Development of the micro pixel chamber based on MEMS technology

T Takemura ,D Tomono,Y Nakamasu,Makoto Oda ,Yoshihiro Matsuoka ,T Motomura ,T Tanimori ,H Kubo ,S Miyamoto ,Tatsuya Sawano ,Yoshitaka Mizumura ,Atsushi Takada ,Kiseki Nakamura ,K Miuchi ,S Sonoda ,Kimihiro Ohta ,Tetsuya Mizumoto ,J D Parker ,T Kishimoto ,Shingo Komura ,Kenichi Yoshikawa

doi:10.1051/epjconf/201817402010

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.

Highlights

Tron imaging applications require a position resolution of less than 100 μm and MeV gamma-ray astronomy requires precise tracking of charged particles with an angular resolution of less than 5◦
Micro electro mechanical system (MEMS) technology enables the use of thicker substrates compared with those for printed circuit board (PCB) technology
The substrates used in MEMS technology comprise silicon, which is a semiconductor; the effect of a semiconducting substrate being substituted for the insulating substrate of μ-PICs should be investigated

Summary

Introduction

Tron imaging applications require a position resolution of less than 100 μm and MeV gamma-ray astronomy requires precise tracking of charged particles with an angular resolution of less than 5◦. Because of the limitation of the manufacturing accuracy of PCB technology, the diameter of μ-PIC anode vias is limited to approximately 50 μm. A more advanced technology is needed for manufacturing fine-pitch μ-PICs. Micro electro mechanical system (MEMS) technology is one such capable technology. A MEMS μ-PIC is expected to exhibit a fine position resolution and a high gas gain. We manufactured two MEMS μ-PICs to investigate their behavior. We report the results of both the simulations and experiments

Simulation study of MEMS μ-PIC

Measurements of the gas gains of MEMS μ-PICs

Summary