Development of the micro pixel chamber based on MEMS technology

Abstract

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 fabricated MEMS µ-PICs and we achieved a maximum gain of approximately 7 ×10 3 and collected their energy spectra under irradiation of X-rays from 55 Fe. 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.

MPGD: new developments and applications

“…MPGD: new developments and applications S. Levorato Mechanical Systems technologies, MEMS, has been attempted in collaboration with DAI Nippon Printing Co., Ltd., Japan: the use of different material, namely Si and SiO 2 , of more challenging geometrical parameters, not easily obtained by the standard PCB technology, and the process accuracy make it possible to obtain larger gain, better response uniformity and increased space resolution [25]. A graphene layer is ideally a membrane transparent to electrons and opaque to ions, namely an ideal tool for IBF control and it can also be considered as a gas separator within a gaseous detector: for instance, if applied to a MICROMEGAS the use of different gas mixtures in the drift and multiplication gaps can be envisaged.…”