  For the purpose of finding benchmark quality solutions to time dependent Sn
transport problems, we develop a numerical method in a Discontinuous Galerkin
(DG) framework that utilizes time dependent cell edges, which we call a moving
mesh, and an uncollided source treatment. The DG method for discretizing space
is a powerful solution technique on smooth problems and is robust on non-smooth
problems. In order to realize the potential of the DG method to spectrally
resolve smooth problems, our moving mesh and uncollided source treatment is
devised to circumvent discontinuities in the solution or the first derivative
of the solutions that are admitted in transport calculations. The resulting
method achieves spectral convergence on smooth problems, like a standard DG
implementation. When applied to problems with nonsmooth sources that induce
discontinuities, our moving mesh, uncollided source method returns a
significantly more accurate solution than the standard DG method. On problems
with smooth sources, we observe spectral convergence even in problems with wave
fronts. In problems where the angular flux is inherently non-smooth, as in
Ganapol's (2001) well known plane pulse benchmark, we do not observe an
elevated order of accuracy when compared with static meshes, but there is a
reduction in error that is nearly three orders of magnitude.
