Bubble dynamics in Liquid Hole Multipliers

TL;DR

This paper presents a new model for understanding bubble stability and electro-mechanical interactions in Liquid Hole Multipliers, supported by optical observations and simulations, advancing the design of noble-liquid radiation detectors.

Contribution

It introduces a novel model for bubble equilibrium in LHM and provides the first optical observations of bubbles in liquid argon, validating predictions with micro-CT imaging.

Findings

Electric field influences bubble shape as an additional pressure.

Optical observations of bubbles in liquid argon were achieved.

Model predictions were validated with micro-CT imaging.

Abstract

In bubble-assisted Liquid HoleMultipliers(LHM), developed for noble-liquid radiation detectors, the stability of the bubble and the electro-mechanical properties of the liquid-to-gas interface play a dominant role in the detector performance. A model is proposed to evaluate the static equilibrium configurations of a bubble sustained underneath a perforated electrode immersed in a liquid. For the first time bubbles were optically observed in LAr; their properties were studied in contact with different material surfaces. This permitted investigating the bubble-electrodynamics via numerical simulations; it was shown that the electric field acts as an additional pressure term on the bubble meniscus. The predictions for the liquid-to-gas interface were successfully validated using X-ray micro-CT in water and in silicone oil at STP. The proposed model and the results of this study are an important milestone towards understanding and optimizing the parameters of LHM-based noble-liquid detectors.