Progress on large area GEMs (VCI 2010)

TL;DR

This paper reports advancements in manufacturing large area GEMs using a novel single mask photolithography process, enabling the production of bigger, more precise detectors with improved control over hole shape and size.

Contribution

It introduces a new single mask photolithography technique for large area GEMs, overcoming previous size and alignment limitations, and demonstrates a prototype for high-area detector applications.

Findings

Successful production of a ~2000 cm² GEM detector prototype

Enhanced control over hole shape and rim size in GEMs

Simulation studies to understand GEM behavior based on hole geometry

Abstract

The Gas Electron Multiplier (GEM) manufacturing technique has recently evolved to allow the production of large area GEMs. A novel approach based on single mask photolithography eliminates the mask alignment issue, which limits the dimensions in the traditional double mask process. Moreover, a splicing technique overcomes the limited width of the raw material. Stretching and handling issues in large area GEMs have also been addressed. Using the new improvements it was possible to build a prototype triple-GEM detector of ~ 2000 cm2 active area, aimed at an application for the TOTEM T1 upgrade. Further refinements of the single mask technique give great control over the shape of the GEM holes and the size of the rims, which can be tuned as needed. In this framework, simulation studies can help to understand the GEM behavior depending on the hole shape.