Crystal growth and Ce3+ concentration optimization in Tl2LaCl5: An excellent scintillator for the radiation detection

摘要

High effective atomic number (70) and density (5.17 g/cm(3)) among the known halide scintillators with excellent scintillation performance make Tl2LaCl5 (TLC) a new potential candidate for X- and gamma-ray detection. The preliminary scintillation performance of TLC was reported earlier for small crystal pieces without any detail information of synthesis, crystal growth optimization conditions and Ce3+ doping concentration, which are investigated in this study. The newly developed melt rotation technique was found to be the best one for the synthesis of TLC and probably for other Tl-based compounds among the known melting techniques. Pure and nominal Ce3+ concentration of 1%, 3%, 5%, 7% and 10% TLC crystals were grown with two zones vertical Bridgman technique in two different type of homemade furnaces and found the optimum thermal gradient, pulling and cooling rate as 25 degrees C/cm, 0.5 mm/h and 20 degrees C/h, respectively. The best energy resolution of similar to 3.3% (FWHM) and light yield of similar to 82,000 ph/MeV were obtained for TLC:3%Ce3+ under 662 keV gamma-rays excitation. The promising scintillation performance of TLC revealed that this crystal could be used in Positron Emission Tomography (PET), environmental radiation monitoring and homeland security applications. (C) 2020 Published by Elsevier B.V.