Current status of the undulator beamline BL-2C at Photon Factory

The undulator beamline BL-2C was constructed for measurements of soft X-ray spectroscopy. It is equipped with a varied line-space plane grating monochromator. High energy-resolution, high photon-flux and tiny spot-size have contributed to research on electronic structure of gaseous samples, solid samples and surfaces. In order to carry out further sophisticated measurement, we have improved the beamline at the following three points. First, optical elements were re-aligned again with great care for higher energy-resolution. To demonstrate the energy-resolution, we measured absorption spectrum of oxygen 1 sσ→π* excitation and evaluated E/ΔE to be more than 10,000. Secondly, mirror holders were altered to reduce the effect of heat load. The remodeling and the replacement of the optical-element holders resulted in energy-drift becoming negligible. Thirdly, the carbon-contaminated optical elements were cleaned by ozone-cleaning method. The photon flux at the carbon absorption-edge is recovered by the cleaning.