We have designed, fabricated and tested a lens with chromatic aberration
coefficient (Cc) of 1.0 mm, a 4.0 mm pole-gap and 2.0 mm bore that is wide
enough to accommodate an anti-contamination system and an objective aperture.
This lens extends the temporal-coherence envelope of the electron microscope
beyond 2 Angstrom, using a low-cost Schottky FEG. We hope that this lens design
can be used to improve all 100 keV electron microscopes designed for
single-particle electron cryomicroscopy (cryoEM).