Time resolving grazing incidence spectrograph with spatial resolution for plasma fusion diagnostics

In order to understand the confinement, impurity transport, and radiation loss mechanisms in a fusion plasma, it is important to know the spatial variation and time evolution of the plasma impurities which emit at characteristic EUV (extreme ultraviolet) wavelengths. For these reasons we are designing a grazing incidence spectrometer which can view 13 chords of a plasma simultaneously and also examine the time history of the species in a single shot. Existing instruments accomplish the spatial imaging by mechanically moving the spectrometer to view a different chord of the plasma per single shot and assume that the plasma is reproduceable from shot to shot. Moreover, the grazing incidence spectrometer will enable us to examine the spectra of the high Z ions in the 16 to 250 A region, a region that is becoming important for diagnostic purposes as tokamak plasmas reach higher temperatures. We are in the design and testing stage of a grazing incidence spectrograph with time and spatial resolution capabilities. The spectrometer is a grazing incidence ''Minuteman'' utilizing a 1200 l/mm holographic grating covering the region from 16 to 250 A. The detector system consists of an image intensifier and area array detectors. The detector system can be moved along the Rowland circle and achieves a simultaneous spectral coverage of 26 A when centered at 16 A and 80 A when centered at 250 A with 1 A resolution. The area array detectors can be read out in approximately 5 ms, thereby determining the time resolution of the instrument