Status and research programs of the multinuclide accelerator mass spectrometry system at the University of Tsukuba

摘要

We present the current status and research programs of a multinuclide accelerator mass spectrometry (AMS) system on the 12UD Pelletron tandem accelerator at the University of Tsukuba (Tsukuba AMS system), Japan. A maximum terminal voltage of 12 MV is available for the AMS system. The Tsukuba AMS system can measure environmental levels of long-lived radioisotopes of ~(14)C, ~(26)Al,~(36)Cl and ~(129)I by employing a molecular pilot beam. Recently, enhancements in AMS techniques and equipment, including sample preparation, the ion source and the data acquisition system, have improved the performance of ~(36)Cl-AMS. The standard deviation of fluctuations is typically ±2%, and the machine background level for the ~(36)Cl/Cl ratio is lower than 1 × 10~(-15) with a halite sample. We have measured over 500 samples in 1 year, including samples for earth and environmental sciences and nuclear safety research.