Self-Bleaching Effects of Radioluminescence on OSL-Responses of Natural Quartz Samples

Fujita, Hiroki; Hashimoto, Tetsuo*

11th International Conference on Luminescence and Electron Spin Resonance Dating (LED 2005), Book of Abstracts, p.68, P. 68, 2005/07

Radioluminescence (RL) phenomena can be observed from many insulating minerals including quartz during radiation-irradiation. The RL attracts much attention to the purpose of both the alternative dosimetry and the elucidation of luminescence mechanism.RL spectrum consists of two RL emission regions assigned to emission peaks at 400 (violet region) and 630nm (Red region) on natural quartz by using an on-line spectrometric system. Increment of RL intensities was observed by increasing dose rate. When the sample was irradiated beforehand, the RL emission intensities depended on the predoses. The above phenomena will lead to a possibility to determine doses using RL measurement. The RL emission peak at 400nm was almost close to stimulated wavelength (470nm) on optically stimulated luminescence (OSL)-measurements. Therefore OSL source would be stimulated by the RL emission wavelength. Overestimated or underestimated OSL-doses were occurred by measuring conditions (high- and low-dose rate), and quartz origins, compared with applied dose. The OSL-doses was related to violet-RL (V-RL) emission intensity but red-RL (R-RL). This result suggested that OSL source would be stimulated by V-RL emission within quartz grain. However, estimated doses by red-TL (RTL) and blue-TL (BTL) measurements were less or not affected by dose rate. These results imply that RL emission is more effective to OSL measurement than TL measurement.