Two-phase Cryogenic Avalanche Detectors with THGEM and hybrid THGEM/GEM multipliers operated in Ar and Ar+N2

TL;DR

This study evaluates two-phase cryogenic avalanche detectors using THGEM and GEM multipliers in argon and argon-nitrogen mixtures, demonstrating high gains and improved signal speed for potential rare-event detection applications.

Contribution

It presents the first performance results of two-phase CRADs with hybrid THGEM/GEM multipliers in argon and argon-nitrogen mixtures, achieving high gains and faster signals.

Findings

Achieved gains of ~1000 with double-THGEM in 10x10 cm2 detectors.

Attained gains of about 5000 with hybrid triple-stage multipliers.

Doping argon with N2 improved signal speed without reducing gain.

Abstract

Two-phase Cryogenic Avalanche Detectors (CRADs) with GEM and THGEM multipliers have become an emerging potential technique for charge recording in rare-event experiments. In this work we present the performance of two-phase CRADs operated in Ar and Ar+N2. Detectors with sensitive area of 10x10 cm2, reaching a litre-scale active volume, yielded gains of the order of 1000 with a double-THGEM multiplier. Higher gains, of about 5000, have been attained in two-phase Ar CRADs with a hybrid triple-stage multiplier, comprising of a double-THGEM followed by a GEM. The performance of two-phase CRADs in Ar doped with N2 (0.1-0.6%) yielded faster signals and similar gains compared to the operation in two-phase Ar. The applicability to rare-event experiments is discussed.