• R. Enparantza, I. Ariz, P. Romano, A. Sedano
  Fundación TEKNIKER, Eibar (Gipuzkoa)
• F.J. Bermejo
  Bilbao, Faculty of Science and Technology, Bilbao
• D.C. Faircloth, A.P. Letchford
  STFC/RAL/ISIS, Chilton, Didcot, Oxon

A Front End Test Stand is being built at the Rutherford Appleton Laboratory in the UK to demonstrate a chopped H− beam of sufficiently high beam quality for future high-power proton accelerators (HPPA). The test stand consists on a negative Hydrogen ion source, a solenoid LEBT, a 324 MHz four vane RFQ, a MEBT composed of rebunching cavities and choppers and a set of diagnostics ending with a beam stop. The beam stop, which has to accept a 3 MeV, 60 mA, 2 ms, 50 Hz (10% duty factor) H− beam, consists of a coaxial double cone configuration where the inner cone's inner surface is hit by the beam and the inter-cone gap is cooled by high-speed water. The cones are situated inside a water tank and mounted at one end only to allow thermal expansion. In order to minimize both prompt and induced radiation pure aluminium is used, but the poor mechanical properties of pure aluminium are overcome by employing a metal spinning process that increases the yield strength to several times the original value of the non-deformed material. CFD and FEM codes have been used to avoid high temperature gradients, to minimize thermal stresses, and to minimize fatigue caused by the pulsed beam.

• A.P. Letchford, M.A. Clarke-Gayther, D.C. Faircloth, S.R. Lawrie, M. Perkins, P. Wise
  STFC/RAL/ISIS, Chilton, Didcot, Oxon
• S.M.H. Alsari, S. Jolly, D.A. Lee, P. Savage
  Imperial College of Science and Technology, Department of Physics, London
• I. Ariz, R. Enparantza, P. Romano, A. Sedano
  Fundación TEKNIKER, Eibar (Gipuzkoa)
• J.J. Back
  University of Warwick, Coventry
• F.J. Bermejo
  Bilbao, Faculty of Science and Technology, Bilbao
• M. Eguiraun
  ESS-Bilbao, Zamudio
• V. Etxebarria
  University of the Basque Country, Faculty of Science and Technology, Bilbao
• C. Gabor, D.C. Plostinar
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon
• N. Garmendia, H. Hassanzadegan
  ESS Bilbao, Bilbao
• A. Kurup
  Fermilab, Batavia
• J.K. Pozimski
  STFC/RAL, Chilton, Didcot, Oxon

The Front End Test Stand (FETS) under construction at the Rutherford Appleton Laboratory is the UK's contribution to research into the next generation of High Power Proton Accelerators (HPPAs). HPPAs are an essential part of any future Spallation Neutron Source, Neutrino Factory, Muon Collider, Accelerator Driven Sub-critical System, Waste Transmuter etc. FETS will demonstrate a high quality, high intensity, chopped H-minus beam and is a collaboration between RAL, Imperial College and the Universtity of Warwick in the UK and the Universidad del Pais Vasco in Spain. This paper describes the current status and future plans of FETS.