Neutron Ray-Tracing Simulations of a New Supermirror Guide for the Osiris Spectrometer

Abstract

A new supermirror guide has been proposed to replace the current neutron guide of the indirect time-of-flight near-backscattering spectrometer OSIRIS at the ISIS facility. Here we present an extensive Monte Carlo simulation study for the design and optimisation of a new guide system. Among the several guide geometry assessed, a curved guide with elliptical defocusing and focusing sections is shown to perform best. The estimated gain in intensity is a factor of 5–6 at the sample position with a homogeneous distribution of the divergence. The elliptic geometry results in a smaller beam spot and smaller samples will particularly benefit from this upgrade. The proposed guide replacement will ensure that the OSIRIS spectrometer will remain competitive in the years to come.

Felix Fernandez-Alonso

Ikerbasque Research Professor

Ikerbasque Research Professor at the Materials Physics Center, Donostia - San Sebastián.