Cold cathode realization for triode electron gun

Summary form only given. The possibility of use cold cathodes as an electron source in vacuum tube device has been already demonstrated [1]. Using cold cathodes instead of thermionic ones could have many advantages [2], in particular it can increase the efficiency of the tube system since the power consumption of the cathode heater is neglected. For the realization of electron gun with cold cathode an extracting grid near the field emitters is necessary in order to obtain current emission.