A Purity Monitoring System for the H1 Liquid Argon Calorimeter

TL;DR

This paper presents a liquid argon purity monitoring system for the H1 calorimeter, detailing ionization probes, their operational results over several years, and insights into charge collection influenced by temperature variations.

Contribution

It introduces a novel purity monitoring system using ionization probes and provides extensive operational data and analysis from CERN and HERA tests.

Findings

High sensitivity of charge measurements improves purity detection.

Observed variation of ionization yield with temperature.

Refined charge collection models based on measurements.

Abstract

The ionization probes used for monitoring the liquid argon purity in the H1 calorimeter are described and results of their operation in tests at CERN and during the period 1992 to the end of 1998 at HERA are given. The high sensitivity of the charge measurements leads to refined charge collection models, and to the observation of a variation of the ionization yield of our electron sources with temperature.