Wide-energy-spectrum neutron measurement system for characteristic peak searching

Abstract

The invention discloses a wide-energy-spectrum neutron measurement system for characteristic peak searching. The system can be used for on-line measurement of energy spectrum and flux of a high-energyand high-current neutron radiation field in a narrow-space strong-irradiation environment. The measurement system comprises a neutron probe, an electronics system and an energy spectrum analysis system. The neutron probe adopts a composite detection structure. The composite detection structure is divided into four neutron sensitive regions, wherein the regions are separated by metal walls; and each region is internally coated or filled with different neutron sensitive materials. The intermediate neutron sensitive region can adjust and control the energy response peak energy region by changingcomponents of the filling materials. In the energy spectrum analysis system, a characteristic peak searching wide-energy-spectrum spectrum unfolding method is adopted. The system is novel in structure, has a small and compact in neutron probe, can carry out real-time measurement in a small space and realizes real-time accurate measurement of neutron flux and energy spectrum. The system has the advantages of high measurement accuracy, needing no preset spectrum and high anti-disturbance capability.

Description

technical field [0001] The invention relates to the field of on-line measurement and analysis of neutron energy spectrum, in particular to an on-line neutron energy spectrum measurement system suitable for high-energy and strong-current radiation fields in a narrow space and strong irradiation environment, which can be used for online real-time energy spectrum and flux of accelerators and reactors Measurement. Background technique [0002] Neutron energy spectrum is of great significance and practical value to the study of neutron nuclear data, reactor design and operation, radiation shielding and protection, etc. [0003] At present, the commonly used neutron spectrum measurement methods include time-of-flight method, multi-sphere spectrometer method, threshold detector method, recoil proton method and nuclear reaction method. [0004] The time-of-flight method often uses the neutron source of the accelerator, which requires a long flight distance; the multi-sphere spectro...

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Problems solved by technology

[0006] In the article "Experimental Research on Neutron Spectrum Measurement of China Experimental Fast Reactor" published in the Journal of Atomic Energy Science and Technology in 2013, the neutron spectrum of the sodium-cooled fast reactor was measured by the activation method. neutron integration measurement with a kind of activated sheet, and obtain the neutron energy spectrum by spectrum analysis, but there is no way to give information such as online neutron flux

[0007] Chinese patent document CN102866416A discloses a continuous neutron spectrum real-time detection system, which uses a thermal neutron sensitive detector, which is bulky and cannot meet the online analysis of fast neutron spectrum in the high temperature and narrow space environment of fast reactors

US patent document US4804514A discloses a neutron dosimetry method and device in the process of nuclear fission. Thermal neutron sensitive detectors are used to measure thermal neutrons, and fast neutron sensitive detectors are used to measure fast neutrons, but no spectrum analysis is involved. Unable to obtain radiation field neutron spectrum

[0008] The neutron energies obtained for D-D and D-T fusion nuclear reactions are 2.5MeV and 14MeV respectively. In the article "Optimization Calculation of ITER Neutron Flux Monitor" published in the Journal of Nuclear Electronics and Detection Technology in 2012, although it is recorded Two detector types consisting of a dual-fission detector and a moderator / shield covering the detector, but online energy spectrum analysis cannot be performed, because the moderator is made of polyethylene material, which is not suitable for use under high temperature conditions

[0009] Chinese patent document CN106908830A discloses a measurement system for measuring neutron flux under strong radiation and high temperature conditions, which uses a thermal neutron sensitive 235 U detector and a fast neutron sensitive 238 The U detector performs energy spectrum analysis, and its energy spectrum analysis method adopts the "few-channel spectral analysis method". Since there are fewer detectors, it is necessary to preset the spectrum, that is, there is prior knowledge of the spectral shape of the radiation field, and the anti-disturbance ability is weak. , it is difficult to measure the radiation field with unknown spectral shape, and the single fission ion chamber detection technology needs to be counted and corrected, so it is difficult to achieve high measurement accuracy

[0010] It can be seen that for the on-line measurement of neutron energy spectrum in a narrow space with strong irradiation environment, the above-mentioned publicly reported technical solution is to directly provide the size of the neutron flux through the reading of a single counter or multiple counters, or it is necessary to know the radiation Prior knowledge of the field energy spectrum, it is difficult to give accurate results for some energy spectrum changes or radiation field energy spectra with disturbances

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