Radioactive contamination of ZnWO4 crystal scintillators
نویسندگان
چکیده
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 × 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 γ spectrometry. The radioactive contaminations of the ZnWO4 samples do not exceed 0.002 – 0.8 mBq/kg (depending on the radionuclide), the total α activity is in the range: 0.2 − 2 mBq/kg. Particular radioactivity, β active Zn and α active W, 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 γ spectrometry. A project scheme on further improvement of the radiopurity level of the ZnWO4 crystal scintillators is briefly addressed.
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