Search for double-β decays of 96Ru and 104Ru by ultra-low background HPGe γ spectrometry

A search for double-β processes in 96 Ru and 104 Ru was realized in the underground Gran Sasso National Laboratories of the INFN (Italy) with the help of ultra-low background HPGe γ spectrometry. After 158 h of data taking with 473 g ruthenium sample, new improved limits on double-beta processes in 96 Ru have been established on the level of 10 18 -10 19 yr. For the first time the double-beta decay of 104 Ru to the 2 + 1 excited level of 104 Pd has been restricted as T 1/2 > 3.5 x 10 19 yr.