Quartz TL decay due to optical bleaching

Abstract

In spite of many years of research our knowledge of the traps responsible for the OSL in quartz is not complete. Many papers report the complexity of this signal, determine its components and discuss their usefulness for dating procedures. However the experiments carried out so far do not clearly show the source of carriers which recombine on the luminescence centres emitting the OSL. The trap connected with TL peak around 325 C commonly accepted as easily bleachable, can not be the only one responsible for the many observed OSL components. There should exist TL peaks corresponding to these various OSL components, although it is possible that they are related to very deep traps (that is having large energy of thermal ionisation) which are not detected in the conventional TL measurements carried out up to 500∞C. With this in mind detailed analysis was made, using sedimentary quartz, of TL curves measured after successively increased time of bleaching performed during the OSL measurement. TL components were determined using fitting procedures and the effect of bleaching on each of these components is demonstrated.