PSI, Villigen
HMI, Berlin
A cyclotron based system for hadron therapy is developed, which allows a phased installation: start with protons and Helium ions and add Carbon ions later. The concept is based on an accelerator system of two coupled cyclotrons. The first cyclotron provides protons or He ions that can be used for the full spectrum of treatments and “low energy” C-ions, with a range of 12.7 cm in water for a subset of tumours and radiobiological experiments. For treatments at all tumor sites with C-ions, the C-ions can be boosted subsequently up to 450 MeV/nucl in a separate sector cyclotron, consisting of six sector magnets with superconducting coils and three RF cavities. First studies of the separate sector cyclotron indicate a relatively robust design with straight forward beam dynamics. This system is smaller than corresponding synchrotrons and possesses the typical advantages for therapy applications of a cyclotron. Present efforts to optimize the design of the superconducting sector magnets indicate that the introduction of a radial gradient in the sector would have many advantages.
