OCCAM researchers apply modern surface spectroscopies to the study of ancient artifacts in unique cross-disciplinary collaboration

Following the acquisition of a portion of ancient pieces, including 627 Roman and Greek coins, from the Diniacopoulos collection of antiquities in 2001, researchers at Queen’s recently prioritized the coin’s classification and authentication. So far, of the small number of coins verified, most have been identified to have been minted in Alexandria, Egypt. For such authentication purposes, a wide range of instrumental analytical techniques representing nondestructive, micro-destructive, and destructive techniques have been applied to the study of ancient coins and other artifacts. However, the techniques utilized for the aforementioned processes only yield elemental composition. Therefore, as the coins in question once belonged to the Diniacopoulos family who were also restorers of antiquities, identifying evidence of past restoration/conservation treatments including the presence of coatings is of high interest. Furthermore, it would be of high value to come up with an innovative technique that does not result in coin destruction.

Recently, researchers at U of T’s Ontario Centre for the Characterization of Advanced Materials (OCCAM) Dr. Rana Sodhi, Dr. Peter Brodersen, and Research Technologist Sal Boccia collaborated with Queen’s University Professors Amandina Anastassiades and Cristiana Zaccagnino to assess the viability of utilizing a combination of specialized surface analytical methods, namely, time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS) in conjunction with energy dispersive Xray analysis (EDX). They managed to obtain ample information results from the selected sample of ancient coins while minimizing the inevitable amount of damage, which would occur if destructive analysis was performed. Their work is currently published in Journal of Vacuum Science & Technology B.

Ontario Centre for the Characterisation of Advanced Materials (OCCAM) is a unique facility providing enabling information for a wide array of applications covering the many disciplines involved with advanced materials. Located in the Departments of Chemical Engineering & Applied Chemistry and Materials Science & Engineering, University of Toronto, OCCAM has maintained its leading-edge capabilities after several successful CFI Leading Edge Fund applications. OCCAM actively caters to both academic and industrial needs by providing solutions to key problems as well as for research and development. Fostering collaboration between universities and industry, OCCAM allows for interactions that traverse the traditional boundaries between science, engineering, medicine and beyond.

The cross-disciplinary nature of the proposed collaboration in combining modern surface analytical techniques to the study of ancient artifacts was of great interest to Dr. Sodhi and his colleagues at OCCAM – Peter Brodersen and Sal Boccia. They saw the opportunity to devise a protocol, utilizing a combination of Time-of-Flight Secondary Ion Mass Spectroscopy, X-ray Photoelectron Spectroscopy and  Energy Dispersive X-ray analysis, by which the most information could be obtained while minimizing the amount of damage that would inadvertently be incurred in such an analysis. The work was presented at SIMS XXI (21st International Conference on Secondary Ion Mass Spectrometry) held in Kraków , Poland September 2017. This is a work-in-progress, with 2 further tetradrachms dated respectively to the time of Tiberius (14-37 AD) and Nero (54-68 AD) currently under investigation.

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