Neutron absorption correction and mean path length calculations for multiple samples with arbitrary shapes -- applications to highly absorbing samples on the Multi-Axis Crystal Spectrometer at NIST

The finite volume algorithm for absorption correction developed by Wunch and Prewitt is examined. This algorithm is based on the numerical integration of the transmission function where three-dimensional quadratic surfaces define the sample boundaries. The algorithm can also calculate the mean path length required for second-extinction calculations. We apply this method to the neutron inelastic scattering measurements of CeRhIn${}_5$ using the Multi-Axis Crystal Spectrometer (MACS) at NIST. The algorithm has been expanded to correct the absorption of multiple coaligned samples. We show that this procedure can account for the angular-dependent absorption, and the technique can be used to correct data and plan experiments.