Crystal Growth of Na-Co-Doped Ce:LiCaAlF₆ Single Crystals and Their Optical, Scintillation, and Physical Properties

Abstract

We have grown Ce- and Na-co-doped LiCaAlF6 (Ce,Na:LiCAF) single crystals with various Ce and Na concentrations by the micro-pulling-down (μ-PD) method. Physical properties such as crystallinity, transmittance, photoluminescence, scintillation, and radiation resistance were investigated to evaluate the effects of charge compensation by Na co-doping in the Ce-doped LiCaAlF6 (Ce:LiCAF) crystal. Ce2%:LiCAF, Ce1%Na1%:LiCAF, Ce1.5%Na1.5%:LiCAF, and Ce2%Na2%:LiCAF crystals with no visible cracks and inclusions were prepared. The Ce1%Na1%:LiCAF crystal showed high crystallinity comparable to the crystal grown by the Czochralski method. In the transmittance and photoluminescence spectra of all crystals, an absorption peak around 270 nm and emission peaks around 285 and 310 nm originating from Ce3+ ions were observed, respectively. With increasing Ce and Na concentrations, the light yield systematically increased, and scintillation decay times decreased. Improvement of radiation resistance accomplished by charge compensation due to Na co-doping is clearly demonstrated.

Microstructure and Mechanical Properties of Platinum Fiber Fabricated by Unidirectional Solidification

“…On the other hand, inorganic single crystals have been manufactured by melt-growth approaches such as the Czochralski (Cz) [2,3], Vertical Bridgman (VB) [4,5], and micro-pulling-down (µ-PD) methods [6][7][8][9][10][11][12][13][14]. In particular, the µ-PD method is suitable for the material research of single crystals because it has a faster growth rate than other conventional melt-growth methods [6][7][8][9]. In addition, a shaped single crystal can be synthesized directly from the melt by controlling the shape of the solid-liquid interface during crystal growth [10][11][12][13][14].…”

Engineering of Eu dopant segregation in colquiriite-type fluoride single crystal scintillators

“…LiCaAlF 6 (LiCAF) and LiSrAlF 6 (LiSAF) single crystals with the colquiriite-type structure have been investigated as an alternative host material of neutron scintillator due to the large capture crosssection for thermal neutron originated from a 6 Li isotope with the relatively large capture cross-section for thermal neutrons. [1][2][3][4][5][6] We have developed LiCAF and LiSAF crystals doped with various emission centers that were grown by a micro-pulling-down method which can grow single crystal from melt using a crucible with a nozzle at higher growth rate than conventional methods. [1][2][3][7][8][9] In the developed series, Eu 2+ -doped LiCAF and LiSAF (Eu:LiCAF, Eu:LiSAF) single crystals indicated the highest light yield under thermal neutron irradiation and they are expected to become an alternative to the 3 He gas.…”

Comparison of thermoluminescence characteristics in γ‐ray and C5+ ion beam‐irradiated LiCaAlF6:Ce phosphor

“…Ce 3+ -activated LiCaAlF 6 is a well-known phosphor with diverse applications in solid-state tunable lasers and scintillators (15)(16)(17)(18)(19). A lot of work has been done on colquirite-type LiCaAlF 6 phosphors explaining their Photoluminescence (PL), Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) properties triggered by different activator ions (20)(21)(22)(23)(24).…”