Dielectric strength of noble and quenched gases for high pressure time projection chambers

L Norman,K Woodruff,M R Tiscareno,K Silva,A D Mcdonald,B J P Jones

doi:10.1140/epjc/s10052-021-09894-z

Abstract

Dielectric breakdown strength is one of the critical performance metrics for pure gases and gas mixtures used in large, high pressure gas time projection chambers. In this paper we experimentally study dielectric breakdown strengths of several important time projection chamber working gases and gas-phase insulators over the pressure range 100 mbar to 10 bar, and gap sizes ranging from 0.1 to 10 mm. Gases characterized include argon, xenon, CO_2, CF_4, and mixtures 90-10 argon-CH_4, 90-10 argon-CO_2 and 99-1 argon-CF_4. We develop a theoretical model for high voltage breakdown based on microphysical simulations that use PyBoltz electron swarm Monte Carlo results as input to Townsend- and Meek-like discharge criteria. This model is shown to be highly predictive at high pressure, out-performing traditional Paschen–Townsend and Meek–Raether models significantly. At lower pressure-times-distance, the Townsend-like model is an excellent description for noble gases whereas the Meek-like model provides a highly accurate prediction for insulating gases.

Highlights

Since their introduction in 1974 [1], time projection chamber (TPC) detectors have become pervasive in neutrino physics and rare event searches [2,3,4,5,6,7,8])
Data was taken at varying gap distances to span the full range of pd values of interest for several gas mixtures of interest to future neutrino detectors: pure argon, pure xenon, pure CO2, pure CF4, Ar–CO2 (90%/10%), Ar–CH4 (90%/10%) and Ar–CF4 (99%/1%)
The largest dataset was accumulated with pure argon gas, with gap spacings 0.1 to 10 mm in order to make detailed comparisons between available high voltage breakdown models

Summary

Introduction

Since their introduction in 1974 [1], time projection chamber (TPC) detectors have become pervasive in neutrino physics and rare event searches [2,3,4,5,6,7,8]). The working principle of a TPC [9] is that ionization electrons or ions created by a charged particle in a liquid or gaseous medium are drifted to a detection plane preserving the three dimensional event structure. The charges can be detected by induction or collection, or amplified through avalanche gain or electroluminescence, depending on the application.

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