Space charge and high intensity studies on ISIS

ISIS is the spallation neutron source at the Rutherford Appleton Laboratory in the UK. Presently, it runs at beam powers of ∼0.2 MW, with upgrades in place to supply increased powers for the new Second Target Station. Studies are also 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 the limitations on beam power. This paper summarises work looking at the key topics of injection painting, half integer resonance, and image effects under high space charge conditions, plus progress on overall machine modelling. A core aim of the work is to experimentally confirm simulations and theory; therefore progress on modelling the machine in both operational and specially configured modes is reported. Closely related diagnostics studies are also described.