The RF Ferrite-Testing Program at NAL

Investigations at NAL on ferrite disclosed a time dependent RF loss phenomenon occuring only at high power. Ferrite toroids of two manufacturers were tested to obtain enough cores of adequate power-handling capability for both the Booster and Main Accelerator cavities. The central portion of the test apparatus was a half wave coaxial cavity impedance matched to a 5kW power amplifier. The core selection criteria for Booster and Main Accelerator tuners differed and is discussed. Tuners assembled with the selected cores have operated satisfactorily at R. F. levels above 1OOkVA per core.