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Design Principles and Applications of a Cooled CCD Camera for Electron Microscopy

  • A. R. Faruqi
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 453)

Abstract

Cooled CCD cameras offer a number of advantages in recording electron microscope images with CCDs rather than film which include: immediate availability of the image in a digital format suitable for further computer processing, high dynamic range, excellent linearity and a high detective quantum efficiency for recording electrons. In one important respect however, film has superior properties: the spatial resolution of CCD detectors tested so far (in terms of point spread function or modulation transfer function) are inferior to film and a great deal of our effort has been spent in designing detectors with improved spatial resolution. Various instrumental contributions to spatial resolution have been analysed and in this paper we discuss the contribution of the phosphor-fibre optics system in this measurement. We have evaluated the performance of a number of detector components and parameters, e.g. different phosphors (and a scintillator), optical coupling with lens or fibre optics with various demagnification factors, to improve the detector performance. The camera described in this paper, which is based on this analysis, uses a tapered fibre optics coupling between the phosphor and the CCD and is installed on a Philips CM12 electron microscope equipped to perform cryo-micros-copy. The main use of the camera so far has been in recording electron diffraction patterns from two dimensional crystals of bacteriorhodopsin—from wild type and from different trapped states during the photocycle. As one example of the type of data obtained with the CCD camera a two dimensional Fourier projection map from the trapped O-state is also included. With faster computers, it will soon be possible to undertake this type of work on an on-line basis. Also, with improvements in detector size and resolution, CCD detectors, already ideal for diffraction, will be able to compete with film in the recording of high resolution images.

Keywords

Point Spread Function Modulation Transfer Function High Dynamic Range Gate Valve Readout Noise 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Faruqi, A.R., Andrews, H.N. and Raeburn, C. Nucl. Instr. and Meth. A348, 659–663 (1994)Google Scholar
  2. 2.
    Faruqi, A.R., Andrews, H.N. and Henderson, R. Nucl. Instr. and Meth. A367, 408–412 (1995)Google Scholar
  3. 3.
    Faruqi, A.R. and Andrews, H.N. Nucl. Instr. and Meth. A392, 233–236 (1997)Google Scholar
  4. 4.
    Brink, J. and Chiu, W. J. Struct. Biol. 113, 23–34 (1994)PubMedCrossRefGoogle Scholar
  5. 5.
    Koster, A.J. and de Ruijter, W.J. Ultramicroscopy 40, 89–107 (1992)CrossRefGoogle Scholar
  6. 6.
    Koster, A.J., Chen, H., Sedat, J.W. and Agard, D.A. Ultramicroscopy 46, 207–227 (1992)PubMedCrossRefGoogle Scholar
  7. 7.
    Sugi, H., Akimoto, T., Sutoh, K., Chaen, S., Onishi, N. and Suzuki, S. Proc.Nat. Acad. Sci.,94(9), 4378–4382, 1997PubMedCrossRefGoogle Scholar
  8. 8.
    Sherman, M.B., Brink, J. and Chiu, W. Micron 27(2), 129–139 (1996)PubMedCrossRefGoogle Scholar
  9. 9.
    Joy, D.C. Monte Carlo Modeling for Electron Microscopy and Microanalysis. Oxford University Press 1995.Google Scholar
  10. 10.
    Faruqi, A.R., Henderson, R. and Subramanium, S. Ultramicroscopy (submitted)Google Scholar
  11. 11.
    Henderson, R., Baldwin, J.M., Ceska, T.A., Zemlin, F., Beckmann, E. and Downing, K.H. J.Mol.Biol. 213, 899–929 (1990)PubMedCrossRefGoogle Scholar
  12. 12.
    Grigorieff, N., Ceska, T., Downing, K.H., Baldwin, J.M. and Henderson, R. J.Mol. Biol. 259, 393–421 (1996)PubMedCrossRefGoogle Scholar
  13. 13.
    Subramanium, S., Faruqi, A.R., Oesterhelt, D. and Henderson, R. Proc. Natl. Acad. Sci. USA 94, 1767–1772, (1997)CrossRefGoogle Scholar
  14. 14.
    Lindahl, M. and Henderson, R. Ultramicroscopy (in press)Google Scholar

Copyright information

© Plenum Press, New York 1998

Authors and Affiliations

  • A. R. Faruqi
    • 1
  1. 1.Laboratory of Molecular BiologyMRCCambridgeUK

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