Ageing of AgCl/Cd nuclear track detectors monitored by luminescence spectroscopy

Solid-state nuclear track detectors, made of Cd doped AgCl crystals, are commonly prepared by rolling into the form of thin foils. Subsequent long-term relaxation is however needed to obtain good quality tracks. The present communication shows for the first time that this detector ''ageing'' is reflected in low-temperature (77 K) luminescence spectra. Maximum of the emission band shows a slow (lasting for ∼ 100 hours) blue shift, the magnitude of which (as much as 25 nm) depends on the compression ratio caused by the rolling. The shift is believed to be due to the rearrangement of Cd++ ions around freshly introduced dislocations. This finding opens the possibility of monitoring non-destructively the process of detector ageing and to determine the minimum time required for saturation. (author)