A digital scanning and recording system for spot electron diffraction patterns

Abstract

The system drives the tilt coils of a transmission electron microscope in order to bring each spot in the diffraction pattern from a single crystal in turn onto a central fixed scintillator-photomultiplier detector. The intensity of each spot is measured by integrating the photomultiplier current for a known time. The digitized intensity is then stored in a memory and may be displayed on an oscilloscope or punched out on paper tape for computer processing. Among the facilities incorporated are data accumulation with overwriting of previous data or with addition to or subtraction from previous data, and independent rotation and gain control of the two directions of scan.