A Cheaper, Smaller, and Sometimes Better Approach To X-ray Spectroscopy

Jerry Seidler
UW Physics

X-ray spectroscopic methods at synchrotron light sources are important for ongoing research in numerous fields, including condensed matter physics, physical chemistry, biology, and nanoscience. Surprisingly, although the x-ray sources, methods for optics fabrication, and available detectors are seeing continuing, rapid development, the overall design for most high-resolution x-ray spectrometers has remained largely unchanged since the 1930's. After reviewing the very interesting history which led to the present situation, I will present an alternative approach to x-ray spectrometer design having the potential to improve measurement efficiency by two orders of magnitude or more, as compared to many conventional apparatus. For 83 dollars and a few favors, we recently constructed and tested a prototype instrument based on this design. Its performance on benchmark studies rivaled that of existing spectrometers based on traditional x-ray optics and costing well over $1M to construct. The potential for new science to be enabled by these instrument will be discussed, with some emphasis on one unique example: These spectrometers are by far the most cost-effective method for single-pulse x-ray emission spectroscopy at the Linac Coherent Light Source (LCLS), where optical-pump/x-ray probe measurements with 1 fs resolution will be possible.