Radiation-induced luminescence from quartz grains to evaluate naturally accumulated radiation doses

Radiation-induced luminescence, involving optically stimulated luminescence (OSL) and red thermoluminescence (RTL), was utilized to the evaluation of naturally accumulated dose using quartz grains. The purified quartz grains from coastal sands revealed the RTL properties with high dose-sensitivity, while the OSL offered poor dose-response. The luminescence was measured by an automated OSL/TL measuring system, installed with a small X-ray irradiator, using a single aliquot technique. The RTL-results gave the residual or naturally accumulated doses amounted to about 250 and 450 Gy for Kashiwazaki-Kariwa and Agano-river mouth regions, respectively. However, the OSL was resulted in negligibly weak intensity of natural luminescence. These background dose measurements based on natural luminescence from quartz grains will be preferable for the retrospective dose evaluation in the vicinity of nuclear facilities as well as in geological and archaeological fields. (author)