Combining non-destructive nuclear techniques to study Roman leaded copper coins from Ilipa (II–I centuries B.C.)

A set of 32 bronze coins (II–I centuries B.C.) from the Roman city of Ilipa Magna (present-day Alcalá del Río, Seville) have been analyzed by means of non-destructive techniques. These coins are classified in different series according to their numismatic characteristics. They are very interesting from the archaeological point of view because a freshwater fish is depicted on the obverse (unusual in Mediterranean Cultures) and a spike on the reverse (also unusual but frequent in the South of the Iberian Peninsula). A comparative study has been made by PIXE (Proton Induced X-ray Emission) and XRF (X-ray Fluorescence) both corrected by GRT (Gamma Ray Transmission) in order to avoid the polishing of the coins. The results show that after the correction with GRT both independent methods give compatible concentrations for all of the coins that can be assumed as the actual bulk compositions . The average concentrations of the different series have been calculated and they could help to classify the series of coins chronologically.