A method for obtaining energy spectrum and angular distribution of deuterium-tritium neutron source

Abstract

The present invention discloses a method for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source. The method adopts a D-T neutron radiation field measurement system based on a SiC detector, can simultaneously measure the companion particles of the two reactions, can distinguish them in the energy spectrum, and obtain the counting rates of alpha particles and protons; takes into account the influence of the D-D reaction caused by target deposition in the D-T reaction, obtains the energy spectrum and angular distribution of the D-T and D-D neutron sources, and effectively improves the accuracy of the energy spectrum and angular distribution; the method of the present invention has no requirements for target tube-related parameters such as a pipeline and a grating for the companion particles, is simple to operate, only needs to measure a set of data to obtain the energy spectrum distribution in the entire space, does not need to measure different angles one by one, and can measure all D-T neutron sources; and the method of the present invention can be applied to a DC beam or pulsed beam D-T accelerator neutron source with a reserved companion particle channel, especially when there is deuterium beam deposition on the target, and can more accurately obtain the energy spectrum and angular distribution of the D-T neutron source.

Description

Technical Field

[0001] The invention belongs to the field of nuclear technology, and in particular relates to a method for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source. Background Art

[0002] Fusion deuterium-tritium (DT) neutron source is widely used in research fields such as nuclear data measurement, fast neutron photography, explosive detection, single event effect and detector efficiency calibration. The neutron source generates D ions through an accelerator and bombards the T-Ti target. 4 The He reaction produces approximately 14 MeV neutrons for experimental use.

[0003] In the actual process of nuclear data measurement and detector efficiency calibration, it is often necessary to use a DT neutron source for a long time of irradiation to accumulate experimental counts to ensure the statistical accuracy of the experimental data. In this case, when the D ions generated by the accelerator bombard the T-Ti target to produce neutrons, some D ions will be deposited in the T-Ti target, and these D ions will react with the later incident D ions to form D(d,n) 3 The He reaction produces neutrons of about 2.8 MeV (DD neutrons). As the irradiation time increases, the T deposited in the T-Ti target will be continuously consumed, while the deposited D ions will continue to increase, resulting in the generation of D(d,n) 3 The probability of He reaction increases, and the energy spectrum and angular distribution of the neutron source will change as the use time of the T-Ti target increases.

[0004] The energy spectrum and angular distribution of a neutron source directly affect the accuracy of nuclear data measurements and detector efficiency calibration. There are two methods for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source: experimental measurement and simulation calculation. Experimental measurement typically uses the time-of-flight method to measure the neutron energy spectrum at different angles. The deuterium beam of the accelerator is required to be a pulsed beam. To reduce the impact of scattered neutrons, a very open experimental environment is required, which cannot be widely applied to all deuterium-tritium neutron sources. Simulation calculations mainly use Monte Carlo simulations to obtain the energy spectrum at different angles. Programs such as Geant4, MCNPX, and TARGET are usually used to theoretically calculate radiation field information. However, simulation calculations cannot simultaneously consider DD neutrons and DT neutrons. Summary of the Invention

[0005] In view of the above technical problems existing in the prior art, the purpose of the present invention is to provide a method for accurately obtaining the energy spectrum and angular distribution of a DT neutron source, which can solve the problem of T(d,n) in the long-term use of the DT neutron source. 4 During the He reaction, D(d,n) will occur. 3 He reaction causes changes in the energy spectrum and angular distribution of the neutron source, resulting in inaccurate experimental measurement results.

[0006] To achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows: A method for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source, comprising the following steps:

[0007] (1) Establish a DT neutron radiation field measurement system based on silicon carbide (SiC) detectors;

[0008] (2) The accompanying particles produced by the DD reaction and the DT reaction are monitored in the system, and T(d,n) is obtained respectively. 4 The accompanying particles α particles produced by the two reactions of He and D(d,t)p ( 4 He) and proton (p) counts;

[0009] (3) According to the above-mentioned companion particle α particle ( 4 The DD and DT yield ratios were calculated by the formula:

[0010] (4) Simulate and calculate the energy spectrum and angular distribution of DT neutron source and DD neutron source respectively;

[0011] (5) Set the above-mentioned companion particles α particles in the energy spectrum and angular distribution of the simulated DT neutron source and DD neutron source ( 4 The energy spectrum and angular distribution of the real DT and DD neutron sources are obtained by calculating the ratio of the count rates of He) and protons (p).

