Thermoluminescence and optically stimulated luminescence studies on LiMgPO4 crystallized by micro pulling down technique

LiMgPO4 (LMP) crystals were grown by micro pulling down technique. Samples were irradiated with different β-particle doses of the 90Sr/90Y source. Thermally and optically stimulated luminescence spectra were measured with the automatic Risø TL/OSL-DA20 reader under the different modes of stimulation. The dose-response dependence, reproducibility, the lowest measurable dose and short-time fading were investigated. TL and OSL dose-response of LiMgPO4 crystals was found to be linear up to around 1 kGy, what makes this material suitable for high dose measurements. Discrepancies between successive measurements did not exceed 10%, regardless of the applied growth parameters. The lowest measurable dose, defined as three standard deviations of the signal of unexposed detector, was determined around 0.5 mGy. About 73% of the initial OSL signal value was measured 24 h after the irradiation. For longer periods of time the level of signal stabilizes so that there was no further loss of signal observed. In case of TL, the level of signal does not stabilize and decreases to 69% within 2 weeks after the irradiation. The obtained results tend to suggest that LiMgPO4 crystals may be considered as promising dosimeters for both personal and high dose dosimetry.