CARVEL experiment with 48CaWO4 crystal scintillators for the double β decay study of 48Ca

Abstract The CARVEL (CAlcium Research for VEry Low neutrino mass) experiment to search for the double β decay of 48 Ca with the help of enriched 48 CaWO 4 crystal scintillators has been considered. Scintillation properties (energy resolution, α/β ratio, pulse-shape discrimination ability) and radiopurity of CaWO 4 scintillators were studied. Despite rather high radioactive contaminations, the background rate of the CaWO 4 detector in the energy region 3.6–5.4 MeV (energy window of the 48 Ca neutrinoless 2β decay) was reduced down to 0.07 counts/(yr keV kg). With ≈100 kg array of the 48 CaWO 4 crystals the sensitivity of the CARVEL experiment (in terms of the half-life limit for the 0ν2β decay) is estimated as T 1 / 2 0 ν > 10 27  yr. This value corresponds to the neutrino mass constraint m ν