Accurate dating requires calibration down to the last ion (Vol. 46 No. 3)

Accurate dating requires calibration down to the last ion
Illustration of the experimental setup used for calibrating irradiation

A new solution accurately counting the exact amounts of ions from laboratory radiation exposure helps to simulate the natural radiation of quartz samples used for thermoluminescence dating.

Thermoluminescence is used extensively in archaeology and the earth sciences to date artefacts and rocks. When exposed to radiation quartz, a material found in nature, emits light proportional to the energy it absorbs. Replicating the very low dose of background radiation from natural sources present in quartz is a key precondition for precise and accurate dating results. The authors have now developed a method to control the accuracy of the dose calibrations delivered to the samples during laboratory irradiation with heavy particles, replicating natural radiation exposure. Using oxygen and lithium ions from the Tandem accelerator at INFN LABEC in Florence, they found that their measurements were accurate to within 1%, despite large fluctuations in the irradiation beam.

L. Palla, C. Czelusniak, F. Taccetti, L. Carraresi, L. Castelli, M.E. Fedi, L. Giuntini, P. R. Maurenzig, L. Sottili, and N.Taccetti,, Accurate on line measurements of low fluences of charged particles, Eur. Phys. J. Plus 130, 39 (2015)
[Abstract]