On Scanning Electron Diffraction†

Abstract

The paper describes a new instrument for investigations of the solid state : the high-speed direct-recording electron diffraction instrument. Its chief advantages are direct presentation of the intensity profiles of diffracted peaks to an accuracy of butter than 2%, and recording times which may be as short as 50 msec for a radial traverse across a complete pattern of the Debye—Scherrer ring typo. Typical results are given, including stills from a cine-film of a rapid amorphous-to-crystalline transformation in silver. The factors limiting the performance of the system are discussed : a precision of measurement of 0–1% on diffracted peaks of moderate intensity should be possible in a recording time of a, second ; conversely reduction of accuracy to 4% should permit recording times for entire patterns of a millisecond.