Strioscopic Electron Microscopy

Abstract

The dark field technique of strioscopy has provided high contrast with reasonable resolution at the organelle level for diffusely scattering, biological-type specimens and information concerning scattering processes in electron microscopy. It has involved the removal of the direct beam from the diffraction pattern by a central wire and subsequent image formation by diffracted beams, limited by a central back focal plane aperture. Strioscopic apertures (Fig. 1) have been constructed by microwelding 10µ platinum wire onto conventional platinum objective apertures. These strioscopic apertures were carried in the normal objective lens aperture holder. The focal length of a Siemens Elmiskop IA E/M was shortened to achieve coincidence of aperture and diffraction planes (Fig. 2).