Improvement of radiopurity level of enriched ¹¹⁶CdWO₄ and ZnWO₄ crystal scintillators by recrystallization

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• 作者：A.S. Barabash^a ; P. Belli^b ; R. Bernabei^b ; ^c ; ^{rita.bernabei@roma2.infn.it" class="auth_mail" title="E-mail the corresponding author} ; Yu.A. Borovlev^d ; F. Cappella^e ; V. Caracciolo^e ; R. Cerulli^e ; F.A. Danevich^f ; A. Incicchitti^g ; ^h ; V.V. Kobychev^f ; S.I. Konovalov^a ; M. Laubenstein^e ; V.M. Mokina^f ; ^g ; O.G. Polischuk^f ; O.E. Safonovaⁱ ; V.N. Shlegel^d ; V.I. Tretyak^f ; ^g ; I.A. Tupitsyna^j ; V.I. Umatov^a ; V.N. Zhdankov^k
• 关键词：Radioactive contamination of scintillators ; Low counting experiments ; CdWO4 crystal scintillator ; ZnWO4 crystal scintillator
• 刊名：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
• 出版年：2016
• 出版时间：11 October 2016
• 年：2016
• 卷：833
• 期：Complete
• 页码：77-81
• 全文大小：767 K

文摘

As low as possible radioactive contamination of a detector plays a crucial role to improve sensitivity of a double beta decay experiment. The radioactive contamination of a sample of ¹¹⁶CdWO₄ crystal scintillator by thorium was reduced by a factor ≈10, down to the level 0.01 mBq/kg (²²⁸Th), by exploiting the recrystallization procedure. The total alpha activity of uranium and thorium daughters was reduced by a factor ≈3, down to 1.6 mBq/kg. No change in the specific activity (the total α activity and ²²⁸Th) was observed in a sample of ZnWO₄ crystal produced by recrystallization after removing ≈0.4 mm surface layer of the crystal.