UTTAC University of Tsukuba, Tsukuba
KEK/RSC, Tsukuba
Tokyo University/MALT, Tokyo
Funding: Work supported by Grants-in-Aid for Scientific Research Programs of the Ministry of Education, Culture, Sports, Science and Technology, Japan.
The 12UD Pelletron tandem accelerator was installed at the University of Tsukuba in 1975. In recent years, the main research field of the 12UD Pelletron tandem accelerator has shifted to accelerator mass spectrometry (AMS) research from nuclear physics. AMS is an ultrasensitive technique for the study of long-lived radioisotopes, and stable isotopes at very low abundances. The high terminal voltage is an advantage in the detection of heavy radioisotopes. It is important for sensitive measurements of heavy radioisotopes that background interference of their stable isobars are suppressed by AMS measurements. With the multi-nuclide AMS system at the University of Tsukuba (Tsukuba AMS system), we are able to measure long-lived radioisotopes of 14C, 26Al, 36Cl and 129I by employing a molecular pilot beam method that stabilize the terminal voltage with 0.1% accuracy. Much progress has been made in the development of new AMS techniques for the Tsukuba AMS system. As for 36Cl AMS, 36Cl9+ at 100 MeV is used for AMS measurements. The standard deviation of the fluctuation is typically ± 2%, and the machine background level of 36Cl/Cl is lower than 1 × 10-15. This report presents the overview and progress of the Tsukuba AMS system.
