SUBNANOSECOND OPTICAL GATING USING COAX CABLE INPUT MICROCHANNEL PLATE IMAGE INTENSIFIER

Proximity focused microchannel plate image intensifiers (MCPIIs) with a mesh underlay photocathode are analyzed for their irising time, whic h is found to be of the order of 650 ps. This is much longer than prev iously reported but is finally explained by the mesh thickness. The re duction of this effect requires further investigation. A newly introdu ced impedance match has real broadband characteristics, and the irisin g is fully caused by other effects. The minimum gate time observable w as clearly below 1 ns. The mesh underlay MCPII did not open to ifs ful l diameter at the shortest applied times. The long laser diode pulse a nd a too flat voltage slope of the driving generator prevented exact r esults for subnanosecond timing. Continued development of the system i i; underway. (C) 1998 Society of Photo-Optical Instrumentation Enginee rs.