Search for double beta decay of $^{136}$Ce and $^{138}$Ce with HPGe   gamma detector
  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. 
P. Belli (1), R. Bernabei (1,2), R. S. Boiko (3), F. Cappella (4,5),   R. Cerulli (6), F. A. Danevich (3), A. Incicchitti (4...
nucl-ex physics.ins-det