Application of Large Scale GEM for Digital Hadron Calorimetry

TL;DR

This paper reports on the development and testing of large-scale GEM detectors for digital hadron calorimetry, demonstrating their performance, radiation tolerance, and progress towards constructing 1-meter scale detectors for future collider experiments.

Contribution

It introduces large-scale GEM prototypes and evaluates their performance, radiation resistance, and readiness for use in future high-energy physics calorimeters.

Findings

Chamber gain over 6500 at 395 V with 55Fe source

Good fit of cosmic ray spectra to Landau distributions

Successful testing of large-scale GEM foils and progress towards 1-meter detectors

Abstract

The High Energy Physics group of the University of Texas at Arlington Physics Department has been developing Gas Electron Multiplier (GEM) detectors for use as the sensitive gap detector in digital hadron calorimeters (DHCAL) for the future International Linear Collider. In this study, two kinds of prototype GEM detectors have been tested. One has 30x30 cm2 active area double GEM structure with a 3 mm drift gap, a 1 mm transfer gap and a 1 mm induction gap. The other one has two 2x2 cm2 GEM foils in the amplifier stage with a 5 mm drift gap, a 2 mm transfer gap and a 1 mm induction gap. We present characteristics of these detectors obtained using high-energy charged particles, cosmic ray muons and 106Ru and 55Fe radioactive sources. From the 55Fe tests, we observed two well-separated X-ray emission peaks and measured the chamber gain to be over 6500 with a high voltage of 395 V across each GEM electrode. Both the spectra from cosmic rays and the 106Ru fit well to Landau distributions as expected from minimum ionizing particles. We also present the chamber performance after high dosage exposure to radiation as well as the pressure dependence of the gain and correction factors. Finally, we discuss the quality test results of the first set of large scale GEM foils and discuss progress and future plans for constructing large scale (100cmx100cm) GEM detectors.