Search for double $\beta$ decay of $^{ 136}$Ce and $^{ 138}$Ce was realized with 732 g of deeply purified cerium oxide sample measured over 1900 h with the help of an ultra-low background HPGe $\gamma$ detector with a volume of 465 cm$^3$ at the STELLA facility of the Gran Sasso National Laboratories of the INFN (Italy). New improved half-life limits on double beta processes in the cerium isotopes were set at the level of $\lim T_{ 1/2}\sim 10^{ 17}-10^{ 18}$~yr; many of them are even two orders of magnitude larger than the best previous results.
Categories: nucl-ex physics.ins-det