Comparison of naturally accumulated radiation-doses between RTL, BTL, OSL, and IRSL using white minerals from burnt archaeological materials and usefulness of RTL-dating from quartz extracts

Abstract

Naturally accumulated doses after pottery manufacture were compared between optically stimulated luminescence (OSL) from quartz grains and infrared-stimulated luminescence (IRSL) from feldspar grains, together with a red-thermoluminescence (RTL) result from quartz grains. Quartz and feldspar extracts from nine Jomon pottery pieces, which were manufactured and used 3,500-6,000 years ago, were subjected to three kinds of luminescence measurements using a new automated luminescence measuring system. Since this system included a small X-ray irradiator, a single-aliquot regenerative-dose (SAR) protocol was applicable to each luminescence dosimetry. Naturally accumulated doses from RTL were higher than OSL- and IRSL-dose results. This is probably due to relatively easy-bleaching effects or unstable luminescence properties related to the OSL in quartz grains and well-known anomalous fading effects of feldspar grains. On the basis of these results, the RTL-luminescence ages, estimated using the accumulated doses and annual doses, are closer to the predicted archaeological ages. In conclusion, it was also confirmed here that the RTL-dating is most suitable dating-method when quartz extracts from burnt archaeological materials are available.