Confocal micro-X-ray fluorescence spectroscopy with a liquid metal jet source

For XRF and other applications that require an X-ray focus with exceptional intensity or very small focus size away from the synchrotron, the MetalJet X-ray tube combined with a polycapillary optic is likely the system of choice. The broad-band reflectivity and large focusing angles of the polycapillary allows the focusing of a very high X-ray flux to a small spot. Combining this with the brightest X-ray tube in the world can give flux densities of 2.4e13 photons/s in a 13 um focus. Polycaps works well both for the strong 9.25 keV gallium line of the MetalJet and the bremstrahlung up to about 20 keV, and they can be made to either give a very tight focus, or a larger focus with a longer work distance and a larger depth of focus.