Author: Deng, H.X.
Paper Title Page
MOPME049 Status of Non-destructive Bunch Length Measurement based on Coherent Cherenkov Radiation 583
 
  • H.X. Deng, S.L. Lu, T. Yu, J.B. Zhang
    SINAP, Shanghai, People's Republic of China
  • G.A. Naumenko, A. Potylitsyn, M.V. Shevelev, D.A. Shkitov
    TPU, Tomsk, Russia
  
  Funding: This work was supported by the joint Russian-Chinese grant (RFBR 110291177 and NSFC 11111120065) and partially by the Program of Russian MES “Nauka” and the Chinese NSFC 11175240.
As a novel non-de­struc­tive bunch length di­ag­nos­tic of the elec­tron beam, an ex­per­i­men­tal ob­ser­va­tion of the co­her­ent Cherenkov ra­di­a­tion gen­er­ated from a di­elec­tric cae­sium io­dide crys­tal with large spec­tral dis­per­sion was pro­posed for the 30MeV fem­tosec­ond lin­ear ac­cel­er­a­tor at Shang­hai In­sti­tute of Ap­plied Physics (SINAP). In this paper, the the­o­ret­i­cal de­sign, the ex­per­i­men­tal setup, the ter­a­hertz op­tics, the first an­gu­lar dis­tri­b­u­tion ob­ser­va­tions of the co­her­ent Cherenkov ra­di­a­tion, and the fu­ture plans are pre­sented.
* Shevelev M. et al., Journal of Physics: Conf. Ser. 357 (2012) 012023. 		 
 
MOPME067 Non-Invasive Bunch Length Diagnostics Based on Interferometry From Double Diffraction Radiation Target 631
 
  • D.A. Shkitov, G.A. Naumenko, A. Potylitsyn, M.V. Shevelev
    TPU, Tomsk, Russia
  • H.X. Deng, S.L. Lu, T. Yu, J.B. Zhang
    SINAP, Shanghai, People's Republic of China
  
  Funding: This work was supported by the joint Russian-Chinese grant (RFBR 110291177 and NSFC 11111120065) and partially by the Program of Russian MES “Nauka” and the SINAP Xinrui Program Y15501A061.
Re­li­able and pre­cise non-in­va­sive beam di­ag­nos­tics tech­nique to mea­sure length of sub-pi­cosec­ond elec­tron bunches are re­quired for new ac­cel­er­a­tor fa­cil­i­ties (FEL, et al.). In­ves­ti­ga­tions of co­her­ent ra­di­a­tion gen­er­ated by such bunches using dif­fer­ent in­ter­fer­om­e­ters allow to de­ter­mine a bunch length*. Mea­sur­ing a de­pen­dence of ra­di­a­tion yield in­ten­sity from two DR tar­gets on a dis­tance be­tween them (the in­trin­sic DR in­ter­fer­o­gram), it is pos­si­ble to ob­tain the same in­for­ma­tion. Such a non-in­va­sive tech­nique can be di­rectly used for ul­tra-short bunch length mea­sure­ments. Re­cently the first ex­per­i­ment with a dou­ble DR tar­get was car­ried out at the SINAP fs linac fa­cil­ity** with pa­ra­me­ters de­scribed in***. The dou­ble DR tar­get was con­sisted of two plates made from Al foil. The pyro-elec­tric de­tec­tor SPI-D-62 was used. Here we re­port the re­sults of the sec­ond stage of our in­ves­ti­ga­tions. The DR in­ter­fer­o­grams of dif­fer­ent elec­tron bunch length were mea­sured. The bunch length was re­con­structed using the heuris­tic model based on the di­men­sion the­ory and sim­u­la­tion data. We com­pare the re­sults from DR in­ter­fer­o­grams and Michel­son in­ter­fer­om­e­ter mea­sure­ments and show their sim­i­lar­ity.
*Murokh A. et al., NIMA 410 (1998) 452.
**Zhang J.B., Shkitov D.A. et al., IBIC’12 MOPB65 (2012).
***Lin X., Zhang J. et al., Chin. Phys. Let. V. 27 N. 4 (2010) 044101. 		 
 
