Speaker
Description
The JAEA Tokai Tandem Accelerator, at the Japan Atomic Energy Agency (JAEA), is one of the largest electrostatic accelerators in the world, with a maximum accelerating voltage of 20 MV. It has been in continuous operation since 1982.
In general, the advantages of a tandem accelerator include ion-species versatility, adjustable accelerating voltage, continuous beam operation, a small beam spot size, and a narrow energy spread. At the Tokai Tandem Accelerator, these advantages are further enhanced by the electron cyclotron resonance ion source (ECRIS) and by the experimental environment that allows the use of radioactive targets.
The ECRIS is installed in the high-voltage terminal and enables single-ended acceleration using positive ions, thereby realizing the acceleration of ion beams with high charge states and high beam currents. The ECRIS can provide noble-gas ions, molecular ions, as well as several metallic ions. Furthermore, because charge-state conversion is not required in single-ended acceleration, rapid changes in ion-beam energy are possible.
Such rapid adjustment of the accelerating voltage facilitates the acquisition of excitation functions and depth profiling of hydrogen using nuclear reaction analysis (NRA).
Another rare feature of the Tokai Tandem facility is the possibility to irradiate radioactive targets on several licensed beamlines. This, coupled to the ~1 mm beam spot size, enables meaningful experiments with extremely small target quantities, including radioactive targets such as ²⁵⁴Es at the 10 ng level.
In this symposium, we present these distinctive features of the Tokai Tandem Accelerator, together with recent trends in its utilization and future prospects.