Design of a multi-beam electron gun for high power S-band Klystron

In multi-beam Klystron (MBK), several electron beams are used to interact with the r.f. signal in a single interaction structure. MBK has a number of advantages over single beam klystron. As it uses several low perveance beams, for the same overall perveance, the beam voltage is substantially lower than single beam klystron for same DC input power. This leads to possible increase in pulse length, increased reliability of the HV power supply, fewer risks of gun arcing and smaller size at a given power level. The lower perveance of individual beams also results in higher efficiency. Design of multi-beam electron gun is a critical task in MBK, due to focusing required for multiple beams in a single interaction structure. The present paper shall discuss the design of a four beam electron gun using TRAK and MAGIC codes.