Development of a custom on-line ultrasonic vapour analyzer/flowmeter for the ATLAS inner detector, with application to gaseous tracking and Cherenkov detectors

TL;DR

This paper presents a custom ultrasonic vapor analyzer/flowmeter developed for the ATLAS detector, capable of precise gas mixture and flow measurements with applications in gaseous tracking and Cherenkov detectors.

Contribution

A novel ultrasonic analyzer with custom electronics demonstrating high precision in gas composition and flow measurements for particle detector applications.

Findings

0.3% mixture precision for C3F8/C2F6

< 10-4 resolution for N2/C3F8

Flow resolution of +/- 2% F.S. up to 250 l/min

Abstract

Precision sound velocity measurements can simultaneously determine binary gas composition and flow. We have developed an analyzer with custom electronics, currently in use in the ATLAS inner detector, with numerous potential applications. The instrument has demonstrated ~0.3% mixture precision for C3F8/C2F6 mixtures and < 10-4 resolution for N2/C3F8 mixtures. Moderate and high flow versions of the instrument have demonstrated flow resolutions of +/- 2% F.S. for flows up to 250 l.min-1, and +/- 1.9% F.S. for linear flow velocities up to 15 ms-1; the latter flow approaching that expected in the vapour return of the thermosiphon fluorocarbon coolant recirculator being built for the ATLAS silicon tracker.