PowderTAS: Neutron Scattering Cross-sections for Powder Samples

PowderTAS is a Matlab code designed to calculate neutron scattering cross-sections of powder samples, represented as Q-E scattering maps, using "single-crystal" phonon calculation eigenvectors as input. The name comes from the original not-to-be-repeated neutron experiment where we put a powder sample on a three-axis spectrometer (TAS). The whole concept of this code is to do a powder average over a high-number of Q-points, randomly generated at a distance |Q| from the origin, forming a sphere (the positive quadrant of it). At each point on this sphere, the eigenvectors are obtained by trilinear interpolation, and using them, the scattering cross-sections (elastic and inelatic, coherent and incoherent) are calculated. These cross-sections are then used to make an histrogram-spectra, which can be seen as a line in a frequency/momentum map. This process is repeated for a serie of Q-values, hence forming the complete scattering map of a powder sample.