Germanium Detector Array

rdf:langString Germanium Detector Array

rdf:langString The Germanium Detector Array (or GERDA) experiment was searching for neutrinoless double beta decay (0νββ) in Ge-76 at the underground Laboratori Nazionali del Gran Sasso (LNGS). Neutrinoless beta decay is expected to be a very rare process if it occurs. The collaboration predicted less than one event each year per kilogram of material, appearing as a narrow spike around the 0νββ Q-value (Qββ = 2039 keV) in the observed energy spectrum. This meant background shielding was required to detect any rare decays. The LNGS facility has 1400 meters of rock overburden, equivalent to 3000 meters of water shielding, reducing cosmic radiation background. The GERDA experiment was operated from 2011 onwards at LNGS. After completing the GERDA experiment, the GERDA collaboration merged with MAJORANA-collaboration to build a new experiment . GERDA reported its final results in December 2020 in the Physical Review Letters. The experiment reached all the goals that it set to itself, but no detection of any 0νββ events was made. The experience from GERDA led to the expectation that further background reduction was in reach so that a background-free experiment with an even larger source strength, respectively exposure, became possible. The LEGEND collaboration, continuing GERDA's work, was aiming at increasing the sensitivity to the half-life of 0νββ decay up to . In a first phase, it planned to deploy a mass of 200 kg of enriched germanium detectors in the slightly modified infrastructure of GERDA with the start of data taking planned for 2021.