Method and device for measuring dose equivalent in mixed radiation field based on fiber-optic OSL

Abstract

The application discloses a kind of mixed radiation field dose equivalent measurement method and device based on optical fiber-OSL, it is related to radiation measurement technical field, solve the technical problem that the measurement of dose equivalent in mixed radiation field is not accurate enough, its technical scheme main point is that the average detection efficiency and average energy transfer line density in mixed radiation field are obtained by the light emission decay curve fitting calculation of OSL crystal, the measured dose is corrected, to realize the measurement of mixed radiation field dose equivalent.In providing a new method for spatial radiation field dose evaluation, the accurate measurement of mixed radiation field dose equivalent is also realized, and the measurement accuracy is improved.

Description

Technical Field

[0001] This application relates to the field of radiation measurement technology, and in particular to a method and apparatus for measuring the dose equivalent of a hybrid radiation field based on fiber-optic OSL. Background Technology

[0002] The luminescence principle of optically stimulated luminescence (OSL) crystals is as follows: Figure 1 As shown, when an OSL crystal is irradiated, electrons in the valence band are excited to the conduction band and then captured by the trapping energy level in the band gap, storing the radiation energy. When the crystal is excited by light of a specific wavelength, electrons in the trapping energy level jump to the conduction band. The electrons recombine with the luminescent centers in the band gap, emitting fluorescent photons within a certain wavelength range. The amount of light emitted is proportional to the radiation dose.

[0003] The space radiation environment is a complex mixed radiation field, including various types of radiation such as gamma rays, electrons, protons, neutrons, alpha particles, and high-energy heavy ions. Therefore, the influence of various radiation particles must be comprehensively considered when measuring space radiation dose. For mixed radiation fields, the contributions of different types of radiation need to be considered when calculating the total absorbed dose D, as shown in the following formula:

[0004] D = ∑ i D i (1)

[0005] To determine the absorbed dose according to equation (1), it is necessary to know the dose D contributed by different rays i in the mixed radiation field under study. i However, for unknown mixed radiation fields, traditional active and passive dose measurement methods struggle to accurately measure the dose D of various types of radiation. i Distinguishing measurement.

[0006] The response of OSL crystals differs for radiation with different LET (linear energy transfer) densities. For low-LET radiation such as gamma rays or X-rays, the energy is deposited almost uniformly in the OSL crystal. However, for high-LET charged particles, the energy is deposited along the particle's track, with the dose deposited at the track center potentially reaching as high as 10. 5 The dose equivalent in OSL (Optical State Lattice) is Gy, and the dose is lower the farther away from the track center, and is inversely proportional to the square of the distance from the track center. Because the particle deposition energy varies spatially, OSL crystals respond significantly differently to different types of radiation. Therefore, how to accurately measure the dose equivalent in mixed radiation fields using OSL remains a challenge. Summary of the Invention

[0007] This application provides a method and apparatus for measuring dose equivalent in a mixed radiation field based on fiber-optic OSL, the technical purpose of which is to accurately measure the dose equivalent in a mixed radiation field.

[0008] The above-mentioned technical objective of this application is achieved through the following technical solution:

[0009] A method for measuring the dose equivalent of a hybrid radiation field based on fiber-optic OSL, comprising:

[0010] The LET-η relationship curves for each LET particle were obtained based on the detection efficiency η of different LET particles; where the detection efficiency η of different LET particles was obtained through an OSL probe.

[0011] The OSL luminescence decay curves of different LET particles were fitted to obtain the fitting parameter τ1, and the LET-τ1 relationship curves of each LET particle were obtained based on the fitting parameter τ1.

[0012] The OSL emission decay curve of the mixed radiation field is fitted to obtain the fitting parameter τ2, and the LET-τ2 relationship curve of the mixed radiation field is obtained based on the fitting parameter τ2.

[0013] Substituting the fitted parameter τ2 into the LET-τ1 relationship curve yields the average linear energy transfer density LET of the mixed radiation field. mean ;

[0014] Based on the average linear energy transfer density LET mean Estimate the quality factor;

[0015] Average energy transfer linear density LET mean Substituting into the LET-η relationship curve, we obtain the average detection efficiency η of the mixed radiation field. mean ;

[0016] Based on the average detection efficiency η mean The measured absorbed dose is corrected to obtain the corrected absorbed dose of the mixed radiation field.

[0017] The dose equivalent of the mixed radiation field is obtained based on the corrected absorbed dose and quality factor of the mixed radiation field.

