SPACE-RESOLVED EXTREME-ULTRAVIOLET (XUV) SPECTROSCOPY USING A TOROIDAL MIRROR

In order to collect radiation from a distant light source and to compe nsate astigmatism, a toroidal mirror is often placed in front of a gra zing-incidence spectrograph. In this study, characteristics of space-r esolved spectra obtained with such a system have been investigated usi ng a ray-tracing analysis. The following was found: in the stigmatic f ocal region of the spectrum, the spatial resolution along the sagittal direction is excellent but that along the meridional direction is poo r; on the other hand, in the astigmatic wavelength region, the trend i s reversed, i.e., the spatial resolution along the sagittal direction is poor but that along the meridional direction is good, particularly in the wavelength region which is far from the stigmatic focus. The me thod was successfully applied to the space-resolved spectroscopic stud y of a capillary discharge plasma. (C) 1995 American Institute of Phys ics.