Development of position sensitive neutron detector element using circular cathode bumps

円形カソードバンプを用いた位置敏感型中性子検出器素子の開発

藤 健太郎  ; 中村 龍也  ; 坂佐井 馨  ; 山岸 秀志*

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

ポリイミド絶縁体と小型の円形カソードバンプからなるバンプカソード素子を開発し、Cf中性子線源を用いた照射試験を実施した。有感面積は128128mmであり、XY方向に1mm間隔でバンプを配置している。照射試験はガス圧7気圧(He/CF=0.6/0.1)の条件下で実施された。128128chのすべてのピクセルにおいて中性子による信号が確認され、波高分布における中性子による明瞭な信号パルスピークも測定することができた。また、印可電圧の増加に伴う信号パルスピークの増加、および二次元イメージの均一性の向上を確認することができた。

A bump cathode element that consists of a polyimide insulator and small-sized circular cathode bumps was developed, and an irradiation experiment was performed using a Cf neutron source. The sensitive area is 128 mm 128 mm with a pitch of 1 mm in both directions. The element was placed on the base plate that had multichannel connectors (X: 128 ch, Y: 128 ch) for signal transmission from the element to signal processing electronics mounted outside of the pressure vessel. The experiments were performed using a gaseous mixture of He and carbon tetrafluoride (CF) at a total pressure of 0.7 MPa (He/ CF = 0.6/0.1). The neutron-induced signals of all pixels were observed using 128 128 ch test element, and the signal pulse peak of neutron can be observed in the pulse height distribution of anode wires. The signal pulse peak become high and the uniformity become well as the applied voltage increases.