title: Multichannel grazing-incidence spectrometer for plasma impurity diagnosis: SPRED.
abstract: A compact vacuum ultraviolet spectrometer system has been developed to provide time-resolved impurity spectra from tokamak plasmas. Two interchangeable aberration-corrected toroidal diffraction gratings with flat focal fields provide simultaneous coverage over the ranges 100-1100 A or 160-1700 A. The detector is an intensified self-scanning photodiode array. Spectral resolution is 2 A with the higher dispersion grating. Minimum readout time for a full spectrum is 20 msec, but up to seven individual spectral lines can be measured with a 1-msec time resolution. The sensitivity of the system is comparable with that of a conventional grazing-incidence monochromator.
authors.affiliation: Princeton University, Plasma Physics Laboratory, Princeton, New Jersey 08544, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Fonck
authors.forename: A T
authors.initials: AT
authors.lastname: Ramsey
authors.forename: R V
authors.initials: RV
authors.lastname: Yelle