Method for calibrating energy of high-energy gamma spectrometer

Abstract

The invention discloses a method for calibrating energy of a high-energy gamma spectrometer, which comprises the following steps of: exciting different materials by adopting an Am-Be neutron source to obtain instant single-energy gamma rays in an energy region of 2-10MeV, and calibrating the energy of the gamma spectrometer; the Am-Be neutron source emits 4.43 MeV gamma rays after (alpha, n) reaction, and does not emit gamma rays with higher energy; the 241 Am emits gamma rays, and the gamma rays are low-energy 59.5 keV; 4.43 MeV gamma rays generated by the Am-Be neutron source can be used as known energy rays to carry out calibration on a gamma spectrometer; the gamma spectrometer can effectively scale at 4MeV; iron Fe, nickel Ni, hydrogen H, nitrogen N, chlorine Cl and fluorine F are selected as neutron converters to capture thermal neutrons to generate gamma rays for instrument energy calibration. According to the invention, gamma rays within 10MeV can be calibrated by the gamma spectrometer, so that unknown sources within 10MeV can be identified, and the identification range and accuracy are greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of neutron energy spectrum measurement, and in particular to a method for energy calibration of a high-energy gamma spectrometer. Background Art

[0002] The gamma spectrometer can accurately analyze the radioactive nuclides in the sample through the correct energy calibration, so that it can provide reliable data support in the fields of scientific research, environmental monitoring, medical diagnosis, etc.

[0003] Energy calibration is to use the peak position corresponding to the energy of the currently known standard source (multi-energy peak or mixed source), and make a relationship curve between the measured energy and the peak position address. By using this relationship curve, the peak position address of the gamma ray of the unknown source can be measured to obtain the energy corresponding to the ray, thereby determining the type of nuclide contained in the unknown source.

[0004] The existing energy scale generally uses 5 to 8 standard gamma-ray energy peaks for calibration; the gamma-ray sources currently used for calibration include 241Am (59.6keV), 57Co (121.9keV), 203Hg (279.1keV), 137Cs (661.6keV), 54Mn (534.8keV), 22Na (1274.5keV) 232Th (2614,511keV) and other radioactive sources; these gamma-ray sources all have energies below 3MeV.

[0005] The existing technology can only calibrate the gamma spectrometer below 3MeV, so the instrument calibrated with the current technology can only accurately measure nuclides below 3MeV. When it is necessary to measure nuclides above 3MeV, its accuracy cannot be guaranteed. Summary of the invention

[0006] The purpose of the present invention is to provide a method for energy calibration of a high energy gamma spectrometer, which can conveniently provide a series of characteristic energy peaks not less than 10 MeV, which can be used for energy calibration, thereby ensuring that the instrument can accurately measure nuclides below 10 MeV. In this way, when encountering nuclides below 10 MeV, they can be accurately measured.

[0007] To achieve the above object, the method of energy calibration of a high-energy gamma spectrometer of the present invention uses an Am-Be neutron source to excite different materials to obtain prompt monoenergetic gamma rays in the energy range of 2-10 MeV, and performs energy calibration of the gamma spectrometer;

[0008] The Am-Be neutron source emits 4.43MeV gamma rays after the (α, n) reaction, but does not emit higher energy gamma rays; 241Am itself emits gamma rays of low energy 59.5keV; the 4.43MeV gamma rays produced by the Am-Be neutron source can be used as known energy rays to calibrate the gamma spectrometer, so that the gamma spectrometer can be effectively calibrated at 4MeV;

[0009] Iron Fe, nickel Ni, hydrogen H, nitrogen N, chlorine Cl and fluorine F are selected as neutron converters to capture thermal neutrons and produce gamma rays for energy calibration of the instrument.

[0010] Furthermore, after the iron Fe captures thermal neutrons, the proportion of double lines with energies of 7631keV and 7645keV in the high-energy gamma rays emitted is 52.6%; after the Am-Be source neutrons are moderated by paraffin, the gamma rays generated by iron capture are the effect caused by thermal neutron capture, and the emitted line spectrum is the same as the gamma line spectrum generated by thermal neutron capture; the gamma rays with energies of 7631keV and 7645keV generated by iron capturing thermal neutrons are very obvious and very stable, so when the gamma spectrometer collects the spectrum, it will be easy to find the peak positions in the energy spectrum corresponding to the gamma rays of 7631keV and 7645keV; the gamma rays with energies of 7631keV and 7645keV obtained by iron capturing thermal neutrons can be used as known energy peaks to calibrate the gamma spectrometer, so that the gamma spectrometer can be effectively calibrated at 7MeV.

