The world wide shortage of helium-3 is forcing the development of new detectors for neutron spectroscopy. A candidate for new detector design that consists of multiple detection volumes in depth, in contrast to the traditional single volume helium-3 detector, is being developed at ESS in Lund. One advantage of the new design is the possibility of utilising the additional depth dimension to extract information about the beams used in neutron spectroscopy, more exactly their wavelength compositions. The work done in this thesis aim to describe the beamline compound with a prarametric probabilistic model. Parameter estimates are obtained using a non-linear least squares regression approach on both experimental and simulated data. The distributions and condence intervals for the estimated parameters are constructed using the parametric bootstrap.
