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SESAME Workshop on Materials Research; Ankara,
September 21-22, 2000
E. Alp, E. Ozdas, H. Winick
Scientists from 8 SESAME member countries
(Armenia, Egypt, Greece, Iran, Israel, Jordan, Oman and Turkey) met at
Hacettepe University in Ankara Turkey on September 21-22, 2000 at a workshop
aimed at developing the plans for materials research using
SESAME. Financial support for the workshop was provided by Hacettepe
University and UNESCO. The workshop was organized by the SESAME
Scientific Committee [cochairs Ercan Alp (APS/Argonne) and Herman Winick
(SSRL/SLAC)] and was cochaired by Alp and Engin Ozdas (Hacettepe University).
The Ankara workshop had two main objectives:
To assess the present level of activity in materials research in SESAME member
countries and to project the level and range of activity in this field once
SESAME is in operation.
To define the beam lines, user-support facilities, and scientific and technical
support staff required for a world-class materials research program at SESAME.
After a warm welcome to the participants from
Hacettepe University President Tuncalp Ozgen, and a report by Winick on the
status of the SESAME Project and the performance of the ring as a light source
over a broad spectral from IR to hard x-rays, participants form each of the
SESAME member countries presented material which addressed the first
objective.The result is that, integrated over all SESAME member countries, it
is anticipated that several hundred materials scientists will use the facility
a few years after it starts operation, presently projected for 2003.
The workshop benefited greatly from the
participation by experienced synchrotron radiation scientists from outside the
Middle East region who gave tutorial talks on the various aspects of materials
research.These included:
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Ronald Frahm (Duesseldorf University) on XAFS
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Giorgio Margaritondo (EPFL-Lausanne) on photoemission spectroscopy
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Franz-Joseph Patenburg (Karlsruhe) on LIGA
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Peter Stephen (SUNY Stony Brook) on powder diffraction
Contributions to the discussions and working
groups were also made by Ercan Alp, Bob Batterman, and Herman Winick, as well
as the many participants from SESAME member countries.
In anticipation of discussions at the Ankara
workshop about a deep lithography (LIGA) program on SESAME to produce
micromechanical devices, SESAME Scientific Committee member Adel El-Nadi of
Cairo University spent 5 weeks working with Derek Mancini's LIGA group at the
Advanced Photon Source at Argonne National Laboratory.Support for this visit
was provided by the US Department of Energy Cooperative Research Program.
For details of the DOE program and other SESAME
programs to give scientists from Middle East countries opportunities to work on
accelerator technology and synchrotron radiation applications, see the SESAME
web site (www.sesame.org.jo). The final report on the Ankara workshop will be
posted on the SESAME web site.
The Ankara workshop was focused on four
specific synchrotron radiation techniques pertinent to Materials Science
applications:
a) x-ray powder diffraction (XPD),
b) x-ray absorption spectroscopy (XAFS),
c) Photoemission spectroscopy (PE), and
d) micromanufacturing methods (LIGA).
The participants emphasized the need for standard
materials preparation and characterization support laboratories, in addition to
specialized clean rooms and a processing laboratory for LIGA.
An important outcome of this workshop was a
discussion on source requirements for LIGA and other techniques, and beamline
sharing. It was agreed that 3 branch lines can be built on a wiggler line. The
two side stations could be used for XAFS, XPD, and LIGA. The center branch
could be used for microfocusing, as well as for protein crystallography, using
focusing optics to exploit the small source size (one standard deviation
horizontal/vertical of 440/30 microns) at these wiggler locations.
Franz-Joseph Patenburg pointed out that LIGA
requires intensity uniformity at the sample of +/- 4% over 100 mm. Subsequent
ray tracing by Tom Rabedeau of SSRL showed that side stations on either of the
two 13 pole, 7.5 T SESAME superconducting wigglers can easily provide such
uniformity and very high intensity at x-ray energies up to around 10-15 KeV in
an unfocused beam.
Since microfocusing was not part of this
workshop, details of the XPD and XAFS were discussed. It was concluded that a
white beam collimating mirror, followed by a double crystal monochromator (with
the second crystal used as a sagittal bender for horizontal focussing) and
finally a vertical focussing mirror, represents a state-of-the-art beamline.
For x-ray absorption, a QUICK-EXAFS type fast-scanning monochromator design was
considered advantageous. There was a detailed discussion on standard and
state-of-the-art high resolution alternatives for photemission spectroscopy.
Cost estimates were presented. Finally, the needs of a functioning LIGA
facility was discussed in detail.
The Ankara workshop was the second such meeting
to focus on a particular area of research at SESAME. The first was the
Structural Molecular Biology workshop held at the University of Athens on April
6-7, 2000. See SR News Vol. 13, No. 4, July/August 2000 for a brief report on
this workshop. The full report is on the SESAME web page. The Athens workshop
concentrated on protein crystallography. A follow up to the Athens workshop
will be held in Cyprus on December 5-7, 2000, focusing mostly on biological
applications of small angle scattering, EXAFS, and infra-red techniques.
It is anticipated that the SESAME Scientific
Committee will conduct additional workshops in 2001, with sponsorship by
UNESCO. A follow-up workshop to the Ankara workshop on Materials Research,
primarily to cover areas not covered in the Ankara workshop, might take place
in the Spring 2001. It will focus on microscopy and imaging with applications
in soil, geological, and environmental sciences. The techniques will include
x-ray fluorescence, small angle scattering, and if necessary, a review of XAFS
and white beam powder diffraction. Archeological applications can be
incorporated into this workshop. The location and time of this workshop are not
yet determined. Interest in hosting a future workshop has been expressed by
SESAME member country Iran.
E. Alp, E. Ozdas, H. Winick
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