LDRD Seminar Series: ‘Isotope Geochemistry via Sn Isotope Fractionation Using Inelastic X-Ray Scattering of Synchrotron Radiation’
Senior Physicist Esen Ercan Alp (XSD) will discuss his Laboratory-Directed Research and Development (LDRD) sponsored work at the LDRD Seminar Series presentation Tuesday, March 13, 2018. “Isotope Geochemistry via Sn Isotope Fractionation Using Inelastic X-Ray Scattering of Synchrotron Radiation” begins at 12:30 p.m. in the Building 203 Auditorium. All are welcome to attend.
Stable isotope fractionation is a consequence of geological processes, and it has important applications in geochemistry. While the effect is easier to observe in light elements, the heavier elements may also show natural stable isotope fractionation and give valuable petrogenetic information. Iron isotope fractionation has been quite popular, particularly with the possibility of obtaining reliable results with multiple methods. Among them, our group has advanced the application for isotope fractionation by using a relatively new technique of measuring force constant via nuclear resonant scattering. Based on the success of iron-based measurements, we have expanded this method to tin geochemistry. Tin possesses the largest number of stable isotopes and the greatest mass range of any element, ranging in atomic weight from 112 to 124, largely due to the “magic number” closed proton shell for Z = 50. However, established methods of mass spectroscopy requires spiking with isotopes that may not be available due to scarcity.
We developed a synchrotron-based method to circumvent difficulties related to determination of Sn isotope fractionation. It is important to develop a new proxy for isotope geochemistry studies that will indicate redox conditions at the time of earth’s formation. We have measured Sn and iron phonon density of states in several Fe-Ni-Sn alloys, and in several glasses under pressure to determine force constant and isotope fractionation.
Esen Ercan Alp is a senior scientist in the X-ray Science Division. He received his BSc and MSc degrees from the Middle East Technical University in Ankara, and his Ph.D. from Southern Illinois University. Alp joined Argonne in 1984 and worked with the first group of scientists to prepare the scientific case for the Advanced Photon Source. He is known for his pioneering work in nuclear resonant X-ray spectroscopy and inelastic scattering with synchrotron radiation. He formed the inelastic X-ray scattering group at the APS, and he was responsible for the design and construction of two beamlines dedicated to nuclear resonant and inelastic X-ray scattering. Alp was a member of international science advisory committees for many synchrotrons including SESAME, Canadian Light Source and the Turkish Accelerator Center. He was the chair of Forum on International Physics of the APS in 2014, and a member of the Committee on International Scientific Affairs. He is currently chair of the SESAME Scientific Advisory Committee.
He has published 290 papers, book chapters and chaired many international conferences. Alp received the University of Chicago Distinguished Scientific Performance Award in 1999. He is an elected member of the Academy of Science, Turkey.