Operation of two-dimensional gas detector using micro-pixel detector element under high pressure for neutron measurement

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

An improved micro-pixel detector element was fabricated, and neutron irradiation experiments were conducted. The micro-pixel detector element was fabricated using printed circuit board (PCB) technologies. Therefore, it is easy to fabricate and reproduce detector element with a large number of pixels. A gas-based neutron detection system capable of individual line readout, consisting of the developed detector element, gas chamber, amplifier-shaper-discriminator boards, optical signal transmission device, and a fast data acquisition device, was constructed for the experiment. The measured gas gain was approximately 280 at the total pressure of 5 atm (4.5 atm of He and 0.5 atm of CF), and supplied voltage of 670 V. The gas gain did not decrease (due to the charge-up effect) when the detection system was operated for 120 h. The average gain spread in two-dimensional imaging was 3.3%.