MICROFOCUSING USING K-B OPTICS FOR GEOCARS-APS: FIRST RESULTS Peter J. Eng, Mark Rivers, B.X. Yang*, Tom Duffy CARS, University of Chicago, Chicago, IL 60637, *Present address: Argonne National Laboratory, Argonne IL 60439

We present the test results of micro-focusing a continuous spectrum (4KeV - 65KeV) of x-rays using two, 100 mm long, actively bent mirrors in a Kirkpatrick-Baez geometry, as well as design results for much longer mirrors (~1m) optimized for producing small beams at the Advanced Photon Source. The mirrors are figured by applying in situ two different moments on the ends resulting in a surface figure that approximates an ellipse. We have demonstrated the ability to doubly focus NSLS bending magnet x-rays from 4 KeV to 13 KeV to a spot size less than 4 microns in diameter with a net gain of 2000 over a similar size beam produced with slits. In the bending magnet test the beam was focused in the vertical direction with a high quality rhodium coated Si mirror with a RMS surface roughness and slope error less than 2 and 2rad, respectively. The horizontal mirror consisted of uncoated float glass with significantly greater roughness and slope error. This combination of mirrors worked extremely well, pointing the direction for inexpensive micro-focusing optics. Additional high energy focusing tests were carried out at the NSLS superconducting wiggler beamline X17. In this case a continuous x-ray spectrum was both vertically and horizontally focused using the Si, and W coated float glass, mirror receptively. In this double focusing tests a cutoff energy of 60KeV (at an incident angle of 1mrad) was achieved with a FWHM focal spot size of 10microns horizontal by 3.0microns vertical and a net gain of 150. The system is now routinely used for energy disperseive high pressure diamond anvil cell diffraction measurements at X17, with a substantial improvement in signal to noise compared to beams produced by slits.