Study On The Gd-coated RPC Thermal Neutron Detector

Firstly, the reaction mechanism of the thermal neutron with Gd and the basic principles of the Gd-coated thermal neutron resistive plate chambers detector was investigated in this paper. Secondly, the sensitivities of y-ray and the neutron in the Gd-coated thermal neutron resistive plate chambers detector were simulated using MCNP code and Garfield code. The electron energy spectra that the detector interacts with the thermal neutron and 1.25 MeVγ-ray were also presented. The relationship of the time resolution and the detection efficiency vs the electric field and the proportion of the mixture gas were calculated. Based on the simulating data, the optimal electric field and the proportion of the mixture are presented. A new method using the characteristicγ-ray absorption spectroscopy was developed to measure the thickness of the Gd-coated. At last, the Gd-coated thermal neutron resistive plate chambers detector was tested at theγray source of Na-22 and Cs-137. The the signal amplitude spectrum and energy resolution of theγ-ray were presented. A D-D neutron and a polythene moderator were used to get a thermal neutron beam. Using this thermal neutron beam, thermal neutron efficiency of the detector was also tested to find the better conditions.