Signal regeneration in ESR dating of tephra with quartz

Electron spin resonance (ESR) dating has been applied previously to quartz derived from tephra deposits using the additive dose method. In this study we compare results obtained using both additive dose and regeneration dose methods on a Japanese tephra sample. A further intercomparison is carried out using two different signals corresponding to Al and Ti-Li centres, and two different grain sizes (0.25-0.5 mm and 0.5-1 mm). Possible sensitivity changes due to heating required for zeroing the signals was checked by the regenerative - additive dose technique. The estimates of equivalent dose (DE) obtained using the regeneration method were generally consistent with those obtained using additive dose; however, as expected the uncertainties were much smaller for the regeneration DE estimates. A significant difference was observed between the equivalent dose (DE) derived using the Al or Ti-Li centres, and using different grain sizes.