First demonstration of a bubble-assisted Liquid Hole Multiplier operation in liquid argon

TL;DR

This paper reports the first successful demonstration of a bubble-assisted Liquid Hole Multiplier operating in liquid argon, showing its potential for detecting ionization electrons and scintillation photons with electroluminescence.

Contribution

It introduces the first operation of a bubble-assisted Liquid Hole Multiplier in liquid argon, extending previous xenon-based work to argon and demonstrating its detection capabilities.

Findings

Validated bubble containment under THGEM electrode

Recorded detector response to alpha particles

Demonstrated electroluminescence and imaging capabilities

Abstract

We demonstrate, for the time, the operation of a bubble-assisted Liquid Hole Multiplier (LHM) in liquid argon. The LHM, sensitive to both radiation-induced ionization electrons and primary scintillation photons, consists of a perforated electrode immersed in the noble liquid, with a stable gas-bubble trapped underneath. Electrons deposited in the liquid or scintillation-induced photoelectrons emitted from a photocathode on the electrode's surface, are collected into the holes; after crossing the liquid-gas interface, they induce electroluminescence within the bubble. After having validated in previous works the LHM concept in liquid xenon, we provide here first preliminary results on its operation in liquid argon. We demonstrate the bubble containment under a Thick Gas Electron Multiplier (THGEM) electrode and provide detector response to alpha particles, recorded with a SiPM - under electroluminescence and with modest gas multiplication; the imaging capability is also demonstrated.