High-resolution Neutron Diffraction using Larmor Precession

A polarized neutron beam travels through a precession coil with field B and the intensity in a detector behind the analyser is recorded as a function of B. Fourier transformation of the intensity signal gives the wavelength spectrum of the beam entering the detector. Any (diffraction) experiment can be set up in the optical pathway between the analyser and detector. This technique is applied in an array of high-resolution diffraction experiments along the path of the neutron beam through a bent Al strip. The detector intensities are measured only over a small range of B away from . The phase shift between the intensity signals from compressed/extended regions, relative to the signal from a reference region in the strip, reveals the deformation of the Al lattice.