GeV Electron Accelerator Research Articles

Physics with a GeV-electron accelerator

Physics with a GeV-electron accelerator

A Grazing Incidence Vacuum Ultraviolet Monochromator with Fixed Exit Slit

A new monochromator with parallel incident light, a fixed exit aperture, and higher order rejection properties has been built and tested with the 7.5 GeV electron accelerator DESY which was used as a synchrotron light source. The parameters of the instrument are chosen to match the source characteristics at DESY. The exit beam is focused on a spot of 50×300 μ at the exit slit yielding about 107 monochromatic photons/sec at the intensity maximum (100 Å). The resolution attained is about 500 over the whole range 40–350 Å. Virtually no higher order admixing occurs in this range. The instrument can be used up to 1000 Å in a different mode of operation with less ideal performance.

OPTICAL ABSORPTION OF METALS IN THE X-UV RANGE

The absorption spectra in the soft X-ray range show features which are commonly not found in the ordinary X-ray region. Several typical shapes of the absorption are discussed with examples of measurements which were obtained with synchrotron radiation from the 7.5 GeV electron accelerator DESY. The shift of oscillator strength to higher energies and the frequent absence of edge discontinuities is discussed with Au as an example. The atomic calculations give good overall agreement but are unable to explain broad prominent peaks in several light metals (Na, Mg, Al). Moreover, in these metals the electron hole interaction gives rise to a prominent narrow peak near the edge. Interchannel interaction appears to have an important influence on transition metal spectra (Ti to Ni).