OSL and RL of LiMgPO4 crystals doped with rare earth elements

Abstract

LiMgPO4 (LMP) doped with a combination of Tb, B, Eu, Er, Gd or Tm activators in form of the crystals grown by micro-pulling down process (MPD) was examined as optically stimulated luminescence detectors using continues wave and time-resolved modes (CW and TR-OSL) as well as radioluminescence (RL) under X-ray tube irradiation. The RL-OSL measurements were performed using a HELIOS-3 OSL reader with a 460 nm diode light stimulation and 240–400 nm emission wavelength range for signal recording and compared with CW-OSL measured by Risoe reader. In TR-OSL mode the most sensitive samples were the crystals doped with Tb, B and doped with Tb, B, Er, in CW-mode the highest signal was recorded for crystal doped with Tb, B, Gd. The linear dose response was observed in the range from 0.5 to 10 Gy. RL signals measured for the dose rates of 62 mGy/min of X-rays was very high for all investigated crystals, especially for the crystal doped with Tm and Tb, B. The highest RL signal was observed for the crystal doped with 1.2mol% of Tm.