Dealing with non-conventional LM-OSL curve shapes in quartz following bleaching; a deconvolution approach

Abstract In the linear modulation (LM) technique of optically stimulated luminescence (OSL), the stimulation power changes with a linear ramping rate, while the signal intensity starts to increase from background level and continues by forming peaks. In some cases as in the present study, the LM-OSL curve has a non-conventional shape with a strongly decaying signal at the beginning of the stimulation. In order to deal with this dominant decaying component, two different deconvolution approaches were used by adding to the initial part of the LM-OSL curves, besides the conventional LM-OSL components, (a) a phosphorescence (PH) decaying component and (b) a continuous wave (CW) - OSL decaying component . The fitting results showed that temperature dependences of the fitting parameters (τ and σ) contradict standard OSL theory, so the non-conventional dominant decay component is not another CW-OSL. This non-conventional component could be attributed to an intense optically stimulated phosphorescence (OSP) component, due to the experimentally verified stimulated temperature dependence of the decay coefficient λ. This signal is much more intense at stimulation temperatures 125 °C and below, with various arguments suggesting that at these temperatures the signal originates from the 110 °C TL trap.