LArGe: Background suppression using liquid argon (LAr) scintillation for 0νββ decay search with enriched germanium (Ge) detectors

Measurements with a bare p-type high purity germanium diode (HPGe) submerged in a 19 kg liquid argon (LAr) scintillation detector at MPIK-Heidelberg are reported. The liquid argon–germanium system (LArGe) is operated as a 4π anti-Compton spectrometer to suppress backgrounds in the HPGe. This R&D is carried out in the framework of the Gerda experiment which searches for 0νββ decays with HPGe detectors enriched in 76Ge. The goal of this work is to develop a novel method to discriminate backgrounds in 0νββ search which would ultimately allow to investigate the effective neutrino mass free of background events down to the inverse mass hierarchy scale. Other applications in low-background counting are expected.