Method and apparatus for producing electron beam diffraction patterns

摘要

A method is disclosed of producing electron beam diffraction patterns, in which the object to be examined is one which is liable to be altered substantially by an electron beam when that beam is accelerated by a predetermined voltage to the energy density necessary for the production of an image. The object is irradiated by an electron beam and the electrons of the electron beam, diffracted by the object, are imaged using an integrating image apparatus or an integrating image material, for example a photographic layer. One or more regions of the object corresponding in size to the cross section of the electron beam are irradiated intermittently using an electron beam accelerated by the pre-determined voltage, the electron beam having an electron density which is lower than the electron density at which the object is substantially altered. Irradiation is carried out for such a period of time that the electron density of the electron beam, integrated during this time, is at least equal to the electron density necessary to produce an image.