Lorentz factor for triple-axis spectrometers

Abstract

An expression for the Lorentz factor relevant to a triple-axis neutron spectrometer is presented. The expression relates the structure factor of a Bragg peak to the integrated intensity obtained with any scan which passes through the Bragg point and which follows a linear path in reciprocal space. The important exact result obtained here is that the Lorentz factor is the same for double-axis spectrometers when theta-2 theta scan is used and when the sample is a single crystal with a narrow mosaic. (NL)