Simulation and optimization of the boron-lined MWPC neutron detectors

Abstract

Boron-lined gas detectors are prospective alternatives to helium-3-based neutron detectors. For boron-lined multi-wire proportional chamber (MWPC) with neutron grazing incident angle geometry, high neutron detection efficiency and 3D position sensitive can be realized. In this paper, a multi-layer boron-lined MWPC was studied. Influences of the boron coating thickness, coating layer numbers and neutron incident angle on the neutron detection efficiency were studied and optimized with Geant4 simulation. The output signal properties including induced signal width on the readout plane, the time resolution and gas gain uniformity of the detector were studied with Garfield program. The results show that the neutron detection efficiency can be significantly increased by using neutron grazing incident geometry. For 4 layers of 10B4C with thickness of 1 µm, the neutron detection efficiency can reach to 54.56%, 49.17% and 44.36% when neutron incident angle is 6°, 8° and 10°, respectively. For detector with curved geometry, the gas gain is nonuniform among the anode wires, and using separate high voltage for each anode wire or wires group can effectively reduce the nonuniform of the gas gain. The results of this work can be used to optimize the detector design.