A lightweight design method and system for a multi-moderator neutron spectrometer

Abstract

The present invention discloses a lightweight design method and system for a multi-ball neutron spectrometer, the method comprising: S101, obtaining a theoretical neutron energy spectrum; S102, establishing a Monte Carlo theoretical model of a multi-ball neutron spectrometer; S103, calculating the response function of the multi-ball neutron spectrometer according to a certain energy interval, and drawing a corresponding function curve; S104, adjusting the energy interval of the response function of the multi-ball neutron spectrometer to be consistent with the energy interval of the theoretical neutron energy spectrum. The present invention can quantitatively determine the change in the measurement uncertainty of the multi-ball spectrometer after changing the mass of the multi-ball spectrometer, can greatly reduce the mass and size of the multi-ball spectrometer to improve its portability and reduce transportation costs, and can perform specific lightweight transformation on the multi-ball spectrometer according to different occasions for which it is applicable, so that it can adapt to different measurement needs.

Description

Technical Field

[0001] The present invention relates to the field of multi-moderator neutron spectrometer design, and in particular to a multi-moderator neutron spectrometer lightweight design method and system. Background Art

[0002] Mixed field neutron spectrum information is of great concern in the fields of nuclear device design verification, neutron shielding material testing and evaluation, and research on neutron radiation effects of radiation-resistant reinforcement. Multi-sphere is a representative of multi-moderator neutron spectrometers, so we will take the multi-sphere spectrometer as an example to describe it.

[0003] At present, in the field of on-site neutron spectrum measurement, multi-ball neutron spectrometers occupy an important position. This is because multi-ball neutron spectrometers have the advantages of isotropy, insensitivity to gamma rays, simple structure, easy operation and good stability. However, multi-ball spectrometers also have obvious disadvantages. Since the multi-ball spectrometer mainly relies on polyethylene of different thicknesses to change the detector's response to neutrons of different energies, and then uses the deconvolution spectrum algorithm to deconvolve the neutron spectrum. A set of polyethylene balls has a diameter ranging from 2.5 inches to 12 inches, plus a total of 10 balls with bare balls. The total mass of electronics and the outer box of the spectrometer is about 35 to 40 kg, and the portability is relatively low. In some special occasions where the mass of the spectrometer is limited, such as when performing space neutron spectrum measurement, the neutron multi-ball spectrometer needs to be launched into space for measurement. If the mass of the spectrometer is too large, the launch cost is high. Therefore, how to reduce the mass of the multi-ball spectrometer as much as possible under the condition of ensuring the measurement uncertainty of the multi-ball spectrometer is the main problem that the present invention needs to solve. Summary of the invention

[0004] In view of the defects existing in the prior art, the object of the present invention is to provide a lightweight design method and system for a multi-moderator neutron spectrometer, which can quantitatively determine the change in the measurement uncertainty of the spectrometer after changing the mass of the multi-sphere spectrometer.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A lightweight design method for a multi-moderator neutron spectrometer, comprising:

[0007] (1) Obtain theoretical neutron energy spectrum;

[0008] (2) Establish a Monte Carlo theoretical model for multi-sphere neutron spectrometer;

[0009] (3) calculating the response function of the multi-sphere neutron spectrometer at a certain energy interval and drawing a corresponding function curve, wherein the response function refers to a curve showing the change of neutron fluence of polyethylene ball detectors of different sizes in the multi-sphere neutron spectrometer with neutron energy;

[0010] (4) adjusting the energy interval of the response function of the multi-sphere neutron spectrometer to be consistent with the energy interval of the theoretical neutron energy spectrum;

[0011] (5) multiplying the response function of the multi-sphere neutron spectrometer by the theoretical neutron energy spectrum to obtain a theoretical count of each polyethylene ball detector in the multi-sphere neutron spectrometer;

[0012] (6) inputting the theoretical count of each polyethylene ball detector in the multi-ball neutron spectrometer into a neutron spectrum analysis program to obtain a complete spectrometer neutron spectrum;