[0018] Furthermore, the fitting of the OSL luminescence decay curve of the mixed radiation field is expressed as follows:

[0019]

[0020] Among them, I OSL I represents the OSL emission decay curve of the mixed radiation field obtained after fitting; OSL,k This represents the k-th luminescence decay curve that follows an exponential decay law; t represents time; A kI represents the k-th luminescence decay curve at time t=0. OSL,k The value of t; k This represents the decay time constant, which occurs every t. k I OSL,k The value decreases by 1 / e.

[0021] Furthermore, the quality factor is expressed as:

[0022]

[0023] Where Q(L) represents the LET based on the average energy transfer linear density. mean The quality factor of the mixed radiation field; L represents the average energy transfer linear density LET. mean .

[0024] Furthermore, the method based on the average detection efficiency η mean The measured absorbed dose is corrected to obtain the corrected mixed radiation field absorbed dose, expressed as:

[0025]

[0026] Where D represents the corrected absorbed dose of the mixed radiation field; D sum D represents the total measured dose of the mixed radiation field. sum =∑ i D i D i This represents the dose contributed by ray i in the mixed radiation field.

[0027] Furthermore, the dose equivalent of the mixed radiation field is expressed as: H = Q(L)D.

[0028] Furthermore, the fitting parameter τ2 is expressed as:

[0029] τ2=t1 / t2;

[0030] Where t1 represents time t=1; t2 represents time t=2.

[0031] Furthermore, the LET particles are neutrons, protons, 4 He 12 C 20 Ne、 28 Si、 56 Any of the following Fe atoms, wherein the mixed radiation field is composed of neutrons, protons, 4 He 12 C 20 Ne、 28 Si、 56 Any combination of particles in Fe.

[0032] A fiber-optic OSL-based hybrid radiation field dose equivalent measurement device is disclosed. This device is used to implement any of the measurement methods described above. The device includes an OSL probe, an optical fiber, an excitation source, a photomultiplier tube, a first filter, a second filter, a control unit, and a computing unit. The control unit controls the excitation source to emit light. The excitation light passes through the first filter and is then transmitted via the optical fiber to the OSL probe. The radiation deposited in the OSL probe is excited to generate a fluorescence signal. The fluorescence signal is transmitted via the optical fiber and the second filter to the photomultiplier tube. The photomultiplier tube converts the fluorescence signal into an electrical signal and outputs it to the control unit. The control unit then outputs the electrical signal to the computing unit. The computing unit performs online measurement of the absorbed dose of the radiation energy deposited in the OSL probe based on the electrical signal and obtains the dose equivalent of the hybrid radiation field based on the absorbed dose. The control unit achieves online measurement of the absorbed dose by continuously exciting the radiation energy deposited in the OSL probe.

[0033] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements any of the above-described methods for measuring the dose equivalent of a mixed radiation field.

[0034] A computer storage medium storing a computer program that, when executed by a processor, implements any of the above-described methods for measuring the dose equivalent of a mixed radiation field.

[0035] The beneficial effects of this application are as follows: The fiber-optic-OSL-based method and apparatus for measuring the dose equivalent of a mixed radiation field, as described in this application, calculates the average detection efficiency and average energy transfer linear density in the mixed radiation field by fitting the luminescence attenuation curve of the OSL crystal, corrects the measured dose, and thus realizes the measurement of the dose equivalent of the mixed radiation field. While providing a new method for space radiation field dose assessment, it also achieves accurate measurement of the dose equivalent of the mixed radiation field, improving measurement precision.

[0036] Meanwhile, this application can also be used for personal dose monitoring during radiotherapy, and regional dose monitoring in strong radiation fields such as reactors, high-intensity irradiation devices, and spent fuel pools, and has broad application prospects. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the photoluminescence process of an OSL crystal.

[0038] Figure 2 The average energy transfer linear density LET is obtained from the LET-τ1 relationship curve. mean Schematic diagram;

[0039] Figure 3The average detection efficiency η of the mixed radiation field is obtained from the LET-η relationship curve. mean Schematic diagram;

[0040] Figure 4 This is a structural diagram of the hybrid radiation field dose equivalent measurement device based on fiber-optic OSL described in this application. Detailed Implementation

[0041] The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0042] The method for measuring the dose equivalent of a hybrid radiation field based on fiber-optic OSL described in this application includes:

[0043] 100: The LET-η relationship curves of each LET particle are obtained based on the detection efficiency η of different LET particles; where the detection efficiency η of different LET particles is obtained through the OSL probe.

[0044] Specifically, when performing precise measurements of the mixed radiation field, the detection efficiency of the OSL probe for different LET particles (such as neutrons, protons, 4He, 12C, 20Ne, 28Si, 56Fe, etc.) is first determined. The OSL probe is placed in a known particle field, and the number of light emitted per unit absorbed dose under irradiation of particles with different linear energy transfer densities (LET) is determined. The detection efficiency η of different particles is then calculated, thus obtaining the LET-η relationship curve.

