The status of the soft x-ray beamline BL25SU at SPring-8 is reported. The beamline performance for circular dichroism measurements using the helicity switching of helical undulator radiation is focused on. Light spots on a sample of the opposite helicities have been observed with a photoelectron emission microscope. The vertical profiles of the spots have almost the same line shape and a positional difference of ∼ 0.5 μm. The horizontal spot positions coincide, but the horizontal spot widths are different by ∼ 7 %. The energy difference of the monochromatized light between the opposite helicities has been estimated to be less than or comparable to 1 meV in the Ne 1s absorption region. The kick angle of the kicker magnets has been increased from 0.2 to 0.3 mrad to avoid penetration of the higher harmonics.
|Title of host publication||AIP Conference Proceedings|
|Number of pages||4|
|Publication status||Published - 2007|
|Event||SYNCHROTRON RADIATION INSTRUMENTATION: 9th International Conference on Synchrotron Radiation Instrumentation - Daegu, Korea, Republic of|
Duration: May 28 2006 → Jun 28 2006
|Other||SYNCHROTRON RADIATION INSTRUMENTATION: 9th International Conference on Synchrotron Radiation Instrumentation|
|Country||Korea, Republic of|
|Period||5/28/06 → 6/28/06|
- Circular dichroism.
- Helicity switching
- Soft x-ray beamline
- Twin helical undulators
ASJC Scopus subject areas
- Physics and Astronomy(all)