Background suppression in massive TeO$_2$ bolometers with Neganov-Luke amplified light detectors

TL;DR

This paper demonstrates a highly sensitive light detector using the Neganov-Luke effect that enables event-by-event discrimination of particle types in TeO$_2$ bolometers, significantly improving the potential for neutrinoless double-beta decay detection.

Contribution

It introduces a novel Neganov-Luke amplified light detector for TeO$_2$ bolometers, achieving unprecedented sensitivity and enabling effective particle discrimination.

Findings

Achieved RMS baseline noise of 19 eV in the light detector.

Demonstrated event-by-event identification of electron/gamma and alpha particles.

Enhanced sensitivity of TeO$_2$ bolometers for 0$ uetaeta$ searches.

Abstract

Bolometric detectors are excellent devices for the investigation of neutrinoless double-beta decay (0$\nu\beta\beta$). The observation of such decay would demonstrate the violation of lepton number, and at the same time it would necessarily imply that neutrinos have a Majorana character. The sensitivity of cryogenic detectors based on TeO$_2$ is strongly limited by the alpha background in the region of interest for the 0$\nu\beta\beta$ of $^{130}$Te. It has been demonstrated that particle discrimination in TeO$_2$ bolometers is possible measuring the Cherenkov light produced by particle interactions. However an event-by-event discrimination with NTD-based light detectors has to be demonstrated. We will discuss the performance of a highly-sensitive light detector exploiting the Neganov-Luke effect for signal amplification. The detector, being operated with NTD-thermistor and coupled to a 750 g TeO$_2$ crystal, shows the ability for an event-by-event identification of electron/gamma and alpha particles. The extremely low detector baseline noise, RMS 19 eV, demonstrates the possibility to enhance the sensitivity of TeO$_2$-based 0$\nu\beta\beta$ experiment to an unprecedented level.