NATURE OF THE 1385.6 AND 1438 EV POSITIVE GLITCHES IN THE TRANSMISSION FUNCTION OF THE YB66 SOFT-X-RAY MONOCHROMATOR

In the course of the development of the YB66 004 monochromator for sof t-X-ray spectroscopy in the 1-2 keV region, two positive glitches at 1 385.6 and 1438 eV have been observed in the transmission function of t his material in a double-crystal configuration. The nature of these gl itches has been elucidated using a combination of photoemission experi ments, reflectivity measurements and anomalous scattering calculations . Analyses of these results show that these positive glitches are due to the transmission at an energy 3/2 times higher than the 004 reflect ion and correspond to the yttrium L-III and L-II absorption edges at 2 080 and 2156 eV, respectively. Reflectivity measurements and structure -factor calculations for the 006 reflection confirm that these glitche s are caused by the sharp reflectivity increases associated with anoma lous scattering for the 006 reflection at the yttrium L-III and L-II a bsorption edges.