ESR dating of optically bleached quartz grains: assessing the impact of different experimental setups on dose evaluations

The samples used in the present study have been collected from Bizat Ruhama site with the support of Y. Zaidner, from the University of Haifa, Israel. V.G. research stay in the Australian Research Centre for Human Evolution at Griffith University was funded by a Jose Castillejo Mobility Fellowship CAS18/00285 from the Spanish Ministry of Science, Innovation and Universities. Aspects of this study have been funded by the Australian Research Council Future Fellowship grant FT150100215 granted to M.D. ; In recent years, our investigation has been centred on improving the reliability and accuracy of the ESR method applied to quartz grains. As part of this ongoing investigation, we present an intra-laboratory study to evaluate the impact of different experimental setups on the ESR measurement precision and dose evaluation for ESR dating of optically bleached quartz grains. Repeated measurements of quartz samples have been performed at CENIEH, Spain, using two different Bruker spectrometers (EMXmicro and Elexsys E500) and resonators (standard rectangular ER4102ST and cylindrical Super High QE cavities). Their performance in terms of sensitivity, measurement repeatability and dose determination are presented in this study. This intra-laboratory work has allowed to evaluate the robustness of our protocol for ESR dating of quartz grains and to study the potential impact of different experimental setups on dose evaluation, which is essential for future standardization of the ESR dating method. Our results indicate that all the different experimental setups provide comparable precision of the ESR intensity measurements. Moreover, all the ESR dose estimates are within 1-sigma error, suggesting that it is possible to compare results obtained by different laboratories when similar analytical procedures are followed. Finally, the higher sensitivity achieved by the SHQE resonator appears to be of particular interest when dealing with samples showing low ESR signal intensities. ; Spanish Government CAS18/00285 ; Australian ...