Thermoluminescence study of rare earth ion (Dy3+) doped LiF:Mg crystals grown by EFG technique

This work describes investigation of radiation dosimetry characteristics of magnesium (Mg) doped lithium fluoride (LiF) crystals co-doped with different concentrations of dysprosium (Dy). These crystals were grown by edge defined film fed crystal growth (EFG) technique. Thermoluminescence (TL) measurements were made on as grown (AG) and annealed (AN) crystals after they were irradiated with a gamma dose of 15 Gy. The influence and advantage of optimized Dy3+ concentration in enhancing the thermoluminescence (TL) properties of LiF:Mg samples were discussed. The normalized peak height of the annealed crystals was nearly 3 times that of the as grown crystals for the particular concentration samples irradiated with Co60 gamma source showed linearity up to 10 Gy. Thermoluminescence signal observed over a period of one month showed negligible fading. Thermoluminescence glow curve structure of optimized phosphor remained stable for higher doses of gamma rays of 103 Gy. Glow curve was analyzed using computer glow curve deconvolution (CGCD) method and trapping parameters were calculated.