Electron holography with a superconducting objective lens

The design of a transmission electron microscope with a superconducting objective lens and a field-emission gun operating at 80–100 kV is described. The microscope, equipped with an electrostatic biprism is designed for the holographic analysis of objects at liquid helium temperatures, e.g. to make use of the cryoprotection of biological objects from radiation damage. Special care was taken to achieve a high electrical and mechanical stability of the microscope. Fundamental phase resolution limits are discussed as well as the construction and performance of the instrument.