VERY HIGH-SENSITIVITY EXTREME-ULTRAVIOLET SPECTROMETER FOR DIFFUSE-RADIATION

A compact instrument to measure the diffuse extreme ultraviolet backgr ound with unprecedented resolution and high sensitivity is described. The instrument can cover a bandpass from 350 to 1100 Angstrom, has sim ilar to 5 Angstrom spectral resolution, and has simultaneous field ima ging with similar to 5' resolution. Several new techniques were employ ed to achieve this performance, including the development of a unique, fast optical system optimized for diffuse spectroscopy, a novel low-n oise microchannel plate photon detector, a mechanism that permits an a ccurate determination of all the expected backgrounds, and an electron ic system with active baseline restoration and coordinate digitization that is free of differential nonlinearity. This instrument will provi de a factor of 1000 increase in sensitivity over existing measurements with reasonable observing times.