Experimental study of double beta decay modes using a CdZnTe detector array

TL;DR

This study used a 16-detector CdZnTe array at LNGS to search for double-beta decay, setting new half-life limits for various isotopes, demonstrating the technology's potential for rare decay detection.

Contribution

First application of a high-granularity CdZnTe detector array for double-beta decay searches, achieving improved half-life limits and demonstrating feasibility.

Findings

Half-life limits beyond 10^20 years for several isotopes

Improved limit for Te 120 beta+/EC decay

Technology performance comparable to other methods

Abstract

An array of sixteen 1 cm^3 CdZnTe semiconductor detectors was operated at the Gran Sasso Underground Laboratory (LNGS) to further investigate the feasibility of double-beta decay searches with such devices. As one of the double-beta decay experiments with the highest granularity the 4 x 4 array accumulated an overall exposure of 18 kg days. The setup and performance of the array is described. Half-life limits for various double-beta decay modes of Cd, Zn and Te isotopes are obtained. No signal has been found, but several limits beyond 10^20 years have been performed. They are an order of magnitude better than those obtained with this technology before and comparable to most other experimental approaches for the isotopes under investigation. An improved limit for the beta^+/EC decay of Te 120 is given.