Patent ID: 7471053

Claim:
A multi-beam klystron apparatus comprising: an electron gun unit configured to generate a plurality of electron beams; an input unit configured to input radio-frequency power; a radio-frequency interaction unit configured to amplify the radio-frequency power, which is input from the input unit, by an interaction between the electron beams, which are generated by the electron gun unit, and a radio-frequency electric field; an output unit configured to output the radio-frequency power from the radio-frequency interaction unit; a collector unit configured to collect the electron beams which pass through the radio-frequency interaction unit; and a converging magnetic field device configured to include an electron-gun-unit-side magnetic field generating unit having a magnetic field generating element which is located around the electron gun unit and a magnetic pole which covers the magnetic field generating element and has a plurality of magnetic gaps in an inner peripheral surface thereof in a direction of travel of the electron beams, and configured to converge the electron beams generated by the electron gun unit.