Study of radioluminescence in LiMgPO4 doped with Tb, B and Tm

Abstract

Lithium magnesium phosphate (LiMgPO4, called LMP) crystals doped with different concentration of Tb, B and Tm were tested in regard to their radioluminescence emitted during irradiation. LMP crystals were grown with a micro-pulling down method as rods at IFJ PAN. The samples in the form of the thin slices were very sensitive to the ionizing radiation. Differently doped LMP samples were tested in a fiber optic measurement system (called PORTOS) which was constructed and adopted to the specific spectral properties of LMP. The LMP detector placed at the end of 15 m fiber connected to the PORTOS device was tested with gamma rays emitted from Co-60 Theratron 780E as well as with a Cs-137 source in a Laboratory for Calibration of Radiation Protection In- struments at IFJ PAN. RL signal was roughly proportional to the dose rates in the wide range of the dose rates. The highest RL signal was recorded for LMP crystals doped with 0.8 mol% of Tb as well as doped with 0.8 mol% Tm. The radioluminescence signal was discussed in regard to the thermoluminescence (TL) glow curves and optically stimulated luminescence (OSL) decay curves for 14 differently doped LMP crystals.