Heavy-metal-multiplication wide-energy neutron source intensity measurement system

Abstract

The invention discloses a heavy-metal-multiplication wide-energy neutron source intensity measurement system, which can be suitable for single-energy or wide-energy neutron radiation field source intensity measurement and value transfer of a high-energy accelerator and a reactor and the like. The system comprises a neutron probe, a signal processing system and a data analysis system. The neutron probe is formed by a central thermal neutron detector, an inner-layer moderator, a neutron multiplication layer, a peripheral thermal neutron detector, a reflecting layer, a lateral thermal neutron absorber, an external-layer moderator and a forward thermal neutron absorber. The central thermal neutron detector adopts a position-sensitive neutron detector to obtain energy spectrum information of aradiation field; and an energy weighting factor is set to compensate for energy response of the central thermal neutron detector, thereby improving measurement precision. The system is novel in structure, wide in energy range and good in angle response performance, can carry out energy response compensation and is high in source intensity measurement precision and the like.

Description

technical field [0001] The invention relates to a wide-energy neutron source intensity measurement system multiplied by heavy metals, in particular to the neutron source intensity measurement and magnitude transfer of high-energy accelerators and reactor directional radiation fields. Background technique [0002] A basic requirement for research work using neutron sources is to give accurate and reliable neutron source strength. Commonly used are activation method, accompanying particle method, recoil proton telescope, fission ionization chamber and long neutron counter. [0003] The activation method has high measurement accuracy, and it is an offline measurement method, which cannot realize online measurement; the accompanying particle method has a certain scope of application, and is only suitable for a specific type of nuclear reaction; the recoil proton telescope can detect the number of monoenergetic neutrons more accurately, but Problems such as electronic blockage, ...

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Problems solved by technology

[0009] In the Chinese patent document CN104898156A, a directional wide-energy neutron monitor probe is disclosed, which uses fission breeding materials and neutron reflection materials to broaden the energy range and improve high-energy angular response. Due to the use of fission materials, it will inevitably bring protection problems, and adopts The energy range of a single thermal neutron detector is usually less than 6 energy levels, and it cannot take into account both high-energy and low-energy energy regions, and the source intensity measurement does not take into account the problem of response compensation, resulting in decreased accuracy and the interaction between other high-energy particles such as high-energy protons and the probe. The secondary neutrons produced by the action cause the problem of accuracy drop

[0010] The multi-detector measurement method has certain applications in the neutron peripheral dose equivalent meter. In the Chinese patent document CN101419290A, a binary moderated high-energy neutron dosimeter is disclosed, which uses the measurement method of the central counting area and the peripheral counting area To solve the problem of unsatisfactory energy response of the high-energy neutron dosimeter, the energy response of the dosimeter can be between 0.65-1.5, although it can meet the measurement requirements of radiation protection instruments such as dosimeters (response error is ±100%), However, due to the use of the ratio method to determine the average energy, it is impossible to finely compensate the response of the entire energy region, and it is difficult to meet the accuracy requirements of source intensity measurement (usually less than 10%), and its spherical design is suitable for isotropic radiation fields such as the environment Sub-dose measurement, not suitable for neutron intensity measurement in accelerator, reactor directional radiation field

[0011] None of the above public reports have provided a high-precision wide-energy neutron source intensity measurement system design, which needs to be improved

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