LEGEND-1000 - a next generation detector for searches of neutrino-less double beta decay

The LEGEND experiment has been designed to search for neutrino-less double-beta decay in 76Ge. Its discovery would have profound implications for neutrino physics and cosmology providing unambiguous evidence for the Majorana nature of neutrinos, lepton number non-conservation and the absolute neutrino mass scale. The LEGEND-1000 detector represents the ton-scale phase of the LEGEND program, following the current intermediate stage, LEGEND-200, carried out at LNGS in Italy. The LEGEND-1000 will be based on p-type, inverted-coaxial, point-contact germanium detectors enriched in 76Ge up to about 90 %. The detectors will be operated in an active shield based on underground argon. This gas is extracted from an underground source and it is depleted in 39Ar and 42Ar. This approach proved to guarantee the lowest background levels and the best energy resolution at the decay Q value as established by the GERDA and MAJORANA DEMONSTRATOR experiments. The anticipated quasi background-free operation will allow the search for neutrino-less double-beta decay in 76Ge at a half-life beyond 1028 yr and a discovery sensitivity spanning the inverted-ordering neutrino mass scale. The LEGEND Collaboration is successfully seeking funding from US and European agencies. The construction of the detector in Hall C of the underground laboratory of LNGS in Italy should start early 2027 and will take about 8 years. Start of data taking is foreseen for 2031.