Low background detector with enriched 116CdWO4 crystal scintillators to search for double beta decay of 116Cd

A cadmium tungstate crystal boule enriched in $^{116}$Cd to 82% with mass of 1868 g was grown by the low-thermal-gradient Czochralski technique. The isotopic composition of cadmium and the trace contamination of the crystal were estimated by High Resolution Inductively Coupled Plasma Mass-Spectrometry. The crystal scintillators produced from the boule were subjected to characterization that included measurements of transmittance and energy resolution. A low background scintillation detector with two $^{116}$CdWO$_4$ crystal scintillators (586 g and 589 g) was developed. The detector was running over 1727 h deep underground at the Gran Sasso National Laboratories of the INFN (Italy), which allowed to estimate the radioactive contamination of the enriched crystal scintillators. The radiopurity of a third $^{116}$CdWO$_4$ sample (326 g) was tested with the help of ultra-low background high purity germanium $\gamma$ detector. Monte Carlo simulations of double $\beta$ processes in $^{116}$Cd were used to estimate the sensitivity of an experiment to search for double $\beta$ decay of $^{116}$Cd.Comment: 24 pages, 13 figures, 3 tables, accepted for publication on Journal of Instrumentatio

developmwnts of enriched cadmium tungstate crystal scintillators to search for double beta decay processes of 106Cd

R&D of cadmium tungstate (CdWO 4 ) crystal scintillators with cadmium enriched in 106 Cd is in progress with aim to realize an experiment to search for double beta processes in 106 Cd. Samples of cadmium (with natural isotopic composition and enriched in 106 Cd) were purified by vacuum distillation. Cadmium tungstate compounds (natural and enriched) to grow CdWO 4 crystals were synthesized from solutions. Contamination of the cadmium samples and synthesized compounds were measured by mass spectrometry. Concentration of iron was determined by atomic absorption spectroscopy. CdWO 4 crystal boule was grown by Czochralsky method from the natural cadmium tungstate compound. The total losses of cadmium on the stages of purification, raw material synthesis, crystal growth and scintillator production do not exceed 4 %. An excellent energy resolution FWHM = 8.1 % was measured by ∅22 × 29 mm CdWO 4 scintillator for 662 keV γ quanta of 137 Cs source

CdWO4 crystal scintillators from enriched isotopes for double beta decay experiments

Cadmium tungstate crystal scintillators enriched in 106Cd and 116Cd were developed. The produced scintillators exhibit good optical and scintillation properties, and a low level of radioactive contamination. Experiments to search for double beta decay of 106Cd and 116Cd are in progress at the Gran Sasso National Laboratories of the INFN (Italy). Prospects to further improve the radiopurity of the detectors by recrystallization are discussed

First results of the experiment to search for 2β decay of 106Cd with the help of 106CdWO4 crystal scintillators

An experiment to search for 2β processes in 106Cd with the help of 106CdWO4 crystal scintillator (mass of 215 g), enriched in 106Cd up to 66 %, is in progress at the Gran Sasso National Laboratories of the INFN (Italy). After 1320 h of data taking, limits on double beta processes in 106Cd have been established on the level of 1019 − 1020 yr, in particular (all the results at 90 % C.L.): T1/2(0ν2ε) > 3.6 · 1020 yr, T1/2(2νεβ+) > 7.2 · 1019 yr, and T1/2(2ν2β+) > 2.5 · 1020 yr. Resonant 0ν2ε processes have been restricted as T1/2(0ν2K) > 1.4 · 1020 yr and T1/2(0νLK) > 3.2 · 1020 yr. A possible resonant enhancement of the 0ν2ε processes is estimated in the framework of the QRPA approach

First Results of the Experiment to Search for 2beta Decay of 106Cd with the Help of 106CdWO4 Crystal Scintillators

First Results of the Experiment to Search for 2beta Decay of 106Cd with the Help of 106CdWO4 Crystal Scintillators are presente

Development of enriched 106CdWO4 crystal scintillators to search for double beta decay processes in 106Cd

DAMA/LIBRA is running at the Gran Sasso National Laboratory of the I.N.F.N. The data collected in the first six annual cycle have already been released. The cumulative exposure – including that of the former DAMA/NaI experiment (0.29 ton × yr) – is now 1.17 ton x yr, corresponding to 13 annual cycles; this exposure is orders of magnitude larger than the exposures typically collected in the field. The data further confirm the model independent evidence of the presence of Dark Matter (DM) particles in the galactic halo on the basis of the DM annual modulation signature (8.9 σ C.L. for the cumulative exposure). In particular, the modulation amplitude of the single-hit events in the (2 - 6) keV energy interval measured in NaI(Tl) target is (0.0116 ± 0.0013) cpd/kg/keV, the measured phase is (146 ± 7) days and the measured period is (0.999 ± 0.002) yr, values well in agreement with those expected for the DM particles. Various related arguments are addressed

Development of CdWO4 Crystal Scintillators from Enriched Isotopes for 2β-Decay Experiments

Cadmium tungstate crystal scintillators enriched in 106Cd (106CdWO4) and 116Cd (116CdWO4) have been developed to search for 2β-decay of 106Cd and 116Cd