BAC method of increasing the efficiency in klystrons

The method BAC that allows increasing the efficiency of klystrons up to 80% on a short length of interaction space is proposed. It includes several series of bunching (B), alignment velocity spread of electrons (A) and collecting particles-outsiders (C). Comparisons of traditional bunching and the BAC bunching are carried out. First comparison is 2 devices in S-band with same length - BAC method leads to 10% increase of efficiency. Second comparison is 2 devices in L-band with same efficiency - BAC method leads to 2 times diminishing of the length of the interaction space.