The proposed National Heavy‐ion Laboratory will be provided with a multi‐stage accelerator system integrated with the existing Oak Ridge Isochronous Cyclotron (ORIC) facilities. The main accelerator stage is to be a four‐sector isochronous cyclotron that will provide beam energies up to 100 MeV/u. Ions may be injected into the large cyclotron from either a 20 MV tandem electrostatic accelerator or from the ORIC. The ion energies range from 100 MeV/u for oxygen to 10 MeV/u for uranium. Maximum beam intensities range from ∼ 1013 particles/second for oxygen to 2 × 1012 particles/second for uranium. The sector magnet angle for the cyclotron is 52° which yields radial and axial focusing frequencies of νr = 1.1 – 1.2 and νz = 0.6 – 0.8. The field‐radius product of the magnet is 3018 kG‐cm at a maximum magnetic field of 16 kG. The rf system is tunable over the range 6 – 14 MHz to accommodate acceleration on harmonics 2 – 11. Second harmonic resonators are provided to increase the phase acceptance and/or the energy resolution.The proposed National Heavy‐ion Laboratory will be provided with a multi‐stage accelerator system integrated with the existing Oak Ridge Isochronous Cyclotron (ORIC) facilities. The main accelerator stage is to be a four‐sector isochronous cyclotron that will provide beam energies up to 100 MeV/u. Ions may be injected into the large cyclotron from either a 20 MV tandem electrostatic accelerator or from the ORIC. The ion energies range from 100 MeV/u for oxygen to 10 MeV/u for uranium. Maximum beam intensities range from ∼ 1013 particles/second for oxygen to 2 × 1012 particles/second for uranium. The sector magnet angle for the cyclotron is 52° which yields radial and axial focusing frequencies of νr = 1.1 – 1.2 and νz = 0.6 – 0.8. The field‐radius product of the magnet is 3018 kG‐cm at a maximum magnetic field of 16 kG. The rf system is tunable over the range 6 – 14 MHz to accommodate acceleration on harmonics 2 – 11. Second harmonic resonators are provided to increase the phase acceptance and/or the ener...