Evaluating short-term post-irradiation instability of radiation-induced ESR signals in quartz

This study investigates the potential short-term fading of radiation-induced Electron Spin Resonance (ESR) signals in quartz grains following gamma-irradiation, a critical issue for the optimization of Single Aliquot (SA) measurement protocols. Through a signal stability experiment carried out on two quartz samples, we evaluated the evolution of the Al and Ti ESR signal intensities over 2 to 8 months after gamma-irradiation. Our results indicate that the variation of the ESR intensities remains within typical experimental uncertainties, although data might also suggest a potential trend during the first day after irradiation. This trend is, however, non-systematic and could be sample- and signal-dependent, if not directly related to the stability of the experimental setup. Regardless, for precaution we may nevertheless recommend waiting for 1 day after gamma-irradiation before carrying out the ESR measurements. Importantly, this finding implies that ESR measurements of quartz samples can be performed relatively soon after gamma-irradiation, enabling the implementation of more time-efficient SAR protocols for ESR dating applications.