Tl2LaCl5 (Ce3+): New Fast and Efficient Scintillator for X- and γ-ray detection

Abstract: Scintillation properties of the new Tl2LaCl5: xCe3+ where x = 0, 0.5, 1 and 10 mole % (TLC: Ce3+) single crystals are presented. Two zones vertical Bridgman technique is used for the growth of this scintillation material. High Z-number (79) of this material offer excellent detection efficiency for X- and {\gamma}-rays. Grown samples are characterized under X- and {\gamma}-rays excitation in order to find the emission wavelength, energy resolution, light yield, and decay time. Emission spectra exhibit Ce3+ emission bands between 350 - 550 nm and peaking at 389 nm. The obtained energy resolution and light yield increases with high Ce-concentration. Energy resolution and light yield of 10%Ce-doped sample are found to be 6.9% (FWHM) and 51,000+-5000 ph/MeV, respectively at room temperature. For the grown samples, two exponential decay time constants are found. The measured decay time constants showed variation in their values with respect to Ce-concentrations in the host crystal. Fast decay time constant of 31 ns with 87% light emission is found for 10%Ce sample. Scintillation results suggested that TLC will be one of the promising next generation scintillator for the medical imaging techniques such as Positron Emission Tomography (PET).