DEVELOPMENTS IN THE MEASUREMENT OF ACTINIDES AND AT LLNL BY ACCELERATOR MASS SPECTROMETRY

The application of ultra-sensitive heavy isotope measurements continues to expand in a variety of fields relevant to the management of nuclear materials, including nuclear isotope forensics and radiobioassay. We have developed a heavy isotope accelerator mass spectrometry (AMS) system at Lawrence Livermore National Laboratory’s (LLNL) Center for Accelerator Mass Spectrometry (CAMS). The system was designed particularly for the measurement of actinide concentrations and isotopic ratios, but also allows the measurement of other heavy isotopes such as 129I. The system includes a fast isotope switching capability that allows flexibility in isotope selection and for the quasi-continuous normalization to a reference isotope spike. Current background levels for 239Pu and 240Pu are equivalent to