• B. Jones, D.J. Adams, S.J.S. Jago, H. V. Smith, C.M. Warsop
  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. The accelerator facility consists of a 70 MeV H^- linac and a 50 Hz proton synchrotron accelerating up to 3.75x10¹³ protons per pulse from 70 to 800 MeV, delivering a mean beam power of 0.24 MW. Present upgrade studies are investigating how replacement of the existing linac and increased injection energy could increase beam power in the existing ISIS ring. Such an upgrade would replace one of the oldest sections of the ISIS machine, and with reduced space charge and optimised injection, may allow substantially increased intensity in the ring, perhaps towards the 0.5 MW regime. A critical aspect of such an upgrade would be the new higher energy injection straight. This paper summarises beam dynamics and hardware requirements for 180MeV H^- charge exchange injection into ISIS including; optimisation of the injection magnets; requirements for beam dumps and results of stripping foil simulations with estimates of stripping efficiency and foil heating.

• J.W.G. Thomason, D.J. Adams, D.J.S. Findlay, I.S.K. Gardner, S.J.S. Jago, B. Jones, A.P. Letchford, R.J. Mathieson, S.J. Payne, B.G. Pine, A. Seville, H. V. Smith, C.M. Warsop, R.E. Williamson
  STFC/RAL/ISIS, Chilton, Didcot, Oxon
• J. Pasternak
  STFC/RAL, Chilton, Didcot, Oxon
• C.R. Prior, G.H. Rees
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon

The ISIS Facility based at the Rutherford Appleton Laboratory in the UK is the world's most productive spallation neutron source. Presently it runs at beam powers of 0.2 MW, with RF upgrades in place to supply increased powers for the new Second Target Station. Increasing injection energy into the synchrotron beyond the existing 70 MeV level has significant potential to increase intensity as a result of reduced space charge. This paper outlines studies for this upgrade option, which include magnet and power supply upgrades to achieve a practical injection system, management of increased injection region activation levels due to higher energy un-stripped particles and ensuring the modified longitudinal and transverse beam dynamics during injection and acceleration are possible with low loss at higher intensity levels.