Contribution of ESR dosimetry for irradiation of geological and archaeological samples with a 60Co panoramic source

A very precise dosimetry of a field of artificial irradiation is essential to estimate an accurate ESR Equivalent Dose (ED) in archaeology and geology. Archaeological powder samples and one sample of DL-alanine powder as control were prepared by IPH. Some alanine dosimeters of LMRI, constituted of L-alanine pellets, were joined to the IPH samples and together, irradiated in boxes using panoramic 60Co source under different experimental conditions. The LMRI had in charge the control of the process of irradiation and the measurement of each absorbed dose and dose rate delivered to the different series of boxes. This study consists in the evaluation of the distribution of dose on the samples. The ESR measurements made by the two laboratories were analysed and then compared. These experiments showed a significant gradient in the absorbed dose delivered to each LMRI dosimeter. The dispersion in each box was easily observable. However, a good agreement between the dosimeters and the alanine powder was observed in a same box.