Experimental Astronomy

, Volume 5, Issue 3–4, pp 221–246 | Cite as

The selection of filters for reduction of optical contamination in astronomical CCD X-ray images

  • N. La Palombara
  • A. J. Court
  • G. F. Bignami


The European Photon Imaging Camera(EPIC), is the X-ray imaging and medium spectroscopy instrument for theESA X-ray Multi Mirror telescope(XMM) mission. TheCCD detectors to be used in the three focal plane cameras will provide images in the energy band from 0.1 to 10 keV. However, spectral studies may be compromised by low energy, optical photon contamination. In order to reduce this effect, a number of filters will be incorporated onto a rotating mechanism in the camera head. The filters will be chosen to provide a significant reduction in the optical contamination from a source whilst minimising the attenuation of the X-ray flux. Four commercial filters are described here and their effects on calculated typical source fluxes evaluated. In addition, two alternative filter designs are described and their effects on a simulated source spectra are debated. In both cases, particular attention is given to the problem of maintaining high sensitivity at soft X-ray energies (less than 2 keV).


Focal Plane Filter Design Typical Source Source Spectrum Camera Head 
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  1. Alig R.C. et al., 1980,Phys. Rev. B,B22, p. 5565.Google Scholar
  2. Allen C.W., 1973, “Astrophysical Quantities”, The Athlone Press, University of London.Google Scholar
  3. Bignami G.F., 1989,EPIC: European (X-ray) Photon Imaging Camera, proposal submitted to the ESA for the XMM cornerstone mission.Google Scholar
  4. Chiappetti L. et al., 1991,EPIC operating modes, Report of the OMWGGoogle Scholar
  5. Fraser G.W., 1989, “X-ray detectors in astronomy”, Cambridge University Press.Google Scholar
  6. Golub L. et al., 1983,Astroph. J. 271, p. 264.Google Scholar
  7. Heise J. et al., 1988,Astroph. J. 334, p. 958.Google Scholar
  8. Janesick J. et al., 1985, in “X-ray Instrumentation in Astronomy”, SPIE proc.597, p.364.Google Scholar
  9. Long K.S. & White R.L., 1980,Astroph. J. 239, p.L65.Google Scholar
  10. Lumb D.H. et al., 1991,Experim. Astron. 2/3, p.179.Google Scholar
  11. LUXEL Corporation, 1991,private communication.Google Scholar
  12. MPI Garching, 1991,private communication.Google Scholar
  13. Peacock A. &Ellwood J., 1988,Sp. Sci. Rev. 48, p.343.Google Scholar
  14. Perry J.J. et al., 1987,Mon. Not. Royal Astron. Soc. 228, p.623.Google Scholar
  15. Snow T.P. &Morton D.C., 1976,Astroph. J. Suppl. 32, p.429.Google Scholar

Copyright information

© Kluwer Academic Publishers 1994

Authors and Affiliations

  • N. La Palombara
    • 1
    • 2
  • A. J. Court
    • 1
    • 3
  • G. F. Bignami
    • 3
    • 4
  1. 1.Istituto di Fisica CosmicaC.N.R.Milano
  2. 2.University of MilanItaly
  3. 3.ABEN S.p.A.Italy
  4. 4.University of CassinoItaly

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