• Y. Giboudot, R. Nilavalan
  Brunel University, Middlesex
• T.R. Edgecock
  STFC/RAL, Chilton, Didcot, Oxon
• A. Wolski
  The University of Liverpool, Liverpool

The Non Scaling Fixed Field Alternating Gradient EMMA has a compact linear lattice. Effect of Fringe Field on the beam has to be studied carefully. A numerical magnetic field map is generated by magnet measurements or magnet design softwares. We developed a technique that produces from the numerical field map, a dynamical map for a particle travelling in the entire EMMA cell for a reference energy without acceleration. Since the beam dynamics change with energy, a set of maps have been produce with different reference energies between 10 and 20MeV. For each reference energy, simulated tune and time of flight (TOF) have been compared with results in Zgoubi - tracking directly through numerical field map. The range of validity of a single map has been investigated by tracking particle with large energy deviation. From that, a sensible acceleration scheme has been implemented.

yoel.giboudot@stfc.ac.uk

• T.R. Edgecock
  STFC/RAL, Chilton, Didcot, Oxon
• C.D. Beard, J.A. Clarke, S.A. Griffiths, C. Hill, S.P. Jamison, J.K. Jones, A. Kalinin, K.B. Marinov, N. Marks, P.A. McIntosh, B.D. Muratori, J.F. Orrett, Y.M. Saveliev, B.J.A. Shepherd, R.J. Smith, S.L. Smith, S.I. Tzenov, A.E. Wheelhouse
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• J.S. Berg
  BNL, Upton, Long Island, New York
• N. Bliss, B.G. Martlew, C.J. White
  STFC/DL, Daresbury, Warrington, Cheshire
• M.K. Craddock
  UBC & TRIUMF, Vancouver, British Columbia
• J.L. Crisp, C. Johnstone
  Fermilab, Batavia
• Y. Giboudot
  Brunel University, Middlesex
• E. Keil
  CERN, Geneva
• D.J. Kelliher, S. Machida
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon
• S.R. Koscielniak
  TRIUMF, Vancouver
• F. Méot
  CEA, Gif-sur-Yvette
• J. Pasternak
  Imperial College of Science and Technology, Department of Physics, London
• S.L. Sheehy, T. Yokoi
  JAI, Oxford

The Electron Model for Many Applications (EMMA) will be the World's first non-scaling FFAG and is under construction at the STFC Daresbury Laboratory in the UK. Construction is due for completion in March 2010 and will be followed by commissioning with beam and a detailed experimental programme to study the functioning of this type of accelerator. This paper will give an overview of the motivation for the project and describe the EMMA design and hardware. The first results from commissioning will be presented in a separate paper.

• F. Méot
  CEA, Gif-sur-Yvette
• Y. Giboudot
  Brunel University, Middlesex
• D.J. Kelliher
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon
• T. Yokoi
  JAI, Oxford

The Electron Model for Many Applications FFAG (EMMA) has been the object of extensive beam dynamics simulations during its design and construction phases, using the ray-tracing code Zgoubi, which has been retained as the on-line simulation engine. On the other hand EMMA commissioning requires further advanced beam dynamics studies as well as on-line and off-line simulations. This contribution reports on some aspects of the studies so performed during the last months using Zgoubi.

• F. Méot
  CEA, Gif-sur-Yvette
• J.S. Berg
  BNL, Upton, Long Island, New York
• Y. Giboudot
  Brunel University, Middlesex
• D.J. Kelliher, S. Machida
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon
• B.J.A. Shepherd
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• S.C. Tygier
  UMAN, Manchester

The EMMA (Electron Model for Many Applications) FFAG experiment at Daresbury will involve on-line modeling (a ‘‘Virtual EMMA'') based on stepwise ray-tracing methods. Various aspects of the code of concern and of its interfacing to real world - machine and users - are addressed.

• S.I. Tzenov, J.K. Jones, B.D. Muratori
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• Y. Giboudot
  Brunel University, Middlesex

Described in the paper are systematic procedures to inject and keep the beam on the reference trajectory for a fixed energy, as applied to the EMMA non scaling FFAG accelerator. The notion of accelerated orbits in FFAG accelerators has been introduced and some of their properties have been studies in detail.

• Y. Giboudot
  Brunel University, Middlesex
• I. Kirkman, A. Wolski
  The University of Liverpool, Liverpool

The Non Scaling Fixed Field Alternating Gradient (NS-FFAG) EMMA accelerator has a purely linear lattice and thus allows important tune variation. The crossing of resonances during acceleration is a key characteristic of the beam dynamics. An accurate measurement of the tune is therefore mandatory. However commonly used measurement techniques requires the beam to perform an important number of turns in the machine. Simulations have shown that fast decoherence of the beam requires the study of another measurement technique. The model independent analysis (MIA) has been investigated. The singular value decomposition (SVD) of a matrix composed of simulated BPMs reading of various bunches trajectories gives a description of the optics function at each Beam Position Monitor. Including misalignment errors and electronic noise, an accurate value of the tune has been derived from statistical treatment repeating this process few hundreds of time.

yoel.giboudot@stfc.ac.uk