Mathematical formulation of Tmax–Tstop method for LM-OSL and its experimental validation on α-Al2O3:C

• Mathematical formulation of Tmax–Tstop method for LM-OSL is described.
• The theory is validated experimentally on α-Al2O3:C.
• The photoionization cross-section of OSL components of α-Al2O3:C are evaluated.

A mathematical formulation and its experimental validation on α-Al2O3:C for evaluating the number of OSL components has been described. The method consists of various partial bleaching steps of LM-OSL curve and as a result, the peak position (Tmax) of the resultant curve shifts if the system contains multiple components. However, for single component system the peak position of the resultant curve doesn’t change on partial bleaching for a phosphor obeying first order kinetics. The method has been theoretically formulated for single and multiple component system with different order of kinetics and validated experimentally on the commercial α-Al2O3:C OSL phosphor. The slope of the curve between shift in Tmax and bleaching time gives the number of the OSL components and measure of their closeness in terms of photoionization cross-section. Based on this result, the photoionization cross-section of the two embedded peaks in the LM-OSL curve of α-Al2O3:C were found to be 1.51 × 10−18 cm2 and 5.02 × 10−19 cm2 using CW-OSL and NL-OSL method.