Dr Sam Webb

Staff Scientist, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory

1996                  B.S. Geochemistry, California Institute of Technology

1996                  M.S. Environmental Engineering, California Institute of Technology

2001                  Ph.D. Civil and Environmental Engineering, Northwestern University

2001-2004         Post Doctoral Researcher, SLAC National Accelerator Laboratory

2004-2007         Beam line Scientist, SLAC National Accelerator Laboratory

2007-                 Staff Scientist, SLAC National Accelerator Laboratory

Sam has a strong background in the chemistry of environmental and geological materials. During his Ph.D. research he began to use synchrotron-based techniques to examine the chemistry of contaminants in the environment using non-invasive x-ray analyses. This has led to the development of a strong research program using x-ray fluorescence, x-ray spectroscopy, and x-ray diffraction to investigate a wide variety of chemistries in materials that cross many disciplines. This interdisciplinary work has led to his current research, focusing on examining ancient and cultural heritage materials. Sam’s works in the field include: the investigation of the chemistry of pigment changes from the exposure to light and humidity ; using the chemical nature of lapis lazuli to examine the provenance of ultramarine pigments ; using x-ray spectroscopy to examine the radiation dose effect on ultramarine pigments; the fluorescence imaging of ancient manuscripts to reveal hidden writings.

Sam operates the micro-scale x-ray imaging program at SSRL, and manages the science program at four beam lines stations. Here he has designed and built the in-hutch experimental stations, and has a strong focus on the development of experimental procedures and methodologies for the efficient and safe collection of x-ray imaging and spectroscopy data. The use of complementary multi-modal data collection, using visible and IR wavelengths at the same time as x-ray analyses, has been integrated into the facilities in order to extended the information content of synchrotron techniques and provide a framework for monitoring samples during measurement. He also is the developer of a suite of software programs, both at the beam lines and for analysis at the user’s home institutions, to intuitively process and extract data.