A simple model of image formation in the x-ray microscope is used to investigate the relationship between contrast, signal to noise ratio, dose and image resolution. The important feature of this model is the role that the depth of field is expected to play in determining the dose to the specimen when imaging at high resolution, with the result that the dose can be expected to increase as the inverse sixth power of the resolution. Some deficiencies in this model are examined for the case of thin specimens, where linear contrast transfer theory can be applied, and it is shown that there are some advantages associated with the use of phase contrast imaging conditions. Finally, methods of producing phase contrast in the imaging microscope and the scanning microscope are compared in terms of their contrast transfer functions and the ease with which they can be realised in practice.

Date Published: 27 November 1989
PDF: 9 pages
Proc. SPIE 1140, X-Ray Instrumentation in Medicine and Biology, Plasma Physics, Astrophysics, and Synchrotron Radiation, (27 November 1989); doi: 10.1117/12.961801

Published in SPIE Proceedings Vol. 1140:
X-Ray Instrumentation in Medicine and Biology, Plasma Physics, Astrophysics, and Synchrotron Radiation
Rene Benattar, Editor(s)