Axisymmetric Grazing-Incidence Focusing Optics for Small-Angle Neutron Scattering

TL;DR

This paper introduces novel Wolter optics for small-angle neutron scattering, significantly enhancing neutron flux and resolution, enabling more compact and efficient SANS instruments.

Contribution

It presents the design and simulation of Ni-based Wolter optics with multilayer coatings for improved neutron focusing in SANS.

Findings

Over an order-of-magnitude increase in neutron flux.

Reduction in minimum wave vector transfer.

Potential for shorter, high-resolution SANS instruments.

Abstract

We propose and design novel axisymmetric focusing mirrors, known as Wolter optics, for small-angle neutron scattering instruments. Ray-tracing simulations show that using the mirrors can result in more than an order-of-magnitude increase in the neutron flux reaching detectors, while decreasing the minimum wave vector transfer. Such mirrors are made of Ni using a mature technology. They can be coated with neutron supermirror multilayers, and multiple mirrors can be nested to improve their flux-collection ability. Thus, these mirrors offer simple and flexible means of significantly improving existing and future SANS instruments. In addition, short SANS instruments might become possible, especially at compact neutron sources, when high-resolution detectors are combined with Wolter optics.