Development of an imaging vacuum-ultraviolet monochromator in the normal incidence region

An imaging vacuum-ultraviolet monochromator has been developed to provide the space-resolved impurity line emissions from magnetically confined plasmas. With minor modifications of a commercial normal incidence monochromator, a pinhole entrance slit and a microchannel plate detector displaced away from the exit slit, the instrument performs two-dimensional spectroscopic observations in the wavelength range from 400 to 2000 A. Ray tracing has been performed to understand the spatial imaging properties in the practical geometric configuration. The measured spatial resolution is about 0.5 and 1 mrad in dispersion and vertical plane, respectively, with the entrance slit of 0.1 mm width and height. The results of the testing experiments and the measurements carried out on the JIPP T-IIU tokamak plasma are presented and discussed. copyright 1996 American Institute of Physics