Analysis for improvement of simultaneity of shuttering in an ultra high-speed framing camera

The authors suggest a method to improve the shuttering characteristics of an ultra high-speed camera that consists of a proximity focused image intensifier with a micro channel plate (MCP) and an external transparent electrode (ETE). Over a range of gating times of several tens of picoseconds, using this apparatus, there are two obstacles to the system's simultaneity, i.e., accuracy of photographing phenomena. First, the time required for the shuttering pulse to propagate on the electrode creates a time delay between different areas of the image photons passing through the ETE. Second, the photoelectrons do not reach the MCP simultaneously. If one attempts to speed-up the gating time using nonlinear operation of the MCP, the latter problem has an undesirable effect on the resulting image. The authors' proposal is to compensate for the latter problem and improve the simultaneity of the arrival time of photoelectrons at the MCP input surface by controlling the electric field between the photocathode and the MCP. This is achieved by optimizing the shape of the electrode. Further analysis by FDTD and an electron trajectory tracking method verified that the variance of arrival time is reduced from 30 ps to 5 ps with the altered electrode shape.