Implementation of the ORIC Magnetic Field Measurements

The experimental details and methods employed in an extensive remapping of the magnetic field of the Oak Ridge Isochronous Cyclotron (ORIC) were reported previously. The medium- to high-field data (from 12 to 20 kgauss) have been Fourier analyzed and each of the coefficients parameterized in terms of the currents in the main coil, trim, harmonic and valley coils and the average field at each of the radii at which measurements were made. By inclusion of the average field in the formulation, the nonlinear effects of the iron are implicitly taken into account. This procedure has reduced the overall size of the data base by a factor of 100. Synthesis of the field from this parameterization reproduces the absolute field to within 10 gauss and the relative field to within 5 gauss. A field optimization program, which incorporates these results, is currently under development in an effort to enhance the heavy ion acceleration capabilities of the cyclotron and as an aid in the development of new beams.