|Answering the demand for a variable polarization beamline, the SRC/PSL staff designed and built a
quadruple reflection circular polarizer (QRP). Although the QRP is to be installed on the Plane Grating
Monochromator (PGM) beamline when it is completed, it has been successfully used and characterized on
the Amoco Beamline. The first results from the polarizer include a Magnetic Circular Dichroism study
(see figure below).
This first ever built UHV quadruple reflection polarizer uses the phase difference between the s and p
components of reflected light to create circularly polarized light. This design was chosen as a safer and
higher throughput alternative to other known methods of extracting circularly polarized light such as
crossed-field undulators or the use of apertures on bending magnet beamlines. In the 8 eV to 130 eV
range, the QRP has a figure of merit (TP2circ) fifty times greater than a crossed-field undulator. It can be
tuned to produce pure circular polarization, or set to provide a compromise between polarization and flux.
The QRP should be available to users on the PGM beamline sometime this winter.
The figure shows the Magnetic Circular Dichroism (MCD) effect
by the normalized intensity difference between right and left circularly
polarized light reflected from an iron surface. Data courtesy of H> Hoechst.
The QPR Update -- a Study Using MCD
Aladdin -- Editor Brian Tonner email@example.com