Megawatt upgrades for the ISIS facility
Thomason JWG., Adams DJ., Findlay DJS., Gardner ISK., Jones B., Letchford AP., Payne SJ., Pine BG., Seville A., Warsop CM., Williamson RE., Plostinar DC., Prior CR., Rees GH.
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 due to start operation in Autumn 2008. This paper outlines possible schemes for major upgrades to the facility in the megawatt regime, with options for 1, 2 and 5 MW. The favoured ideas centre around new ∼3 GeV rapid cycling synchrotron (RCS) designs that can be employed to increase the energy of the existing ISIS beam to provide powers of ∼1 MW or, possibly as a second upgrade stage, accumulate and accelerate beam from a new 0.4-0.8 GeV linac for 2-5 MW beams. Key features for a new ring design are presented, along with a brief summary of the main aspects of a future design study.