[0012] Furthermore, in step (1), the DT neutron radiation field measurement system based on silicon carbide (SiC) detector includes a SiC detector accompanied by a particle monitor and a SiC detector measurement system.

[0013] Furthermore, in step (1), the SiC detector accompanying particle monitor includes a vacuum accompanying target tube and a detector, and the vacuum accompanying target tube and the detector are located at a fixed angle with the axis of the D beam.

[0014] Furthermore, the SiC detector measurement system includes a preamplifier, a main amplifier, a multi-channel analyzer, and a bias power supply.

[0015] Furthermore, the detector monitors the DD reaction and the DT reaction, and the SiC detector measurement system obtains T(d,n) 4 The accompanying particles α particles produced by the two reactions of He and D(d,t)p ( 4 He) and proton (p) counts.

[0016] Furthermore, in step (3), the DT neutron source yield ratio is calculated by formula (1),

[0017]

[0018] Among them, Y is the corresponding neutron yield; A a is the anisotropy factor, which is related to the cross-sectional and angular distribution correction factor of the reaction; N a is the yield of accompanying particles; δ is the cross-section value of DT reaction; is the solid angle of the SiC detector to the center of the tritium titanium target.

[0019] Furthermore, in step (3), the DD neutron source yield ratio is calculated by formula (2):

[0020]

[0021] Among them, Y is the corresponding neutron yield; A p is the anisotropy factor, which is related to the cross-sectional and angular distribution correction factor of the reaction; N p is the yield of accompanying particles; δ is the cross-section value of DT reaction; is the solid angle of the SiC detector to the center of the tritium titanium target.

[0022] Furthermore, in the step (4), the energy spectrum and angular distribution of the DT neutron source and the DD neutron source are respectively simulated and calculated using the TARGET program according to the thickness of the Ti film in the T-Ti target.

[0023] The beneficial effects brought about by the technical solution of the present invention are: a method for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source, using a DT neutron radiation field measurement system based on a SiC detector, which can simultaneously measure the accompanying particles of the two reactions, and can distinguish the counting rates of alpha particles and protons on the energy spectrum; taking into account the influence of the DD reaction caused by target deposition in the DT reaction, the energy spectrum and angular distribution of the DT and DD neutron sources are obtained, and the accuracy of the energy spectrum and angular distribution is effectively improved; the method of the present invention has no requirements on target tube related parameters such as the pipeline of the accompanying particles and the grating, and is simple to operate. It only needs to measure a set of data and then combine it with T The energy spectrum and angular distribution of the DT neutron source and the DD neutron source calculated by the ARGET program can obtain the energy spectrum distribution in the entire space, without the need to measure different angles one by one, and can be measured on all DT neutron sources; and the method of the present invention can be applied to a DC beam or pulsed beam DT accelerator neutron source with a reserved accompanying particle channel, especially when there is a deuterium beam deposited on the target, the energy spectrum and angular distribution of the DT neutron source can be obtained more accurately, meeting the test requirements, and can effectively correct the low-energy end of the experiment, which is of great significance for experimental research and technological breakthroughs based on DT neutron sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of a DT neutron radiation field measurement system based on a silicon carbide (SiC) detector according to an embodiment of the present invention;

[0025] Figure 2 This is an energy spectrum diagram of a companion particle measured by a SiC detector according to an embodiment of the present invention;

[0026] Figure 3 Schematic diagram of the energy spectrum and angular distribution of a DT neutron source obtained by the method of an embodiment of the present invention;

[0027] Figure 4 is a schematic diagram of the energy spectrum and angular distribution of a DD neutron source obtained by the method of an embodiment of the present invention;

[0028] Figure 5 The actual energy spectrum and angular distribution of the DT neutron source when the accompanying particles are 1724.51:51.53 in the method of the embodiment of the present invention;

[0029] Figure 6 The comparison and corresponding ratio of the DT neutron angular distribution and the accompanying particle yield angular distribution of 1724.51:51.53 obtained by the method of the embodiment of the present invention are shown;

