A study of 8.5 mu m microchannel plate X-ray optics

We have investigated the X-ray focusing properties of microchannel plates ( MCPs) with square channels of side length 8.5 mu m. Both planar and spheric ally slumped MCPs (radius of curvature R-slump = 0.5m) have been examined. We have observed foci of 7(up arrow) and 14(up arrow)FWHM, respectively. In addition, we have measured the 8 keV X-ray reflectivity of channel surface s which have been subjected to a variety of chemical treatments. These refl ectivities are found to correspond closely to theoretical, values calculate d by a simple two-layer model of the MCP reflecting surfaces. The inferred values of surface roughness for those MCPs thermally annealed at 430 degree s C is similar to 11 Angstrom, about a factor of two better than previously measured. (C) 1999 Elsevier Science B.V. All rights reserved.