# Development and Characterisation of a Gas System and its Associated Slow-Control System for an ATLAS Small-Strip Thin Gap Chamber Testing Facility

## TL;DR

This paper details the development and characterization of a gas and slow-control system for testing small-strip Thin Gap Chamber detectors using cosmic rays, ensuring safe, continuous operation and precise gas mixture control.

## Contribution

It introduces a novel gas system with a Peltier TEC condenser and a state-machine slow-control system for reliable detector testing.

## Key findings

- Gas system successfully maintained 45% pentane concentration.
- The slow-control system enabled safe, automated, continuous operation.
- The facility improved quality assurance for ATLAS muon detectors.

## Abstract

A quality assurance and performance qualification laboratory was built at McGill University for the Canadian-made small-strip Thin Gap Chamber (sTGC) muon detectors produced for the 2019-2020 ATLAS experiment muon spectrometer upgrade. The facility uses cosmic rays as a muon source to ionise the quenching gas mixture of pentane and carbon dioxide flowing through the sTGC detector. A gas system was developed and characterised for this purpose, with a simple and efficient gas condenser design utilizing a Peltier thermoelectric cooler (TEC). The gas system was tested to provide the desired 45 vol% pentane concentration. For continuous operations, a state-machine system was implemented with alerting and remote monitoring features to run all cosmic-ray data-acquisition associated slow-control systems, such as high/low voltage, gas system and environmental monitoring, in a safe and continuous mode, even in the absence of an operator.