Abstract:

Crystal structure of Cs₂LiY_0.95Cl₆:5%Ce crystal (CYLC) grown by vertical Bridgement method from polycrystal raw materials was measured by X-ray diffraction (XRD) and was proved to have elpasolite structure. The detected structure of Cs₂LiYCl₆:Ce crystal was agreed well with theoretical structure. Six optical absorption bands which are suggested to originate from the transition of electron from 4f to 5d_1~5 of Ce ions and self-trapped excition (STE), can be identified in the absorption spectra of the CLYC:Ce crystal. X-ray and ultraviolet excited luminescence spectra of Cs₂LiY_0.95Cl₆:5%Ce crystal present an emission band from 350 nm to 450 nm corresponding to 5d-4f transitions of Ce³⁺ ions. The peaks locating at 300 nm and 321 nm can be ascribed to core to valence luminescence and STE luminescence. Under the excitation of γ-rays from ¹³⁷Cs, Cs₂LiY_0.95Cl₆:5%Ce crystal presents energy resolution of 8.1%, and scintillation decay time of 58 ns and 580 ns. All of these properties show that Cs₂LiYCl₆:Ce crystal is a promising scintillator for neutron and gamma detection applications.

Key words: Cs2LiYCl6:Ce crystal, vertical Bridgement method, crystal structure, scintillation property