z +: Neutron cross section separation from wide-angle uniaxial polarization analysis

Abstract

We introduce a simple method to extract the nuclear coherent and isotope incoherent, spin incoherent, and magnetic neutron scattering cross section components from powder scattering data measured using a single neutron beam polarization direction and a position-sensitive detector with large out-of-plane coverage. The method draws inspiration from polarized small-angle neutron scattering and contrasts with conventional so-called "xyz " polarization analysis on wide-angle instruments, which requires measurements with three orthogonal polarization directions. The viability of the method is demonstrated on both simulated and experimental data for the classical "spin ice " system Ho2Ti2O7, the latter from the linear energy transfer direct geometry spectrometer at the International Science Information Service facility. The cross section components can be reproduced with good fidelity by either fitting the out-of-plane angle dependence around a Debye-Scherrer cone or grouping the data by angle and performing a matrix inversion. The limitations of the method and its practical uses are discussed. (C) 2022 Author(s).