Author: Avrakhov, P.V.
Paper Title Page
WEPRB072 Ultra-High Gradient Short RF Pulse Gun 2987
 
  • S.P. Antipov, P.V. Avrakhov, S.V. Kuzikov, A. Liu
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • G. Ha, J.G. Power
    ANL, Argonne, Illinois, USA
 
  Funding: DOE SBIR DE-SC0018709
High brightness beams enable novel applications like x-ray free electron lasers and ultrafast electron microscopes. High brightness beams essentially consist of a large number of electrons in a small phase space volume, i.e. a high peak current. When such beams are generated from the cathode, there is a strong space charge force, which elongates the bunch and reduces its brightness. An optimal solution is to raise the accelerating voltage in the gun. However, the maximum gradient is limited by the effects of RF breakdown. The probability of RF breakdown is reduced as the RF pulse length decreases. We present a development of an electron photoinjector operating with short RF pulse, 10 ns scale. We have designed an X-band gun including the RF design, beam quality optimization, and engineering. The gun will be fed by 10 ns, 300 MW RF pulse generated at the Argonne Wakefield Accelerator Facility for two-beam acceleration experiments. We also manufactured an aluminum prototype and measured its microwave properties, most importantly, fill time. The proposed high brightness beam source can be used as the main beam in wakefield accelerators. It will find commercial applications in ultrafast electron diffraction and microscopy systems.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB072  
About • paper received ※ 21 May 2019       paper accepted ※ 24 May 2019       issue date ※ 21 June 2019  
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WEPRB073 CW Room Temperature Accelerating Structures 2990
 
  • S.P. Antipov, P.V. Avrakhov, E. Gomez, S.V. Kuzikov
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
 
  To this day CW linear electron accelerators were based only on expensive and bulky (embedded in a cryostat) superconducting accelerating structures. CW regime can in principle be realized with normal conducting structures provided the shunt impedance is high. Such structures can be designed using dielectrics (ultra-pure ceramics in C-band and diamond in mm-waves) with ultra-low loss tangent (~10-6). The use of dielectrics allows to concentrate the electromagnetic energy density in the dielectric region and thus minimize fields and ohmic loss on metallic walls. The thermal loss in dielectric can be relatively low given the loss tangent is small. We report here the design of structures with shunt impedance on the order of 104 MOhm/m, which is several orders of magnitude higher than shut impedance in copper structures in GHz and THz range. High shunt impedance makes it possible to accelerate electrons to 1 MeV using kW-level CW RF sources like magnetrons in C-band and gyrotrons in THz range. Such CW accelerators will find applications in sterilization, food irradiation, industrial radiography and cargo inspection.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB073  
About • paper received ※ 21 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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