Search for beta+EC and ECEC processes in Sn-112 and beta(-) beta(-) decay of Sn-124 to the excited states of Te-124

摘要

Limits on beta+EC and ECEC processes in Sn-112 and on beta(-) beta(-) decay of Sn-124 to the excited states of Te-124 have been obtained using a 380 cm(3) HPGe detector and an external source consisting of natural tin. A limit with 90% C.L. on the Sn-112 hall-life of 0.92 x 10(20) y for the ECEC(0 nu) transition to the 0(3)(+) excited state in Cd-112 (1871.0 keV) has been established. This transition is discussed in the context of a possible enhancement of the decay rate by several orders of magnitude given that the ECEC(0 nu) process is nearly degenerate with an excited state in the daughter nuclide. Prospects for investigating such a process in future experiments are discussed. The beta- beta- decay limits for Sn-124 to the excited states of Te-124 were obtained on the level of (0.8-1.2) x 10(21) y at the 90% C.L.