Energy distribution of electrons from cathode in magnetron injection gun

Triode type magnetron injection gun produces an annular electron beam in the presence of the external magnetic field through the thermionic emission from the cathode. A good quality electron beam emission can enhance the performance of a gyrotron device. This paper reports the normal energy distribution under the applied electric field and the Schottky emission effect on the rate of thermionic emission. Computational analysis has been carried out with the gyrotron design constraints and the three region model to evaluate the tunneling coefficient with the inclusion of field and Schottky emissions. The Fermi Dirac distribution has been adopted to derive the expression for the rate of electron emission.