Proposal for continuation of the Front End Test Stand

i Executive summary High power proton accelerators (HPPAs) are at the heart of many future large-scale scientific facilities such as a spallation-neutron source, Neutrino Factory and the Muon Collider, high energy physics at the energy or intensity frontier, accelerator driven sub-critical systems, and the transmutation of nuclear waste. Controlling beam-loss induced machine activation during injection into a circular accelerator (synchrotron or FFAG) is essential for safe operation of HPPAs and requires the beam in the injector linac to be chopped very precisely at the synchrotron revolution frequency. The Front End Test Stand (FETS) at RAL has as its primary aim to demonstrate perfect chopping of a high quality, high intensity, negative Hydrogen ion beam at an energy of 3 MeV. Although primarily a hardware construction project, the FETS collaboration has become an efficient mechanism for sharing the wealth of real-world accelerator expertise within ISIS and the ASTeC Intense Beams Group with the wider academic community as well as benefitting from the specialisations and expertise of the university groups. The work already undertaken has contributed to the UK's continuing international reputation as a centre of excellence and has stimulated collaborations with leading international accelerator institutes such as CERN, FNAL, ESS and CNS. FETS consists of a high-brightness Penning surface plasma negative-hydrogen-ion source, magnetic Low Energy Beam Transport (LEBT) at 65 keV to match the beam into a 3 MeV Radio Frequency Quadrupole (RFQ) operating at 324 MHz which delivers the 60mA beam to the Medium Energy Beam Transport (MEBT) where the chopping systems are situated. Comprehensive, state-of-the-art diagnostics measure the performance of the system and the beam quality. The ion source, LEBT and high power RF systems have been commissioned and the manufacture of the RFQ is underway. With this proposal we seek the resources to complete the construction of FETS in a timely manner. This will entail:  The installation, testing and commissioning of the RFQ;  Accelerating the desired beam intensity and beam quality through the RFQ;  The completion of the engineering design and the manufacture of the chopper systems;  The installation, testing and commissioning the MEBT and chopper systems;  The transmission of beam through the MEBT and the demonstration of precise and efficient beam chopping; and  Evaluating the performance of the complete test stand. In addition, we proposed to evaluate the additional benefits that will accrue from exploiting the FETS as a driver for …