Isochronization Studies of the IUCF 200 MeV Cyclotron

A non-intercepting movable beam phase probe recently installed in the south valley of the IUCF 200 MeV isochronous cyclotron has been used to study the relative beam phase variation during acceleration for the various beams accelerated by the facility. Small differences between the measured phase histories and the predictions of the field map data were observed and explained. Phase compression during acceleration has been measured, and a method for making rapid small energy changes (± 500 keV) while operating on a single RF frequency using trim coil adjustments at large radius has been developed. These and other consequences of the isochronization studies are discussed.