Vertical Bridgman growth and low temperature luminescence properties of NaY(MoO4)2 crystal

Abstract

NaY(MoO4)2 crystal was investigated as a promising scintillator for neutrinoless double beta decay experiment. In this study, NaY(MoO4)2 crystal was grown by the Vertical Bridgman method using spontaneous crystallization. The as-grown NaY(MoO4)2 crystal appeared dark blue in color. The powder X-Ray Diffraction, optical transmission spectra at room temperature, luminescence properties and decay time from room temperature to 10 K excited by a 280 nm light emitting diode source were investigated. The transmittance of the annealed NaY(MoO4)2 crystal sample with the thickness of 3 mm was about 80%. The NaY(MoO4)2 crystal did not luminescence from room temperature to 200 K and the emission spectra were observed down from 175 K. With the temperature decreasing, the luminescence light yield increased and had maximum peak at 10 K. Compared to Li2MoO4 crystal, the luminescence light yield of NaY(MoO4)2 was much higher at 10 K. The longest average decay time was observed at 10 K (425 μs) and the shortest average decay time was observed at 175 K (88 μs). NaY(MoO4)2 crystal has a higher light yield at cryogenic temperature and no any heavy elements, so it is a promising candidate as a cryogenic detector for investigating the neutrinoless double-beta decay (0υββ) mechanism.