Crystal growth and scintillation properties of Thallium-based halide scintillators
Abstract
In this paper we report on the crystal growth and characterization of thallium-based halide scintillators of composition Tl2MXn (M = La, Hf; X = Cl, Br; n = 5, 6). Single zone Vertical Bridgman furnaces were used to grow crystals of Tl2LaCl5 and Tl2LaBr5 doped with different Ce concentrations. In the case of Tl2HfCl6 and Tl2HfBr6, crystals were grown using a low melting point halide flux to control the high vapor pressure of the hafnium tetrahalide starting materials. In two separate cases however, crystals of Tl2HfCl6 and Tl2HfBr6 were also grown by first sintering TlCl (TlBr) with HfCl4 (HfBr4) under reduced pressure before the crystal growth commenced. Crystal thus obtained were typically 1 cm3 or smaller.
Radioluminescence spectra of Tl2LaCl5:Ce and Tl2LaBr5:Ce crystals exhibit a broad emission band peaking at about 385 nm and 416 nm, respectively. Light yields obtained with small crystals of Tl2LaCl5:Ce and Tl2LaBr5:Ce typically are ≥ 60,000 ph/MeV, while energy resolutions as good as 3.2% (FWHM) at 662 keV have been measured. Radioluminescence spectra of Tl2HfCl6 and Tl2HfBr6 crystals exhibit a broad emission band peaking at about 425 and 550 nm, respectively. Light yields obtained with small crystals of Tl2HfCl6 and Tl2HfBr6 typically are about 20,000 ph/MeV.- Publication:
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Journal of Crystal Growth
- Pub Date:
- February 2020
- DOI:
- 10.1016/j.jcrysgro.2019.125438
- Bibcode:
- 2020JCrGr.53225438V
- Keywords:
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- A1. Characterization;
- A2. Bridgman crystal growth;
- A2. Flux growth;
- B1. Halides;
- B2. Scintillator materials