and interpreting the liquid scintillation spectrum of a sample containing two β nuclides with different energies according to claim 4, characterized in that, In step (4), a known amount of B nuclide standard solution is added to the blank sample. According to the system and preparation method of the sample to be tested, a B efficiency calibration sample is obtained. The B efficiency calibration sample is measured using a liquid scintillation spectrometer to obtain the counting efficiency of B nuclide in the A counting window and the B counting window.

6. The method for measuring and interpreting the liquid scintillation spectrum of a sample containing two β nuclides with different energies according to claim 5, characterized in that, In step (4), the calculation formulas for the counting efficiency of nuclide B in counting windows A and B are as follows: In the formula, E BA The counting efficiency of nuclide B within the counting window of nuclide A; n BS,A The count rate of the sample within the counting window A is the efficiency scale of B. -1 ;n BA The min value represents the count rate of the background sample within the A counting window. -1 A B The activity of B nuclide added to the B efficiency calibration sample is given by Bq; BB The counting efficiency of B nuclides within the B counting window; n BS,B The B-efficiency calibration sample count rate within the B-counting window, min -1 ;n BB The min value represents the count rate of the background sample within the B counting window. -1 .

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