Quantifying strain/stress in small perfect crystal neutron interferometers

We have fabricated two perfect silicon crystal neutron interferometers (NI) that are well-suited for various fundamental physics applications. The interferometers are small and will be used to test aspects of dynamical diffraction (DD) theory, which describes how neutrons and X-rays propagate through perfect crystals. The main goal with be to analyze the strain/stress and imperfections in the perfect crystal interferometer base and blades as these things vastly alter the contrast of the interferometer. This work also provides unique tests for the recently developed quantum information model for DD theory that is ideally suited for studying complex crystal geometries, strains/stress, and/or imperfections that are beyond the scope of the standard theory of DD. The experiment will analyze the Bragg diffracted beams at IMAT and measure the contrast of the two perfect crystal neutron interferometers. We will use the quantum information model for DD to compare with experimental results and quantify effects that alter the interference pattern such as temperature gradients or vibrations and consider crystal defects, strain/stress, surface roughness and machining imperfections. This work is of fundamental interest in the neutron science community as any experiments involving perfect crystals rely on DD theory which can be uniquely tested with the smaller interferometers.