FINEMET-core loaded untuned RF cavity

A testing machine for an untuned RF cavity loaded with FINEMET cores was fabricated to realize a wide operation frequency range and a high accelerating gap voltage. The cavity performance was examined in low and high power tests. The operation frequency range was widened to 0.5–10 MHz, where the voltage standing wave ratio (VSWR) was lower than 2. A heat-up test showed the cavity could induce an accelerating gap voltage of 200–300 V/core, only by forced air cooling. Applications of the untuned RF cavity to various kinds of synchrotrons are discussed, based on the results of the performance tests.