[0045] 101: Fit the OSL luminescence decay curves of different LET particles to obtain the fitting parameter τ1, and obtain the LET-τ1 relationship curve of each LET particle based on the fitting parameter τ1.

[0046] 102: Fit the OSL emission decay curve of the mixed radiation field to obtain the fitting parameter τ2, and obtain the LET-τ2 relationship curve of the mixed radiation field based on the fitting parameter τ2.

[0047] Preferably, the fitting of the OSL luminescence decay curve of the mixed radiation field is expressed as follows:

[0048]

[0049] Among them, I OSL I represents the OSL emission decay curve of the mixed radiation field obtained after fitting; OSL,k This represents the k-th luminescence decay curve that follows an exponential decay law; t represents time; A k I represents the k-th luminescence decay curve at time t=0. OSL,k The value of t; k This represents the decay time constant, which occurs every t. k I OSL,kThe value decreases by 1 / e.

[0050] Preferably, the fitting parameter τ2 is expressed as:

[0051] τ2=t1 / t2;

[0052] Where t1 represents time t=1; t2 represents time t=2.

[0053] 103: Substituting the fitted parameter τ2 into the LET-τ1 relationship curve yields the average energy transfer linear density LET of the mixed radiation field. mean ,like Figure 2 As shown.

[0054] 104: Based on the average linear energy transfer density (LET) mean Estimate the quality factor.

[0055] Preferably, the quality factor is expressed as:

[0056]

[0057] Where Q(L) represents the LET based on the average energy transfer linear density. mean The quality factor of the mixed radiation field; L represents the average energy transfer linear density LET. mean .

[0058] 105: Average energy transfer linear density LET mean Substituting into the LET-η relationship curve, we obtain the average detection efficiency η of the mixed radiation field. mean .

[0059] 106: Based on the average detection efficiency η mean The measured absorbed dose is corrected to obtain the corrected absorbed dose of the mixed radiation field.

[0060] Specifically, to achieve mixed-field radiation dose measurement, an "average detection efficiency η" is introduced. mean ", using η mean Total measured dose D of the mixed radiation field sum Make corrections.

[0061] Preferably, the corrected absorbed dose of the mixed radiation field is expressed as:

[0062]

[0063] Where D represents the corrected absorbed dose of the mixed radiation field; D sum D represents the total measured dose of the mixed radiation field. sum =∑ i D i D i This represents the dose contributed by ray i in the mixed radiation field.

[0064] 107: The dose equivalent of the mixed radiation field is obtained based on the corrected absorbed dose and quality factor of the mixed radiation field.

[0065] Preferably, the dose equivalent of the mixed radiation field is expressed as: H = Q(L)D.

[0066] The fiber-optic-OSL-based hybrid radiation field dose equivalent measurement device described in this application is as follows: Figure 4 As shown, the measuring device is used to implement the mixed radiation field dose equivalent measurement method described in this application. The measuring device includes an OSL probe, an optical fiber, an excitation source, a photomultiplier tube, a first filter, a second filter, a control unit, and a computing unit. The computing unit consists of several functional modules of computer software.

[0067] In actual radiation measurements, the OSL probe is placed in the radiation field. The control unit controls the excitation source to emit light, which passes through filter A to ensure monochromaticity. The light is then transmitted via optical fiber to the OSL probe, where the radiation deposited within the probe is excited to generate a fluorescence signal. This fluorescence signal is transmitted via optical fiber to a photomultiplier tube (PMT). Filter B is installed at the coupling point between the signal transmission fiber and the PMT to reduce fluorescence signal impurities and improve the signal-to-noise ratio. The PMT converts the fluorescence signal into an electrical signal and outputs it to the control unit. The control unit then outputs the electrical signal to the calculation unit. The calculation unit performs online measurement of the absorbed dose of the radiation energy deposited in the OSL probe based on the electrical signal and obtains the dose equivalent of the mixed radiation field based on the absorbed dose. The control unit achieves online measurement of the absorbed dose by continuously exciting the radiation energy deposited in the OSL probe.

[0068] The computing unit performs the following functions:

[0069] The LET-η relationship curves for each LET particle are obtained based on the detection efficiency η of different LET particles.

[0070] The OSL luminescence decay curves of different LET particles were fitted to obtain the fitting parameter τ1, and the LET-τ1 relationship curves of each LET particle were obtained based on the fitting parameter τ1.

