Combined device for vacuum electron diode adjustment

The article describes a principle, design and test results of a device for simultaneous capture of electron beam current ejected through an anode and optical image of a cathode surface. The device was tested on “ASTRA-M” pulsed electron accelerator (TPU, Russia) with the following parameters: 300 kV, 0.6 kA and beam current duration of 150 ns (FWHM). Light emission points have been registered for several individual emitters of the tested cathode. CMOS optical sensor of the device provides PC compatibility and detection of disturbances in the cathode or vacuum diode operation for single pulses and in burst mode. The efficiency of electron beam current ejection can be also estimated during vacuum diode adjustment. Detailed cathode images captured by photographic film include both frontal and angle (circular) projections of the cathode surface and can be used to study processes in the accelerating gap.