Radiocarbon determinations using a minicyclotron: Applications in archaeology

The first international minicyclotron AMS facility has been brought into ro utine operation after many years of effort. The mass resolution of this dev ice is greater than 3000, and the precision of isotopic ratio measurements is 1%. The age limit for C-14 dating is about 42,000 yr BP. We have used th e International Oxalic Acid Standards together with geological and archaeol ogical samples of known age as cross-checks, to evaluate the precision and accuracy of the machine: All of the cross-check results agree within two st andard deviations. The performance of the machine has achieved the level of routine dating normally achieved by Tandem accelerators. The authors have used this new technique to provide a chronology for metallurgical relies in Ruichang, Janxi province. The results obtained provide significant proof f or the existence of an extensive copper mining and refining industry which was 500 years earlier than previously thought. (C) 2000 Elsevier Science B. V. All rights reserved.