Testing, Installation, Commissioning and First Operation of the ISIS RFQ Pre-Injector Upgrade

Situated at the Rutherford Appleton Laboratory (Oxon., UK), ISIS is currently the world's most intense pulse spallation neutron source, delivering 160 kW of 800 MeV protons to a tungsten target at 50 Hz. A major facility upgrade programme involves the construction of a second, 10 Hz target and an increase in the total beam power of up to 50% (i.e. up to 240 kW). To achieve the planned increase in average beam current to 300 μA whilst maintaining the current manageable levels of beam loss, four 2nd harmonic RF cavities have been installed in the synchrotron and the ageing Cockcroft-Walton preinjector in the linac has been replaced with a 665 keV, 202.5 MHz, 4-rod Radio Frequency Quadrupole (RFQ). This paper describes the extensive testing, installation, commissioning and successful initial operation of the RFQ pre-injector upgrade.