Abstract
The energy loss spectra of 25 keV electrons traversing thin films of the nucleic acid bases adenine (C5N5H5), thymine (C5N2O2H6), and uracil (C4N2O2H4) have been obtained at room temperature in the region of K‐shell excitation (>285 eV), and fine structure near the carbon K edge of these materials has been analyzed. The inelastic scattering cross sections have also been determined for both K‐shell and valence shell excitation. Preliminary results on the effect of electron beam damage of these specimens will also be presented.