The HVEE Tandetron AMS system at Nagoya University

In 1996/97, we installed a second-generation AMS system (model 4130-AMS) manufactured by HVEE, B.V., The Netherlands. Although we encountered a lot of problems during the installation and tuning up of the machine, our new system has now reached good stability and reproducibility in performing C-14/C-12 and C-13/C-12 measurements. According to the reproducibility tests conducted in January 1999, where six graphite targets prepared from HOxII standard material were measured, the standard deviation for C-14/C-12 reproducibility is around 1.6 parts per thousand (comparable with counting statistics) and that for C-13/C-12 is 0.28 parts per thousand. The background level of the AMS system was measured using a pure graphite (commercial graphite rod). It lies between 50 and 55 ka BP. We are still on the way to reduce the background. However, we are now prepared to start routine measurements of unknown-age samples. (C) 2000 Elsevier Science B.V. All rights reserved.