No abstract

No abstract

No abstract

Nanocrystalline Ba0.97Ca0.03SO4 : Eu having a grain size of 58 nm has been prepared and a comparative study has been done with its corresponding microcrystalline form. The thermoluminescence (TL) glow curve of the nanophosphor has a prominent peak at 161 °C and a very small hump at 225 °C. The TL sensitivity of the nanophosphor is about 0.1 times that of the microphosphor. Kinetics parameters of the TL peaks of the nanophosphor are obtained and are compared with those of the microphosphor. The TL response of the nanophosphor is linear in the dose range 1 Gy–20 KGy, which is much wider than that of its corresponding microcrystalline form. The glow curve shape and structure also do not change in the linear dose range and, since the TL response is linear at higher doses, the nanophosphor is quite well suited for high dose measurements. Photoluminescence emission spectra of the nano- and the microphosphors are also studied and their results correlated with other experimental findings.

K3Na(SO4)2 : Eu nanocrystalline powder was synthesized by the chemical co-precipitation method. The x-ray diffraction pattern of the nanomaterials shows a hexagonal structure for its crystals having grain size of ∼28 nm. Transmission electron microscopy revealed that the K3Na(SO4)2 : Eu nanoparticles are single crystals with almost a uniform shape and size. Thermoluminescence (TL) was taken after irradiating the samples at various exposures of γ-rays from a 60Co source. A prominent TL glow peak is observed at 423 K along with three small peaks/shoulders at around 382, 460 and 509 K. The observed TL sensitivity of the prepared nanocrystalline powder is around 4 times more than that of LiF : Mg,Ti (TLD-100) phosphor. The 423 K peak of the nanomaterial phosphor eventually shows a near linear response with exposures increasing up to very high values (as high as 70 kGy), where all the other TLD phosphors saturate. This property along with its other desired properties such as high sensitivity, relatively simple glow curve structure and low fading makes the nanocrystalline phosphor a suitable dosimeter to estimate low as well as high exposures of γ-rays. TL analysis using the glow curve deconvolution technique was also done for determining different trapping parameters.