New results on search for 2β decay processes in ¹⁰⁶Cd using ¹⁰⁶CdWO₄ scintillator

Abstract Preliminary researches on double beta decay transitions in 106Cd were carried out using a cadmium tungstate scintillator enriched in 106Cd at 66% (106CdWO4, mass 215.4 g), in coincidence (anticoincidence) with two CdWO4 scintillation detectors composed of natural Cd. The detector system is inserted in the DAMA/R&D setup, placed in the Gran Sasso National Laboratory of the INFN (LNGS, Italy). The contaminations which appear in the different materials of the experimental apparatus were simulated using Monte Carlo coding. New calculations of half-life limits have been done for various double beta decay channels of 106Cd and are of order of lim T 1 / 2 ∼ 10 20 −10 21 yr. These results were derived by means of the analysis of the data accumulated for 467 days. The preliminary estimation on T 1 / 2 for the positron-emitting electron capture with two neutrinos emission in 106Cd is equal to T 1 / 2 ≥ 1.5 × 10 21 yr, which is close to the theoretical forecasts for this process, T 1 / 2 ∼ 10 21 −10 22 yr.