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Harkay, K.C.

 
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MOPCH054 Plans for the Generation of Short Radiation Pulses at the Diamond Storage Ring 160
 
  • R. Bartolini
    Diamond, Oxfordshire
  • M. Borland, K.C. Harkay
    ANL, Argonne, Illinois
 
  Diamond is a third generation light source under commissioning in Oxfordshire UK. In view of the increasing interest in the production of short radiation pulses, we have investigated the possibility to operate with a low-alpha optics, the use of a third harmonic cavity for bunch shortening and the implementation of a crab cavity scheme in the Diamond storage ring. The results of the initial accelerator studies will be described, including the modification of the beam optics, non-linear beam dynamics optimisation and choice of RF parameters for the crab cavity operation. The expected performance of these schemes will be summarised.  
MOPCH126 Accelerator Research on the Rapid Cycling Synchrotron at IPNS 339
 
  • G.E. McMichael, F.R. Brumwell, L. Donley, J.C. Dooling, W. Guo, K.C. Harkay, Q.B. Hasse, D. Horan, R. Kustom, M.K. Lien, M.E. Middendorf, M.R. Moser, S. Wang
    ANL, Argonne, Illinois
 
  The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a national user facility for neutron scattering. Neutrons are produced by 70 ns pulses of protons (~3x 1012 protons per pulse) impacting a depleted-uranium target at a pulse repetition rate of 30 Hz. Three accelerators in series (a 750 keV Cockcroft-Walton, 50 MeV Alvarez linac accelerating H- ions, and a 450 MeV rapid-cycling proton synchrotron) provide the beam that is directed to the target. New diagnostics and a third rf cavity that can be operated at either the fundamental or second harmonic of the ring frequency have recently been installed and an experimental program established to try to gain understanding of an instability that limits the charge-per-bunch in the RCS. This program will be described, and preliminary results presented.  
WEXFI02 Observation and Modeling of Electron Cloud Instability 1887
 
  • K.C. Harkay
    ANL, Argonne, Illinois
 
  This presentation will review experimental results and the state of the art in the analysis and simulation of the electron cloud instability in hadron and positron storage rings.  
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THPLS076 Status of RF Deflecting Cavity Design for the Generation of Short X-Ray Pulses in the Advanced Photon Source Storage Ring 3460
 
  • G.J. Waldschmidt, M. Borland, Y.-C. Chae, K.C. Harkay, D. Horan, A. Nassiri
    ANL, Argonne, Illinois
 
  The Advanced Photon Source (APS) at Argonne National Laboratory is exploring the possibility of using radio frequency deflection to generate x-ray radiation pulses on the order of 1 pico-second (Delta t - 70%) or less*. This scheme is based on a proposal by A. Zholents et al.** that relies on manipulating the transverse momenta of the electrons in a bunch by using an rf deflecting cavity to induce a longitudinally dependent vertical deflection of the beam. The beam will then travel through a number of undulators before arriving at a second set of deflecting cavities where the deflection is reversed such that the remainder of the storage ring is largely unperturbed***. Considerable effort has been expended on the design of a superconducting rf deflecting cavity operating in the S-Band at 2.8 GHz to address fundamental design issues including cavity geometry, deflecting voltage, rf power coupling, tuning, and damping of higher-order and lower-order modes. In this paper we present simulation results and analysis of an optimized superconducting rf deflecting cavity design for the APS storage ring.

*K. Harkay et al. Proceedings of 2005 PAC, Knoxville, TN, May 2005, p. 668. **A. Zholents et al. Nucl. Instrum. Methods, A425, 385 (1999). ***M. Borland and V. Sajaev. Proceedings of 2005 PAC, Knoxville, TN, May 2005, p. 3886.