Simultaneous scintillation light and charge readout of a pure argon filled Spherical Proportional Counter

TL;DR

This paper explores the use of a spherical proportional counter with simultaneous scintillation light and charge readout in pure argon, aiming to enhance detection capabilities for neutrinoless double beta decay searches.

Contribution

It demonstrates for the first time the use of scintillation light for triggering in a spherical proportional counter with pure argon.

Findings

Scintillation light can effectively trigger the detector.

Measured drift times match simulation predictions.

Light signals show potential for event characterization.

Abstract

The possible use of a Spherical Proportional Counter for the search of neutrinoless double beta decay is investigated in the R2D2 R&D project. Dual charge and scintillation light readout may improve the detector performance. Tests were carried out with pure argon at 1.1 bar using a 6x6 mm2 silicon photomultiplier. Scintillation light was used for the first time to trigger in a spherical proportional counter. The measured drift time is in excellent agreement with the expectations from simulations. Furthermore the light signal emitted during the avalanche development exhibits features that could be exploited for event characterisation.