Progress of studies on AMS and history of the Japan Society for Accelerator Mass Spectrometry

A cyclotron accelerator was first used as a sensitive mass spectrometer by Alvarez and Cornog in 1939 for mass-separation of contaminating backgrounds and measuring ³He abundance accurately. Since the study of measuring long-lived radioisotopes by Muller in 1977 using a cyclotron, techniques of accelerator mass spectrometry (AMS), using mainly a tandem Van de Graaff accelerator, have been extensively developed to measure low-abundance cosmogenic nuclides such as ¹⁰Be, ¹⁴C, ²⁶Al, ³⁶Cl, ⁴¹Ca, ¹²⁹I, etc., in natural samples. Most efforts to date have been directed to measurements of ¹⁰Be and ¹⁴C. In particular, developments of AMS have triggered a wide area of application in radiocarbon (¹⁴C) dating. The AMS system requires only 1 mg of carbon in precise determination of ¹⁴C/¹²C and ¹³C/¹²C isotope ratios, and this advantage has broadened the applicability of ¹⁴C measurements. Nowadays, AMS contributes to almost all kinds of researches that utilize ¹⁴C dating in archaeology, cultural property science, geology, and those that employ ¹⁴C tracer in environmental sciences, medical sciences and even forensic studies. Here the author briefly describes the beginning history of AMS, and summarizes the status of AMS research in Japan as well as in Korea and China. Perspectives of AMS in near future are discussed based on commercially produced AMS systems by the three main manufacturers, High Voltage Engineering (HVE), National Electrostatic Corporation (NEC) and Ion Plus. (author)