Author: Park, S.
Paper Title Page
THP009
 Spatiotemporal Optimization of UV-Pump Pulses for the Ultrafast Electron Diffraction  
 
  • I.H. Baek, B. Han, K.H. Jang, Y.U. Jeong, H.W. Kim, K. Lee, S. H. Park, S. Park, N. Vinokurov
    KAERI, Daejon, Republic of Korea
  
  Ul­tra­vi­o­let (UV) light has been de­voted to es­cape elec­trons from com­mon met­als due to their work func­tion en­er­gies. Nowa­days the pulsed elec­tron beam has trig­gered nu­mer­ous fun­da­men­tal stud­ies and tech­no­log­i­cal ap­pli­ca­tions. Elec­tron beam-based pump/probe spec­troscopy re­quires a low tim­ing jit­ter be­tween pump- and probe-beams for the pre­cise ob­ser­va­tion and analy­sis. Herein, we per­formed the sys­tem­atic char­ac­ter­i­za­tion of elec­tron bunches de­pend­ing on UV pulse con­di­tions using the elec­tro-op­tic streak­ing of elec­tron pulses for the ul­tra­fast elec­tron dif­frac­tion (UED) ex­per­i­ment. The tem­po­ral sta­bi­liza­tion be­tween UV-pump and elec­tron-probe beams within a 100 fem­tosec­onds jit­ter is in progress by com­pen­sat­ing a rel­a­tive phase shift of RF mas­ter os­cil­la­tor and Ti:sap­phire laser os­cil­la­tor. We are under op­ti­miza­tion of the spa­tial dis­tri­b­u­tion and size of the UV light for get­ting elec­tron bunches with low emit­tance and en­ergy spread.  
 
THP010 Analysis of Beam Stability in the KAERI Ultrashort Pulse Accelerator 697
 
  • H.W. Kim, S. Bae, B.A. Gudkov, K.H. Jang, Y.U. Jeong, Y. Kim, K. Lee, S.V. Miginsky, J. Mun, S. H. Park, S. Park, N. Vinokurov
    KAERI, Daejon, Republic of Korea
  • K.H. Jang, Y.U. Jeong, H.W. Kim, K. Lee, S.V. Miginsky, S. H. Park, N. Vinokurov
    UST, Daejeon City, Republic of Korea
  • S.V. Miginsky, N. Vinokurov
    BINP SB RAS, Novosibirsk, Russia
  
  An RF-pho­to­gun-based lin­ear ac­cel­er­a­tor for the Korea Atomic En­ergy Re­search In­sti­tute (KAERI) ul­tra­short pulse fa­cil­ity is under con­struc­tion. It has a sym­me­try struc­ture with four dif­fer­ent beam­lines. The UED beam­lines will gen­er­ate ul­tra­short elec­tron pulses with over 106 elec­trons per pulse for the sin­gle-shot mea­sure­ments on fem­tosec­onds dy­nam­ics of atomic or mol­e­c­u­lar struc­tures. Elec­tron bunches with an en­ergy of ~3 MeV from the RF pho­to­gun can be com­pressed up to less than 50 fs by achro­matic and isochro­nous bends. The in­trin­sic r.m.s. tim­ing jit­ter of the pulses through the bends is es­ti­mated to be less than 30 fs with the r.m.s. en­ergy fluc­tu­a­tion of 0.1%. In the THz pump and X-ray probe beam­line, two suc­ces­sive laser pulses with a time in­ter­val of ~10 ns are used to gen­er­ate two elec­tron bunches hav­ing bunch charges more than 100 pC. Two elec­tron bunches are ac­cel­er­ated by a linac up to ~25 MeV and sep­a­rated into in­di­vid­ual beam­lines by a fast kicker. We will pre­sent on es­ti­mated tim­ing jit­ter and ef­fects of mag­net er­rors to the beam dy­nam­ics in the ac­cel­er­a­tor by con­sid­er­ing beam di­lu­tion ef­fects.