Determination of the magnetic spin direction from the nuclear forward-scattering line intensities

An expression is derived for the line intensities in a nuclear forward-scattering energy spectrum that is obtained via a Fourier transformation of the time dependence of the wavefield. The calculation takes into account the coherent properties of the nuclear forward-scattering process and the experimental limitations on the observable time window. It is shown that, for magnetic samples, the spin direction can be determined from the ratios between the different lines in the energy spectrum. The theory is complemented with experimental results on α-iron.