Polycapillary optics provide a promising approach for coupling highly-divergent x-ray emission or inelastic scattering to high-resolution crystal analyzers. We present recent results looking at the application of polycapillary collimators to emission spectrometers. The first application uses a collimating optic and a flat crystal to provide a tunable x-ray fluorescence detector. At high-flux synchrotron radiation sources there is sufficient flux (~1013 ph/sec) to allow application of X-ray Absorption Spectroscopy (XAS) to ppb concentrations if the fluorescence signal can be isolated from an intense background. The polycapillary based analyzer easily achieves the <106 background reduction needed for such measurements. It has the additional advantage of being confocal, only collecting the signal from a small volume at the optic focus, effectively eliminating background from sample substrates, windows, or air scattering. Second, the same type of analyzer can be used for higher-resolution emission spectroscopy if operated close to 90° Bragg angle, and we report results of the commissioning of a user-available instrument suitable for few-eV resolution emission spectroscopy, including the demonstration of roughly order-of-magnitude improved measurement times compared to use of a traditional, single spherically-bent crystal analyzer. As part of this effort, we have developed a process for enhancing the integral reflectivity of Si analyzer crystals through plastic deformation at high temperatures.
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