Bridgman Growth and Characterization of LuAlO3—Ce3+ Scintillator Crystals

Abstract

Chemical and structural effects in LuAlO3‐Ce3+ single crystals grown by the Bridgman method were studied using spectral emission, x‐ray, etching and optical techniques. The Ce concentration distribution was found to exhibit the normal freeze behavior with partition coefficient of 0,17. The expansion of the unit cell volume due to incorporation of Ce was measured. Dislocation etch pits were revealed on (010), (100) and (001) crystal faces. Thermal expansion behavior of LuAlO3 was studied along the major crystallographic axes in between the room temperature and 1000 °C. The scintillation performance of 5 × 5 × 10 mm3 samples was measured using a 662 keV gamma source with a shaping time of 1.2 μs. The light yield was increasing from 40% BGO to 70% BGO with increasing of the Ce3+ content from 0.13 at.% to 0.9 at.%.

Crystal growth and optical properties of Ce-doped (Y, Lu)AlO3 single crystal

“…Considering the lattice constants of LuAP, Petrosyan et al reported that the lattice constants a, b and c are determined to be 5.100 Å, 5.330 Å and 7.294 Å, respectively. 28) In comparison with the lattice constants of LuYAP obtained in this study with the results of LuAP, the lattice constants of a and c were negatively correlated with Lu concentration, while b was almost constant regardless Lu concentration. This is because the ionic radii of Y 3+ (8-coordination) and Lu 3+ (8-coordination) are 1.019 Å and 0.977 Å, respectively, which suggests that the increase of Lu concentration caused the decrease of the lattice constants.…”

Wide Band Gap Scintillation Materials: Progress in the Technology and Material Understanding

“…The problem of twins was reported recently for YAP:Nd single crystal growth [229]. The boules of LuAP : Ce grown by the Bridgman method [219] approach dimensions of diameter about 1.2 cm  6 cm length with similar Ce concentrations. Mixed (Y±Lu)AP : Ce crystals grown by the Czochralski method at CRYTUR Ltd. have typical dimensions of diameter about 2 cm  6 cm length.…”

“…Spectrally unresolved scintillation decay of a YAlO 3 : Ce 3+ single crystal excited by 22 Na radioisotope. Slower decay components and background enhancement are related to the delayed radiative recombination of charge carriers at Ce 3+ emission centres LuAP single crystal (density 8.35 g/cm 3 ) was intensively studied and was grown mainly by the Czochralski method, but also by the Bridgman method [219]. Optical properties of LuAP : Ce are in all aspects similar to those of YAP : Ce including the unwanted absorption tail around 330 nm which causes a significant decrease of LY for larger (about 10 to 15 mm in length) samples [220].…”

Untangling the controversy on Ce3+ luminescence in LaAlO3 crystals

“…Its heavier structural analog, LuAlO 3 (LuAP) with a high density of 8.35 g cm −3 and an effective atomic number as high as 64.9, has attracted attention from the scintillation material community since 1990s. 22–25 However, due to the very low stability of the perovskite phase and difficulties in crystal growth, its commercialization was not successful even in the case of a more stable Y-admixed LuAP (LuYAP) variant. 26 Similar to the garnet counterparts, 7–9 the anti-site defects (rare-earth ions substituting Al 3+ in the AlO 6 octahedra) and related deterioration of scintillation characteristics can also be observed in perovskites.…”