Further investigations into the effect of charge imbalance on luminescence production

Previous experiments and modelling suggest that quartz and feldspar grains receive a net negative charge when irradiated with electrons. Here we used silt-sized grains of quartz and feldspar to investigate the behaviour of luminescence at very high electron doses, when electrostatic effects become possible. Both quartz and feldspar show an increasing luminescence response up to 700 kGy, after which we observe a non-linear decrease in luminescence with dose which eventually stabilises, in contrast to modelling predictions using charge imbalance. The presence of an electric field on the grains is investigated as a possible explanation for the non-linear decrease, using several electron energies. Charge leakage and de-stabilisation of the electron trap at high doses is also discussed.