SPACE-RESOLVING FLAT-FIELD VACUUM-ULTRAVIOLET SPECTROGRAPH FOR PLASMADIAGNOSTICS

A spatial imaging vacuum ultraviolet (VUV) spectrograph has been const ructed for simultaneous observation of spatial and spectral distributi ons of plasma radiation in the wavelength range 150-1050 angstrom. The spectrograph consists of an entrance slit of limited height which pro vides spatial resolution, an aberration-corrected concave grating with varied spacing grooves which gives a flat-field spectral output plane , and an image-intensified two-dimensional detector system. The basic characteristics of the spectrograph have been investigated by ray-trac ing calculations. The expected performance has been confirmed through experiments using a dc glow discharge source on the recirprocal disper sion, the spatial resolution, or the incident angle dependence of spec tral images. VUV spectra with spatial and time resolution have been ob tained successfully in the GAMMA10 tandem mirror experiment.