Analysis of Purity Probes H1 Liquid Argon Calorimeter

TL;DR

This paper refines liquid argon purity measurement techniques by introducing an analytical spectrum model, analyzing temperature effects on ionization yield, and improving charge collection models for better detector calibration.

Contribution

It presents a new analytical spectrum model for 207Bi sources, investigates temperature-dependent ionization yield variations, and enhances charge collection models for liquid argon detectors.

Findings

Analytical spectrum model for 207Bi sources across purity levels.

Discovery of temperature-dependent variation in ionization yield.

Refined charge collection models linking recombination and attachment to electric field.

Abstract

The sensitivity of our liquid argon purity measurement -around 0.03%- leads us to refine the tools used classically in this field. First we introduce an analytical form describing the spectrum of a 207Bi source for different values of purity and ionisation chamber gap. Second we analyse a surprising new effect: the variation of the ionisation yield of this source with the liquid argon temperature. Third we use our data to refine the charge collection models which relate electron recombination and attachment cross-sections to the electrical field.