Georges Bonani at the AMS conference in Zurich, 1984

Looking back at a long and creative career in radiocarbon dating of Dr. Georges Bonani, one can say for sure that Georges had all qualities needed to build the solid reputation of the ETH ¹⁴C laboratory. His background in physics (studies at ETH and his doctoral thesis (Bonani Reference Bonani1977) was essential to the development of the AMS by the team around Willy Wölfli (Bonani et al. Reference Bonani, Balzer, Hofmann, Morenzoni, Nessi, Suter and Wolfli1984a; Suter et al. Reference Suter, Balzer, Bonani, Hofmann, Morenzoni, Nessi, Wolfli, Andree, Beer and Oeschger1984; Synal et al. Reference Synal, Beer and Suter2021). The first applications were published in the early 1980s (Bill et al. Reference Bill, Keller, Erne, Bonani and Wolfli1984; Bonani et al. Reference Bonani, Satish, Wanner and Wolfli1984b; Giger et al. Reference Giger, Sturm, Sturm, Schaffner, Bonani, Balzer, Hofmann, Morenzoni, Nessi and Suter1984). Until 2012, i.e., when the transition to the AMS ¹⁴C analysis using MICADAS took place, Georges performed the demanding tuning of the EN 6 MV tandem for ¹⁴C analysis and data reduction. These would take place every 4 to 6 weeks, the time that Georges filled with talking to users, sampling unique objects and working on data, and sending the letters with results. His perfectly organized files are still my source of information whenever data produced 30 years ago has to be revisited. But the list of his involvement in our laboratory life is not ending there. He was always helpful with any questions. His problem-solving skills, so prominent with the EN tandem tuning, were appreciated in the group, and everyone could always count on his friendly support even with everyday issues.

Simultaneously, Dr. Bonani was one of the most cited scientists at ETH when the citation index started to be an important issue in the late 1990s. His involvement in studies which employed ¹⁴C dating was not only by providing the AMS analysis. Georges was actively involved in data analysis and interpretation of the results. Often, he was also involved in designing the sampling strategies and supported experimental and pioneering approaches such as dating pollen grains (Hauenstein Reference Hauenstein1994) and ¹⁴C dating of paint (unpublished data). He was extremely helpful during my PhD project when measuring macrofossil samples as small as 0.3–0.5 mg of carbon (Hajdas et al. Reference Hajdas, Ivy, Beer, Bonani, Imboden, Lotter, Sturm and Suter1993). In the early 1990s, that required a considerable effort, sometimes even manual running of the target to maximize the counts collected (targets were a flat disc). The experimentation was written into his “physicist’s DNA.” Moreover, Georges could often foresee the outcome and communicate it openly. Nevertheless, he would give his full support to all experiments if required by the project because he considered it a learning process.

Besides the remarkable work for archeology, especially Swiss archeology and climate research, Georges liked working with art. His office bookshelves were filled with publications, which included radiocarbon dating, for which he wrote short articles explaining the method. One must say that sometimes the experience had annoying consequences such as letters following the dating of the medieval textile known as the “Shroud of Turin” (Damon et al. Reference Damon, Donahue, Gore, Hatheway, Jull, Linick, Sercel, Toolin, Bronk and Hall1989). Georges was always calm and good-humored, just waved them away and continued his work. The most remarkable effort was put into dating Anatolian textiles. Georges worked with Jürg Rageth on the book. They showed the power of radiocarbon dating (Rageth Reference Rageth1997) applied to objects from the last 300 years (previously, the wiggles between mid-17th and mid-20th century were considered a huge obstacle). Georges’ interest in cultural heritage was contagious, and my projects dedicated to dating mortars and paintings are rooted in the first work by Bonani and Wölfli. They made the first excellent contacts with museums and art researchers as well as art connoisseurs. The most prominent samples, such as the Iceman found in the Alps (Bonani et al. Reference Bonani, Ivy, Hajdas, Niklaus and Suter1994), the “Bundesbrief” (the Swiss Charter), and the Dead Sea Scrolls (Bonani et al. Reference Bonani, Ivy, Wolfli, Broshi, Carmi and Strugnell1992) were radiocarbon dated at the ETH laboratory, which led to the media interest. The remarkable quality of the data produced in 1991 when dating the “Bundesbrief” is illustrated by the excellent agreement obtained using the modern AMS technique (Hajdas et al. Reference Hajdas, Synal and Wacker2019).

It was a privilege to work with Georges and learn from him about ¹⁴C dating. He was a mentor, a good colleague, and a friend. From the time perspective, I can say that I have never met someone like Georges, who lived his professional life so intently at the same time it was so clear that he was very much a family person. One of the examples was a wooden slab from a birch tree that grew near his family home in Brig (VS) in southern Switzerland. For years, Georges had it in his office to explain tree rings, but I like to think that it reminded him of his hometown. At some point, this wood was a subject in one of our many school projects. Georges retired fully in 2015, and our contacts were limited to occasional phone calls. He was always happy to hear about the projects of the lab. Unfortunately, Georges’ fragile health did not allow him to enjoy retirement time. He left us all too soon, but he is remembered by the radiocarbon community, and our thoughts are with his family.