CdWO4 scintillating bolometer for Double Beta Decay: Light and Heat anticorrelation, light yield and quenching factors

TL;DR

This study demonstrates a CdWO4 scintillating bolometer's ability to discriminate particles and improve energy resolution for double beta decay detection by analyzing heat-light anticorrelation and quenching factors.

Contribution

It introduces a novel method to utilize heat-light anticorrelation in CdWO4 bolometers to enhance energy resolution and accurately evaluate alpha quenching factors.

Findings

Achieved up to 2.6 times better energy resolution at 2615 keV.

Estimated extremely low internal trace contaminations of 232Th and 238U.

Developed a new method to evaluate thermal quenching factors for alpha particles.

Abstract

We report the performances of a 0.51 kg CdWO4 scintillating bolometer to be used for future Double Beta Decay Experiments. The simultaneous read-out of the heat and the scintillation light allows to discriminate between different interacting particles aiming at the disentanglement and the reduction of background contribution, key issue for next generation experiments. We will describe the observed anticorrelation between the heat and the light signal and we will show how this feature can be used in order to increase the energy resolution of the bolometer over the entire energy spectrum, improving up to a factor 2.6 on the 2615 keV line of 208Tl. The detector was tested in a 433 h background measurement that permitted to estimate extremely low internal trace contaminations of 232Th and 238U. The light yield of gamma/beta, alpha and neutrons is presented. Furthermore we developed a method in order to correctly evaluate the absolute thermal quenching factor of alpha particles in scintillating bolometers.