Scintillation properties and radioactive contamination of CaWO4 crystal scintillators

Energy resolution, alpha/beta ratio and the pulse-shape discrimination ability of the CaWO4 crystal scintillators were studied. The radioactive contamination and background of the crystals were measured in the Solotvina Underground Laboratory. Despite a rather high level of radioactive impurities, the background rate of the CaWO4 detector in the energy window of the Ca-48 neutrinoless 2beta decay (3.6-5.4 MeV) was reduced to 0.07 counts/(yr keV kg). The indication for a decay of W-180 (Phys. Rev. 67 (2003) 014310) was confirmed (the measured half-life is T-1/2 = 1.0(-0.3)(+0.7) x 10(18)yr). (C) 2004 Elsevier B.V. All rights reserved.