The X-ray ring at NSLS in normal operation mode accelerates electrons
to energies of about 2.5 GeV for optimized X-ray emission in the range
of 1 to 10 keV. A table of the operating parameters of the NSLS X-ray storage
ring is provided at their Web site.
Our experiment was setup on beamline X8A, one of 56 X-ray beamlines attached
to the X-ray storage ring. The beam energy incident on the filters was
selected by adjusting the orientation of the crystal element of a double
crystal monochromator located upstream from the vacuum chamber. Each crystal
element spans a certain energy range. In particular a W/Si multilayer covers
the energy range 0.26-2.0 keV with energy resolution (delta E / E) of 2x10-2,
a Si(111) crystal covers the range 2.1-5.9 keV with a resolution of 5x10-4,
and a Beryl(1010) crystal covers the range from 0.8-2.0 keV with a resolution
of 8x10-4. In Table 5.1, we list
the energies surveyed and the monochromator crystal elements used for the
transmission measurements of the ACIS-I and ACIS-S UV/Optical blocking
filters. Detailed fine energy scans were performed above the absorption
K edges of C, N, O, and Al to investigate extended X-ray absorption fine
structure (EXAFS) and shifts in the location of the Al-K edge due to possible
Al2O3 contamination.
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The configuration of the test setup is shown in Figure 5.1.
Witness samples made with the ACIS filters were placed into the UC/SAO
spectrometer-reflectometer chamber and mounted onto a mechanical fixture.
The fixture was made to support both image and spectrometer filters and
was mounted on a rotary stage that allowed for the selection of the portion
of the filter to be intercepted by the X-ray beam. The X-ray beam was collimated
with a set of vertical and horizontal entrance slits to a size of 2 mm
by 2 mm. The beam flux was monitored using a detector that was moved in
and out of the X-ray beam with a computer controlled actuator.
Figure 5.1: Schematic of the test
configuration for the measurement of the x-ray transmission of the ACIS
filters.
