CONTROL METHOD OF CATHODE HEATING CURRENT OF HOTTCATHODE ELECTRON GUN

摘要

PURPOSE:To stabilize the electron beam emitted from electron gun and to lengthen the service life of cathode, by supplying the beam current measured by capacitor throtle to control circuit as input signal and operating the control circuit such that the beam current is constant. CONSTITUTION:Cathode current is set by cathode current control circuit 26 then the magnitude of beam current is fed back from capacitor throtle 28 to cathode current heating control circuit 25 to operate said control circuit such that the magnitude of beam current is constant. The magnitude of electron beam current is maintained constant even when the thining due to the disperse of cathode occurred, thereby the electorn beam is stabilized and the overheat of cathode is prevented resulting in the lengthening of service life of cathode.