Publications by Suzie Sheehy


Acceleration in the linear non-scaling fixed-field alternating-gradient accelerator EMMA

Nature Physics 8 (2012) 243-247

S Machida, R Barlow, JS Berg, N Bliss, RK Buckley, JA Clarke, MK Craddock, R D'Arcy, R Edgecock, JM Garland, Y Giboudot, P Goudket, S Griffiths, C Hill, SF Hill, KM Hock, DJ Holder, MG Ibison, F Jackson, SP Jamison, C Johnstone, JK Jones, LB Jones, A Kalinin, E Keil, DJ Kelliher, IW Kirkman, S Koscielniak, K Marinov, N Marks, B Martlew, PA McIntosh, JW McKenzie, F Méot, KJ Middleman, A Moss, BD Muratori, J Orrett, HL Owen, J Pasternak, KJ Peach, MW Poole, YN Rao, Y Saveliev, DJ Scott, SL Sheehy, BJA Shepherd, R Smith, SL Smith, D Trbojevic, S Tzenov, T Weston, A Wheelhouse, PH Williams, A Wolski, T Yokoi

In a fixed-field alternating-gradient (FFAG) accelerator, eliminating pulsed magnet operation permits rapid acceleration to synchrotron energies, but with a much higher beam-pulse repetition rate. Conceived in the 1950s, FFAGs are enjoying renewed interest, fuelled by the need to rapidly accelerate unstable muons for future high-energy physics colliders. Until now a 'scaling' principle has been applied to avoid beam blow-up and loss. Removing this restriction produces a new breed of FFAG, a non-scaling variant, allowing powerful advances in machine characteristics. We report on the first non-scaling FFAG, in which orbits are compacted to within 10 mm in radius over an electron momentum range of 12-18 MeV/c. In this strictly linear-gradient FFAG, unstable beam regions are crossed, but acceleration via a novel serpentine channel is so rapid that no significant beam disruption is observed. This result has significant implications for future particle accelerators, particularly muon and high-intensity proton accelerators. © 2012 Macmillan Publishers Limited. All rights reserved.


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