A wide tuning range RF cavity with external ferrite biasing

A wide tuning range RF cavity with external quadrupole ferrite biasing was successfully built and has been in operation in the Indiana University Cooler Synchrotron Ring. The new biasing scheme was proposed by S. Papureanu and allows a large number of turns on the biasing coils. Large ampere-turns achieving a strong biasing B field can therefore be achieved by a power source of much smaller current rating. The external biasing also makes the RF cavity design straightforward, eliminating biasing structure related parasitic effects, such as hard to predict high order modes