Development of doped fused quartz for radiation dosimetry

Full text: Fused quartz plates were doped with Cu+ using simple technique. The plates were heated in tubular furnace at 800 deg C for three hours and cooled to room temperature. The plates were ground in mortar, sieved, to the 90-210 micron particle size. All the samples were irradiated to 60Co gamma rays to an absorbed dose of 0.5 Gy. The thermoluminescence (TL) readouts were carried out on the irradiated samples using the BARC made TL reader systems. The continuous wave optically stimulated luminescence (CW-OSL) measurements were carried out using blue laser (473 nm) based CW-OSL measurement setup. The photoluminescence measurements were carried out on the samples using Hitachi F4000 spectrofluorometer. The emission band in Cu+ doped quartz is observed at 395 nm with the excitation at 247 nm. The undoped quartz did not show any emission. The emission band is attributed to 3d94s1 → 3d10 transition of copper. The TL peak for the doped sample is observed at 175 deg C whereas in case of undoped sample the peak is observed at 200 deg C, but with low intensity. The TL/OSL properties of doped samples were found be enhanced. The results show that there is enhancement of OSL as well as TL in Cu+ doped quartz. The dosimetric peak of doped sample is 1.5 times than that of the dosimetric peak of undoped sample. The CW-OSL response is 20 times greater than that of undoped sample. The luminescence decay of SiO2:Cu is faster as compared with Al2O3:C. Its OSL sensitivity is 0.33 of Al2O3:C with blue light stimulation. Since natural quartz is being used for archaeological dating due to its good retentivity of the stored signal, chemical inertness and low-fading doped fused quartz will be a promising phosphor for its use in radiation dosimetry using OSL technique. However, doping of Cu+ needs to be optimized in SiO2 for optimizing the phosphor with good OSL sensitivity