Numerical Evaluation of a Screened Rutherford Pencil Beam Solution

Two different numerical procedures are suggested for evaluating a previous analytic result for the scalar flux for the pencil beam problem with screened Rutherford scattering. The first of these is an asymptotic evaluation of a divergent integral, and the second is based upon an asymptotic expansion method due to Molière. Both are relatively simple algorithms, and comparisons with each other and with benchmark Monte Carlo results are given to establish the accuracy of each.