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).

• 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.

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:

• Ronald Frahm (Duesseldorf University) on XAFS
• Giorgio Margaritondo (EPFL-Lausanne) on photoemission spectroscopy
• Franz-Joseph Patenburg (Karlsruhe) on LIGA
• 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).

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