Optimization of neutron diffraction from phase-gratings

TL;DR

This paper investigates how to optimize neutron diffraction from phase-gratings to enhance contrast in neutron interferometry, using Bragg diffraction to assess and improve grating alignment and performance.

Contribution

It introduces a quantitative method to assess and optimize phase-gratings for neutron interferometry using Bragg diffraction, addressing contrast limitations.

Findings

Well-defined diffraction peaks observed

Alignment perturbations affect diffraction and contrast

Technique enables in-situ grating alignment optimization

Abstract

The recent development of phase-grating moir\'e neutron interferometry promises a wide range of impactful experiments from dark-field imaging of material microstructure to precise measurements of fundamental constants. However, the contrast of 3 % obtained using this moir\'e interferometer was well below the theoretical prediction of 30 % using ideal gratings. It is suspected that non-ideal aspects of the phase-gratings was a leading contributor to this deficiency and that phase-gratings needed to be quantitatively assessed and optimized. Here we characterize neutron diffraction from phase-gratings using Bragg diffraction crystals to determine the optimal phase-grating orientations. We show well-defined diffraction peaks and explore perturbations to the diffraction peaks and the effects on interferometer contrast as a function of grating alignment. This technique promises to improve the contrast of the grating interferometers by providing in-situ aides to grating alignment.