# Efficient polarization analysis for focusing neutron instruments

## TL;DR

This paper introduces a novel polarization analysis method for focused neutron beams using bent transmission supermirrors shaped as equiangular spirals, achieving over 95% polarization efficiency without compromising beam quality.

## Contribution

The paper presents a new polarization analysis technique based on bent supermirrors for focused neutron beams, suitable for pulsed sources and high-divergence beams, with practical implementations tested and planned.

## Key findings

- Achieved polarization above 95% with good transmission
- Successfully tested on the AMOR reflectometer
- Next-generation device planned for the Estia instrument

## Abstract

Polarized neutrons are a powerful probe to investigate magnetism in condensed matter on length scales from single atomic distances to micrometers. With the ongoing advancement of neutron optics, that allow to transport beams with increased divergence, the demands on neutron polarizes and analyzers have grown as well. The situation becomes especially challenging for new instruments at pulsed sources, where a large wavelength band needs to be polarized to make efficient use of the time structure of the beam. Here we present a polarization analysis concept for highly focused neutron beams that is based on transmission supermirrors that are bend in the shape of equiangular spirals. The method allows polarizations above 95\% and good transmission, without negative impact on other beam characteristics. An example of a compact polarizing device already tested on the AMOR reflectometer is presented as well as the concept for the next generation implementation of the technique that will be installed on the Estia instrument being build for the European Spallation Source.