Fading and broadening of electron diffraction spot from beam-damaged multiple monolayer films

In contrast to the increase in the extinction dose for thick specimens, observed broadening rates of diffraction spots from behenic acid multiple monolayers were independent of specimen thickness. This result leads to the conclusion that specimens are always decaying at the same rate although the periodicity of crystals still remains in thick specimens. The conclusion is interpreted as being the result of the radiation damage mechanism based on longitudinal motions of long chain molecules. For the evaluation of beam damage effect the broadening rate and the extinction dose should be used as indicator for the radiation sensitivity of crystals and for the possibility of observing diffraction patterns, respectively.