XPS and TOF‐SIMS applied to the study of ancient artifacts: Further studies on Alexandrian tetradrachms from the time of the Julio‐Claudian dynasty

• Published in: Surface and interface analysis Vol. 52; no. 12; pp. 1004 - 1010
• Main Authors: Sodhi, Rana N.S., Brodersen, Peter M., Zaccagnino, Cristiana
• Format: Journal Article
• Language: English
• Published: Bognor Regis Wiley Subscription Services, Inc 01.12.2020
• Subjects: Coins; Collection; Corrosion products; Historic artifacts; Photoelectrons; Secondary ion mass spectrometry; Spectroscopy
• ISSN: 0142-2421; 1096-9918
• DOI: 10.1002/sia.6830

Two tetradrachms from the Diniacopoulos collection housed at Queen's University are the subject of this study. Previously, a protocol had been developed for a coin of the Emperor Claudius from the same collection, which showed that a combination of Time‐of‐Flight Secondary Ion Mass Spectrometry (TOF‐SIMS), Energy Dispersive X‐ray Spectroscopy (EDX), and X‐ray Photoelectron Spectroscopy (XPS) could provide information and identify areas of interest for additional analysis, thereby minimizing the amount of damage incurred. This is now applied to two more tetradrachms issued by the same mint and dated respectively to the time of Tiberius (14–37 AD) and Nero (54–68 AD). Preliminary results have indicated both differences and similarities between these coins and that from the time of Claudius. By comparing these results, it is hoped that information as to how the coins were made can be elucidated, shedding light on the different components and composition of the alloys produced in the same mint but at different time periods. Moreover, the detection and the identification of corrosion products, along with understanding what restorations methods may have been applied in the past, can guide conservators to determine what conservation treatment and preservation strategies are most appropriate for these antiquities.