Geiger Mode APD performance in a cryogenic two-phase Ar avalanche detector based on THGEMs

TL;DR

This study demonstrates that Geiger Mode APDs in a cryogenic two-phase argon detector exhibit improved signal and noise characteristics at low temperatures, enabling effective detection of avalanche scintillations without wavelength shifters.

Contribution

The paper presents the first characterization of G-APD performance in a cryogenic two-phase argon detector with THGEMs, showing enhanced detection capabilities at cryogenic temperatures.

Findings

G-APD noise and signal amplitude are better at cryogenic temperatures.

Effective detection of avalanche scintillations without wavelength shifter.

Avalanche scintillation yield of 0.9 photoelectrons per avalanche electron at gain 60.

Abstract

Characteristic properties of a Geiger Mode APD (G-APD) in a THGEM-based cryogenic two-phase Ar avalanche detector were studied in view of potential applications in rare-event experiments. G-APD signal amplitude and noise characteristics at cryogenic temperatures turned out to be superior to those at room temperature. The effective detection of avalanche scintillations from THGEM-multiplier holes in two-phase Ar has been demonstrated using a G-APD without wavelength shifter. At an avalanche gain of 60, the avalanche scintillation yield measured by the G-APD was as high as 0.9 photoelectrons per avalanche electron, extrapolated to 4pi acceptance.