Development of the micro pixel chamber based on MEMS technology

¹ Kyoto University, Department of Physics, Japan
² Kobe University, Department of Physics, Japan
³ Dai Nippon Printing Co., Ltd.
⁴ CROSS-Tokai, Neutron R&D Division, Japan
⁵ Kanazawa University, School of Mathematics and Physics, Japan

^a e-mail: takemura@cr.scphys.kyoto-u.ac.jp

Published online: 21 February 2018

Abstract

Micro pixel chambers (μ-PIC) are gaseous two-dimensional imaging detectors originally manufactured using printed circuit board (PCB) technology. They are used in MeV gamma-ray astronomy, medicalimaging, neutron imaging, the search for dark matter, and dose monitoring. The position resolution of the present μ-PIC is approximately 120 μm (RMS), however some applications require a fine position resolution of less than 100 μm. To this end, we have started to develop a μ-PIC based on micro electro mechanical system (MEMS) technology, which provides better manufacturing accuracy than PCB technology. Our simulation predicted the gains of MEMS μ-PICs to be twice those of PCB μ-PICs at the same anode voltage. We manufactured two MEMS μ-PICs and tested them to study their behavior. In these experiments, we successfully operated the fabricatedMEMS μ-PICs and we achieved a maximum gain of approximately 7×10³ and collected their energy spectra under irradiation of X-rays from ⁵⁵Fe. However, the measured gains of the MEMS μ-PICs were less than half of the values predicted in the simulations. We postulated that the gains of the MEMS μ-PICs are diminished by the effect of the silicon used as a semiconducting substrate.