On the Electric Breakdown in Liquid Argon at Centimeter Scale

TL;DR

This study investigates how electrode geometry and distance affect electric breakdown in liquid argon, revealing a slow streamer phase and providing benchmarks for safer detector design.

Contribution

It provides the first detailed analysis of breakdown voltage evolution and streamer development in liquid argon at centimeter scales, with spectroscopic insights.

Findings

Identification of a slow streamer development phase

Spectroscopic evidence of electro-luminescence during breakdown

Establishment of breakdown voltage benchmarks for detector safety

Abstract

We present a study on the dependence of electric breakdown discharge properties on electrode geometry and the breakdown field in liquid argon near its boiling point. The measurements were performed with a spherical cathode and a planar anode at distances ranging from 0.1 mm to 10.0 mm. A detailed study of the time evolution of the breakdown volt-ampere characteristics was performed for the first time. It revealed a slow streamer development phase in the discharge. The results of a spectroscopic study of the visible light emission of the breakdowns complement the measurements. The light emission from the initial phase of the discharge is attributed to electro-luminescence of liquid argon following a current of drifting electrons. These results contribute to set benchmarks for breakdown-safe design of ionization detectors, such as Liquid Argon Time Projection Chambers (LAr TPC).