Variational calculation of the angular width of the multiple scattering distribution in foil transmission
A simple formula is derived for calculating the angular width of multiple scattering distributions for atomic particles traversing thin foils. The universal result is obtained by applying the variational method on standard multiple scattering theory. This procedure can be carried through in a straight-forward way, thus saving lengthy series expansions and Fourier transforms. In the case of power cross sections exact analytical expressions can be obtained. A remarkably good agreement is found between our calculation and previous theories, as well as with results from our computer simulations.