X-RAY HOLOGRAPHIC MICROSCOPY OF BIOLOGICAL SPECIMENS WITH AN ELECTRONIC ZOOMING TUBE

X-ray holographic microscopy of biological specimens has been performe d using in-line holography with the following improvements: (i) an ele ctronic zooming tube is utilized as a detector, and (ii) the object pl anes are restricted by a metal frame which is not transparent to X-ray s at the wavelengths used in the present experiments. The latter modif ication is useful in computer reconstruction and serves as a reference area where there are no photons in the reconstructed images. This sys tem can minimize the inclusion of errors when recording and reading ou t holograms compared with methods using an X-ray resist as a detector, or optical reconstruction methods. Two-dimensional images of human ce lls have been successfully obtained with the present system. Compariso n of these images with optical images revealed a good coincidence in s tructure outlines but not in internal structure images. Holographic ob servation of HeLa cells at different wavelengths showed a wavelength d ependence of the reconstructed images. Since the electronic zooming tu be is applicable to a wide range of X-ray wavelengths and has a promis ing potential to improve its resolution, these results strongly sugges t that the present system is a good candidate for the development and establishment of an X-ray holographic microscopy system.