Keeping the background low: Production and testing of the GERDA phase II detectors

The GERmanium Detector Array (GERDA) experiment at the INFN Laboratori Nazionali del Gran Sasso searches for neutrinoless double beta decay of ⁷⁶Ge. The first phase using ~15 kg of coaxial germanium detectors is ongoing. In a second phase, additional ~20 kg of newly produced Broad Energy Germanium (BEGe) detectors will be deployed. To limit the generation of cosmogenically induced radioisotopes, the exposure of the germanium to cosmic radiation during the detector production and testing was minimized. An acceptance and characterization campaign of the newly produced detectors was carried out at the HEROICA facility in the HADES underground laboratory in Mol, Belgium. An overview over the complete production process, from isotopic enrichment of the material to the detector testing protocol, is given.