New micro-pattern gas detector based on a 2D position readout mesh

Abstract

Micro-pattern gas detectors (MPGD) could become suitable devices to carry out time-resolved X-ray diffraction experiments in the sub-millisecond time scale at synchrotron radiation facilities. Nevertheless, these devices are not free of problems. Among other problems are the build-up of ions in the detector components and the susceptibility of the materials in the structure to dielectric breakdown. Here, we present a new MPGD design we have called micro reading mesh chamber (MRMC). Its layout is based on a resistive anode, support pillars and a mesh formed by two planes of pick-up strips. In order to prevent charging up, a common problem with GEMs and MPGD in general, a minimum amount of dielectric material has been used in the design. The aim has been to avoid dielectric near the drift paths of the ions. To prevent dielectric breakdown, a resistive anode with guard rings at the base of the pillars has been designed. Finally, to improve the cathode signals quality, we use a mesh to read the avalanche. In this manner the size of the induced charge is larger than in more conventional eometries.