Omega-P, Inc., New Haven, Connecticut
Columbia University, New York
Yale University, Beam Physics Laboratory, New Haven, Connecticut
NSC/KIPT, Kharkov
Funding: US Department of Energy, Office of High Energy Physics, Advanced Accelerator R & D.
A rectangular two-beam dielectric wakefield accelerator (DWA) module is described which, when energized by a 14 MeV, 50 nC drive bunch moving in one channel, is shown to deflect a test bunch which originates from an independent source moving in a parallel channel. We show that such a module, 30 cm in length, can deflect transversely a 1 GeV electron by ~ 1 mrad in 1 ns, after which a following bunch can pass undeflected. Apparatus required to accomplish this task consists of a laser-cathode RF gun and an optional linac to generate the drive bunch. The associated DWA components could be used for kicker applications in a storage ring or a more energetic electron linear accelerator. An example we describe is tailored to a DWA demonstration project underway at the Argonne Wakefield Accelerator, but the design can be altered to allow for changes including a lower-energy but still relativistic drive bunch. The kicker, through appropriate design, can deflect one out of several bunches in a storage ring, leaving the remaining bunches essentially unaffected by the structure.
NSC/KIPT, Kharkov
Yale University, Physics Department, New Haven, CT
Omega-P, Inc., New Haven, Connecticut
Yale University, Beam Physics Laboratory, New Haven, Connecticut
Funding: The research was supported by US Department of Energy, Office of High Energy Physics, Advanced Accelerator R & D.
A new scheme for a dielectric wakefield accelerator is proposed that em-ploys a cylindrical multi-zone dielectric structure configured as two concentric dielectric tubes with outer and inner vacuum channels for drive and accelerated bunches. Analytical and numerical studies have been carried out for such coaxial dielectric-loaded structures (CDS) for high-gradient acceleration. An analytical theory of wakefield excitation by particle bunches in a multi-zone CDS has been formulated. Numerical calculations were made for an example of a CDS using dielectric tubes of material with dielectric permittivity 5.7, having external diameters of 2.121 mm and 0.179 mm with inner diameters of 2.095 mm and 0.1 mm. An annular 5 GeV, 5 nC electron bunch with RMS length of 0.14 mm energizes a wakefield on the structure axis having an accelerating gradient of ~600 MeV/m with a transformer ratio ~8. The period of the accelerating field is ~0.38 mm. Full numerical simulation using a PIC code has confirmed results of the linear theory and furthermore has shown the important influence of the quenching wave. The simulation also has shown stable transport of drive and accelerated bunches through the CDS.