Search for double-β decays of tin isotopes with enhanced sensitivity

A search for the various double-beta decay modes of Sn-124 and Sn-112 has been performed on 75 kg days of data. New half-life limits for excited states in Sn-124 have been obtained including a lower limit for decay into the first excited 2(+) state of Te-124 of T-1/2 > 0.87 x 10(20) yr (90% C.L.) and into the first excited 0(+) state of T-1/2 > 1.08 x 10(20) yr (90% C.L.). Ground state and excited state transitions of Sn-112 have also been experimentally explored. A limit for the 2 nu EC/EC of T-1/2 > 1.8 x 10(19) yr (90% C. L.) is obtained. The nonobservation of deexcitation gamma from the 0(+) at 1888.5 keV results in a lower half-life limit on the 0 nu EC/EC decay of Sn-112 of T-1/2 > 0.8 x 10(19)yr (90% C.L.), despite a possible resonant enhancement of the decay rate due to degenerated states.