This opportunity focuses on advancing fundamental measurement science of material characterization using X rays. These characterization methods have broad impacts across any field in materials research wherein the structure of interest possesses order on the length scale of the X-ray wavelength. These include the pharmaceutical, semiconductor, chemical, ceramic, metal, and physical infrastructure market sectors, and will provide a wealth of future employment opportunities for those trained in these measurement capabilities. Our program focuses on production of standard structures, instrumentation, advanced data modeling, as well as the examination of capabilities and limitations to techniques used in the field. This approach focuses onto the full range measurement methods, using both X-ray and neutrons, including powder diffraction, high-resolution X-ray diffraction; low-angle scattering; and x-ray reflectometry. Active areas of instrumentation development include the method of circle closure (angle accuracy), characteristic emission spectra determination (wavelength accuracy), x-ray optics (wavelength stability), and system design kinematics (system stability). We have custom, in-house constructed, powder diffraction, high-resolution X-ray diffraction, double-crystal diffraction, and X-ray reflectometry instrumentation available for research. Active areas for data modeling include advanced optimization approaches for powder diffraction analysis using the “fundamental parameters approach” and whole pattern (Rietveld) methods, and statistical solution methods for high-resolution X-ray diffraction and X-ray reflectometry (Monte Carlo). Potential projects which focus on either or both instrumentation and modeling development are possible. Both thrusts support the over-arching effort of developing X-ray characterization Standard Reference Materials, which are used throughout the world to assess the accuracy of X-ray measurement methods and are under constant research to improve this accuracy.

 

Reference

Cline JP, et al: Acta Crystallographica Section A A67: 357, 2011

 

key words

Powder diffraction (XRD); Materials research; X-ray reflectivity (XRR); Standards (SRMs); Metrology; Thickness; Lattice spacing (d spacing); Fundamental parameters approach; High-resolution X-ray diffraction (HRXRD);

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral applicants