03 Particle Sources and Alternative Acceleration Techniques
A12 FFAG
Paper Title Page
TUYB01 Vertical Orbit-excursion Fixed Field Alternating Gradient Accelerators (V-FFAGs) and 3D Cyclotrons 956
 
  • S.J. Brooks
    BNL, Upton, Long Island, New York, USA
 
  FFAGs with vertical orbit excursion (VFFAGs) provide a promising alternative design for rings with fixed-field (e.g. superconducting) magnets. They have a vertical magnetic field component that increases with height in the vertical aperture, yielding a skew quadrupole focussing structure. Scaling type VFFAGs have fixed tunes and no intrinsic limitation on momentum range; they are also isochronous in the ultra-relativistic limit. Extending isochronism to lower velocities requires a slanted orbit excursion: a three-dimensional analogue of a spiral sector cyclotron from 40 to 1500MeV is developed, which is flat at low energies and acquires a slope as the protons become relativistic. This provides more stable tunes than a comparable planar cyclotron. Such machines are promising future candidates for nuclear transmutation using high average power CW beams at ~GeV energies.  
slides icon Slides TUYB01 [16.187 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUYB01  
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TUPRI009 Study of Resonance Crossing in Non-scaling FFAGs using the S-POD Linear Paul Trap 1571
 
  • D.J. Kelliher, S. Machida, C.R. Prior, S.L. Sheehy
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • K. Fukushima, K. Ito, K. Moriya, H. Okamoto, T. Okano
    HU/AdSM, Higashi-Hiroshima, Japan
 
  Experiments on EMMA have shown that with rapid acceleration (~10 turns) a linear non-scaling FFAG can accelerate through several integer tunes without detrimental effects on the beam [1]. Proton and ion applications such as hadron therapy will necessarily have a slower acceleration rate, so their feasibility depends on how harmful resonance crossing is in this regime. A simple and useful tool to answer such fundamental questions is the S-POD linear Paul trap at Hiroshima University, which can be set up to simulate the dynamics of a beam in an FFAG. We report here results of experiments to explore different resonance crossing speeds, quantify beam loss and study nonlinear effects. We also discuss the implications of these experimental results in terms of limits on acceptable acceleration rates and alignment errors.
[1] S.Machida et al, Nature Physics, N8, 243-257 (2012)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI009  
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TUPRI013 Dynamic Aperture Studies of the nuSTORM FFAG Ring 1574
 
  • R. Appleby, J.M. Garland, H.L. Owen, S.C. Tygier
    UMAN, Manchester, United Kingdom
  • K.M. Hock
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • J.-B. Lagrange, J. Pasternak
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
 
  Funding: Research supported by STFC grant number ST/K002503/1 "Racetrack FFAGs for medical, PRISM and energy applications".
FFAG rings with a racetrack configuration are very promising as their flexible design allow for dedicated spaces for injection/extraction, RF cavities etc. A racetrack FFAG is considered as an option for the nuSTORM facility, which aims to deliver neutrino beams produced from the decay of muons stored in a ring with long sections pointing towards detectors. In this paper we discuss the definition of dynamic aperture in these machines and use the PyZgoubi framework to compute the many turn motion in the nuSTORM ring. The roles of machine imperfections and symmetry are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI013  
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