Micro Pixel Chamber with resistive electrodes for spark reduction

Abstract

The Micro Pixel Chamber (μ-PIC), a detector using resistive electrodes,has been developed and tested. The surface cathodes are made fromresistive material, which helps to reduce the electrical field in alarge flow of current. Two-dimensional readouts are provided byanodes and pickup electrodes, on which the signals are induced. Highgas gain ( > 6 × 104 ) was measured using a 55Fe (5.9 keV)source, and extensive spark reduction was attained with fast neutrons.The spark rate of the resistive μ-PIC was 10−4 times lowerthan that of the conventional μ-PIC at a gain of 104. Withthese developments, a new MPGD with a non-floating structure isachieved, offering the required levels of both gain and stability todetect MIP particles. In addition, by using resistive cathodes,μ-PIC can be operated with no HV applied on the anodes. NeitherAC coupling capacitors nor HV pull-up resistors are needed for anyanode. Consequently, the signal readout can be dramaticallysimplified by this configuration.