[0013] (7) according to the requirements of the object to be measured for the neutron energy measurement range, removing the theoretical counts and corresponding response functions of one or several polyethylene ball detectors in the multi-ball neutron spectrometer;

[0014] (8) inputting the remaining theoretical counts in the multi-sphere neutron spectrometer into the neutron spectrum analysis program to obtain a lightweight spectrometer neutron spectrum;

[0015] (9) comparing and analyzing the complete spectrometer neutron spectrum and the lightweight spectrometer neutron spectrum with the theoretical neutron spectrum to determine whether the result of the lightweight spectrometer neutron spectrum meets the requirements;

[0016] (10) If the requirements are not met, repeat the above steps (7)-(9) until the result meets the measurement requirements.

[0017] Furthermore, in the method described above, in step (1), a theoretical neutron energy spectrum is obtained by simulation calculation or empirical method.

[0018] Further, in the method as described above, the response function includes bare ball, 2.5 inches, 3 inches, 3.5 inches, 4 inches, 5 inches, 6 inches, 8 inches, 10 inches and 12 inches.

[0019] Furthermore, in the method as described above, in step (9), based on the spectrum shape and the total neutron fluence, the neutron energy spectrum of the complete spectrometer and the neutron energy spectrum of the lightweight spectrometer are compared and analyzed with the theoretical neutron energy spectrum to determine whether the result of the neutron energy spectrum of the lightweight spectrometer meets the requirements.

[0020] Furthermore, in the method as described above, step (9) includes: when some balls are removed, the measurement uncertainty does not increase significantly, and when the number of removed balls increases to a certain extent, the measurement uncertainty increases significantly.

[0021] A lightweight design system for a multi-moderator neutron spectrometer, the system being used for:

[0022] (1) Obtain theoretical neutron energy spectrum;

[0023] (2) Establish a Monte Carlo theoretical model for multi-sphere neutron spectrometer;

[0024] (3) calculating the response function of the multi-sphere neutron spectrometer at a certain energy interval and drawing a corresponding function curve, wherein the response function refers to a curve showing the change of neutron fluence of polyethylene ball detectors of different sizes in the multi-sphere neutron spectrometer with neutron energy;

[0025] (4) adjusting the energy interval of the response function of the multi-sphere neutron spectrometer to be consistent with the energy interval of the theoretical neutron energy spectrum;

[0026] (5) multiplying the response function of the multi-sphere neutron spectrometer by the theoretical neutron energy spectrum to obtain a theoretical count of each polyethylene ball detector in the multi-sphere neutron spectrometer;

[0027] (6) inputting the theoretical count of each polyethylene ball detector in the multi-ball neutron spectrometer into a neutron spectrum analysis program to obtain a complete spectrometer neutron spectrum;

[0028] (7) according to the requirements of the object to be measured for the neutron energy measurement range, removing the theoretical counts and corresponding response functions of one or several polyethylene ball detectors in the multi-ball neutron spectrometer;

[0029] (8) inputting the remaining theoretical counts in the multi-sphere neutron spectrometer into the neutron spectrum analysis program to obtain a lightweight spectrometer neutron spectrum;

[0030] (9) comparing and analyzing the complete spectrometer neutron spectrum and the lightweight spectrometer neutron spectrum with the theoretical neutron spectrum to determine whether the result of the lightweight spectrometer neutron spectrum meets the requirements;

[0031] (10) If the requirements are not met, repeat the above steps (7)-(9) until the result meets the measurement requirements.

[0032] Furthermore, the system as described above obtains a theoretical neutron energy spectrum through simulation calculation or empirical method.

[0033] Further, in the system as described above, the response functions include bare ball, 2.5 inches, 3 inches, 3.5 inches, 4 inches, 5 inches, 6 inches, 8 inches, 10 inches and 12 inches.

[0034] Furthermore, the system as described above compares and analyzes the complete spectrometer neutron spectrum and the lightweight spectrometer neutron spectrum with the theoretical neutron spectrum based on the spectrum shape and the total neutron fluence to determine whether the result of the lightweight spectrometer neutron spectrum meets the requirements.

