Construction of large-area micro-pattern gaseous detectors

Abstract

Particle physics experiments often comprise tracking detectors with areas of up to a few square meters. If a spatial resolution of the order of 100μm and high-rate capability are required, Micro Pattern Gaseous Detectors (MPGD) are a cost-effective solution. However, the construction of large-area MPGDs is challenging, since tight fabrication tolerances have to be met to guarantee a stable and homogeneous performance. A precision granite table and an automated 3-D positioning system with an attached laser sensor, both inside a laminar-flow cell, have therefore been set up in the PRISMA Detector Lab at Mainz. Currently, this infrastructure is used to produce drift panels for the upgrade of the ATLAS muon spectrometer at CERN with Micro Mesh Gaseous Structure (Micromegas) detectors. In order to parallelize production steps, movable vacuum table boards with a surface planarity of about 20μm (root mean square) have been designed and built. We present preliminary results on the achieved precision of drift panel prototypes. These results are in particular relevant for future construction of large-area MPGDs, such as the Gas Electron Multiplier (GEM) detectors for experiments at the future MESA accelerator at Mainz.