The modification of the electron microscope for special crystallographic applications.

The conversion of the transmission electron microscope to a convergent-beam camera and shadow microscope with facilities for experiments using two specimens located in different planes is discussed, with particular reference to older models such as the Elmiskop 1. The conversion requires the removal of the intermediate lens in some microscopes and thus prevents them from operating in their original capacity. The Elmiskop 1 has a wide intermediate lens pole-piece which does not unduly restrict the diffraction angle. The smallest crystal spacing contributing to the convergent-beam diffraction pattern is 0.05 nm.