• Y. Iwata, T. Furukawa, K. Mizushima, K. Noda, T. Shirai, E. Takada, E. Takeshita
  NIRS, Chiba-shi
• T. Fujimoto, T. Kadowaki, Y. Sano, H. Uchiyama
  AEC, Chiba

Tumor therapy using energetic carbon ions, as provided by the HIMAC, has been performed since June 1994, and more than 5000 patients were treated until now. With the successful clinical results over more than ten years, we are constructing a new treatment facility. The new facility would have three treatment rooms; two of them have both horizontal and vertical fixed-irradiation-ports, and the other has a rotating-gantry-port. For all the ports, a scanning irradiation method is applied. The new facility is constructed in conjunction with the HIMAC, and heavy-ion beams will be provided by the HIMAC accelerators. To fulfill requirements for the scanning irradiation, we proposed multiple-energy operation with the quasi-DC extension of a flat top. With this operation, the beam energy can be successively varied within a single synchrotron-cycle, and therefore no energy degrader or the range shifter is required. The beam acceleration and extraction tests of the multiple-energy operation were successfully made. We will present the development of this operation as well as results of the beam acceleration tests.