The COBRA demonstrator at the LNGS underground laboratory

TL;DR

The COBRA demonstrator at LNGS is a prototype experiment using CdZnTe detectors to explore the feasibility of detecting neutrinoless double beta-decay in a low-background underground environment, focusing on technical and stability challenges.

Contribution

This paper presents the design, implementation, and initial results of a large-scale CdZnTe detector array for neutrinoless double beta-decay research at LNGS.

Findings

Over 250 kg·d of data collected since 2011

Demonstrated long-term stability of detectors

Identified key background sources in low-background operation

Abstract

The COBRA demonstrator, a prototype for a large-scale experiment searching for neutrinoless double beta-decay, was built at the underground laboratory Laboratori Nazionali del Gran Sasso (LNGS) in Italy. It consists of an array of 64 monolithic, calorimetric CdZnTe semiconductor detectors with a coplanar-grid design and a total mass of 380g. It is used to investigate the experimental challenges faced when operating CdZnTe detectors in low-background mode, to identify potential background sources and to show the long-term stability of the detectors. The first data-taking period started in 2011 with a subset of the detectors, while the demonstrator was completed in November 2013. To date, more than 250kg d of data have been collected. This paper describes technical details of the experimental setup and the hardware components.