A new version of an intensified charge-coupled device(ICCD)system

which is based on the incorporation of a CsI mesh photocathode and a thinned backside-illuminated CCD into a Space Telescope design Digicon tube

is being developed for future use in spacebased observations in the Extreme Ultraviolet waveband. In this paper

we report the results of computer simulations involving the effects of the nan-uniform electrostatic field near the mesh photocathode on imaging properties(especially

the spread function and modulation transfer function) of the detector system. The results are of importance in the design of the front end of the tube and the selection of optimum tube operating conditions. The overall resolution characteristics of the tube

including the effects of the mesh

the electron optics of the region between the mesh photocathode and the CCD target

and the structure of the CCD itself

are estimated.