Transport Problems in Media with Periodic Structure.

The problem of transport of particles in a slab geometry is considered, the unique feature being that the slab is assumed to have a periodic structure. It is shown that the particle density at any point in the slab can be obtained numerically by integrating a set of differential equations of initial value type over one period, followed by the use of certain relatively easy difference and functional equations. There are strong indications that considerable advantage is gained in time, accuracy, stability, etc. over the standard method of handling such problems. Several rather simple numerical examples are given. Agreement with results obtained in other ways is excellent. It is noted that the algorithm produced is really applicable to a wide class of two-point boundary value problems having little or nothing to do with transport theory per se. (Author)