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.