[0030] Figure 7 The DT neutron 0° energy spectrum obtained by the method of the embodiment of the present invention is compared with the 0° energy spectrum of the accompanying particle with a ratio of 1724.51:51.53. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0032] An embodiment of the present invention provides a method for obtaining an energy spectrum and angular distribution of a deuterium-tritium neutron source, comprising the following steps:

[0033] Refer to the attached Figure 1 (1) establishing a DT neutron radiation field measurement system based on a silicon carbide (SiC) detector; the SiC detector is about 50 microns thick;

[0034] (2) The accompanying particles produced by the DD reaction and the DT reaction are monitored in the system, and T(d,n) is obtained respectively. 4 The accompanying particles α particles produced by the two reactions of He and D(d,t)p ( 4 He) and proton (p) counts;

[0035] (3) According to the above-mentioned companion particle α particle ( 4 The DD and DT yield ratios were calculated by the formula:

[0036] (4) Simulate and calculate the energy spectrum and angular distribution of DT neutron source and DD neutron source respectively;

[0037] (5) Set the above-mentioned companion particles α particles in the energy spectrum and angular distribution of the simulated DT neutron source and DD neutron source ( 4 The energy spectrum and angular distribution of the real DT and DD neutron sources are obtained by calculating the ratio of the count rates of He) and protons (p).

[0038] Preferably, in step (1), the DT neutron radiation field measurement system based on silicon carbide (SiC) detector includes a SiC detector accompanied by a particle monitor and a SiC detector measurement system.

[0039] Preferably, in step (1), the SiC detector accompanying particle monitor includes an accompanying particle vacuum target tube and a SiC detector, and the accompanying particle vacuum target tube and the SiC detector are located at a fixed angle with the axis of the D beam. 3 He reacts to release 3 The He energy is relatively low, only 0.78 MeV, and it is difficult to distinguish it from the scattering of the D beam on the target. In order to accurately obtain D(d,n) 3 The method of the present invention measures the protons produced by the competing reaction D(d,t)p, which produces neutrons from the He reaction. The energy of the alpha particles produced by the DT reaction is approximately 3.5 MeV, higher than the energy of the protons produced by the DD reaction (approximately 2.8 MeV). Using the SiC detector of the present invention, the two accompanying particles can be distinguished.

[0040] Preferably, the companion particle vacuum target tube and the SiC detector are located at an angle of 135° with the axis of the D beam.

[0041] Preferably, the SiC detector measurement system includes a bias power supply, a preamplifier, a main amplifier, and a multi-channel analyzer.

[0042] During actual measurement, the electronic plug-in is adjusted so that the peak of the accompanying particle appears on the energy spectrum.

[0043] Refer to the attached Figure 2 The lower energy peak is the proton p accompanying the DD reaction, and the higher energy peak is the α particle accompanying the DT reaction.

[0044] Preferably, the detector monitors the DD reaction and the DT reaction, and the SiC detector measurement system obtains the accompanying particles α particles ( 4 He) and proton (p) counts.

[0045] Preferably, in step (3), the DT neutron source yield ratio is calculated by formula (1):

[0046]

[0047] Among them, Y is the corresponding neutron yield; A α is the anisotropy factor, which is related to the cross-sectional and angular distribution correction factor of the reaction; N α is the yield of accompanying particles; δ is the cross-section value of DT reaction; is the solid angle of the SiC detector to the center of the tritium titanium target.

[0048] Preferably, in step (3), the DD neutron source yield ratio is calculated by formula (2):

[0049]

[0050] Among them, Y is the corresponding neutron yield; A p is the anisotropy factor, which is related to the cross-sectional and angular distribution correction factor of the reaction; N p is the yield of accompanying particles; δ is the cross-section value of DT reaction; is the solid angle of the SiC detector to the center of the tritium titanium target.

[0051] In the same system, the solid angle and measurement time can be ignored. When the angle between the companion particle vacuum target tube and the SiC detector and the axis of the D beam is 135°, the yield ratio is obtained respectively.

[0052] DT A α =1.263, δ(tot)=3.984b, δ(0)=0.336b, A in DD p =2.3412, δ(tot)=35mb, δ(0)=5.56mb. According to formulas (1) and (2), the DD / DT yield ratio and the accompanying particle count ratio are 1.0161 at 135°.

