  Using test particle simulations we study particle acceleration at highly
perpendicular ($\theta_{Bn}\geq 75^\circ$) shocks under conditions of modeling
magnetic turbulence. We adopt a backward-in-time method to solve the
Newton-Lorentz equation using the observed shock parameters for
quasi-perpendicular interplanetary shocks, and compare the simulation results
with $ACE$/EPAM observations to obtain the injection energy and timescale of
particle acceleration. With our modeling and observations we find that a large
upstream speed is responsible for efficient particle acceleration. Our results
also show that the quasi-perpendicular shocks are capable of accelerating
thermal particles to high energies of the order of MeV for both kappa and
Maxwellian upstream distributions, which may originate from the fact that in
our model the local background magnetic field has a component parallel to the
shock normal.
