Discrimination of alpha and beta/gamma interactions in a TeO$_2$ bolometer

TL;DR

This study demonstrates a method to distinguish alpha from beta/gamma interactions in TeO$_2$ bolometers by detecting Cerenkov light, significantly improving background rejection in neutrinoless double beta decay searches.

Contribution

The paper introduces a novel technique of simultaneous heat and luminescence detection in TeO$_2$ crystals to discriminate alpha particles from beta/gamma events, enhancing background rejection capabilities.

Findings

Beta/gamma particles produce detectable Cerenkov light.

Alpha particles do not produce detectable light.

Effective alpha background rejection achieved.

Abstract

TeO$_2$ crystals have proven to be superb bolometers for the search of neutrinoless double beta decay in many respects. However, if used alone, they do not exhibit any feature that allows to discriminate an alpha energy deposit from a beta/gamma one. This fact limits their ability to reject the background due to natural radioactivity and eventually affects the sensitivity of the search. In this paper we show the results of a TeO$_2$ crystal where, in coincidence with its bolometric heat signal, also the luminescence light escaping the crystal is recorded. The results show that we are able to measure the light produced by beta/gamma particles, which can be explained as due to Cerenkov emission. No light is detected from alpha particles, allowing the rejection of this background source.