Performance evaluation of high-pressure MWPC with individual line readout under Cf-252 neutron irradiation

To, Kentaro  ; Nakamura, Tatsuya  ; Sakasai, Kaoru  ; Soyama, Kazuhiko  ; Yamagishi, Hideshi*

A multiwire proportional chamber (MWPC) neutron detector system is developed for use in the Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex. In the developed MWPC system, a short response time and high spatial resolution can be obtained through the use of an individual line readout method. The developed system consists of a 256 channel detector element (x: 128 lines, y: 128 lines) equipped with a pressure vessel, amplifier-shaper-discriminator (ASD) boards, optical signal transmission devices, position encoders with field-programmable gate arrays (FPGAs), and a data acquisition device. The measured uniformity of all pixels in the two-dimensional image was 7.9%. The average intrinsic spatial resolution was 1.55 mm full width at half-maximum in the sensitive region calculated by taking into account measured track lengths of secondary particles.