SESAME and the APS: Opening Doors Helps the Light Shine In
SEPTEMBER 16, 2008
As Guvenc Akgul goes about learning the finer points of x-ray spectroscopy from his colleagues at the U.S. Department of Energy’s (DOE’s) Advanced Photon Source (APS) at Argonne National Laboratory, he represents a bridge between countries that, while separated by culture, distance, or regional factionalism, can find common ground in science at synchrotron x-ray research facilities.
Akgul, who hails from Adana in Turkey, is working toward his Ph.D. by doing hands-on research at the APS. He will use knowledge gained at the APS to help in the development of SESAME, the Synchrotron-light for Experimental Science and Applications in the Middle East light-source facility under construction in Jordan that is bringing together scientists from several Middle Eastern countries.
According to the SESAME Web site, “the idea of an international synchrotron light source in the Middle East was first proposed in 1997 by Herman Winick of the Stanford Linear Accelerator Center (SLAC) at Stanford University, and Gustaf-Adolf Voss of the German Synchrotron Deutsches Elektronen Synchrotron during two seminars organized in 1997 in Italy and in 1998 in Sweden by Tord Ekelof with the CERN-based Middle East Scientific Co-operation group headed by Sergio Fubini.” Winick and Ercan Alp of the Argonne X-ray Science Division (XSD) co-chaired the SESAME Scientific Committee between 2000 and 2003, and they continue to serve the new facility, Winick on the Beamline Committee and Alp on the Technical Advisory Committee.
In a 2006 article about SESAME that appeared in the Stanford Report, Winick said, “My main motivation [for proposing SESAME was] to help create a project in which people can work constructively and collectively.” Now, in a collaboration that Winick characterized as “reasonably unusual,” Baharanian, Cypriot, Egyptian, Iranian, Israeli, Jordanian, Pakistani, Palestinian, and Turkish scientists are working together to make SESAME a reality.
Akgul is a member of that multinational team. His Ph.D. studies have him learning how to conduct extended x-ray absorption fine structure (EXAFS) experiments, and how to apply that technique to the study of materials related to the development of new detectors for experimental physics at synchrotron x-ray facilities such as the APS and SESAME. In his work on the development of advanced x-ray detectors, Akgul is contributing to the mission of the DOE as the major steward of light source facilities and science in the U.S. His stint at the APS is funded by the Turkish government; the APS, which is funded by the DOE Office of Basic Energy Sciences; and SLAC, with funds from the DOE Cooperative Research Program for SESAME.
“We call it the ‘DOE Cooperative Research Program for SESAME’ to emphasize that supporting scientists from the Middle East at U.S. synchrotron radiation facilities contributes to research at these facilities while giving the visitor valuable experience related to SESAME,” Winick said for this article. “Guvenc is contributing to SESAME, to the APS, and to synchrotron radiation science by his work on detector development, as well as gaining experience himself on x-ray techniques.”
Akgul is working at the APS under the guidance of Klaus Attenkofer of the XSD and Prof. Yüksel Ufuktepe of Cukurova University in Turkey. During his stay at Argonne, Akgul is hosted by Alp of XSD. “During the past year, Guvenc has worked very efficiently and independently as part of an international and interdisciplinary team,” said Attenkofer. “His achievements are surely extraordinary, and it will be a great benefit for our program if he is able to continue his work at Argonne and participate in our collaboration.”
“The SESAME project has motivated me to get involved with x-rays, and many others will follow,” Akgul said. “Thus, SESAME is very important for Turkey and the Middle East. With respect to using x-rays to do new research, Turkey and SESAME will be in collaboration in the future, and this collaboration will give young researchers a big opportunity, like the one I am enjoying now.
“Specifically, I am part of an effort to develop a highly efficient electron emitter that will be used as a photocathode for a streak-camera detector. For this photocathode, we plan to use doped semiconductor nanomaterials such as Ti-doped ZnO and Co-doped ZnO, so we are working to obtain the structural information that will help us meet our objective.
“With the great availability of synchrotron radiation sources, x-ray absorption spectroscopy techniques have become widely used tools for the structural study of materials. This is accomplished by identifying the local structure around certain selected atoms in a sample. In EXAFS, the number and species of neighbor atoms, their distance from the selected atom, and the thermal or structural disorder of their positions can be determined from the oscillatory part of the absorption coefficient above a major absorption edge. The analysis can be applied to crystalline, nanostructural, or amorphous materials, liquids, and molecular gases.
“EXAFS is often the only practical way to study the arrangement of atoms in materials without long-range order. So, EXAFS spectroscopy is a powerful experimental tool for extracting structural information from the investigated material.
“Because I am learning about spectroscopic techniques like EXAFS at the APS, I will be able to do similar research at SESAME in the future.
“The APS is a great place to learn how to do research using x-rays: great people, a friendly atmosphere, an excellent opportunity to learn and practice science. And it is great to learn new things from the famous scientists at the APS.”
– Richard Fenner