TUPEA030 High Brightness and Fully Coherent X-ray Pulses from XFELO Seeded High-gain FEL Schemes 1214
 
  • H.X. Deng, C. Feng
    SINAP, Shanghai, People's Republic of China
  
  The suc­cess­ful op­er­a­tion of the hard x-ray self-seed­ing ex­per­i­ment at the LCLS opens the era of fully co­her­ent hard x-ray free elec­tron lasers (FELs). How­ever, the shot-to-shot ra­di­a­tion fluc­tu­a­tion is still a se­ri­ous issue. In this paper, high-gain, sin­gle-pass x-ray FEL schemes seeded by the nar­row band­width ra­di­a­tion sig­nal from an x-ray FEL os­cil­la­tor were pro­posed and in­ves­ti­gated, which are ex­pected to gen­er­ate high bright­ness, fully co­her­ent and sta­ble x-ray pulse. A sim­ple model has been de­vel­oped to fig­ure out the tem­po­ral and the spec­tral struc­tures of the out­put pulses in x-ray FEL os­cil­la­tor. And op­tions using two syn­chro­nized ac­cel­er­a­tors and using one ac­cel­er­a­tor were con­sid­ered, re­spec­tively.  
 
TUPEA042 Linac Design for Dalian Coherent Light Source 1226
 
  • M. Zhang, H.X. Deng, D. Gu, Q. Gu
    SINAP, Shanghai, People's Republic of China
  
  Dalian Co­her­ent Light (DCL) Source is a FEL user fa­cil­ity in which HGHG scheme is adopted. Beam qual­ity re­quire­ments for the lin­ear ac­cel­er­a­tor (linac) are crit­i­cal, in­clud­ing not only the beam bright­ness, but also the sta­bil­ity and the re­li­a­bil­ity. In this paper, op­ti­miza­tion study is per­formed for the linac. Based on beam sta­bil­ity sim­u­la­tion in the lon­gi­tu­di­nal di­rec­tion, the tol­er­ant bud­get is formed for the short pe­riod jit­ter. For the trans­verse orbit error, beam based align­ment (BBA) tech­nique is im­ple­mented by beam dy­nam­ics sim­u­la­tions and the trans­verse jit­ter is also pre­sented ac­cord­ingly. Mea­sure­ment method for the beam qual­ity is also de­scribed in the paper.  
 
WEODB102 Generating Polarization Controllable FELs at Dalian Coherent Light Source 2071
 
  • T. Zhang, H.X. Deng, D. Wang, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  • D.X. Dai, G.R. Wu, X.M. Yang, W.Q. Zhang
    DICP, Dalian, People's Republic of China
  
  Funding: 973 Program of China (2011CB808300), NSFC 11175240 and 11205234.
The prop­erty of the FEL po­lar­iza­tion is of great im­por­tance to the user com­mu­nity. FEL pulses with ul­tra-high in­ten­sity and flex­i­ble po­lar­iza­tion con­trol abil­ity will ab­solutely open up new sci­en­tific realms. In this paper, sev­eral po­lar­iza­tion con­trol ap­proaches are pre­sented to in­ves­ti­gate the great po­ten­tial on Dalian co­her­ent light source, which is a gov­ern­ment-ap­proved novel FEL user fa­cil­ity with the ca­pa­bil­ity of wave­length con­tin­u­ously tun­able in the EUV regime of 50-150 nm. The nu­mer­i­cal sim­u­la­tions show that both cir­cu­larly po­lar­ized FELs with highly mod­u­lat­ing fre­quency and 100 mi­cro­joule level pulse en­ergy could be gen­er­ated at Dalian co­her­ent light source*.
*T. Zhang, et al., FEL Polarization Control Studies on Dalian Coherent Light Source, Chinese Physics C, 2013, to be published. 		 
slides icon Slides WEODB102 [6.131 MB]