Stability of the quartz fast-component in insensitive samples

We report on experiments designed to test whether a quartz sample showing an insensitive fast component in the optically stimulated luminescence signal can be sensitised by repeated dose/bleach cycles without any heating. The luminescence characteristics of insensitive samples from the Tatra Mountains (Poland) are first contrasted with more typical material from Sweden and Russia. The effects on sensitivity of repeated dose/bleach cycles, including and not including heat treatment, are then presented. It is shown that such cycles do sensitise the fast component, but that most (but not all) of the increase produced without heat treatment is thermally unstable at preheat temperatures up to 260∘C. This is in contrast to the sensitivity increase produced by cycles including heat treatment, where most of the increase is thermally stable. Finally it is shown that the fast component discussed in this work is indistinguishable from that described in the literature. It is concluded that the considerable changes in sensitivity described in this paper are most likely the result of changes in luminescent recombination probability, rather than in trapping probability.