High q-resolution neutron scattering technique using triple-axis spectrometers

TL;DR

This paper introduces a novel neutron scattering technique that significantly enhances wave-vector resolution in triple-axis spectrometers by matching the measurement wave-vector to a perfect crystal reflection, enabling precise detection of small structural changes.

Contribution

The paper presents a new method to improve q-resolution in triple-axis spectrometers by matching wave-vector to crystal reflection, achieving a Bragg width of about 10^-4.

Findings

Achieved high q-resolution with δ/Q ~ 10^-4

Enhanced ability to measure small structural changes

Maintained all advantages of conventional triple-axis spectrometers

Abstract

We present a new technique which brings a substantial increase of the wave-vector $q$-resolution of triple-axis-spectrometers by matching the measurement wave-vector $q$ to the reflection $\tau_a$ of a perfect crystal analyzer. A relative Bragg width of $\delta/Q \sim 10^{-4}$ can be achieved with reasonable collimation settings. This technique is very useful in measuring small structural changes and line broadenings that can not be accurately measured with conventional set-ups, while still keeping all the strengths of a triple-axis-spectrometer.