[0011] Furthermore, the strongest gamma ray generated by nickel Ni after capturing thermal neutrons has an energy of 8999keV, which accounts for 37.7% of the total number of high-energy gamma rays, and the other energies are 8533keV, 7819keV, 7537keV, 6837keV and 5817keV, and the numbers of these gamma rays for every 100 neutrons captured are 17, 8, 4.5, 10.8 and 2.1 respectively; 7638keV generated by iron capturing neutrons is the background caused by surrounding iron-containing materials; the gamma rays of 8999keV, 8533keV, 7819keV, 7537keV and 6837keV in this reaction can all be used as known energy rays for calibrating a gamma spectrometer; the gamma rays obtained by the reaction enable the gamma spectrometer to be effectively calibrated within 7MeV to 9MeV.

[0012] Furthermore, the high-energy gamma rays of the thermal neutron capture gamma rays of chlorine Cl with intensities greater than 2.75 and / or capturing 100 neutrons are shown, which are 8578 (2.91), 7790 (8.55), 7414 (10.4), 6627.6 (4.54), 6619.5 (8.01), 6111 (20.0), 5715.3 (5.5), respectively. The energy unit of the above numerical values ​​is keV, and the values ​​in brackets represent The figure shows the number of gamma rays produced for every 100 neutrons captured; 6627.6keV and 6619.5keV are not distinguished; using MgCl2 crystalline powder as the radiator, the gamma rays of 8578keV, 7790keV, 7414keV, 6111keV, and 5715.3keV produced by this reaction can be used as known energy rays to calibrate the gamma spectrometer, so that the gamma spectrometer can be effectively calibrated within 6MeV to 8MeV.

[0013] Furthermore, the fluorine F reacts with neutrons (n, α) to produce gamma-ray thermal neutrons; the converter material used is polytetrafluoroethylene; three spectral lines with an energy of 6129 keV are given, and this gamma ray is produced by

[0014] n+ 19 F→ 16 N * + 4 He

[0015] 16 N * → 16 O * +β -

[0016] 16 O * → 16 O+γ(6.129MeV)

[0017] Reaction, by 16 N has a 65% chance of decaying to 16 O at the 6129keV energy level, exciting the nucleus 16 O* is emitted when it is de-excited. This reaction can produce 6129keV gamma rays, which can be used as known energy to calibrate the gamma spectrometer at 6129keV, allowing the gamma spectrometer to be effectively calibrated at around 6MeV.

[0018] Furthermore, the hydrogen H captures thermal neutrons to produce gamma rays, and the characteristic gamma ray energy of the H element is 2.223245 MeV. The 2MeV gamma rays produced by this reaction can be used as known energy rays for gamma spectrometer calibration, so that the gamma spectrometer can be effectively calibrated at around 2MeV.

[0019] Furthermore, the nitrogen N captures thermal neutrons to produce gamma rays, and the characteristic gamma ray energy of the N element is 10.83MeV. The 10.83MeV gamma rays produced by this reaction can be used as known energy rays for gamma spectrometer calibration, so that the gamma spectrometer can be effectively calibrated at around 10MeV.

[0020] The present invention also provides a device for implementing the method for energy calibration of a high-energy gamma spectrometer, which consists of two parts: one is a gamma ray generating part, and the other is a data acquisition part, characterized in that:

[0021] The gamma ray generating part is composed of a target / radiator (1), paraffin (2), an Am-Be neutron source (4), and lead (5); the data acquisition part is composed of a gamma spectrometer detector support cabinet, a gamma spectrometer (7), a data transmission cable (8), and a data acquisition computer (9); the gamma spectrometer detector support cabinet is composed of a combination of lead (5) and cadmium (6);

[0022] Further, placing the Am-Be neutron source (4) at a working position;

[0023] Moving the target / radiator 1 to the Am-Be neutron source (4);

[0024] Moving the gamma spectrometer detector support cabinet composed of lead (5) and cadmium (6) to the target / radiator (1);

[0025] Placing the gamma spectrometer (7) in the gamma spectrometer detector support cabinet;

[0026] Connecting the gamma spectrometer (7) and the data collection computer (9) using a data transmission cable (8);

[0027] Powering on the gamma spectrometer detector;

[0028] Using the computer 9 for acquisition to acquire data;

[0029] The gamma spectrometer 7 is calibrated.