[0035] Furthermore, in the system described above, when some balls are removed, the measurement uncertainty does not increase significantly. However, when the number of balls removed increases to a certain extent, the measurement uncertainty increases significantly.

[0036] The beneficial effects of the present invention are as follows: the present invention can quantitatively determine the change in the measurement uncertainty of the multi-sphere spectrometer after changing the mass of the multi-sphere spectrometer, can keep the measurement range of the multi-sphere spectrometer unchanged at thermal energy ~15MeV, can greatly reduce the mass and size of the multi-sphere spectrometer, and can perform specific lightweight modifications on the multi-sphere spectrometer according to different occasions where it is used, so that it can adapt to different measurement needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic flow chart of a lightweight design method for a multi-moderator neutron spectrometer provided in an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of a typical multi-sphere neutron spectrometer response function provided in an embodiment of the present invention;

[0039] Figure 3 A schematic diagram of the neutron energy spectrum of a bare ball-12-inch complete spectrometer provided in an embodiment of the present invention;

[0040] Figure 4 A schematic diagram of a neutron spectrum of a 2.5-6 inch lightweight spectrometer provided in an embodiment of the present invention;

[0041] Figure 5 A schematic diagram of a neutron spectrum of a 2.5-8 inch lightweight spectrometer provided in an embodiment of the present invention;

[0042] Figure 6 A schematic diagram of a neutron spectrum of a 2.5-10 inch lightweight spectrometer provided in an embodiment of the present invention;

[0043] Figure 7 It is a schematic diagram of the neutron energy spectrum of a 2.5-12 inch lightweight spectrometer provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved more clearly, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0045] The method to reduce the quality of neutron multi-sphere spectrometer is mainly calculated through parameters such as theoretical neutron energy spectrum, multi-sphere spectrometer response function, neutron energy spectrum decomposition program, etc. The functions and effects of the relevant parameters are introduced below:

[0046] 1) Theoretical neutron energy spectrum. Theoretical neutron energy spectrum is the theoretical calculated value of the neutron field energy spectrum to be measured. In the process of reducing mass calculation, it is mainly used together with the response function to calculate the multi-sphere spectrum theoretical count.

[0047] 2) Multi-sphere spectrometer response function. The multi-sphere spectrometer response function refers to the curve of neutron flux of polyethylene ball detectors of different sizes versus neutron energy. Typical response functions are as follows: Figure 2 shown.

[0048] 3) Neutron spectrum deconvolution program. The neutron spectrum can be deconvolved by using a certain deconvolution algorithm through the measurement counts of each multi-ball detector and the corresponding response function. The neutron spectrum deconvolution program is a Windows serial port program developed based on C++. It adopts an internationally original improved genetic algorithm and can obtain reliable spectrum deconvolution effects without the need for an initial theoretical spectrum. In the present invention, after the theoretical multi-ball counts and response functions are input into the spectrum deconvolution program, the neutron spectrum can be deconvoluted. By comparing the difference between the results after spectrum deconvolution and the theoretical neutron spectrum, the change in measurement uncertainty after the quality of the multi-ball spectrometer is reduced can be obtained.

[0049] Based on the above parameters, an embodiment of the present invention provides a lightweight design method for a multi-moderator neutron spectrometer, such as Figure 1 As shown, the method includes:

[0050] S101, obtain theoretical neutron spectrum;

[0051] In the embodiment of the present invention, the theoretical neutron energy spectrum can be obtained by simulation calculation or empirical method.

[0052] S102. Establish a Monte Carlo theoretical model for multi-sphere neutron spectrometer;

[0053] S103, calculating the response function of the multi-sphere neutron spectrometer according to a certain energy interval, and drawing a corresponding function curve, wherein the response function refers to a curve of the change of neutron fluence of polyethylene ball detectors of different sizes in the multi-sphere neutron spectrometer with neutron energy;

[0054] In the embodiment of the present invention, the response function includes bare sphere, 2.5 inches, 3 inches, 3.5 inches, 4 inches, 5 inches, 6 inches, 8 inches, 10 inches and 12 inches. Other sizes can also be used for other multi-moderator neutron spectrometers.

