A 10.7-m Grazing Incidence Spectrometer for the Study of Highly-Ionized Atoms

A high-resolution grazing incidence spectrometer has been constructed for the purpose of analysing the spectra of highly-ionized atoms. The diameter of the Rowland circle is 10.7 m and the grazing angle can be varied from 0.5 to 1.0 degrees. The wavelength coverage is from 100 A down to several A. The characteristics of the spectrometer are described here in detail. The shortest wavelength observed in our light source is the 8.34 A line of Al Kα. The resolution is found experimentally to be better than 0.016 A at about 42.2 A, judged from two close lines of the Mo XVII spectrum taken with an entrance slit 3 µm wide and a grating of 300 grooves/mm. This spectrometer is used mainly as a spectrograph, but it can also be used as a monochromator.