Single-Aliquot Regenerative-Dose (SAR) Protocol

The single-aliquot regenerative-dose (SAR) protocol is the measurement methodology that underlies modern optically stimulated luminescence (OSL) dating, providing the recipe by which the equivalent dose of a sediment sample is estimated from a single sub-sample. Its central problem is that exposing a mineral grain to light and radiation in the laboratory changes how brightly it luminesces, so a naive comparison of natural and laboratory signals is biased. Murray and Wintle's protocol solves this by measuring, after every luminescence readout, the response to a fixed small 'test dose' and using it to normalize for sensitivity change, so that natural and regenerated signals can be compared on a common footing. The aliquot's natural signal is then interpolated onto a regeneration growth curve to read off the equivalent dose, and a suite of internal checks — recycling, recuperation, and dose recovery — verifies that the procedure behaved correctly. Because the entire measurement is done on one aliquot, the protocol is efficient, reproducible, and the de facto standard for quartz OSL.