[0055] S104, adjusting the energy interval of the response function of the multi-sphere neutron spectrometer to be consistent with the energy interval of the theoretical neutron energy spectrum;

[0056] S105, multiplying the response function of the multi-sphere neutron spectrometer by the theoretical neutron energy spectrum to obtain a theoretical count of each polyethylene ball detector in the multi-sphere neutron spectrometer;

[0057] S106, inputting the theoretical count of each polyethylene ball detector in the multi-ball neutron spectrometer into a neutron spectrum analysis program to obtain a complete spectrometer neutron spectrum; Figure 3 It is the neutron energy spectrum of the bare ball-12-inch complete spectrometer.

[0058] S107, according to the requirements of the object to be measured for the neutron energy measurement range, removing the theoretical counts and corresponding response functions of one or several polyethylene ball detectors in the multi-ball neutron spectrometer;

[0059] S108, inputting the remaining theoretical counts in the multi-sphere neutron spectrometer into a neutron spectrum analysis program to obtain a lightweight spectrometer neutron spectrum;

[0060] In the embodiment of the present invention, the theoretical counts are input into the spectrum analysis program, and the neutron energy spectrum of the lightweight spectrometer is solved. Figure 4-7 They are 2.5-6 inches, 2.5-8 inches, 2.5-10 inches, and 2.5-10 inches lightweight spectrometer neutron spectra.

[0061] S109, comparing and analyzing the neutron energy spectrum of the complete spectrometer and the neutron energy spectrum of the lightweight spectrometer with the theoretical neutron energy spectrum to determine whether the result of the neutron energy spectrum of the lightweight spectrometer meets the requirements;

[0062] In the embodiment of the present invention, based on the spectrum shape and the total neutron fluence, the neutron spectrum of the complete spectrometer and the neutron spectrum of the lightweight spectrometer are compared and analyzed with the theoretical neutron spectrum to determine whether the result of the neutron spectrum of the lightweight spectrometer meets the requirements. The total fluence and its relative error are shown in Table 1 below. It can be seen from the data in Table 1 that since the method of measuring the neutron spectrum with multiple balls itself has a certain uncertainty (the relative error of the bare ball-12 is 3.18%), when some balls are removed, the measurement uncertainty does not increase significantly, such as 2.5-8, 2.5-10 and 2.5-12 (relative error 3%-4%); however, when the number of balls removed increases to a certain extent, such as removing 12, 10 and 8 inches, the measurement uncertainty increases significantly (more than 10%).

[0063] Table 1

[0064] Ball diameter range / inch 2.5-6 2.5-8 2.5-10 2.5-12 Bare Balls - 12 Calculated spectrum <![CDATA[Total injection volume / cm -2 > 0.624 0.584 0.583 0.590 0.580 0.562 Total injection relative error 11.02％ 3.88％ 3.76％ 4.87％ 3.18％ 0％

[0065] S110: If it does not meet the requirements, repeat the above S107 to S109 until the result meets the measurement requirements.

[0066] By adopting the method of the embodiment of the present invention, the change in the measurement uncertainty of the multi-sphere spectrometer after changing the mass of the spectrometer can be quantitatively determined, the measurement range of the multi-sphere spectrometer can be kept unchanged at thermal energy ~15MeV, the mass and size of the multi-sphere spectrometer can be greatly reduced, and the multi-sphere spectrometer can be specifically lightweight modified according to different occasions where it is used to adapt it to different measurement needs.

[0067] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0068] According to another aspect of an embodiment of the present invention, a lightweight design system for a multi-moderator neutron spectrometer is provided, the system being used for:

[0069] (1) Obtain theoretical neutron energy spectrum;

[0070] In the embodiment of the present invention, the theoretical neutron energy spectrum can be obtained by simulation calculation or empirical method.

