Abstract :
A versatile electron-optical bench has been constructed recently at the National Bureau of Standards (NBS) for the extensive study of electron-optical elements. Carriages for magnetic lenses, mirrors, or prisms, and holders for apertures, objectives, and meshes are arranged appropriately in a vacuum chamber. External positioning controls are also provided, offering three degrees of freedom for each element. The bench was developed by the NBS electron physics laboratory. It has become an integral part of a program devoted to the investigation of extremely small electric and magnetic fields in spaces that heretofore have been inaccessible to conventional types of measurement.1
