Picosecond framing camera based on electron pulse time-dilation

A dilation framing camera based on the gated microchannel plate (MCP) technology and the time-dilation technology was reported. In the camera, the photo-cathode (PC) was applied with a high voltage fast step pulse with gradient of 2.1 V/ps. The electron pulse generated at the PC was accelerated by a time varying electric field between the PC and the anode mesh, which leads to an energy dispersion of the electron signal. The electrons generated early in time obtain a larger energy. Therefore, the initial electrons transit the drift space between the mesh and the MCP at a higher velocity than those coming later. While the electrons travel through the 50 cm drift space to the MCP, the temporal shape of the electron signal was dilated or temporally magnified due to the time-dilation system. Then, the dilated electron pulse was detected by the gated MCP framing camera. Therefore, the temporal resolution of the framing camera was improved. The camera has three transmission photo-cathodes coated with 80 nm Au. The width of each PC is 8 mm. Both the PC and the MCP were applied with pulse, therefore the laser pulse, the PC pulse, and the MCP pulse should be synchronized accurately. The synchronized process was analyzed. While the PC was applied with dc bias only, the measured temporal resolution of the camera without time-dilation was about 78 ps. While the high voltage fast step pulse was applied on the PC, the temporal resolution was improved to 12 ps. The relationship between the temporal resolution and the synchronized point was also provided.