[0071] The OSL emission decay curve of the mixed radiation field is fitted to obtain the fitting parameter τ2, and the LET-τ2 relationship curve of the mixed radiation field is obtained based on the fitting parameter τ2.

[0072] Substituting the fitted parameter τ2 into the LET-τ1 relationship curve yields the average linear energy transfer density LET of the mixed radiation field. mean ;

[0073] Based on the average linear energy transfer density LET mean Estimate the quality factor;

[0074] Average energy transfer linear density LET mean Substituting into the LET-η relationship curve, we obtain the average detection efficiency η of the mixed radiation field. mean ;

[0075] Based on the average detection efficiency η mean The measured absorbed dose is corrected to obtain the corrected absorbed dose of the mixed radiation field.

[0076] The dose equivalent of the mixed radiation field is obtained based on the corrected absorbed dose and quality factor of the mixed radiation field.

[0077] The above are exemplary embodiments of this application, and the scope of protection of this application is defined by the claims and their equivalents.

Claims

1. A method for measuring the dose equivalent of a hybrid radiation field based on fiber-optic OSL, characterized in that, include: Based on the detection efficiency of different LET particles Obtain the LET- of each LET particle Relationship curves; where the detection efficiency of different LET particles is... Acquired via OSL probe; The OSL luminescence decay curves of different LET particles were fitted to obtain the fitting parameter τ1, and the LET-τ1 relationship curves of each LET particle were obtained based on the fitting parameter τ1. The OSL emission decay curve of the mixed radiation field is fitted to obtain the fitting parameter τ2, and the LET-τ2 relationship curve of the mixed radiation field is obtained based on the fitting parameter τ2. Substituting the fitted parameter τ2 into the LET-τ1 relationship curve yields the average linear energy transfer density LET of the mixed radiation field. mean ; Based on the average linear energy transfer density LET mean The quality factor is estimated, and the quality factor is expressed as: ； in, Indicates LET based on average energy transfer linear density mean The quality factor of the mixed radiation field; LET represents the average linear energy transfer density. mean ; Average energy transfer linear density LET mean Substitute into LET- The relationship curve yields the average detection efficiency of the mixed radiation field. ; Based on average detection efficiency The measured absorbed dose is corrected to obtain the corrected mixed radiation field absorbed dose, expressed as: ； in, This indicates the absorbed dose of the mixed radiation field after correction; This represents the total measured dose of the mixed radiation field. , This represents the dose contributed by ray i in the mixed radiation field; The dose equivalent of the mixed radiation field is obtained based on the corrected absorbed dose and quality factor of the mixed radiation field. The dose equivalent of the mixed radiation field is expressed as: H = D; The fitting of the OSL luminescence attenuation curve of the mixed radiation field is expressed as follows: ； in, The OSL emission decay curve of the mixed radiation field obtained after fitting is shown. This represents the k-th emission decay curve that follows an exponential decay law; t represents time. This represents the k-th emission decay curve at time t=0. The value; Represents the decay time constant, every [time value]. , The value decreases by 1 / e.

2. The method for measuring the dose equivalent of a mixed radiation field as described in claim 1, characterized in that, The LET particles are neutrons, protons, 4 He 12 C 20 Ne、 28 Si、 56 Any of the following Fe atoms, wherein the mixed radiation field is composed of neutrons, protons, 4 He 12 C 20 Ne、 28 Si、 56 Any combination of particles in Fe.

3. A hybrid radiation field dose equivalent measurement device based on fiber-optic OSL, the device being used to implement the hybrid radiation field dose equivalent measurement method according to any one of claims 1-2, characterized in that, The measuring device includes an OSL probe, an optical fiber, an excitation source, a photomultiplier tube, a first filter, a second filter, a control unit, and a computing unit. The control unit controls the excitation source to emit light. The excitation light passes through the first filter and is then transmitted to the OSL probe via the optical fiber. The radiation deposited in the OSL probe is excited to generate a fluorescence signal. The fluorescence signal is transmitted to the photomultiplier tube via the optical fiber and the second filter. The photomultiplier tube converts the fluorescence signal into an electrical signal and outputs it to the control unit. The control unit then outputs the electrical signal to the computing unit. The computing unit performs online measurement of the absorbed dose of the radiation energy deposited in the OSL probe based on the electrical signal and obtains the dose equivalent of the mixed radiation field based on the absorbed dose. The control unit achieves online measurement of the absorbed dose by continuously exciting the radiation energy deposited in the OSL probe.

4. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method for measuring the dose equivalent of a mixed radiation field as described in any one of claims 1 to 2.

5. A computer storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for measuring the dose equivalent of a mixed radiation field as described in any one of claims 1 to 2.

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