INVERSE MAGNETRON INJECTION GUN FOR A COAXIAL 1.5MW, 140 GHZ GYROTRON

A 50 A electron gun with a beam power of 4.5 MW for a 1.5 MW, 140 GHz coaxial gyrotron has been designed, manufactured and tested. An axial rod close to the ground (anode) potential is surrounded by the cathode . The gun is of the diode type with no independent adjustment of the v elocity ratio alpha. Therefore only a low influence of the mechanical tolerances on a can be accepted. The beam properties have been measure d using scaled-down parameters. The experimental values of the velocit y ratio agree well with calculation. The measured velocity distributio n shows a transverse velocity spread delta beta(perpendicular to) less than or equal to 15%.