AXAF synchrotron witness mirror calibrations 2-12 keV

We have completed another full year of reflectance calibrations of AXAF witness mirrors at the National Synchrotron Light Source. At the NSLS, we have used Beamlines X8C (5-12 keV) and X8A (2-6.2 keV), sponsored by Los Alamos National Laboratory. All of the flats have been calibrated in the 5-12 keV range, and approximately 1/4 of all our flats have been calibrated in the 2-6.2 keV range. The repeatability in the coating processes reported in Denver has continued with the measurement of additional mirrors. Optical constants from reflectances have been derived for six of the eight AXAF mirror elements, and a degree of spatial uniformity information exists for three of these six. The addition of a semitransparent monitor has markedly increased efficiency of measurements in the 5-12 keV range, and efforts are being made to provide such a monitor detector for the lower energy ranges. We report the progress in reflectance data acquisition and optical constant derivations, and discuss implications of the results for the AXAF program.