Simulation of waviness in neutron guides

TL;DR

This paper introduces a stochastic waviness model for neutron guide simulations, implemented in McStas, enabling more realistic and complex guide design analysis.

Contribution

A novel stochastic waviness model is developed and integrated into McStas, improving the realism of neutron guide simulations with imperfections.

Findings

The new waviness model shows significant differences compared to previous models.

Simulations with the new model better match experimental data.

Implementation enhances the predictive power of neutron guide design simulations.

Abstract

As the trend of neutron guide designs points towards longer and more complex guides, imperfections such as waviness becomes increasingly important. Simulations of guide waviness has so far been limited by a lack of reasonable waviness models. We here present a stochastic description of waviness and its implementation in the McStas simulation package. The effect of this new implementation is compared to the guide simulations without waviness and the simple, yet unphysical, waviness model implemented in McStas 1.12c and 2.0.