Resolution and shutter profile measurements with point source inputs for a microchannel-plate image intensifier (MCPII) with a 160-ps FWHM whole-image shutter

The modulation transfer function (MTF) of a shuttered, 18-mm-diameter, proximity-focused MCPII was measured as a function of time in the shutter sequence. Electrical gate pulses were delivered to the MCPII with microstrip impedance transformers for reduced pulse dispersion and reflections. Using 30 ps FWHM, 600 nm pulses from a sync-pumped dye, argon-ion laser as a probe, the MCPII's shutter speed (off-off) for point-source (6-micrometers -diameter) illumination and 230 ps FWHM, -590 V gate pulses was measured to be <EQ 250 ps and the FWHM shutter was measured to be as low as 120 ps. The MTF of the MCPII was measured by analyzing the point spread function for inputs at several different locations on the MCPII and at different times in the shutering sequence. The best resolution, a 50% MTF of 16.2 lp/mm, was found with illumination near the edge where the gate pulse enters the MCPII and at 120 ps into the shutter sequence. The shutter speed (off-to-off) of the MCPII with a fully illuminated 18-mm-diameter photocathode was measured to be 270 ps and the FWHM was 160 ps.