The cryogenic RWELL: a stable charge multiplier for dual-phase liquid-argon detectors

TL;DR

This paper introduces the cryogenic RWELL, a novel charge multiplier for liquid-argon detectors, demonstrating improved stability and discharge quenching at cryogenic temperatures through experimental characterization.

Contribution

First demonstration of a cryogenic RWELL with resistive anode, showing enhanced stability and discharge quenching compared to traditional multipliers.

Findings

Achieved stable operation at 90 K in saturated argon vapor.

Demonstrated superior gain and stability over standard THGEM and WELL multipliers.

Confirmed discharge quenching benefits of the resistive RWELL design.

Abstract

The operation of a cryogenic Resistive WELL (RWELL) in liquid argon vapor is reported for the first time. It comprises a Thick Gas Electron Multiplier (THGEM) structure coupled to a resistive Diamond-Like Carbon (DLC) anode deposited on an insulating substrate. The multiplier was operated at cryogenic temperature (90~K, 1.2~bar) in saturated argon vapor and characterized in terms of charge gain and electrical stability. A comparative study with standard, non-resistive THGEM (a.k.a LEM) and WELL multipliers, confirmed the RWELL advantages in terms of discharge quenching - thus superior gain and stability.