High-resolution concave grating grazing incidence spectrometer for the spectral region of ultrasoft x rays

Abstract

A concave grating grazing incidence spectrometer with a new type scanning device has been built for high-resolution spectroscopy in the ultrasoft x-ray region. The radiation source used consists of a high power x-ray tube with rotating anode permitting one to study emission spectra in fluorescence as well as absorption spectra. The spectometer is equipped with curved slits to achieve optimum performance with respect to resolving power and luminosity. Entrance slit and grating are kept fixed under operation, the exit slit and detector assembly is mounted on cross-stacked carriages driven by computer-controlled stepper motors. By appropriate computer programming the exit slit can be made to follow any focal curve. The system thus permits the use of gratings with different radii. Absolute wavelength determination capability is also provided. First results concerning emission as well as absorption spectra are presented.