Performance of the double delay line microchannel plate detectors for the Far Ultraviolet Spectroscopic Explorer

The microchannel plate, delay line, detectors developed for the Far Ultraviolet Spectroscopic Explorer(1) mission to be launched in 1998 are described. The two FUSE detectors have a large format (approximate to 184mm x 10mm split into two 88.5 x 10mm segments), with high spatial resolution (<20 mu m x 50 pi m FWHM, >9000 x 200 resolution elements) and good linearity (+/-25 mu m), high image stability, and counting rates in excess of 4 x 10(4) events sec(-1). KBr opaque photocathodes have been employed to provide quantum detection efficiencies of 30-40% in the 900 - 1200 Angstrom range. Microchannel plates with 10 mu m pores and an 80:1 pore length to diameter ratio, with a 95mm x 20mm format have been used in a Z stack configuration to provide the photon amplification (gain = 2 x 107). These show narrow. pulse height distributions (<35% FWHM) even with uniform flood illumination, and good background levels (<0.3 event cm(-2) sec(-1)). Flat field images are dominated by the microchannel plate multifiber boundary fixed pattern noise and are stable.