[0030] Further, the working position of the gamma spectrometer is changed for calibration;

[0031] Spectrometers with other detectors can also be calibrated in this way, including: spectrometers with NaI(Tl) scintillator probes, bismuth germanate HPGe probes, and LaBr3(Ce3+) probes;

[0032] Nickel, iron, polytetrafluoroethylene, polyvinyl chloride, polyethylene, C3H6N6, NH4Cl can be used as target materials, and materials containing Fe, Ni, H, N, Cl and F elements can also be used as target materials.

[0033] The present invention has the following advantages:

[0034] The present invention can calibrate the gamma rays within 10MeV on the gamma spectrometer, so that it can identify unknown sources within 10MeV, greatly increasing the range and accuracy of identification.

[0035] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites a preferred embodiment and describes it in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is the gamma spectrum of neutron capture by iron;

[0037] Figure 2 The gamma spectrum of neutron capture by nickel;

[0038] Figure 3 is the gamma spectrum of chlorine neutron capture;

[0039] Figure 4 for 19 F(n, α) 16 N reaction gamma spectrum;

[0040] Figure 5 for 16 N decay outline;

[0041] Figure 6 is a schematic diagram of the layout;

[0042] Figure 7 This is a schematic diagram of data collection;

[0043] Figure 8 for 58 Ni+ paraffin spectrum acquisition diagram;

[0044] Fig. 9 for 60 Co+ paraffin spectrum acquisition diagram;

[0045] Fig.10 for 58 Ni+paraffin energy linearity curve;

[0046] Fig.11 It is the energy spectrum of NH4Cl+ paraffin;

[0047] Fig.12 It is the linear curve of NH4Cl+paraffin energy;

[0048] Fig.13 Schematic diagram for calibrating the position changes of the gamma spectrometer. DETAILED DESCRIPTION

[0049] The present invention provides a series of characteristic energy peaks of not less than 10 MeV, which can be used for energy calibration, thereby ensuring that the instrument can accurately measure nuclides below 10 MeV.

[0050] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but those skilled in the art should understand that the embodiments described below are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] The energy of the radiation source used in the calibrated gamma spectrometer is usually limited to below 3MeV.

[0052] The invention provides a method for energy calibration of a high-energy gamma spectrometer, which uses an Am-Be neutron source to excite different materials to obtain prompt monoenergetic gamma rays in the 2-10 MeV energy range to perform energy calibration of the gamma spectrometer.

[0053] The Am-Be neutron source mainly emits 4.43MeV gamma rays after the (α, n) reaction, and the probability of emitting higher energy gamma rays is very small. 241Am itself emits gamma rays, which are low-energy 59.5keV. The 4.43MeV gamma rays produced by the Am-Be neutron source can be used as known energy rays to calibrate the gamma spectrometer; so that the gamma spectrometer can be effectively calibrated at around 4MeV.

[0054] Fe, Ni, H, N, Cl and F can be selected as neutron converters to capture thermal neutrons and produce gamma rays for energy calibration of the instrument.

[0055] 1. As Figure 1 As shown in the figure, after iron captures thermal neutrons, the proportion of the double lines with energies of 7631keV and 7645keV in the high-energy gamma rays emitted is 52.6%. Therefore, after the Am-Be source neutrons are moderated by paraffin, the gamma rays generated by iron capture can be considered to be mainly caused by thermal neutron capture, and the emitted line spectrum is the same as the gamma line spectrum generated by thermal neutron capture. Because the gamma rays with energies of 7631keV and 7645keV generated by iron capturing thermal neutrons are very obvious and very stable, when the gamma spectrometer collects the spectrum, it will be easy to find the peak position in the energy spectrum corresponding to the gamma rays of 7631keV and 7645keV. The gamma rays with energies of 7631keV and 7645keV obtained by iron capturing thermal neutrons can be used as known energy peaks for the calibration of the gamma spectrometer. This enables the gamma spectrometer to be effectively calibrated at 7MeV.

[0056] 2. If Figure 2As shown in the figure, the strongest gamma ray produced by nickel after capturing thermal neutrons is 8999keV, which accounts for 37.7% of the total number of high-energy gamma rays. The other energies are 8533keV, 7819keV, 7537keV, 6837keV and 5817keV. The number of these gamma rays for every 100 neutrons captured is 17, 8, 4.5, 10.8 and 2.1 respectively. It can also be seen that 7638keV is produced by iron capturing neutrons, which is the background caused by the surrounding iron-containing materials. The gamma rays of 8999keV, 8533keV, 7819keV, 7537keV and 6837keV in this reaction can all be used as known energy rays for the calibration of the gamma spectrometer; the gamma rays obtained by the reaction enable the gamma spectrometer to be effectively calibrated within 7MeV to 9MeV.

