Improved computer program for magnetron injection gun design

Gyrotron has received extensive attention owing to its high-power capabilit y, especially when the wavelength shrinks below the millimeter-wave range. The electron beam of a gyrotron is typically generated by a magnetron injec tion gun (MIG). For high cathode current density, the MIG may operate in a region that combines temperature limited and space-charge limited emissions . An improved computer program for electron gun design is appropriate for M IGs that operate between space-charge limited and temperature limited emiss ion. Moreover, the initial input formation of the program resembles that of the EGUN code. Analysis of a Pierce electron gun and MIGs reveals that the simulated beam current appears consistent with the measured results. Howev er, EGUN simulation results in which the cathode emitters of MIGs are chose n for the temperature limited emission differ from those of our simulation results. This difference is most likely owing to that the initial emitting energy can not be completely described in the EGUN simulation. Finally, the improved computer program is used to design a MIG for a Ka-band, TE01 mode gyro-TWT.