Background Suppression in Massive TeO 2 Bolometers with Neganov–Luke Amplified Light Detectors

Bolometric detectors are excellent devices for the investigation of neutrinoless double-beta decay (0 νββ). The observation of such decay would demonstrate the violation of lepton number, and at the same time, it would necessarily imply that neutrinos are Majorana particles. The sensitivity of cryogenic detectors based on TeO2 is strongly limited by the α-background in the region of interest for the 0νββ of 130Te. It has been demonstrated that particle identification in TeO2 bolometers is possible, measuring the Cherenkov light produced by particle interactions. However, the discrimination efficiency is low, and an event-by-event identification 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 TeO2 crystal, shows the ability for an event-by-event identification of electron/gamma and α particles. The obtained results demonstrate the possibility to enhance the sensitivity of TeO2-based 0νββ experiment to an unprecedented level.