[0071] (2) Establish a Monte Carlo theoretical model for multi-sphere neutron spectrometer;

[0072] (3) calculating the response function of the multi-sphere neutron spectrometer at a certain energy interval and drawing a corresponding function curve, wherein the response function refers to a curve showing the change of neutron fluence of polyethylene ball detectors of different sizes in the multi-sphere neutron spectrometer with neutron energy;

[0073] In an embodiment of the present invention, the response function includes bare ball, 2.5 inches, 3 inches, 3.5 inches, 4 inches, 5 inches, 6 inches, 8 inches, 10 inches and 12 inches.

[0074] (4) adjusting the energy interval of the response function of the multi-sphere neutron spectrometer to be consistent with the energy interval of the theoretical neutron energy spectrum;

[0075] (5) multiplying the response function of the multi-sphere neutron spectrometer by the theoretical neutron energy spectrum to obtain a theoretical count of each polyethylene ball detector in the multi-sphere neutron spectrometer;

[0076] (6) inputting the theoretical count of each polyethylene ball detector in the multi-ball neutron spectrometer into a neutron spectrum analysis program to obtain a complete spectrometer neutron spectrum;

[0077] (7) according to the requirements of the object to be measured for the neutron energy measurement range, removing the theoretical counts and corresponding response functions of one or several polyethylene ball detectors in the multi-ball neutron spectrometer;

[0078] (8) inputting the remaining theoretical counts in the multi-sphere neutron spectrometer into the neutron spectrum analysis program to obtain a lightweight spectrometer neutron spectrum;

[0079] (9) comparing and analyzing the complete spectrometer neutron spectrum and the lightweight spectrometer neutron spectrum with the theoretical neutron spectrum to determine whether the result of the lightweight spectrometer neutron spectrum meets the requirements;

[0080] In the embodiment of the present invention, based on the spectrum shape and the total neutron fluence, the neutron spectrum of the complete spectrometer and the neutron spectrum of the lightweight spectrometer are compared and analyzed with the theoretical neutron spectrum to determine whether the result of the neutron spectrum of the lightweight spectrometer meets the requirements. When some balls are removed, the measurement uncertainty does not increase significantly, and when the number of balls removed increases to a certain extent, the measurement uncertainty increases significantly.

[0081] (10) If the requirements are not met, repeat the above steps (7)-(9) until the result meets the measurement requirements.

[0082] The system using the embodiment of the present invention can quantitatively determine the change in the measurement uncertainty of the multi-sphere spectrometer after changing the mass of the spectrometer, can keep the measurement range of the multi-sphere spectrometer unchanged at thermal energy ~15MeV, can greatly reduce the mass and size of the multi-sphere spectrometer, and can perform specific lightweight modifications on the multi-sphere spectrometer according to different occasions where it is used to adapt it to different measurement needs.

[0083] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A lightweight design method for a multi-moderator neutron spectrometer, characterized in that: include: (1) Obtain theoretical neutron energy spectrum; (2) Establish a Monte Carlo theoretical model for multi-sphere neutron spectrometer; (3) calculating the response function of the multi-sphere neutron spectrometer at a certain energy interval and drawing a corresponding function curve, wherein the response function refers to a curve showing the change of neutron fluence of polyethylene ball detectors of different sizes in the multi-sphere neutron spectrometer with neutron energy; (4) adjusting the energy interval of the response function of the multi-sphere neutron spectrometer to be consistent with the energy interval of the theoretical neutron energy spectrum; (5) multiplying the response function of the multi-sphere neutron spectrometer by the theoretical neutron energy spectrum to obtain a theoretical count of each polyethylene ball detector in the multi-sphere neutron spectrometer; (6) inputting the theoretical count of each polyethylene ball detector in the multi-ball neutron spectrometer into a neutron spectrum analysis program to obtain a complete spectrometer neutron spectrum; (7) according to the requirements of the object to be measured for the neutron energy measurement range, removing the theoretical counts and corresponding response functions of one or several polyethylene ball detectors in the multi-ball neutron spectrometer; (8) inputting the remaining theoretical counts in the multi-sphere neutron spectrometer into the neutron spectrum analysis program to obtain a lightweight spectrometer neutron spectrum; (9) comparing and analyzing the complete spectrometer neutron spectrum and the lightweight spectrometer neutron spectrum with the theoretical neutron spectrum to determine whether the result of the lightweight spectrometer neutron spectrum meets the requirements; (10) If the requirements are not met, repeat the above (7)-(9) until the result meets the measurement requirements.