[0053] Preferably, in step (4), the energy spectrum and angular distribution of the DT neutron source and the DD neutron source are respectively simulated and calculated using the TARGET program according to the thickness of the Ti film in the T-Ti target.

[0054] Refer to the attached Figure 3 、 4 The energy spectra and angular distributions of the DT and DD neutron sources were obtained by setting the angles between the D beam axis and 37 satellite particle vacuum target tubes and SiC detectors using the method of an embodiment of the present invention. The angular step size was 5 degrees, and the energy spectrum accuracy was 0.01 MeV.

[0055] Refer to the attached Figure 5 The angular distribution of the deuterium-tritium neutron source energy spectrum when the ratio of α particles to protons is 1724.51:51.53 calculated using the method of an embodiment of the present invention.

[0056] Refer to the attached Figure 6 The angle variation of the DT neutron source yield obtained by the method of the embodiment of the present invention at a certain angle is close to the theoretical value, indicating that the method of the embodiment of the present invention has high accuracy.

[0057] Refer to the attached Figure 7 The energy spectrum distribution of the DT neutron source obtained by the method of the embodiment of the present invention at a certain angle is close to the theoretical value, indicating that the method of the embodiment of the present invention has high accuracy.

[0058] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source, characterized in that: The following steps are involved: (1) Establish a DT neutron radiation field measurement system based on silicon carbide detectors; (2) The accompanying particles produced by the DD reaction and the DT reaction are monitored in the system, and T(d,n) is obtained respectively. 4 The accompanying particles α particles produced by the two reactions of He and D(d,t)p ( 4 He) and proton (p) counts; (3) According to the above-mentioned companion particle α particle ( 4 The DD and DT yield ratios were calculated by the formula: (4) Simulate and calculate the energy spectrum and angular distribution of DT neutron source and DD neutron source respectively; (5) Set the above-mentioned companion particles α particles in the energy spectrum and angular distribution of the simulated DT neutron source and DD neutron source ( 4 The energy spectrum and angular distribution of the real DT and DD neutron sources are obtained by calculating the ratio of the count rates of He) and protons (p).

2. The method for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source according to claim 1, wherein: In the step (1), the DT neutron radiation field measurement system based on silicon carbide (SiC) detector includes a SiC detector accompanied by a particle monitor and a SiC detector measurement system.

3. The method for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source according to claim 2, wherein: In the step (1), the SiC detector companion particle monitor includes a companion particle vacuum target tube and a SiC detector, and the companion particle vacuum target tube and the SiC detector are located at a fixed angle with the axis of the D beam.

4. The method for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source according to claim 2, wherein: The SiC detector measurement system includes a bias power supply, a preamplifier, a main amplifier, and a multi-channel analyzer.

5. The method for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source according to claim 2, wherein: The detector monitors the DD reaction and the DT reaction, and the SiC detector measurement system obtains T(d,n) 4 The accompanying particles α particles produced by the two reactions of He and D(d,t)p ( 4 He) and proton (p) counts.

6. The method for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source according to claim 1, wherein: In step (3), the DT neutron source yield ratio is calculated by formula (1), Among them, Y is the corresponding neutron yield; A α is the anisotropy factor, which is related to the cross-sectional and angular distribution correction factor of the reaction; N α is the yield of accompanying particles; δ is the cross-section value of DT reaction; is the solid angle of the SiC detector to the center of the tritium titanium target.

7. The method for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source according to claim 1, wherein: In step (3), the DD neutron source yield ratio is calculated by formula (2), Among them, Y is the corresponding neutron yield; A p is the anisotropy factor, which is related to the cross-sectional and angular distribution correction factor of the reaction; N p is the yield of accompanying particles; δ is the cross-section value of DT reaction; is the solid angle of the SiC detector to the center of the tritium titanium target.

8. The method for obtaining the energy spectrum and angular distribution of a deuterium-tritium neutron source according to claim 1, wherein: In the step (4), the energy spectrum and angular distribution of the DT neutron source and the DD neutron source are respectively simulated and calculated using the TARGET program according to the thickness of the Ti film in the T-Ti target.

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