Note:

1
The 4-Laue Monochromator At X17B3 Beamline of
National Synchrotron Light Source
On the basis of theory and practice experiments
from the two asymmetric Laue crystals
monochromator system at the X17B1 and X17C beam
lines 1,2, we designed the 4-Laue monochromator
at X17B3. By using 4 Laue crystals to keep the
mono beam and white beam are at the same
position. The goal of the 4-Laue monochromator
is to let users easily switching experiments
between angle dispersive X-ray diffraction (ADXD)
and energy dispersive X-ray diffraction (EDXD)
without moving the samples. The prototype
sagittal focusing monochromator using four
asymmetric Laue crystals with 30 keV X-rays, has
been constructed and tested successfully at the
X17B3 3.
Note The unbending 2-Laue monochromator setup,
like in (3), will be used in combination with
Kinoform lenses for the x-ray focusing at 30KeV
at X17B3. The construction of (3) is also easy
converted to an energy tunable monochromator if
needed. The focusing testing of Laue mono beam by
KB mirrors, with this setup, will be performed
soon. A new, more compact, bending mechanism
for the Laue crystal is currently designed by Z.
Zhong.
A surface scan results of a 6 Si wafer sample by
the LTP-MF instrument.
From the studies on Si crystals surface in the
late of 2007, we have gained a much better
understanding of the coupling problems between
crystals why the coupling between two crystals
some one is much better than others why some
pairs of crystals are easy to be aligned for the
unique mono energy why some pairs are not
stable... The main reason for that is due to
the crystal surfaces, depending on how well a
pair of crystal are matched to each other well.
The flux of 4-Laue monochromator should be
similar as the present two-Laue system uses a
pair of crystals instead of the single one in the
4-Laue mono system at around 30KeV energy.
Discussion of the potential application on
minerals and material sciences at X17B3 1. Some
SXD (single crystal x-ray diffraction)
experiments with DAC can be done by applying the
white-beam with EDXD (energy dispersive x-ray
diffraction) method using a point-detector, as
did as at X17C5. 2. The unknown diffraction
energies of a single crystal Laue with white-beam
X-ray could be solved by using the x-radiation
images technique with different thickness
filters6. Nevertheless, the well-done
calibrations and normalizations are needed. 3.
The combination of Laue diffraction and EDXD is
one of the ways to determining peak energies in
Laue images precisely by using a point-detector.
The X17B3 is equipped to do so. 4. The
energy-tunable 4-Laue mono beam combined the EDXD
technique is capable of collecting all data
needed to refine crystal structures within one
experiment without moving the samples. This is
the goal to design the 4-Laue monochromator at
X17B37,8. 5. It is possible to have a dual
setup of x-ray energies in the 4-Laue system,
which may be useful for the SXD experiments with
DAC ? More experiments are needed to test this.
X17B3 beamline is supported by COMPRES, The
Consortium for Materials Property Research in
Earth Sciences. COMPRES is supported by the
Division of Earth Sciences at the National
Science Foundation via a Cooperative Agreement
for the 5-year period from 2007 to 2012 EAR06
-49658.
1 Z. Zhong, et. al., Acta. Cryst. A 59 (2003)
1-6 2 J. Hu, et. al., Eos. Trans. AGU, 84(46),
Fall Meet. Abstract V42A-0334, 2003. 3 Q. Guo,
et. al., COMPRES Annual Meeting, 2004. 4 Q.
Guo, et. al., COMPRES Annual Meeting, 2007. 5
J. Hu, et. al., GSA Abstracts, Vol. 37, No. 7,
155-11, p.350 (2005). 6 Q. Guo, et. al., APS
Activity Report, ANL 2001. 7.G. E. Ice, et.
al., J. Synchrotron Rad. (2005) 12, 608-617. 8
R. J. Hemley, et. al., J. Synchrotron Rad. (2005)
12, 135-154.
Acknowledgements The authors would like to
thank The Instrumentation Department of BNL,
Shinan Qiang, Peter Takacs and Qiang Kun for
their helps on the flatness measurements of Si
crystals. Q. Guo acknowledges the constructive
comments from Charles Prewitt, John Parise, Peter
Siddons, Lars Ehm and Hexiong Yang.
2
Abstract (2008 COMPRES Annual Meeting) On the
basis of theory and practice experiments from the
two asymmetric Laue crystals monochromator system
at the X17B1 and X17C beam lines, we designed the
4-Laue monochromator at X17B3. By using 4 of Laue
crystals to keep the mono beam and white beam are
at the same position and then let users easily
switching experiments between angle dispersive
X-ray diffraction (ADXD) and energy dispersive
X-ray diffraction (EDXD) without moving the
samples. The prototype sagittal focusing
monochromator using four asymmetric Laue crystals
with 30 keV X-rays, has been constructed and
tested successfully at the X17B3. The x-ray
flux, from the 4-Laue monochromator with the
above prototype setting, is about one tenth of
the magnitude of the two-crystal Laue
monochromators, as expected. The optimized
crystal thickness experiment of Si was performed
to increase the x-ray flux. Recently, from the
studies on Si crystals surface, we have gained
a much better understanding of the coupling
problems between crystals. The flux of 4-Laue
monochromator using a pair of crystals instead of
the single one at around 30KeV energy should be
similar as the present two-Laue system. With the
energy-tunable 4-Laue mono beam combined the EDXD
technique at X17B3 will be the great potential
application for minerals and material scientist.