The RF Cycle of the PIMMS Medical Synchrotron

This paper presents the design of the RF cycle of the medical synchrotron of the PIMMS (Proton-Ion Medical Machine Study) hosted at CERN. The cycle comprises adiabatic trapping, acceleration and RF gymnastics, for either protons or fully stripped carbon ions. The injection energy is 20 MeV for protons and 7 MeV/u for carbon. Maximum extraction energies are 250 MeV for protons and 400 MeV/u for carbon ions. The cycle duration is less than 1 s, with a maximum magnetic field ramp below 3 T/s. The simulations show that the beam stays inside the aperture of the machine, and that, theoretically, there are no longitudinal losses. At the end of the cycle, the beam is ready for extraction with a Dp/p = 0.4 %. The peak RF voltage is 3 kV and the frequency ranges from 0.4 to 3 MHz.