High Performance Dispenser Cathode for the THz Clinotron Tubes

The research and development of thermionic cathodes for the clinotron tubes operating in millimeter and THz ranges resulted in fabrication of several types of electron emitters based on oxide cathode technology, L-cathode and dispenser cathode. Presented consideration of both advantages and disadvantages of these cathodes allows to optimize the electron optical system of the clinotron tubes of different frequency bands taking into account the requirements for the starting current, output power, radiation spectra etc. The development and application of the dispenser cathode, which emitter part consists of fine spherical powder composed of pure tungsten phase with favorable dispersity, allowed us to obtain the beam current density higher than 50A/cm(2) in the compact diode electron gun in the static magnetic field and to form the intense sheet electron beam with the current up to 200mA at the accelerating voltage up to 6kV.