Multiple beam electron gun development for high-power amplifiers

A very attractive class of amplifiers that has the potential to provide high RF power at low beam voltage uses multiple electron beams rather than the single beam of conventional devices. These multiple beam amplifiers (MBAs) typically have individual beam channels with a common RF interaction region. A multiple beam klystron (MBK) illustrates the concept. In such a scheme, individual beamlets have parameters similar to those in conventional, single-beam amplifiers, while multiplying the output power by approximately the number of beamlets. The important result is that the operating voltage and space charge limitations for each beamlet are essentially unchanged, yet the output power can be much greater than that of a corresponding single-beam device. Furthermore, the overall high perveance characteristic of the MBA permits large bandwidth operation, while the low perveance of the individual beamlet enables high efficiency operation.