Neutron polarisation correction to triple-axis data with analytical derivations

TL;DR

This paper derives analytical formulas for correcting polarised neutron scattering data in triple-axis experiments, improving accuracy in magnetic studies despite experimental challenges.

Contribution

It provides the first analytical correction formulas for polarised neutron triple-axis data, applicable to longitudinal polarisation analysis.

Findings

Correction formulas work effectively on experimental data

Analytical approach addresses low flux and complex configurations

Application demonstrated on Y3Fe5O12 experiment

Abstract

Polarised neutron scattering is the method of choice to study magnetism in condensed matter. Polarised neutrons are typically very low in flux, and complex experimental configurations further reduce the count rate. Neutron polarisation corrections would therefore be needed. Here we analytically derive formulae of the corrected partial differential scattering cross-sections. The analytical method is designed for the longitudinal polarisation analysis, and the correction generally holds for time-independent polarised neutrons with a triple-axis spectrometer. We then apply the correction to recent results of our $P_x$ experiment on Y$_3$Fe$_5$O$_{12}$. Although there is a difficulty with the experimental determination of inefficiency parameters of neutron spin polarisers and flippers, the correction appears to work properly.