[0057] 3. Such as Figure 3 As shown, the high-energy gamma rays with intensities greater than 2.75 / 100 neutrons captured by thermal neutron capture gamma rays of chlorine have been displayed. They are 8578 (2.91), 7790 (8.55), 7414 (10.4), 6627.6 (4.54), 6619.5 (8.01), 6111 (20.0), 5715.3 (5.5). The energy units of the above numerical values ​​are keV, and the values ​​in brackets represent the number of gamma rays produced per 100 neutrons captured. 6627.6keV and 6619.5keV are not distinguished. The figure below is the energy spectrum recorded using MgCl2 crystalline powder as the radiator. The γ rays of 8578keV, 7790keV, 7414keV, 6111keV, and 5715.3keV produced by this reaction can be used as known energy rays to calibrate the γ spectrometer, so that the γ spectrometer can be effectively calibrated within 6MeV to 8MeV.

[0058] 4. Such as Figure 4 As shown in the figure, fluorine reacts with neutrons (n, α) to produce gamma-ray thermal neutrons; the converter material used is polytetrafluoroethylene. The high-energy part of the gamma-ray energy spectrum is shown in the figure below. The figure shows three spectral lines with an energy of 6129keV. This gamma-ray is produced by

[0059] n+ 19 F→ 16 N * + 4 He

[0060] 16 N * → 16 O * +β -

[0061] 16 O * → 16O+γ(6.129MeV)

[0062] Reaction, such as Figure 5 As shown by 16 N has a 65% chance of decaying to 16 O at the 6129keV energy level, exciting the nucleus 16 O* is emitted when it is de-excited. This reaction can produce 6129keV gamma rays, which can be used as known energy to calibrate the gamma spectrometer at 6129keV. This allows the gamma spectrometer to be effectively calibrated at around 6MeV.

[0063] 5. Hydrogen captures thermal neutrons to produce gamma rays; the characteristic gamma ray energy of H element is 2.223245 MeV. The gamma rays of about 2 MeV produced by this reaction can be used as known energy rays for gamma spectrometer calibration; so that the gamma spectrometer can be effectively calibrated at about 2 MeV.

[0064] 6. Nitrogen captures thermal neutrons to produce gamma rays; the characteristic gamma ray energy of N element is 10.83MeV. The 10.83MeV gamma rays produced by this reaction can be used as known energy rays for gamma spectrometer calibration, so that the gamma spectrometer can be effectively calibrated at around 10MeV.

[0065] From the above data, we can see that: the capture of thermal neutrons by iron enables the gamma spectrometer to be effectively calibrated at 7MeV;

[0066] Nickel captures thermal neutrons, which enables the gamma spectrometer to be effectively calibrated in the range of 7MeV to 9MeV;

[0067] Chlorine capture of thermal neutrons enables the gamma spectrometer to be effectively calibrated within the range of 6MeV to 8MeV;.

[0068] The reaction of fluorine with neutrons (n, α) produces gamma rays that enable the gamma spectrometer to be effectively calibrated at around 6MeV;

[0069] Thermal neutron capture by hydrogen enables the gamma spectrometer to be effectively calibrated at around 2MeV;

[0070] Thermal neutron capture by nitrogen enables the gamma spectrometer to be effectively calibrated at around 10 MeV;

[0071] The Am-Be neutron source can effectively calibrate the gamma spectrometer at around 4MeV through the (α, n) reaction.

[0072] The device for implementing the method of energy calibration of a high energy gamma spectrometer of the present invention consists of two parts: one is a gamma ray generating part, and the other is a data acquisition part, such as Figure 6 and Figure 7 shown.

[0073] The gamma ray generating part is composed of a target / radiator 1, paraffin 2, an Am-Be neutron source 4, and lead 5;

[0074] The data acquisition part is composed of a γ spectrometer detector support cabinet (composed of lead 5 and cadmium 6), a γ spectrometer 7, a data transmission cable 8, and a collection computer 9.

