Tsukuba, Japan - Accelerator physicists and engineers at KEK, High Energy Accelerator Research Organization announced today (May 1, 2006) the successful acceleration of protons up to 100MeV at a repetition rate of 100Hz with a Fixed Field Alternating Gradient (FFAG) Synchrotron. The high repetition rate of acceleration had not been possible in any other type of accelerators before.
 
"FFAG proton synchrotron opens a door to the new type of research using it's rapid acceleration cycles," Yoshiharu Mori, professor of Kyoto University and of KEK, points out the uniqueness of the accelerator. "It was originally conceived by a Japanese physicist Chihiro Ohkawa in 1953, and has the merits of both traditional synchrotrons and cyclotrons. It enables the acceleration of particles to the desired energy with rapid cycles."
 
In the FFAG synchrotron, particles are accelerated within a finite range of orbits, using the strong focus mechanism of the synchrotron. What is unique about FFAG synchrotron is the field distribution of the bending magnets which control the orbit of the particles. In the traditional synchrotron, the required field strength should increase as the energy of the particles increases. In FFAG, the field strength stays constant. Because the strength of magnets need not change, faster acceleration cycle can be achieved.
 
"FFAG has many potential applications," says Hisayoshi Nakayama, professor emeritus of KEK. "It enables the scanning spot irradiation of proton on cancers. It can also be used for accelerating short lived particles such as muons, high flux protons for a neutron source etc."
 
"Without the development of new magnetic materials for the accelerating cavity, we would not have been able to achieve this goal," says Nakayama. "Which is why it took so long to build this accelerator after its original conception. We are looking forward to seeing further development of this new kind of accelerators."
 
FFAG synchrotron project at KEK has been funded by JSPS, Japan Society for the Promotion of Science. KEK is one of the Inter-University Research Institute Corporations funded by MEXT, Ministry of Education, Culture, Sports, Science and Technology.