Limitations on the accuracy of polarized-neutron diffractometry

The magnetic force on a neutron as it enters a high-field magnet can influence the results of polarized-neutron diffraction experiments. The position of the Bragg peak is slightly different for neutrons in the two spin states and the peak intensity is slightly different. The magnitudes of these effects are calculated and experimental evidence confirming the peak shift calculation is presented. Suggestions for experimental procedures to minimize these effects are presented. The discussion is directed toward experiments in which flipping-ratio accuracies approaching 5x10-5 are desired. (Auth.)