Research and Development of ZnBO4 (B = W, Mo) Crystal Scintillators for Dark Matter and Double Beta Decay Searching

A.M. Dubovika, Yu.Ya. Vostretsova, B.V. Grinyova, F.A. Danevichb, H. Krausc, L.L. Nagornayaa, V.B. Mikhailikc and I.A. Tupitsynaa a Institute for Scintillation Materials, National Academy of Sciences of Ukraine, 60 Lenin Ave., 61001 Kharkov, Ukraine b Institute for Nuclear Research, MSP, 03680 Kyiv, Ukraine c University of Oxford, Department of Physics, Keble Road, Oxford OX1 3RH, UK

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Oxide crystal scintillators play a considerable role in fundamental and applied researches. However, working out of new generation of high-sensitivity equipment and new methods of research puts higher requirements. The ZnBO4 (B = W, Mo) crystals were grown from charge in platinum crucibles with high frequency heating, using the Czochralski method. The raw powder with optimum composition was prepared by solid phase high temperature synthesis using ZnO and BO3 (B = W, Mo) with 4-5N purity. Single crystals with sizes up to ∅ 50 × 100 mm were grown and scintillation elements of various sizes and shapes (cylinders, rectangular and hexahedron prisms) were produced. High spectrometric characteristics were obtained for ZnWO4: R = 8-10% under excitation by 137Cs (Eγ=662 keV), low radiation background (less than 0.2 mBq/kg) and low afterglow (0.002%, 20 ms after excitation). The obtained results demonstrate good prospects for ZnWO4 and ZnMoO4 crystal scintillators for application in low-count rate experiments, searching for double beta decay processes, interaction with dark matter particles, and also studies of rare decay processes. The material has also a good potential for application in modern tomography, scintillation bolometers and for other major researches using scintillators.

DOI: 10.12693/APhysPolA.117.15 PACS numbers: 81.10.Fq, 78.70.Ps