Status report of JAEA-AMS-TONO: Research and technical development in the last four years

Abstract

The JAEA-AMS-TONO facility at the Tono Geoscience Center, Japan Atomic Energy Agency has two accelerator mass spectrometers (AMSs): JAEA-AMS-TONO-5MV and JAEA-AMS-TONO-300 kV. The JAEA-AMS-TONO-5MV has a 5 MV Pelletron™ accelerator (15SDH-2, National Electrostatics Corp., US) and was installed in 1997. The JAEA-AMS-TONO-300kV is a state-of-the-art multi-nuclide AMS with a 300kV Tandetron™ accelerator (4103Bo-AMS, High Voltage Engineering, Europa B.V., Netherlands) and was installed in 2020 in response to an increase of samples. The AMSs have been used to measure radiocarbon, beryllium-10, aluminium-26 and iodine-129 in geological samples in studies on long-term geological stability as a basic research and development related to the geological disposal of high-level radioactive waste. Recently, test measurement of chlorine-36 using the JAEA-AMS-TONO-5MV are proceeding. Furthermore, we are currently promoting the development of techniques for isobar separation in AMS and for sample preparation. To remove isobaric interference, fast ion surface channeling is applied and a prototype for downsizing of the AMS based on this technique has been built. Also, small sample graphitization for 14C has been attempted by using an automated graphitization system (AGE3, Ionplus, Switzerland) equipped with an elemental analyzer (Vario Micro cube, Elementar Analysensysteme GmbH, Germany).