FIRST RESULTS OF SRCS NEW HIGH-ENERGY RESOLUTION VARIABLE LINE DENSITY GRATING MONOCHROMATOR BEAMLINE - HERMON

A new high-resolution soft x-ray beamline utilizing a variable line density grating has been constructed and tested at SRC. In addition to normal grating rotation, the grating housing mechanism allows a translation of the grating. This additional motion of the grating can be used in such a way that grating aberration effects such as defocus, coma, and spherical aberrations are minimized over the entire scan range. In order to achieve the theoretical resolving power of 105-5000 over the photon energy range of 280-1150 eV, extreme care had to be exercised in positioning and controlling the grating scan angle (<0.12 arcsec) and focus drive position (<10 μm). Using a spherical grating with a figure error of <0.2 arcsec and 10 μm slits, we were able to experimentally reproduce our theoretical predicted energy resolution over a wide energy range. We present photoabsorption data of the K-shell edges and associated Rydberg states of Ne, O2, and CO. The high-resolution monochromator unveils structures which were previously not seen or only poorly resolved. A quantitative data analysis of the Ne absorption peak shows the intrinsic lifetime broadening of the Ne 1s state agrees well with theoretical estimates. © 1995 American Institute of Physics.