Optical streak camera with gated photocathode

In order to meet the demand for high signal-to-noise ratio and low-noise optical streak camera in inertial confinement fusion (ICF) physical experiment diagnosis, a cathode-gated optical streak camera with six electrodes streak image tube was developed. To suppress the camera noise, a method that loading DC high voltage while superimposing gated high voltage pulse to the photocathode was used. In this way, the streak image tube of the camera was in the normal working state only during the gated pulse loading time, and the electrons emitted by the cathode could be normally focused and scanned. When the control pulse was not loaded, the voltage at the second focusing electrode could be lower than the cathode voltage, so that the photoelectrons emitted by the cathode would be reversely cut off. Therefore, the camera only measured the useful signals that arriving within the gated pulse loading time, thereby effectively suppressing the background noise introduced by the optical streak camera irradiated by ambient light, and improving the camera's signal-to-noise ratio. The verification experiment shows that by loading the gated pulse voltage with amplitude of − 5.5 kV and pulse width of 203 ns on the cathode, the camera noise can be greatly reduced, and the spatial resolution of the camera can be maintained.