X-ray microscopy

The wavelength limitation on resolution indicates that an x-ray microscope may surpass the optical microscope but will not compete with the electron microscope even if all the technical difficulties could be overcome. However, there are other advantages besides resolution that make x-rays an attractive medium for microscopy.

The penetration of x-rays allows the examination of the internal detail of a specimen on the micro scale without the need for sectioning and reconstruction. The large depth of focus permits the viewing of this internal detail with equal sharpness and stereographically if necessary. The specimen may be in air at atmospheric pressure, while the electron microscope demands high vacuum, and yet the resolution may be better than that of the optical microscope. Most important, the simple absorption and emission spectra of x-rays leads to the extraction of quantitative information from the image in terms of mass and elements present that in many cases cannot be obtained in any other way.

These and other reasons have led to the search for a usable x-ray microscope and the three more successful methods of reflection, contact and projection are discussed here. In addition, recent results on microanalysis show where the bulk of the future work will lie.