One directional Polarized Neutron Reflectometry with optimized reference layer method

TL;DR

This paper presents an optimized method for one-directional polarized neutron reflectometry using reference layers, enabling phase and modulus determination of multilayer films with limited polarization measurement capabilities.

Contribution

The authors improve the reference layer method for polarized neutron reflectometry, allowing phase and modulus measurements without changing the polarization direction, suited for existing neutron reflectometer technology.

Findings

Method successfully measures phase and modulus of unknown films.

Compatible with current neutron reflectometer polarization measurement limits.

Enhances experimental feasibility for polarized neutron studies.

Abstract

In the past decade, several neutron reflectometry methods for determining the modulus and phase of the complex reflection coefficient of an unknown multilayer thin film have been worked out among which the method of variation of surroundings and reference layers are of highest interest. These methods were later modified for measurement of the polarization of the reflected beam instead of the measurement of the intensities. In their new architecture, these methods not only suffered from the necessity of change of experimental setup, but also another difficulty was added to their experimental implementations. This deficiency was related to the limitations of the technology of the neutron reflectometers that could only measure the polarization of the reflected neutrons in the same direction as the polarization of the incident beam. As the instruments are limited, the theory has to be optimized so that the experiment could be performed. In a recent work, we developed the method of variation of surroundings for one directional polarization analysis. In this new work, the method of reference layer with polarization analysis has been optimized to determine the phase and modulus of the unknown film with measurement of the polarization of the reflected neutrons in the same direction as the polarization of the incident beam.