Bubble dynamics in Liquid Hole Multipliers

Abstract

In bubble-assisted Liquid Hole Multipliers (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.

Novel electron and photon recording concepts in noble-liquid detectors

“…for S1, of ∼ 0.7% RMS from pure photon statistics and the measured one by XENON, of ∼ 1.5% RMS [48]. The results of a recent study related to the liquid-gas interface shape and its dependence on the electric fields are discussed in [49]. Model simulations discussed in this work could permit, in principle, designing electrode layouts with optimized electric fields at the interface -to enhance electron transmission, thus the PDE and energy resolution.…”

“…This mechanism depends on the geometry, electric fields and interface shape. Preliminary modeling and experimental efforts have been undertaken [49] to understand the processes involved and to hopefully devise methods for enhancing electron transfer into the bubble; e.g. by adequate shaping of the electric field at the liquid-to-bubble interface.…”

First results on FHM -- a Floating Hole Multiplier

“…Such discrepancy may be due to the meniscus lensing of the liquid-to-gas interface. Although no direct information on the contact angle of liquid xenon with FR4 is available at present, the liquid-gas interface can be expected to have a concave shape within the THGEM holes: for liquid argon the angle of 48±10 • has been measured [22]; for liquid xenon in contact with copper it was found to be ≈70 • [24] (although at a much higher temperature).…”

Cryogenic RPWELL: a novel charge-readout element for dual-phase argon TPCs

“…Experiments were conducted in a dedicated cryostat, WISArD, described in detail in [31][32][33]. The RPWELL assembly consisted of a 3 × 3 cm 2 area and 0.8 mm thick single-sided THGEM (0.5 mm diameter holes distributed in a hexagonal pattern with 1 mm pitch, 0.1 mm hole-rim) pressed onto a resistive plate.…”