Thermoluminescence in annealed and unannealed lif:Mg, ti(tld-100, harshaw) as a function of glow curve heating rate and using computerized glow curve deconvolution

We have studied the phenomenon of changes in glow peak sensitivity in LiF:Mg, Ti(TLD-100, Harshaw) by monitoring changes in the intensity of peaks 4 and 5 following 100°C for 30min post-irradiation and pre-irradiation annealing. In an attempt to aid the dosimetric application of this material we have investigated these changes in sensitivity in both 400 °C annealed and un annealed materials and as a function of glow curve heating rate from 100° min^-1 to 1000° min^-1. Computerized glow curve de convolution (cgcd) is used to resolve peaks 4 and 5 and thus monitor the behaviour of peaks 4 and 5 separately. In a previous publication we found that it was only peak 4 which seemed to show a propensity to possible clustering and consequent increases in sensitivity following room-temperature storage. In the work reported here we also find that peak 4 exhibits significantly anomalous behaviour (changes in sensitivity following 100°C for 30 min annealing, differences in these changes in sensitivity between 400 °C annealed and un annealed material and a tendency to shift in temperature following annealing). At high heating rates above 500° min-1 peaks 4 and 5 merge and become increasingly difficult to resolve, so that changes in the sensitivity of peak 4 can be easily misinterpreted and assigned to peak 5. In dosimetric applications involving long storage or irradiation periods (environmental and personnel dosimetry) where fading corrections are important, the use of peak 5 alone (separated from peak 4 using cgcd with a constant width for peak 4) is recommended. In other applications requiring maximum precision (clinical dosimetry) the use of the area of peaks (4+5) is optimal, again using cgcd to separate peaks (4+5) from peaks 2, 3 and 7. In all applications heating rates below 500° min”1 are recommended to allow adequate separation of peaks 4 and 5 from their high-temperature and low-temperature satellites. The common practice of integrating the tl signal to include part of peak 3, peaks 4-6 and part of peak 7 in dosimetric measurements is, we believe, one of the main reasons underlying the non-universality In many of the reported dosimetric characteristics of TLD-100.