LBNL, Berkeley
Notre Dame University, Notre Dame
Funding: This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The DIANA project (Dakota Ion Accelerators for Nuclear Astrophysics) is a collaboration between the University of Notre Dame, University of North Carolina, Western Michigan University, and Lawrence Berkeley National Laboratory to build a nuclear astrophysics accelerator facility 1.4 km below ground. DIANA is part of the US proposal DUSEL (Deep Underground Science and Engineering Laboratory) to establish a crossdisciplinary underground laboratory in the former gold mine of Homestake in South Dakota, USA. DIANA would consist of two high-current accelerators, a 30 to 400 kV variable, high-voltage platform, and a second, dynamitron accelerator with a voltage range of 350 kV to 3 MV. As a unique feature, both accelerators are planned to be equipped with either high-current microwave ion sources or multi-charged ECR ion sources producing ions from protons to oxygen. Electrostatic quadrupole transport elements will be incorporated in the dynamitron high voltage column. Compared to current astrophysics facilities, DIANA could increase the available beam densities on target by magnitudes: up to 100 mA on the low energy accelerator and several mA on the high energy accelerator. An integral part of the DIANA project is the development of a high-density super-sonic gas-jet target which can handle these anticipated beam powers. The paper will explain the main components of the DIANA accelerators and their beam transport lines and will discuss related technical challenges.
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.
ETH/Ion Beam Physics Laboratory, Zürich
Accelerator Mass Spectrometry (AMS) provides instrumentation originally developed by nuclear physicists more than 30 years ago to measure long lived cosmogenic radionuclides such as 10Be, 14C, 26Al, 36Cl, 41Ca, 129I, U, Pu and Pa at natural levels. In the past ten years impressive progress in the measurement technique has been made and with the appearance of compact low energy radiocarbon AMS systems, a new category of AMS instruments has been introduced. This has resulted in a boom of new AMS facilities with more than 20 new installations over the last five years. But low energy AMS is not limited to radiocarbon only and there is a great potential for 10Be, 26Al, 129I and actinides measurements at compact AMS systems. The latest developments towards the low energy limit of AMS resulted in two new types of systems, the NEC Single Stage AMS (SSAMS) and ETH mini carbon dating system (MICADAS) operating with terminal voltages of about 200 kV only. In addition, systems like the HVEE 1 MV Tandetron or the compact ETH 600 kV system are capable to extent the range of applications at compact systems beyond radiocarbon. These systems will have enormous impact, not only on the use of AMS in biomedical research and on radiocarbon dating but also for research applications with 10Be, 26Al, 129I and actinides.
CIAE, Beijing
Guangxi University, Nanning
Funding: Supported by National Natural Science Foundation of China (10576040).
A new method was developed for AMS measurement of 126Sn. Major features of the method include the use of SnF2 as target material, the selection of SnF3- molecular ions for extraction form from the target, and the transmission of 126Sn beam current. A sensitivity of (1.92±1.13)×10-10 (126Sn/Sn) has been reached by measuring a blank sample.