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

Abstract

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.

Detectors and Cultural Heritage: The INFN-CHNet Experience

“…Combining the primary ion beam with a sputter ion beam (dual-beam mode) in repeated cycles, the in-depth distribution of elements and molecules can be also determined, with a nominal lateral resolution of less than 1 nm along the z-axis. In the last decade, ToF-SIMS technique was used in both the non-destructive (static) and destructive (dynamic) modes, taking advantage of the possibility of obtaining chemical maps of organic [281] and inorganic [282,283] materials with high lateral resolution. In the INFN-CHNet experience, ToF-SIMS was employed to investigate dyes and pigments, metal layers and plates, corrosion phenomena and degradation products on both inorganic and organic samples [284][285][286][287][288][289][290][291][292].…”