ISIS UPGRADES — A STATUS REPORT

Since 2002 several accelerator upgrades have been made to the ISIS spallation neutron source at the Rutherford Appleton Laboratory in the UK, and upgrades are currently continuing in the form of the Second Target Station Project. The paper reviews the upgrade processes, and looks forward to possible future schemes at ISIS beyond the Second Target Station. ISIS SPALLATION NEUTRON SOURCE The ISIS spallation neutron source (then simply called SNS) produced its first proton beam on 16 December 1984. At that time it was configured as a 665 kV Cockcroft-Walton preinjector, a 70 MeV H – 4-tank drift tube linac, and a 26 m mean radius 800 MeV proton synchrotron with a cycling rate of 50 Hz driving