Effect of alpha irradiation on the saturation characteristics of fine-grained quartz OSL

Abstract

A negative relationship has been reported for the characteristic saturation dose (D0) of the quartz optically stimulated luminescence (OSL) signal and the quartz grain size, of which the mechanism is still not understood. Here, the natural coarse-grained quartz samples (63–90 μm, 90–125 μm) are artificially ground into fine grains and the effect of alpha irradiation on the D0 values of the ground fine grains is investigated. The ground fine grains (4–11, 11–45, 45–63 μm) have similar D0 values as the coarse grains. Laboratory alpha irradiation is administered on the artificial 4–11 μm quartz fraction. The D0 shows an increasing trend with the amount of alpha irradiation; meanwhile, the proportion of the fast OSL component decreases and the proportions of the medium and slow components increase with alpha irradiation. The higher D0 after alpha irradiation may be a result of the higher proportion of electron traps related to the medium component. However, the increasing trend of D0 stops when the alpha dose reaches a certain amount, and the degree of D0 increase induced by alpha irradiation cannot fully account for the much higher D0 values of the fine quartz grains in nature.