• B.G. Pine, D.J. Adams, B. Jones, C.M. Warsop, R.E. Williamson
  STFC/RAL/ISIS, Chilton, Didcot, Oxon

The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It is based on a 50 Hz proton synchrotron which accelerates ~3·10¹³ protons per pulse (ppp) from 70 to 800 MeV, corresponding to beam powers of ~0.2 MW. Studies are under way for major upgrades in the Megawatt regime. Underpinning this programme of operations and upgrades is a study of the high intensity effects that impose limitations on beam power. The behaviour of the beam in the 50 Hz rapid cycling synchrotron (RCS) is largely characterised by high space charge levels and the effects of fast ramping acceleration. High intensity effects are of particular importance as they drive beam loss, but are not fully understood with only limited analytical models available. This paper reviews several methods by which these effects are explored numerically on ISIS, and compares them where possible with experimental or analytical results. In particular we outline development of a new space charge code Set, which is designed to address key issues on ISIS and similar RCS machines.