Neutron detector and neutron detection method

Abstract

The invention relates to a neutron detector and a neutron detection method. The neutron detector includes an incident window and a detection array. The detection array is provided with a plurality of layers of detection units which are arranged to be laminated. The detection units include a plurality of square detection channels which are mutually parallel and adjacent detection channels are in mutual gas communication. The detection channels are filled with boron trifluoride. An impedance anode wire is axially arranged in each detection channel. A positive high voltage is applied to one end of each impendence anode wire so as to amplify original ionization signals caused by neutrons and output amplified electrical signals. The neutron detector and the neutron detection method are capable of improving the neutron detection efficiency and at the same time, position resolution and TOF time resolution are not reduced.

Description

technical field [0001] The invention relates to a neutron detection technology, in particular to a neutron detector and a neutron detection method. Background technique [0002] Under the current international situation, the development and application of neutron detectors are facing great challenges. For thermal neutrons (wavelength The same below), the nuclear reaction method is generally used for detection, and the commonly used ones are 3 He(n,p)T, 10 B(n,α) 7 Li and 6 Li(n,α)T has three nuclear reactions, and their reaction cross sections with neutrons are relatively large, among which 3 He gas is chemically stable, has a large cross-section, and still has good positive ratio characteristics under high pressure, so it is considered as an ideal thermal neutron detection material. At present, more than 70% of neutron scattering spectrometers in the world use 3 There are two main types of He gas detectors. One is to use multiple position-sensitive high-pressure det...

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Problems solved by technology

In addition to increasing the gas pressure to improve the detection efficiency, another method is to increase the sensitive thickness of the detector. However, with the increase of the detector thickness, on the one hand, the lateral diffusion of electrons becomes larger and the position resolution becomes worse; on the other hand, the incident Increased uncertainty in the position of neutron capture, leading to poor Time of Flight (TOF) resolution; both aspects reduce the resolution of the spectrometer

The tube diameters commonly used for spectrometer detectors are 1 inch, 1 / 2 inch and 1 / 3 inch. figure 1 Concentrated BF for 1atm and 2atm 3 ( 10 The thermal neutron capture efficiencies of different thicknesses of gas with B abundance 96% are given by figure 1 It can be seen that the capture efficiency at the center of the 1-inch tube with a diameter of 2 atm is only 35%.

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