Sample preparation
The preparation procedure was carried out in subdued red light to avoid bleaching effects.
To eliminate the beta dose contribution from the soil, we removed about 3 mm of the pottery’s outer surface.
Then drilled the sample until we obtained an adequate quantity of powder (about 250 mg).
Calcite grain are removed with hydrochloric acid (10% HCl) and organic material was removed by using oxygen peroxide (10% H2O2).
We wash the product in acetone and then wait for 2 min. for a 60 mm column.
We take the suspension and wait for 20 min for also 60 mm column to obtain the grain size range of 1–8 μm for the fine-grain technique.
The separated grains are then allowed to deposit on aluminium discs placed at the bottom of individual flat-bottomed glass tubes.
The grains form a thin layer of a few μm thickness.
Then we put them in an oven to evaporate the acetone. The discs are then placed, in the RISØ set, on the heater plate using tweezers (Aitken, 1985).