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31 October 1996 Modeling the diffraction efficiencies of the AXAF high-energy transmission gratings: II
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In order to characterize the instrumentation on AXAF, each of the science instrument teams carries out sub-assembly calibrations. For the high energy transmission grating (HETG) group, this means individual measurements of the diffraction efficiencies of each of the 336 grating elements that goes into the completed HETG assembly. Measurements are made at a number of energies (corresponding to x-ray emission lines) which fix the parameters of a model. This model is determined from first principles and verified by extensively testing sample grating elements at synchrotron radiation facilities. Here we present new synchrotron radiation (SR) data obtained at the national Synchrotron Light Source (NSLS) and at the radiometry laboratory of the Physikalisch-Technische Bundesanstalt (PTB) using the electron storage ring BESSY in Berlin. The gratings are from AXAF flight lots, and we apply an improved data reduction technique which builds on our experience from last year (Markert et al., SPIE Proceedings 2518, 424, 1995). Our analysis takes into account the effects of small extended wings in the diffraction of the various orders in the NSLS data. Our goal is to obtain efficiencies in the 0th and plus/minus 1st diffraction orders which are accurate in the 1% level, except near absorption edges, where accuracies in the 5% to 10% level are required. With a few exceptions (discussed here) our new data/improved model meets these goals.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kathryn A. Flanagan, T. T. Fang, C. Baluta, John E. Davis, Daniel Dewey, Thomas H. Markert, Dale E. Graessle, Jeremy J. Drake, Jonathan J. Fitch, Jiahong Zhang Juda, Jonathan W. Woo, Stefan Kraft, Peter Bulicke, R. Fliegauf, Frank Scholze, Gerhard Ulm, and James M. Bauer "Modeling the diffraction efficiencies of the AXAF high-energy transmission gratings: II", Proc. SPIE 2808, EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy VII, (31 October 1996);

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