Performance of a large TeO2 crystal as a cryogenic bolometer in searching for neutrinoless double beta decay

TL;DR

This paper reports on the successful operation of a large 2.13 kg TeO2 cryogenic bolometer, demonstrating promising energy resolution and potential for reducing background in neutrinoless double beta decay searches.

Contribution

It presents the first large-scale TeO2 bolometer operating at cryogenic temperatures, showing improved performance and background reduction potential for neutrino physics experiments.

Findings

Achieved energy resolution of 3.9 keV at 145 keV

Operated the largest thermal detector to date at 10.5 mK

Indicated potential for background reduction with larger bolometers

Abstract

Bolometers are ideal devices in the search for neutrinoless Double Beta Decay. Enlarging the mass of individual detectors would simplify the construction of a large experiment, but would also decrease the background per unit mass induced by alpha-emitters located close to the surfaces and background arising from external and internal gamma's. We present the very promising results obtained with a 2.13 kg TeO2 crystal. This bolometer, cooled down to a temperature of 10.5 mK in a dilution refrigerator located deep underground in the Gran Sasso National Laboratories, represents the largest thermal detector ever operated. The detector exhibited an energy resolution spanning a range from 3.9 keV (at 145 keV) to 7.8 keV (at the 2615 gamma-line of 208Tl) FWHM. We discuss the decrease in the background per unit mass that can be achieved increasing the mass of a bolometer.