Investigation Of the low-dose-thermoluminescence characteristics of LiF:Mg,P

Thermoluminescence (TL) characteristics of LiF:Mg,P with varying concentrations (0.4%, 1% and 2%) of phosphorous are investigated and compared with those of the widely used TLD-100. The TL glow curves of the three LiF:Mg,P samples exhibited two apparent peaks around 120 °C and 239 °C. The TL response of each of the two peaks vary linearly with increasing dose (between 0.4 mGy and 12.0 mGy) for each of the three samples. The thermolumiscence intensities from samples with 0.4%, 1.0% and 2.0% of phosphorous concentration were respectively at least 26, 18 and 21 times that of TLD-100. TL response from a repeat use of a single aliquot of the samples with 0.4%, 1.0% and 2.0% of phosphorous concentration did not vary by more than 6%, 8% and 10% respectively. There were 3%, 10% and 12% fading of TL response over three-week storage period at room temperature for samples with 0.4%, 1.0% and 2.0% of phosphorous concentration. Pre-irradiation annealing up to 600 °C did not affect the glow curves structures of all the samples. However, while the sensitivity of samples B and C did not change with the annealing, the intensity of sample A first decreased with temperature up to 500 °C before it significantly rose to a value above that of the unannealed sample. TL intensity of the sample annealed at 500 °C decreased with increasing annealing duration up till one hour beyond which it remains constant. The linearity of the dose-response, negligible fading of response and unchanged sensitivities with pre-irradiation annealing for samples B and C qualify them as suitable TL dosemeters.