Radioactive contamination of ZnWO4 crystal scintillators

Abstract

The radioactive contamination of ZnWO4 crystal scintillators has been measured deep underground at the Gran Sasso National Laboratory (LNGS) of the INFN in Italy with a total exposure 3197 kg x h. Monte Carlo simulation, time-amplitude and pulse-shape analyses of the data have been applied to estimate the radioactive contamination of the ZnWO4 samples. One of the ZnWO4 crystals has also been tested by ultra-low background gamma spectrometry. The radioactive contaminations of the ZnWO4 samples do not exceed 0.002 -- 0.8 mBq/kg (depending on the radionuclide), the total alpha activity is in the range: 0.2 - 2 mBq/kg. Particular radioactivity, beta active 65Zn and alpha active 180W, has been detected. The effect of the re-crystallization on the radiopurity of the ZnWO4 crystal has been studied. The radioactive contamination of samples of the ceramic details of the set-ups used in the crystals growth has been checked by low background gamma spectrometry. A project scheme on further improvement of the radiopurity level of the ZnWO4 crystal scintillators is briefly addressed.

arXiv comment15 pages, 8 figures, 6 tables, submitted for publication

References in corpus (7)

• The DAMA/LIBRA apparatus
• The event generator DECAY4 for simulation of double beta processes and decay of radioactive nuclei
• On the alpha activity of natural tungsten isotopes
• Quest for double beta decay of 160-Gd and Ce isotopes
• ZnWO_4 crystals as detectors for double beta decay and dark matter experiments
• Detection of the Natural Alpha Decay of Tungsten
• Search for double beta decay of Zinc and Tungsten with the help of low-background ZnWO4 crystal scintillators

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• Low background techniques in bolometers for double-beta decay search
• Experimental searches for rare alpha and beta decays
• First observation of alpha decay of 190-Pt to the first excited level (E_{exc}=137.2 keV) of 186-Os
• Measurements of ZnWO${}_4$ anisotropic response to nuclear recoils for the ADAMO project
• Optical, luminescence, and scintillation properties of advanced ZnWO${}_4$ crystal scintillators
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• Optimization of light collection from crystal scintillators for cryogenic experiments
• Radiopure tungstate and molybdate crystal scintillators for double beta decay experiments
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• DAMA/LIBRA results and perspectives, Bled 2013
• Anomalies in Radioactive Decay Rates: A Bibliography of Measurements and Theory
• BINGO innovative assembly for background reduction in bolometric $0\nu \beta \beta$ experiments
• Developments and improvements of radiopure ZnWO${}_4$ anisotropic scintillators
• Identification of radiopure tungsten for low background applications
• ZnO-based scintillating bolometers: New prospects to study double beta decay of ${}^{64}$Zn
• Precise measurement of the scintillation decay constant of ZnWO${}_4$ crystal