Optimization of the low energy electron point source microscope:: imaging of macromolecules

Optimal conditions for low energy electron point source microscopy are investigated by the simulation and numerical reconstruction of holograms of phthalocyaninato polysiloxane, PcPS, a rod-like macromolecule. The effects of the electron energy, width of the electron beam and the detector size on the spatial resolution in the reconstructed images are modeled. We find that for electron energies around 200 eV, with the specimen 0.1 mum from the source, a screen recording the image in a cone of at least 15degrees half angle (7 cm lateral dimension at 10 cm from the source) with at least 512 x 512 pixel and 8-bit resolution will result in near atomic resolution. (C) 2002 Elsevier Science Ltd. All rights reserved.