Thomas Athol Rafter

Thomas Athol Rafter

… although carbon dating was invented in the United States by the chemist Willard Libby, New Zealand scientists played a significant part in its early development. Particularly Athol Rafter is internationally recognised as one of the pioneers of the technique, and his publications form part of the core of radiocarbon literature.

Nuclear scientist Rodger Sparks recognises Athol Rafter’s contribution to radiocarbon dating in ‘Radiocarbon dating – New Zealand beginnings’, New Zealand Science Review, 61, 2 (2004)

Athol Rafter was one of New Zealand’s pioneering nuclear scientists, starting his career as part of Ernest Marsden’s post-war team of nuclear scientists and leading the DSIR’s Institute of Nuclear Sciences through the 1960s and 1970s.

Rafter was educated in Wellington, gaining an MSc in chemistry from Victoria University College in 1938. He worked as a schoolteacher until a job as a research scientist became available at the Dominion Laboratory in 1940. He initially concentrated on analysis of coal ash, but gained much acclaim when he worked with rock analyst Fred Seelye on a new method of analysing uranium-bearing minerals found in West Coast beach sands.

In 1948, following the establishment of a nuclear sciences team at the DSIR, Rafter was sent to the United States to train in radiochemistry and to visit nuclear establishments in the United States, Canada and England. On his return, he began to work with the new technique of radiocarbon dating, which dates organic material by comparing the ratio of radiocarbon atoms (carbon-14) to regular carbon atoms (carbon-12) with established radiocarbon:carbon ratios from the past. Rafter first used the method to date moa bones and ash showers from the North Island volcanoes. After difficulties with the process published by Willard Libby, radiocarbon dating’s American pioneer, Rafter worked with DSIR physicist Gordon Fergusson and their team to perfect a new and reliable method of radiocarbon dating using carbon dioxide gas rather than solid carbon.

In 1959, Rafter was appointed the inaugural director of the DSIR’s Institute of Nuclear Sciences, in Gracefield, Lower Hutt. In his new position, Rafter encouraged research into natural variations in radiocarbon levels, in the process discovering a link between atmospheric nuclear weapons tests and rising levels of radiocarbon in the atmosphere, a phenomenon he and Fergusson called the ‘Atom Bomb Effect’ when they published their results in 1957. Rafter also encouraged the use of naturally-occurring stable (non-radioactive) isotopes for geological research, developing techniques for use in geothermal and environmental studies.

After retiring from the DSIR, Rafter spent two years as director of the United Nations Environment Programme Monitoring and Assessment Research Centre in London. In 1993, the Institute of Geological and Nuclear Sciences marked Rafter’s 80th birthday by naming their radiocarbon dating facility the Rafter Radiocarbon Laboratory.  

By Rebecca Priestley

Medals and awards

OBE 1958

Further reading

Thomas Athol Rafter biography – Dictionary of New Zealand Biography website

Ross Galbreath, ‘Chapter 6: The Atom Bomb Effect’ in DSIR: making science work for New Zealand, Victoria University Press, 1998;

Rodger Sparks, ‘Radiocarbon dating – New Zealand beginnings’, New Zealand Science Review, 61, 2 (2004)

Image courtesy of GNS Science

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