The collective interaction klystron (CIK)

The authors describe the fundamental principles of the CIK and summarize the results of an experimental study of a proof-of-principle (POP) version of the device. the CIK is a microwave amplifier which utilizes circular orbit effects to strongly bunch electrons. The CIK has several important features which make it an attractive source, including high efficiency, a compact geometry, a very modest magnetic field requirement, and the potential to achieve ultra-high power levels. The experimental results are quite encouraging, given the limited beam quality and other constraints of the prototype device. The experiments have validated many of the theoretical predictions, such as the scaling of gain with beam energy and the advantage of alternating-field focusing and have provided strong evidence that the negative-mass instability is responsible for the observed gain. The observed frequency and phase stability of the output indicate that the CIK is a viable amplifier.<>