Author: Vikharev, A.A.
Paper Title Page
MOPC041 Cross-Field Multipactor Discharge in the X-Band Cylindrical Cavity 166
  • S.V. Kuzikov, E.V. Ilyakov, I.S. Kulagin, A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  • D. Lee
    NSRRC, Hsinchu, Taiwan
  The paper represents the experimental study of one-sided cross-field multipactor discharge in the copper cavity with the operating mode TM01 in external DC magnetic field. It was shown that discharge is very sensible to magnitudes of the external magnetic field and rf fields as well. At proper fields the multipactor discharge can be developed for 15 ns and the electron concentration can be comparable with critical one for the given rf frequency. As a result of discharging, the cavity changes its own resonant frequency and can play a role of a switch which can substitute full transmission by full reflection. Switching parameters could be controlled by DC magnetic field as well as by additional rf radiation at different frequency than operating frequency. The high rf absorption of multipactor discharge also can be used in electrically controlled powerful loads and attenuators.  
TUPC060 A Multi-mode RF Photocathode Gun 1135
  • S.V. Kuzikov, A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  • J.L. Hirshfield
    Yale University, Physics Department, New Haven, CT, USA
  • Y. Jiang
    Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
  • V. Vogel
    DESY, Hamburg, Germany
  A photocathode injection gun based on standard emittance compensating techniques and driven by several (N ≥ 2) harmonically related RF sources is considered. Multi-harmonic excitation can provide high-quality flatness in time of the field at the cathode when a bunch is being injected. This allows one to obtain ≥1 nC, 20-40 ps electron bunches with preservation of low emittance. Another advantage is a reduction of Ohmic losses and the required input RF power (for a given cathode field). Preliminary calculations show that input power in a three-mode cavity (0.65 GHz, 1.3 GHz, 2.6 GHz) is nearly half the power needed to feed a single mode with the same cathode field. A further appealing property is the predicted increase of breakdown threshold due to a reduction of surface exposure time to high fields in a symmetric cavity, and due to the so-called anode-cathode effect in a longitudinally asymmetric cavity. These properties may help one to reach bunch energies as high as 3-5 MeV after the first half cell.  
THPC169 Short-Period RF Undulator for a Nanometer SASE Source 3293
  • S.V. Kuzikov, M.E. Plotkin, A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  • J.L. Hirshfield
    Yale University, Physics Department, New Haven, CT, USA
  • T.C. Marshall, G.V. Sotnikov
    Omega-P, Inc., New Haven, Connecticut, USA
  Funding: Sponsored in part by US Department of Energy, Office of High Energy Physics.
A room-temperature RF undulator to produce ~1 nm wavelength radiation using a relatively low energy electron beam (0.5 GeV) is considered. The design features include an effective undulator period of 0.45 cm, an undulator parameter of K = 0.4, an effective field length of 50 cm. These parameters could be be realized using a multi-MW RF power amplifier to drive the undulator (e.g., the 34 GHz pulsed magnicon at Yale or a 30 GHz gyroklystron at IAP) with microsecond pulse duration. Two undulator designs were considered that avoid problems with a co-propagating wave: a dual-mode cylindrical cavity [TE01 (counter propagating) - TE02 (co-propagating)] with an off-axis electron beam; and a traveling HE11 mode resonant ring with an on-axis beam.