An investigation of luminescence properties of CaF: Dy nanophosphor irradiated with gamma rays and low energy proton beams.

This paper reports the luminescence properties of nanocrystalline calcium fluoride doped with dysprosium (CaF: Dy). The nanophosphor has been synthesized by the chemical co-precipitation technique and the dopant concentration has been optimized at 0.3 mol% using thermoluminescence (TL) intensity emitted post 50Gy gamma dose irradiation of samples doped with different dopant concentrations. X-ray diffraction shows the formation of crystalline particles with an average size of 49.233 nm. Photoluminescence (PL) emission spectrum shows the characteristic peaks at 455 nm, 482 nm, 573 nm corresponding to I to H, F to H and F to H Dy transitions respectively. PL excitation spectrum shows a peak at 327 nm which corresponds to the Dy transition of H to L. Gamma (of 1.25 MeV) and low energy proton beam (of 30 keV) irradiated nanophosphor shows a variation in TL glow curve structure and peak position with an increase in radiation dose/fluence. However, the nanophosphor shows a wide linear dose response for Co gamma radiation in the range 10 Gy - 1.5 kGy and for low energy proton beam in the fluence range of 10-10 ions/cm. Srim 2013 has been used to calculate the ion beam parameters including the range of protons in CaF: Dy 0.3 mol%. The nanophosphor CaF: Dy could be further investigated as a potential dosimeter for gamma rays and proton beam by studying its TL properties for different energies of these radiations.