  The multiple scattering model of a quantum particle in a random Lorentz gas
consisting of fixed point scatterers is considered in arbitrary dimension. An
efficient method is developed to numerically compute the map of the density of
scattering resonances in the complex plane of the wavenumber without finding
them one by one. The method is applied to two collision models for the
individual scatterers, namely a resonant model, and a non-resonant hard-sphere
model. The results obtained with the former are compared to the literature. In
particular, the spiral arms surrounding the single-scatterer resonance are
identified as proximity resonances. Moreover, the hard-sphere model is used to
reveal previously unknown structures in the resonance density. Finally, it is
shown how Anderson localization affects the distribution of resonance widths,
especially in the one-dimensional case.
