New observation of 2β2ν decay of 100Mo to the 0 +1 level of 100Ru in the ARMONIA1 experiment

Abstract

Sample of 100MoO3 with molybdenum enriched in 100Mo to 99.5% and mass of 1199 g was measured deep underground (3600 m w.e.) in the Laboratori Nazionali del Gran Sasso of INFN, Italy; during 17249 h with a low-background set-up with 4 HP Ge detectors. After 2β2ν decay of 100Mo to the 0+1 excited level of 100Ru (Eexc 1131 keV), two γ quanta of 540 keV and 591 keV should be emitted in deexcitation process. Both these γ's are observed in the accumulated data as in coincidence spectrum as well in 1-dimensional sum spectrum. Measured half life is T1/2 (7.0 +1.1-0.8) × 1020 yr, in agreement with positive results obtained in previous experiments. © 2010 IOP Publishing Ltd.