Investigation of Large Format Microchannel Plate Z Configurations

The performance of triplet (Z) stacks of microchannel plates (MCP's) has been studied as a part of the instrument development for the Extreme Ultraviolet Explorer [1] (EUVE) satellite mission. Relatively large MCP's with a 60 mm diameter and having an 80:1 channel length to diameter (L/D) ratio were used in several configurations. These have been used in the EUVE prototype imaging detector to provide > 512 × 512 pixels with low image distortion (< 1%). We have examined the gain and pulse height characteristics showing that both high gains (> 2 × 107) and tight output pulse height distributions (< 30% FWHM) may be achieved. Simple distribution techniques have also allowed low intrinsic background event rates (< .15 events cm-2 sec-1) to be obtained. Variation of the quantum efficiency of MCP's over the wavelength range 160 Å to 1216 Å has been investigated for a range of angles of incidence. The effect of temperature variations on MCP operating characteristics has also been evaluated.