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We investigate the multi-ampoule growth at 25 mm diameter of ternary iodide single crystal scintillator KCaI 3 :Eu using the randomly oriented self-seeded Bridgman method. We compare scintillation performance between cubic inch scale crystals containing small variations of low nominal europium concentrations previously shown to balance light yield with self-absorption in the host crystal. Growth conditions were optimized in the developmental furnace and four 2 in 3 KCaI 3 :Eu crystals were grown simultaneously producing a total of six 25 mm × 25 mm cylinders. Small variations in activator concentration did not result in significant performance differences among the six measured crystals. A range of energy resolutions of 3.5–4.7% at 662 keV was achieved, surpassing that of NaI:Tl crystals commonly used in spectroscopic detection applications. The function and basic design of the multi-ampoule furnace as well as the process of growing single crystals of KCaI 3 is included here. [ABSTRACT FROM AUTHOR]

Abstract: The current work describes two new Eu2+-activated scintillator materials, CsCaI3:Eu and CsCaCl3:Eu. Single crystals of CsCaI3:Eu and CsCaCl3:Eu were grown from the melt via the vertical Bridgman method. Scintillation properties, including decay time, light output, X-ray excited luminescence and light output, as a function of excitation energy were measured, as were the photoluminescence emission and excitation spectra. In addition, moisture sensitivity was evaluated by measuring the moisture uptake rate and compared with those of NaI:Tl and Cs2LiYCl6:Ce reference scintillators. [Copyright &y& Elsevier]

• Li+, Na+, and K+ codoped LuYAG: 1.2% Pr crystals were grown by Czochralski method. • Changing growth geometry, translation and rotation rate mitigates cracking in LuYAG. • Codoping with monovalent ions improves light yield, energy resolution, decay time. • Enhanced properties are associated with the removal of charge carrier trap at 300 K. In this paper, we explore codoping with monovalent ions: Li+, Na+, and K+, as a method of altering the scintillation properties of praseodymium-doped (Lu 0.75 Y 0.25) 3 Al 5 O 12 (LuYAG: Pr3+) single crystals. Substantial effort was given to optimizing the growth process to mitigate cracking which occurred in the LuYAG crystals beginning around the shoulder region and continuing throughout the boule. Growth parameters such as the translation and rotation rate, cool down duration, and boule geometry were altered to successfully address this challenge. Scintillation light yield, energy resolution, and scintillation decay time were measured for each of these crystals. It was discovered that monovalent codoping significantly improved scintillation light yield by at least 50%; accelerated and increased the weight of the fast component of scintillation decay; and enhanced energy resolution to values of as low as 3.8%, the best energy resolution reported for an oxide scintillator to date. The enhancements in scintillation performance are related to the effect of monovalent codoping on the formation of defects, in particular oxygen vacancies, within the LuYAG matrix and is proven via thermoluminescence and afterglow measurements. [ABSTRACT FROM AUTHOR]