Improved limits on $β^+$EC and ECEC processes in $^{74}$Se
nucl-ex
/ Authors
A. S. Barabash, V. B. Brudanin, A. A. Klimenko, S. I. Konovalov, A. V. Rakhimov, E. N. Rukhadze, N. I. Rukhadze, Yu. A. Shitov, I. Stekl, G. Warot
and 1 more author
/ Abstract
New limits on $β^+$EC and ECEC processes in $^{74}$Se have been obtained using a 600 cm$^3$ HPGe detector and an external source consisting of 1600 g of a natural selenium powder. For different $β^+$EC and ECEC transitions (to the ground and excited states) obtained limits are on the level $\sim (0.2-4.8)\times10^{19}$ yr at 90\% C.L. In particular, for the potentially resonant transition into the 1204.2 keV excited state of $^{74}$Ge a lower half-life limit of $1.1\times10^{19}$ yr at 90\% C.L. has been obtained. Possibility to increase the sensitivity of such measurements is discussed.