Sector 8: Beamline 8-ID
Beamline 8-ID uses the standard APS Undulator A as the insertion device.
The design of this undulator beamline is a combination
of two established, complimentary designs: that of the Troika Beamline
at the European Synchrotron
Radiation Facility (ESRF) and that of branchline 2-ID-E at the APS.
Principal features of the 8-ID beamline:
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Transmission Monochromator Side Station:
A beam-splitting monochromator allows two experiments to run simultaneously
using a single undulator beam.
It works by horzontally edging a small knife-edge Si crystal
into the incident beam
and deflecting a portion of this beam into a side-station experiment
enclosure.
The remaining incident beam is transmitted to the end station.
-
Mirror as First Optical Component in the First-Optics Enclosure (FOE):
In order to implement the transmission monochromator side
station, it is necessary to bring the non-monochromatic undulator
beam out of the first optics enclosure (FOE) to the monochromators serving
the side and end stations. Using the raw "white"
undulator beam outside of the FOE involves design compromises due to
the Bremssrahlung shielding required all along the
beam line. A solution to this problem is to employ a mirror in the FOE
to separate the usable, "pink" x-ray beam from the
bremsstrahlung. This solution has the important additional benefit of
reducing the heat load on the downstream
monochromators.
-
End Station:
The end station of the undulator beam line is more flexible than
the transmission monochromator side station
because of the variety of monochromator and focusing options available
for the end station. In particular, one can
optimize the trade-off between energy resolution and intensity by a
choice of Si or Ge crystals, or "pink" undulator beam.
Specifications and info for other Sector 8 beamlines:
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