[0075] in:

[0076] 1: Target / radiator: can be selected from nickel target, iron target, polytetrafluoroethylene target, polyvinyl chloride target, polyethylene target, C3H6N6 target, NH4Cl target; 2: paraffin; 3: air; 4: Am-Be neutron source; 5: lead; 6: cadmium; 7: gamma spectrometer; 8: data transmission cable; 9: computer for collection;

[0077] Place the Am-Be neutron source 4 as follows Figure 6 Working position shown;

[0078] Move the target / radiator 1 to the vicinity of the Am-Be neutron source 4;

[0079] Place the gamma spectrometer detector support cabinet (composed of 5 and 6) near the target / radiator 1;

[0080] Place the gamma spectrometer 7 in the support cabinet;

[0081] Use a data transmission cable 8 to connect the gamma spectrometer 7 and the acquisition computer 9;

[0082] Power on the detector;

[0083] Use the collected computer 9 to collect;

[0084] The gamma spectrometer 7 is calibrated.

[0085] The present invention uses a lanthanum bromide spectrometer to carry out a calibration experiment. From the experimental results, it can be seen that this method is feasible and its calibration curve is very linear; the reliability of unknown source nuclides within 10MeV can be ensured.

[0086] The following is the experimental data of this method experiment:

[0087] (1) Nickel target + paraffin + 60 Co energy spectrum, such as Figure 8 , Fig. 9 , Fig.10 As shown;

[0088] Table 1 Channel address energy correspondence table

[0089]

[0090] (2) NH4Cl + paraffin energy spectrum, such as Fig.11 , Fig.12 As shown;

[0091] It can be clearly observed 14 The 10.829 MeV characteristic peak of N (n, γ)

[0092] Table 2 Channel address energy correspondence table

[0093]

[0094]

[0095] The present invention can also change the experimental layout, such as changing the position of the gamma spectrometer for calibration; Fig.13 The positions shown are marked.

[0096] The lanthanum bromide spectrometer was measured this time, but spectrometers with other detectors can also be calibrated in this way; for example: spectrometers with NaI (Tl) scintillator probes, HPGe (bismuth germanate) probes, and LaBr3 (Ce3+) probes.

[0097] Not only can nickel, iron, polytetrafluoroethylene, polyvinyl chloride, polyethylene, C 3 H 6 N 6 NH 4 Cl was used as the target material for the experiment, and materials containing Fe, Ni, H, N, Cl and F elements can also be used as target materials for the experiment.

[0098] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for energy calibration of a high-energy gamma spectrometer, using an Am-Be neutron source to excite different materials to obtain prompt monoenergetic gamma rays in the energy range of 2-10 MeV, and perform energy calibration of the gamma spectrometer; The Am-Be neutron source emits 4.43MeV gamma rays after the (α, n) reaction, but does not emit higher energy gamma rays; 241Am itself emits gamma rays of low energy 59.5keV; the 4.43MeV gamma rays produced by the Am-Be neutron source can be used as known energy rays to calibrate the gamma spectrometer, so that the gamma spectrometer can be effectively calibrated at 4MeV; Iron Fe, nickel Ni, hydrogen H, nitrogen N, chlorine Cl and fluorine F are selected as neutron converters to capture thermal neutrons and produce gamma rays for energy calibration of the instrument.

2. The method for energy calibration of a high energy gamma spectrometer according to claim 1, characterized in that: After the iron Fe captures thermal neutrons, the proportion of double lines with energies of 7631keV and 7645keV in the high-energy gamma rays emitted is 52.6%; after the Am-Be source neutrons are moderated by paraffin, the gamma rays generated by iron capture are the effect caused by thermal neutron capture, and the emitted line spectrum is the same as the gamma line spectrum generated by thermal neutron capture; the gamma rays with energies of 7631keV and 7645keV generated by iron capturing thermal neutrons are very obvious and very stable, so when the gamma spectrometer collects the spectrum, it will be easy to find the peak position in the energy spectrum corresponding to the gamma rays of 7631keV and 7645keV; the gamma rays with energies of 7631keV and 7645keV obtained by iron capturing thermal neutrons can be used as known energy peaks to calibrate the gamma spectrometer, so that the gamma spectrometer can be effectively calibrated at 7MeV.

3. The method for energy calibration of a high energy gamma spectrometer according to claim 1, characterized in that: The strongest gamma ray generated by nickel Ni after capturing thermal neutrons has an energy of 8999keV, which accounts for 37.7% of the total number of high-energy gamma rays. The other energies are 8533keV, 7819keV, 7537keV, 6837keV and 5817keV, and the numbers of these gamma rays for every 100 neutrons captured are 17, 8, 4.5, 10.8 and 2.1 respectively; the 7638keV generated by iron capturing neutrons is the background caused by surrounding iron-containing materials; the gamma rays of 8999keV, 8533keV, 7819keV, 7537keV and 6837keV in this reaction can all be used as known energy rays for calibration of a gamma spectrometer; the gamma rays obtained by the reaction enable the gamma spectrometer to be effectively calibrated within 7MeV to 9MeV.

