Growth and spectroscopic properties of 6Li- and 10B-enriched crystals for heat-scintillation cryogenic bolometers used in the rare events searches

Abstract

We present the crystal growth of centimeter-sized ⁶Li₆Eu(¹⁰BO₃)₃ and Li₆(Eu,Gd)(BO₃)₃ single crystals by combined Czochralski and Kyropoulos methods, initiated on specifically oriented seeds, with a heretofore unexplored concentration range for heat-scintillation cryogenic bolometers application. The crystal structure and lattice thermal expansion of the former, obtained for the first time by single crystal X-ray diffraction (XRD), and the spectroscopic characterizations together with a consistent set of related thermodynamical properties measurements (magnetic susceptibility, specific heat), also unknown to date, are discussed. Finally, preliminary scintillation measurements at low temperature between 300 and 1100 nm under X-ray excitation are shown.