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Browsing by Author "Gieszczyk, Wojciech"

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    OSL and RL of LiMgPO4 crystals doped with rare earth elements
    (Radiation Measurements, 2019) Marczewska, Barbara; Sas-Bieniarz, Anna; Bilski, Paweł; Gieszczyk, Wojciech; Kłosowski, Mariusz; Sądel, Marcin
    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.
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    Study of radioluminescence in LiMgPO4 doped with Tb, B and Tm
    (Radiation Measurements, 2020) Sas-Bieniarz, Anna; Marczewska, Barbara; Bilski, Paweł; Gieszczyk, Wojciech; Klosowski, Mariusz
    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.