2. The method according to claim 1, characterized in that In step (1), a theoretical neutron energy spectrum is obtained by simulation calculation or empirical method.

3. The method according to claim 1, characterized in that The response functions include bare ball, 2.5 inches, 3 inches, 3.5 inches, 4 inches, 5 inches, 6 inches, 8 inches, 10 inches, and 12 inches.

4. The method according to claim 1, characterized in that: In step (9), based on the spectrum shape and the total neutron fluence, the complete spectrometer neutron spectrum and the lightweight spectrometer neutron spectrum are compared and analyzed with the theoretical neutron spectrum to determine whether the result of the lightweight spectrometer neutron spectrum meets the requirements.

5. The method according to claim 1, characterized in that Step (9) includes: when some balls are removed, the measurement uncertainty does not increase significantly; when the number of balls removed increases to a certain extent, the measurement uncertainty increases significantly.

6. A lightweight design system for a multi-moderator neutron spectrometer, characterized in that: The system is used to: (1) Obtain theoretical neutron energy spectrum; (2) Establish a Monte Carlo theoretical model for multi-sphere neutron spectrometer; (3) calculating the response function of the multi-sphere neutron spectrometer at a certain energy interval and drawing a corresponding function curve, wherein the response function refers to a curve showing the change of neutron fluence of polyethylene ball detectors of different sizes in the multi-sphere neutron spectrometer with neutron energy; (4) adjusting the energy interval of the response function of the multi-sphere neutron spectrometer to be consistent with the energy interval of the theoretical neutron energy spectrum; (5) multiplying the response function of the multi-sphere neutron spectrometer by the theoretical neutron energy spectrum to obtain a theoretical count of each polyethylene ball detector in the multi-sphere neutron spectrometer; (6) inputting the theoretical count of each polyethylene ball detector in the multi-ball neutron spectrometer into a neutron spectrum analysis program to obtain a complete spectrometer neutron spectrum; (7) according to the requirements of the object to be measured for the neutron energy measurement range, removing the theoretical counts and corresponding response functions of one or several polyethylene ball detectors in the multi-ball neutron spectrometer; (8) inputting the remaining theoretical counts in the multi-sphere neutron spectrometer into the neutron spectrum analysis program to obtain a lightweight spectrometer neutron spectrum; (9) comparing and analyzing the complete spectrometer neutron spectrum and the lightweight spectrometer neutron spectrum with the theoretical neutron spectrum to determine whether the result of the lightweight spectrometer neutron spectrum meets the requirements; (10) If the requirements are not met, repeat the above (7)-(9) until the result meets the measurement requirements.

7. The system according to claim 6, characterized in that The theoretical neutron energy spectrum is obtained through simulation calculation or empirical method.

8. The system according to claim 6, characterized in that The response functions include bare ball, 2.5 inches, 3 inches, 3.5 inches, 4 inches, 5 inches, 6 inches, 8 inches, 10 inches, and 12 inches.

9. The system according to claim 6, characterized in that Based on the spectrum shape and the total neutron fluence, the neutron spectrum of the complete spectrometer and the neutron spectrum of the lightweight spectrometer are compared and analyzed with the theoretical neutron spectrum to determine whether the result of the neutron spectrum of the lightweight spectrometer meets the requirements.

10. The system according to claim 6, characterized in that When some balls are removed, the measurement uncertainty does not increase significantly. However, when the number of balls removed increases to a certain extent, the measurement uncertainty increases significantly.

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