Measurements of electron beam damage for organic crystals in a high voltage electron microscope with image plates

The critical dose for extinction of the diffraction pattern from behenic acid monolayer crystals increased with increasing accelerating voltages. The mean values at 114, 500 and 1000 kV were 0.6, 1.8 and 2.2 electrons/Angstrom(2), respectively. The critical dose at 500-1000 kV is three or more times as large as that at 114 kV. Considering this with the recent measured value of the detective quantum efficiency of the image plate, 0.5 at 500 kV and 0.4 at 1000 kV, 1.5 times as much information can be collected from a crystal at 500-1000 kV as at 114 kV, Therefore, the combined use of high voltage electron microscopy and image plate detectors offers a significant improvement over conventional electron microscopy approaches for the study of radiation sensitive organic molecule crystals. (C) 2002 Elsevier Science Ltd. All rights reserved.