Liquid Hole Multipliers: bubble-assisted electroluminescence in liquid xenon

TL;DR

This paper investigates bubble-assisted electroluminescence in liquid xenon, revealing a stable mechanism involving xenon bubbles below THGEM holes that could advance single-phase noble-liquid detectors for dark matter and neutrino research.

Contribution

It demonstrates a novel stable electroluminescence mechanism in liquid xenon using xenon bubbles, enabling potential development of Liquid Hole Multipliers for large-volume detectors.

Findings

Electroluminescence occurs in xenon bubbles below THGEM holes.

The process is stable over months of operation.

Energy resolution comparable to dual-phase experiments.

Abstract

In this work we discuss the mechanism behind the large electroluminescence signals observed at relatively low electric fields in the holes of a Thick Gas Electron Multiplier (THGEM) electrode immersed in liquid xenon. We present strong evidence that the scintillation light is generated in xenon bubbles trapped below the THGEM holes. The process is shown to be remarkably stable over months of operation, providing - under specific thermodynamic conditions - energy resolution similar to that of present dual-phase liquid xenon experiments. The observed mechanism may serve as the basis for the development of Liquid Hole Multipliers (LHMs), capable of producing local charge-induced electroluminescence signals in large-volume single-phase noble-liquid detectors for dark matter and neutrino physics experiments.