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O'Shea, F.H.

Paper Title Page
WEPD012 Cryogenic Design of a PrFeB-Based Undulator 3111
 
  • J. Bahrdt, H.-J. Baecker, M. Dirsat, W. Frentrup, A. Gaupp, D. Pflückhahn, M. Scheer, B. Schulz
    Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Elektronen-Speicherring BESSY II, Berlin
  • F.J. Grüner, R. Weingartner
    LMU, Garching
  • D. Just
    Technische Universität Berlin, Berlin
  • F.H. O'Shea
    UCLA, Los Angeles, California
 
 

In collaboration with the Ludwig-Maximilian-University Munich a cryogenic PrFeB- based undulator has been built. The 20-period device has a period length of 9mm and a fixed gap of 2.5mm. The undulator has recently been installed at the laser plasma accelerator at the Max-Planck-Institute for Quantenoptik. The operation of a small gap device at a high emittance electron beam requires stable magnetic material. A high coercivity is achieved with PrFeB- material which is cooled down to 50K. This temperature is 100K lower as compared to the temperature of a NdFeB-based cryogenic undulator. In this paper we present the mechanic and cryogenic design and compare the predictions with measured data. The results are extrapolated to a 2m-long variable gap undulator.

 
WEPE077 Permanent Magnet Quadrupole Final Focus System for the Muon Collider 3524
 
  • F.H. O'Shea, J.B. Rosenzweig
    UCLA, Los Angeles, California
  • G. Andonian
    RadiaBeam, Marina del Rey
 
 

One of the challenges of the proposed muon collider is the beam size at the interaction region. The current target for the beta function (beta-star) is 10mm for the 1.5TeV scenario with a beam emittance of 25mm-mrad. In this paper, we describe the design and development of a final focusing scheme that attempts to reach these parameters. The final focus scheme is based on the use of permanent magnet quadrupoles (PMQ) in a triplet configuration. Initial simulations show that the PMQs reach gradients as high as ~990T/m using Praseodymium based magnets in a Halbach style arrangement. Possible methods for tuning the PMQs at the interaction region, via temperature control and high-resolution movers, are also described.

 
THPEC015 Breaking the Attosecond, Angstrom and TV/m Field Barriers with Ultra-fast Electron Beams 4080
 
  • J.B. Rosenzweig, G. Andonian, A. Fukasawa, E. Hemsing, G. Marcus, A. Marinelli, P. Musumeci, B.D. O'Shea, F.H. O'Shea, C. Pellegrini, D. Schiller, G. Travish
    UCLA, Los Angeles, California
  • P.H. Bucksbaum, M.J. Hogan, P. Krejcik
    SLAC, Menlo Park, California
  • M. Ferrario
    INFN/LNF, Frascati (Roma)
  • S.J. Full
    Penn State University, University Park, Pennsylvania
  • P. Muggli
    USC, Los Angeles, California
 
 

Recent initiatives at UCLA concerning ultra-short, GeV electron beam generation have been aimed at achieving sub-fs pulses capable of driving X-ray free-electron lasers (FELs) in single-spike mode. This uses of very low charge beams, which may allow existing FEL injectors to produce few-100 attosecond pulses, with very high brightness. Towards this end, recent experiments at the Stanford X-ray FEL (LCLS, first of its kind, built with essential UCLA leadership) have produced ~2 fs, 20 pC electron pulses. We discuss here extensions of this work, in which we seek to exploit the beam brightness in FELs, in tandem with new developments at UCLA in cryogenic undulator technology, to create compact accelerator/undulator systems that can lase below 0.15 Angstroms, or be used to permit 1.5 Angstrom operation at 4.5 GeV. In addition, we are now developing experiments which use the present LCLS fs pulses to excite plasma wakefields exceeding 1 TV/m, permitting a table-top TeV accelerator for frontier high energy physics applications.