Abstract. -A new method is proposed for reconstructing the data from coded aperture X /7 -ray telescopes. This technique, based on the Wiener criterion, is essentially a generalisation of existing Wiener filtering methods but is not confined to systems with position independent point source response functions. The reconstruction method trades off the image degrading effects of statistical detector noise with the effects of imperfect source field coding, to produce a minimum error source field estimate. It offers advantages if the coding properties of the mask-detector configuration considered are not 'ideal' and is particularly useful where multiple dithered observations are made of a given source field. The proposed method is applied to simulated data and to data from a recent balloon flight of an experimental coded mask telescope. It is shown to give better quality images than those formed by more conventional methods.
Two identical CsI-coated, low noise microchannel plate (MCP) detectors were taken to the Daresbury Synchrotron Radiation Source (SRS) to measure their quantum efficiencies over two different energy ranges -450 eV to 1200 eV and 4.5 keV to 9.5 keV. The SRS was run in low ring current with the beam flux monitored using single wire gas proportional counters. We present accurate measurements of edge-related absolute quantum efficiency features due to the CsI photocathodes. This data will be incorporated into the calibration program of the Advanced X-ray Astrophysical Facility (AXAF) High Resolution Camera (HRC).
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