# PortGISANS: nested mirror optics for a portable GISANS adapter

## TL;DR

This paper introduces a portable GISANS adapter using nested mirror optics to enhance neutron scattering experiments for surface science.

## Contribution

The novel contribution is a portable GISANS adapter with nested mirror optics that significantly increases flux for neutron scattering.

## Key findings

- The device increases GISANS flux by at least one order of magnitude.
- It preserves lateral resolution while relaxing out-of-plane resolution.
- The adapter enables experiments from free liquid surfaces.

## Abstract

Grazing-incidence scattering techniques are powerful tools for studies in surface science. In particular, grazing-incidence neutron scattering (GISANS) provides unique insights in soft-matter systems and magnetic structures, in particular, if they are buried beneath a surface. However, the brilliance of neutron sources is limited hindering the method from becoming widely used. Here we present focusing nested mirror optics that improve the GISANS capabilities of SANS beamlines. Our device preserves the lateral resolution along an interface and relaxes the resolution out-of-plane, sacrificing depth-resolution. By combining ray tracing simulations with the distorted wave born approximation we show that a portable and easy to install optics increases the flux available for GISANS studies, at least, by one order of magnitude and enables straight forward experiments from free liquid surfaces.