The study of turn on/turn off gated MCP image intensifier

The gated image intensifier has two function, light gating and image enhancement. Coupled with a CCD device, it can constitute a high-sensitivity and high-speed image recording system, widely used in space and time resolved image diagnosis of inertial confinement fusion research. The photocathode gating voltage superimposed by the gate opening and closing time has a strong 'limiter' effect, which effects time within ns level, deeply affecting the image contour intensity profile in ns level time-resolved image diagnosis. This paper firstly analyzes theoretically the physical process leading the 'limiter' effect, and carried out a simulation calculation^[1]. Then some related experimental research was conducted. In the experiment, a pulsed laser with a wavelength of 532 nm and a pulse width of 300 ps is used as the light source. This experiment measures the opening/closing time of the image intensifier. The result shows that, the opening and closing time of the double tightly-stuck MCP image intensifier are approximately 1.8 ns; for electrical pulses with a half-width of nearly 20 ns, the exposure opening time of the MCP is about 30 ns, demonstrating that the pulse width and the actual exposure time exist a certain difference. Further theoretical analysis indicates that in order to obtain a below sub-ns resolved image, we need a single tightly-stuck MCP image intensifier or to increase the thickness of the conductive substrate to sacrifice fluorescence transmission ratio as well as using other technical approaches. (authors)