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

Cf-252中性子照射下における個別読み出し高圧駆動MWPCの特性評価

藤 健太郎  ; 中村 龍也  ; 坂佐井 馨  ; 曽山 和彦  ; 山岸 秀志*

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

J-PARCセンター物質・生命科学実験施設で使用するためマルチワイヤ素子を用いた高圧駆動中性子検出器システムを開発した。この検出器では個別読み出し法を用いることで高速応答・高位置分解能を実現する。開発した検出器は256チャンネルの検出素子,圧力容器,信号増幅・波形整形・波高弁別一体型基板,光信号伝送装置, FPGA実装位置エンコーダ,データ収集機器で構成されている。中性子照射試験の結果、ピクセルごとの均一性: 7.9%、固有の位置応答: 1.55mm(半値幅)という性能を確認することができた。

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.