Use of astigmatic re-focusing at HP-XPS end-station

Walan Grizolli, Franz Hennies, Jan Knudsen, Ralf Nyholm, Rami Sankari, Joachim Schnadt

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceedingpeer-review


In this paper we present the refocusing optics for the new high pressure photoelectron spectroscopy (HP-XPS) branch line at MAX-lab, based on a plane grating monochromator with vertically collimated beam. For the HP-XPS instrument, the required spot size is dictated by the small geometric acceptance of the HP-XPS electron energy analyzer. Whereas a pair of bendable mirrors in a KB configuration has some advantages as refocusing elements, we have studied whether similar performance can be achieved with a single non-bendable mirror. In this solution, however, the need for strong horizontal magnification results in a strong vertical magnification and into a very asymmetric image, the height being just a fraction of the width. We have studied through an analytical geometrical model and ray tracing simulations the use of astigmatism to increase the vertical beam size up to the geometric acceptance of the detector. As a result the vertical beam size at sample plane is mostly determined by the photon angular distribution and is not dependent on the exit slit aperture size. In addition the vertical beam size can be controlled by the grating c(ff) parameter, making possible to adjust the photon density and minimize sample damage by the radiation.
Original languageEnglish
Title of host publication11th International Conference on Synchrotron Radiation Instrumentation (SRI 2012)
PublisherIOP Publishing
Publication statusPublished - 2013
Event11th International Conference on Synchrotron Radiation Instrumentation (SRI) - Lyon, France
Duration: 2012 Jul 92012 Jul 13

Publication series

ISSN (Print)1742-6588
ISSN (Electronic)1742-6596


Conference11th International Conference on Synchrotron Radiation Instrumentation (SRI)

Subject classification (UKÄ)

  • Physical Sciences
  • Atom and Molecular Physics and Optics
  • Natural Sciences


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