Automatic Neutron Diffractometer for Three-Dimensional Structure-Factor Determination

This fully automatic single-crystal diffractometer employs the Eulerian hoop geometry. It is under punchedtape control and the three independent shafts are set simultaneously for each reflection to an accuracy of 0.03° using a moiré fringe positioning system. The reflection is then measured by moving the crystal in steps across the reflecting position. The time on each step is variable, being determined by a monitoring counter, and the number of steps is under program control. Results are both printed in plain language and punched on a paper tape, ready for direct processing in a computer.