4. The method for energy calibration of a high energy gamma spectrometer according to claim 1, characterized in that: The high-energy gamma rays with intensities greater than 2.75 and / or 100 neutrons captured by the thermal neutron capture gamma rays of chlorine Cl are all displayed, which are 8578 (2.91), 7790 (8.55), 7414 (10.4), 6627.6 (4.54), 6619.5 (8.01), 6111 (20.0), 5715.3 (5.5), respectively. The energy unit of the above numerical values ​​is keV, and the values ​​in brackets represent the number of gamma rays generated for every 100 neutrons captured. Using MgCl2 crystalline powder as a radiator, the gamma rays of 8578keV, 7790keV, 7414keV, 6111keV, and 5715.3keV generated by this reaction can be used as known energy rays for the calibration of the gamma spectrometer, so that the gamma spectrometer can be effectively calibrated within 6MeV to 8MeV.

5. The method for energy calibration of a high energy gamma spectrometer according to claim 1, characterized in that: The fluorine F reacts with neutrons (n, α) to produce gamma-ray thermal neutrons; the converter material used is polytetrafluoroethylene; three spectral lines with an energy of 6129 keV are given, and this gamma ray is produced by n+ 19 F→ 16 N * + 4 He 16 N * → 16 0 * +β - 16 0 * → 16 O+γ(6.129MeV) Reaction, by 16 N has a 65% chance of decaying to 16 O at the 6129keV energy level, exciting the nucleus 16 O* is emitted when it is de-excited. This reaction can produce 6129keV gamma rays, which can be used as known energy to calibrate the gamma spectrometer at 6129keV, allowing the gamma spectrometer to be effectively calibrated at around 6MeV.

6. The method for energy calibration of a high energy gamma spectrometer according to claim 1, characterized in that: The hydrogen H captures thermal neutrons to produce gamma rays, and the characteristic gamma ray energy of the H element is 2.223245 MeV. The 2MeV gamma rays produced by this reaction can be used as known energy rays for gamma spectrometer calibration, so that the gamma spectrometer can be effectively calibrated at around 2MeV.

7. The method for energy calibration of a high energy gamma spectrometer according to claim 1, characterized in that: The nitrogen N captures thermal neutrons to generate gamma rays, and the characteristic gamma ray energy of the N element is 10.83MeV. The 10.83MeV gamma rays generated by this reaction can be used as known energy rays for gamma spectrometer calibration, so that the gamma spectrometer can be effectively calibrated at around 10MeV.

8. A device for implementing the method for energy calibration of a high energy gamma spectrometer as claimed in any one of claims 1 to 7, comprising two parts: The first is the gamma ray generating part, and the second is the data acquisition part, which is characterized by: The gamma ray generating part is composed of a target / radiator (1), paraffin (2), an Am-Be neutron source (4), and lead (5); the data acquisition part is composed of a gamma spectrometer detector supporting cabinet, a gamma spectrometer (7), a data transmission cable (8), and a data acquisition computer (9); the gamma spectrometer detector supporting cabinet is composed of a combination of lead (5) and cadmium (6).

9. The device for implementing the method for energy calibration of a high energy gamma spectrometer according to claim 8, characterized in that: Placing the Am-Be neutron source (4) at a working position; Moving the target / radiator 1 to the Am-Be neutron source (4); Moving the gamma spectrometer detector support cabinet composed of lead (5) and cadmium (6) to the target / radiator (1); Placing the gamma spectrometer (7) in the gamma spectrometer detector support cabinet; Connecting the gamma spectrometer (7) and the data collection computer (9) using a data transmission cable (8); Powering on the gamma spectrometer detector; Using the computer 9 for acquisition to acquire data; The gamma spectrometer 7 is calibrated.

10. The device for implementing the method for energy calibration of a high energy gamma spectrometer according to claim 9, characterized in that: Change the working position of the gamma spectrometer for calibration; Spectrometers with other detectors can also be calibrated in this way, including: spectrometers with NaI(Tl) scintillator probes, bismuth germanate HPGe probes, and LaBr3(Ce3+) probes; Nickel, iron, polytetrafluoroethylene, polyvinyl chloride, polyethylene, C 3 H 6 N 6 NH 4 Cl can be used as a target material, and materials containing Fe, Ni, H, N, Cl and F elements can also be used as target materials.

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