Radioactive contamination of ZnWO sub(4 crystal scintillators)

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2011-01, Vol.626-627, p.31-38
• Main Authors: Belli, P, Bernabei, R, Cappella, F, Cerulli, R, Danevich, F A, Dubovik, A M, D'Angelo, S, Galashov, EN, Grinyov, B V, Incicchitti, A, Kobychev, V V, Laubenstein, M, Nagornaya, L L, Nozzoli, F, Poda, D V, Podviyanuk, R B, Polischuk, O G, Prosperi, D, Shlegel, V N, Tretyak, VI, Tupitsyna, IA, Vasiliev, YaV, Vostretsov, YuYa
• Format: Article
• Language: English
• Subjects: Accelerators; Computer simulation; Contamination; Crystal growth; Crystals; Monte Carlo methods; Spectrometry; Spectroscopy
• ISSN: 0168-9002
• DOI: 10.1016/j.nima.2010.10.027

The radioactive contamination of ZnWO sub(4 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 h. Monte Carlo simulation, time-amplitude and pulse-shape analyses of the data have been applied to estimate the radioactive contamination of the ZnWO) sub(4) samples. One of the ZnWO sub(4 crystals has also been tested by ultra-low background gamma spectrometry. The radioactive contaminations of the best ZnWO) sub(4) samples are estimated to be less than 0.002 mBq/kg ( super(228Th and ) super(2)26Ra), the total alpha activity is 0.18 mBq/kg. The beta active super(65Zn and the alpha active ) super(1)80W have been detected in ZnWO sub(4 crystals. The effect of the re-crystallization on the radiopurity of the ZnWO) sub(4) crystal has been studied. The radioactive contamination of the ceramic components of the set-ups used in the crystals growth has been checked by low background gamma spectrometry. Some ideas for future improvement of the radiopurity level of ZnWO sub(4 crystal scintillators are briefly discussed.)