Orbit analysis for the RIKEN superconducting ring cyclotron

An "RI beam factory" has started to be contracted as the next project of the RIKEN Accelerator Research Facility (RARF). The "RI beam factory" aims at production and acceleration of radioactive isotope beams covering the whole mass region. It requires the energy of ion beam to be higher than 100 MeV/nucleon. To accomplish this requirement, the following two ring cyclotrons have been adopted as post-accelerators of the existing RIKEN ring cyclotron (RRC): a 4-sector ring cyclotron for the first stage (IRC) and a 6-sector superconducting ring cyclotron for the second stage (SRC). The sector magnet of the SRC has to be flexible enough to generate isochronous fields in a wide range of energies and for various q/A values. In this report we describe the isochronous field generation and orbit analysis of the SRC.