Protheroe, R.2007-07-052007-07-052001Proceedings of the 27th International Cosmic Ray Conference. 07-15 August, 2001. Under the auspices of the International Union of Pure and Applied Physics (IUPAP): pp.2014-2017http://hdl.handle.net/2440/34505In this paper I present Monte Carlo results for shock acceleration at an ultrarelativistic shock for the case where propagation downstream can be approximated by a random walk with isotropic scattering. An event generator for the downstream part of the cycle was developed and results in extremely efficient Monte Carlo simulation. Two simple scattering models are used upstream: isotropic scattering, and small angle scattering. The angular distribution of particles at the shock, and the distribution of momentum as a function of time after injection are given together with the resulting momentum spectrum of accelerated particles. The results for small angle scattering are in qualitative agreement with more sophisticated treatments.enConference paper002006465550177