Shruti Aggarwal

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

Abstract 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 Dy 3+ 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 Co 60 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 10 3 Gy. Glow curve was analyzed using computer glow curve deconvolution (CGCD) method and trapping parameters were calculated.

Thermoluminescence characteristics of LiF: Cu nanocrystalline phosphor

Copper (Cu) activated LiF phosphor in nanocrystalline form has been prepared by the chemical co-precipitation method for radiation dosimetry application. The formation of nanocrystalline structure has been confirmed by X-ray diffraction and Scanning electron microscopy. Cubical shaped nanostructure with average particle size of 33nm has been formed. The sample was prepared at different concentration of Cu from 0.01mol% to 3 mol%. TL properties were investigated by studying the glow curve after irradiating the phosphor to gamma ray Co60 source with dose of 15 Gy. It has been found that nanocrystalline LiF: Cu show simple glow curve structure with a single glow peak at 404 K where as commercially available phosphors exhibits multi peak complex glow curve structure. The effect of different normality on the TL properties of phosphor has been studied. Maximum TL intensity for LiF: Cu (0.1mol %) phosphor is observed at the normality of 0.5N and annealing temperature of 200°C. The phosphor showed good linearity ...