New pixelized Micromegas detector with low discharge rate for the COMPASS experiment

TL;DR

This paper presents the development and testing of a new pixelized Micromegas detector with low discharge rate, designed for high-luminosity conditions in the COMPASS experiment at CERN, featuring improved robustness and performance.

Contribution

It introduces a novel pixelized Micromegas detector with discharge mitigation techniques and demonstrates its successful performance in large prototypes at CERN.

Findings

Successful implementation of pixelized read-out in high-flux conditions

Effective discharge reduction using resistive layers and GEM foil

Good performance of large prototypes with additional GEM foil

Abstract

New Micromegas (Micro-mesh gaseous detectors) are being developed in view of the future physics projects planned by the COMPASS collaboration at CERN. Several major upgrades compared to present detectors are being studied: detectors standing five times higher luminosity with hadron beams, detection of beam particles (flux up to a few hundred of kHz/mm^{2}, 10 times larger than for the present Micromegas detectors) with pixelized read-out in the central part, light and integrated electronics, and improved robustness. Two solutions of reduction of discharge impact have been studied, with Micromegas detectors using resistive layers and using an additional GEM foil. Performance of such detectors has also been measured. A large size prototypes with nominal active area and pixelized read-out has been produced and installed at COMPASS in 2010. In 2011 prototypes featuring an additional GEM foil, as well as an resistive prototype, are installed at COMPASS and preliminary results from those detectors presented very good performance. We present here the project and report on its status, in particular the performance of large size prototypes with an additional GEM foil.