Author: Vikharev, A.A.
Paper Title Page
TUP040 Flying RF Undulator 474
  • A.V. Savilov, I.V. Bandurkin, S.V. Kuzikov, A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  A new concept for the room-temperature rf undulator, designed to produce coherent X-ray radiation by means of a relatively low-energy electron beam and pulsed mm-wavelength radiation, is proposed. The “flying” undulator is a high-power short rf pulse co-propagating together with a relativistic electron bunch in a helically corrugated waveguide. The electrons wiggle in the rf field of the -1st spatial harmonic with the phase velocity directed in the opposite direction in respect to the bunch velocity, so that particles can irradiate high-frequency Compton’s photons. A high group velocity (close to the speed of light) ensures long cooperative motion of the particles and the co-propagating rf pulse. This work is supported by the Russian Foundation for Basic Research (Projects 14-08-00803 and 14-02-00691).  
poster icon Poster TUP040 [0.189 MB]  
TUP046 Terahertz FEL based on Photoinjector Beam in RF Undulator 485
  • S.V. Kuzikov, I.V. Bandurkin, M.E. Plotkin, A.V. Savilov, A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  • A.V. Savilov
    NNGU, Nizhny Novgorod, Russia
  Photoinjectors, which can produce picosecond electron bunches of MeV-level, are attractive for THz generation. Fortunately, a long distance to reach scattering power saturation in FEL is not necessary, if bunch length is shorter than the produced THz half-wavelength. However, the energy of several MeVs does not allow providing long traveling of the flying bunch without longitudinal divergence. That is why, we suggest using specific RF undulator in a form of the normal wave in the helical waveguide at 3 cm wavelength. The mentioned wave has the -1st space harmonic with transverse fields and negative phase velocity (responsible for particle wiggling). This wave has also the 0th harmonic with longitudinal field and positive phase velocity equal to bunch velocity. Due to the synchronous 0th harmonic one can channel low-energy bunches (due to longitudinal focusing field) as far as several meters distance. One might also inject electron bunches in slightly accelerating field, in this case the output THz pulse obtain nearly linear frequency modulation. Such long THz pulses with the mentioned modulation of the frequency can be effectively compressed by pair of diffraction gratings.  
poster icon Poster TUP046 [2.914 MB]