The Majorana Demonstrator search for neutrinoless double beta decay

TL;DR

The paper discusses the construction and initial data of the MAJORANA DEMONSTRATOR, a low-background germanium detector array designed to search for neutrinoless double beta decay, aiming to inform future large-scale experiments.

Contribution

It presents the design, construction, and first data from the MAJORANA DEMONSTRATOR, demonstrating a scalable approach to ultra-low background germanium detectors for neutrinoless double beta decay searches.

Findings

Initial data collected with the DEMONSTRATOR.

Achieved low background levels in the detector.

Demonstrated scalability of the modular design.

Abstract

The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, modular, HPGe detector array with a mass of 44.8-kg (29.7 kg enriched >88% in Ge-76) to search for neutrinoless double beta decay in Ge-76. The next generation of tonnescale Ge-based neutrinoless double beta decay searches will probe the neutrino mass scale in the inverted-hierarchy region. The MAJORANA DEMONSTRATOR is envisioned to demonstrate a path forward to achieve a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value of 2039 keV. The MAJORANA DEMONSTRATOR follows a modular implementation to be easily scalable to the next generation experiment. First data taken with the DEMONSTRATOR are introduced here.