31 October 1996 Performance of an optical filter for the XMM focal plane CCD camera EPIC
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We have been developing optical filters for ESA's x-ray astronomy project XMM (x-ray multi mirror mission). Specific CCDs will be used as detectors in the focal plane on board the observatory. Since these detectors are sensitive from the x-ray to the NIR (near infrared) spectral range, x-ray observations require optical filters, which combine a high transparency for photon energies in the soft x-ray region and a high opacity for UV (ultraviolet) and VIS (visible) radiation as well. With respect to the mission goal in orbit three types of flight model filters are designed having different spectral transmittance functions. We report on one of these types, a so-called 'thick' filter, which has been realized within the EQM (electrical qualification model)- phase of the project. The filter features a cut-off in the EUV (extreme ultraviolet) spectral range and suppresses radiation below 10 eV photon energy by more than 8 orders of magnitude. It has an effective aperture of 73 mm without any support structure. A 0.35 micrometer thick polypropylene carrier foil is coated with metallic films of Al and Sn. The manufacturing process, the qualification measurements and the environmental tests are described, and the resulting performance data is presented.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Karl-Heinz Stephan, Claus Reppin, Marieluise Hirschinger, Hans-Joerg Maier, Dagmar Frischke, Detlef Fuchs, Peter Mueller, Peter Guertler, "Performance of an optical filter for the XMM focal plane CCD camera EPIC", Proc. SPIE 2808, EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy VII, (31 October 1996); doi: 10.1117/12.256018; https://doi.org/10.1117/12.256018


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