Micro Pixel Chamber with resistive electrodes for spark reduction

Abstract

The Micro Pixel Chamber (mu-PIC) using resistive electrodes has been developed and tested. The surface cathodes are made from resistive material, by which the electrical field is reduced when large current is flowed. Two-dimensional readouts are achieved by anodes and pickup electrodes, on which signals are induced. High gas gain (> 60000) was measured using 55Fe (5.9 keV) source, and very intensive spark reduction was attained under fast neutron. The spark rate of resistive mu-PIC was only 10^-4 times less than that of conventional mu-PIC at the gain of 10^4. With these developments, a new MPGD with no floating structure is achieved, with enough properties of both high gain and good stability to detect MIP particles. In addition, mu-PIC can be operated with no HV applied on anodes by using resistive cathodes. Neither AC coupling capacitors nor HV pull up resisters are needed for any anode electrode. Signal readout is drastically simplified by that configuration.