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Search for double β 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 γ 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 ∼ 10 17 – 10 18 yr ; many of them are even two orders of magnitude larger than the best previous results. [ABSTRACT FROM AUTHOR]

Abstract: A cadmium tungstate crystal scintillator enriched in 106Cd was developed for an experiment to search for double beta processes in 106Cd. With this aim samples of cadmium with natural isotopic composition and enriched in 106Cd were purified by vacuum distillation. Cadmium tungstate compounds were synthesized from solutions. The absolute isotopic composition of the enriched cadmium was accurately determined as 66.4% by thermal ionisation mass-spectrometry. A 106CdWO4 crystal boule was grown by the low-thermal-gradient Czochralski technique. The total irrecoverable loss of the enriched cadmium in all the stages of the crystal scintillator production does not exceed 2.3%. The produced 106CdWO4 crystal scintillator with mass of 216g exhibits good optical and scintillation properties. [Copyright &y& Elsevier]