Performance of an ultrahigh resolution cylindrical grating monochromator undulator beamline

Abstract

An ultrahigh resolution and high-flux undulator beamline U9-CGM, with a cylindrical grating monochromator and covering an energy range from 5to100eV, has been constructed. Two separate entrance slits are included to provide different incident angles, hence to optimize the overall performance. This beamline delivers an average photon flux of 6×1010photons∕s with the entrance and exit slit openings at 10μm. An energy resolving power of 110 000 with a photon flux of 1×1010photons∕s was obtained at 16eV with the 1800line∕mm grating and at 64eV with the 1600line∕mm grating, with the entrance and exit slit openings at 3 and 5μm, respectively. A differentially pumped gas cell is used to attenuate high-order light by up to four orders of magnitude. This beamline will be a powerful tool for research in ultrahigh resolution spectroscopy of atoms, molecules, and condensed matter.