The NRL Cyclotron Ion Optics System

A 9 foot radius, 135 degree, double focusing magnet, having a second order energy resolution less than 2 × 10-4 for 1 mm slits, is the principal element in the NRL Cyclotron Ion Optics System. A 21.5 inch wide pole face and 4.75 inch gap provide radial and axial acceptance angles of 3.0 degrees and 1.3 degrees respectively. This 80 ton magnet can be remotely traversed on a tracking system making it possible to bring the energy-analyzed beam into either of two experimental vaults for use along 8 different beam paths. Also described is the coupling of quadrupoles with the analyzing magnet in a manner that provides a minimum dispersion system when the full cyclotron beam intensity is desired on the experimental target. Ray-tracing calculations have been performed to determine the properties of the composite ion optics system, and the influence on image quality of power supply fluctuations and quadrupole misalignment. The design criteria for the system, the calculational methods used in the ray-tracing programs, and the results of ray-tracing along typical paths is discussed.