From Hiroshima to the Iceman: the Development and Applications of Accelerator Mass Spectrometry by Harry E Gove, Institute of Physics Publishing 07503 0557 6 (hbk £50/$99) 07503 05584 (pbk £15/$27).
Invented some 20 years ago, accelerator mass spectrometry (AMS) is one of the newer success stories in the applications of particle accelerators. It provides a powerful, fast and reliable means of measuring long-lived radio-isotopes using only minute samples.
Radiocarbon-14, which has a half-life of 5730 years, was the first isotope to be measured this way, and AMS radiocarbon dating soon became a powerful tool for determining the age of organic material using small samples. Other isotopes are also suitable for AMS.
Radiocarbon dating was invented by Willard Libby in the 1940s and brought him the 1960 Nobel Prize for Chemistry. In its original form, radiocarbon dating counted the actual decays of residual carbon14, requiring relatively large samples of material.
Jolted by news of carbon14 measurements at a Berkeley cyclotron, Gove participated in pioneer AMS measurements at Rochester in 1977, which dramatically showed how the level of carbon14 in commercial charcoal and fossil graphite is different, using milligram samples. It is usually no problem to take a milligram sample from even the most valuable relic.
Giving a reliable measurement of the age of a specimen can be vital input in archaeology, history and mineralogy, as well as being a focus of public interest. Such measurements can settle disputes and separate fact from myth.
One of the most spectacular AMS applications is the dating of the Turin Shroud, and Gove’s earlier book, Relic or Hoax?: Carbon Dating the Turin Shroud, is a scientific account of this work. Multiple AMS measurements gave the origin of the shroud material, widely believed to be of biblical origin, as AD 1325 ±33 years.
In his latest book, Gove casts the AMS net wider, describing the history and instrumentation of the technique, concentrating on electrostatic tandem accelerators, before turning to its application. The analysis examples, described in graphic detail, include radio-relics from Hiroshima and Nakasaki that provided new insights into the mechanisms of radiation damage; North American archaeological remains; modern radioactive waste; the Turin Shroud revisited; Egyptian mummies; “Oetzi”, the neolithic iceman discovered in 1991 in the Alps on the Austrian-Italian border; and the Dead Sea Scrolls.
For the dating of the Turin Shroud, one theory mentioned is that bacteria on cloth continue to ingest carbon14 from the air, making the cloth look younger.
This is a fascinating account of a major particle accelerator application success by an enthusiastic scientist who played a major role in its development. Harry Gove contributed an article on AMS to the special July 1995 Applying the Accelerator issue of CERN Courier.
