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Available online at www.sciencedirect.com Journal of Electron Spectroscopy and Related Phenomena 162 (2008) 4955
 

Summary: Available online at www.sciencedirect.com
Journal of Electron Spectroscopy and Related Phenomena 162 (2008) 49­55
A simple method for determining linear polarization and
energy calibration of focused soft X-ray beams
B. Watts, H. Ade
Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
Received 12 April 2007; received in revised form 27 August 2007; accepted 28 August 2007
Available online 1 September 2007
Abstract
Although critical to quantitative linear dichroism studies of molecular orientation, the degree of linear polarization of focused soft X-ray beams
delivered by X-ray microscopes has not been previously measured. Here, we present a scaled-down version of a recently developed technique in
which the
near edge X-ray absorption fine structure (NEXAFS) resonance of highly oriented pyrolytic graphite (HOPG) is used to probe the
electric field intensity in each direction and hence deduce the degree of linear polarization of the incident X-ray beam. Applying this technique to
the soft X-ray microscope at beamline 5.3.2 of the Advanced Light Source in Berkeley, CA, yielded a measured value of 79 ± 11%, for the first
Stokes parameter of 0.79 ± 0.11 or as a St¨ohr P factor of 0. 89 ± 0.06. It is expected that the error margin could be significantly reduced via the
use of an in-vacuum rotation actuator. We have also calibrated the energy of the graphite exciton to be 291.65 ± 0.025 eV, improving the utility of
graphite as an energy calibration standard for NEXAFS and allowing the convenience of both energy calibration and polarization determination
with a single inexpensive sample.
Published by Elsevier B.V.

  

Source: Ade, Harald W.- Department of Physics, North Carolina State University

 

Collections: Physics