Exponential discontinuous finite element scheme for coupled charged-uncharged particle transport

High energy beams for cancer therapy, ion implantation in semiconductor materials, accelerator transmutation of waste and cosmic ray interactions with materials are problems of interest to the nuclear engineering community. High energy radiation can produce a variety of particles as a result of fragmented nuclei and the emitted particles can undergo further collisions creating a cascade. Charged and uncharged particles differ in their energy deposition. Uncharged particles can travel large distances between collisions and can produce charged particles deep into the material. These penetrating secondary charged particles deposit their energy through electronic collisions. These effects require that an accurate dose calculation be performed.; Monte Carlo calculations have been the traditional methods of evaluation but require a high computational cost. To overcome the difficulties encountered by Monte Carlo methods, the exponential discontinuous finite element method has been applied to model energy deposition by high energy particle cascades. The straight ahead approximation with CSD energy loss is used and all physical data is taken to be piecewise constant in each cell. Initially the ED method was shown not to capture the primary particle's Bragg peak, but, isolating and treating the primary particle distribution exactly removed this difficulty. The ED method was used to model secondary distribution. The ED method was benchmarked against exact solutions and together with accuracy tests it is shown to be an efficient method for representing the secondary distribution.