PHASE-CONTRAST STUDIES OF BIOLOGICAL SPECIMENS WITH THE X-RAY MICROSCOPE AT BESSY

The transmission x-ray microscope at the BESSY storage ring is being used for investigations in the fields of biology, biophysics, medicine, colloid chemistry, and soil sciences. The system has been instrumented for phase contrast studies with the possibility of quick change between imaging in amplitude and phase contrast mode. Phase contrast has the advantage of considerable higher image contrast and reduced radiation dosage compared to amplitude contrast. A cryogenic object chamber has been implemented on the x-ray microscope. First experiments have shown that at cryogenic temperatures the structural stability of biological specimens is increased by three orders of magnitude in comparison with unfixed wet specimens at room temperature. © 1995 American Institute of Physics.