  Weakly Interacting Massive Particle (WIMP) direct detection event rate
calculations usually rely on fairly simple, essentially static, analytic halo
models. This is largely since the resolution of numerical simulations is not
yet large enough to allow the full numerical calculation of the WIMP density
and velocity distribution. In this paper we study the direct detection rate, in
particular its energy dependence and annual modulation, for the caustic ring
halo model. In this model, which uses simple assumptions to model the infall of
dark matter onto the halo, the distribution of the cold dark matter particles
at the Earth's location has a series of peaks in velocity space. We find that
the sign of the annual modulation in the event rate changes as a function of
recoil energy. These effects provide a potentially distinctive experimental
signal.
