A New Reading out Procedure to Improve the Linearity of Dose Response curve of Lif: mg, TI

The linearity of thermoluminescence (TL) dose response curve, in low dose levels, is affected by background signals appearing at the tail of the glow curves. The effects of these signals also restrict the use of the high temperature glow peaks in many applications. In this study, a new reading out procedure was presented to reduce the background signals and increase the resolution of the high temperature glow peaks in LiF:Mg,Ti (TLD-600 and TLD-700) dosimeters in both gamma and neutron irradiation processes. The new reading out procedure was performed in two steps with different temperature zone range. In the first step, the temperature zone range was set to 100:210 C with heating rate R= 1 C/sec. This step is followed by a second reading (second step) with a temperature zone range of 100:400 C with the same R. A comparison between this new procedure and the usual one (in which the reading out is only one step with a temperature zone of 100:400 C) was performed. The new behavior of the glow peaks due to applying these procedures was also studied. The results show that the new procedure causes in decreasing the maximum value (Im) of the glow peaks. However, their position (Tm) did not affect. The percentage values by which the Im of the glow peaks decreased are the same in both irradiation cases for peaks 2, 3 and 5. The results also show that this procedure decreases the background signals appearing in the tail of the glow curve, especially in the case of neutron irradiation. Hence, it increases the resolution of the high temperature glow peaks, especially peak 7. A significant improvement in the linearity of the TL dose response was observed for due to applying this procedure.