Author: Wang, H.B.
Paper Title Page
TUPA08 The Control System for CAEP FEL 206
 
  • D. Zhang, M. Li, H.B. Wang, X. Yang
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  
  It de­scribes a con­trol sys­tem of CAEP Free Elec­tron Laser (FEL), which is a dis­trib­uted con­trol sys­tem based on EPICS and Vi­sual C++6.0. EPICS is pop­u­lar in large ac­cel­er­a­tor lab­o­ra­to­ries in the world. It is a soft­ware toolkit for build­ing process con­trol sys­tem for a wide va­ri­ety of ex­per­i­ment and in­dus­trial ap­pli­ca­tions. The soft­ware tools in the kit pro­vide in­de­pen­dent and ex­pand­able mod­ules for sys­tem con­fig­u­ra­tion, dis­trib­uted process con­trol, run-time data­base, alarm man­ager, etc. It gives de­tailed de­scrip­tion of the mag­net power sup­ply sys­tem , beam di­ag­nos­tic sys­tem, in­clud­ing the hard­ware struc­ture and soft­ware de­sign. Other sub­sys­tems are also de­scribed in the paper. The con­trol sys­tem has stan­dard mod­ule, in­ter­op­er­abil­ity, and re­peata­bil­ity are avail­able. The con­trol sys­tem is sim­ple di­rect, and sta­ble.  
 
WEPA12 The Driving Laser for FEL-THz 349
 
  • Y. Chen, M. Li, H.B. Wang, D. Wu, X. Yang
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  
  A solid-state dri­ving laser sys­tem have been de­vel­oped to meet the re­quire­ments of the FEL-THz re­search. The de­sign spec­i­fi­ca­tions, con­fig­u­ra­tion and diode-pumped am­pli­fier of the drive-laser sys­tem are also de­scribed. The laser sys­tem can gen­er­ate con­tin­u­ous or 10μs-20μs pulses light with wave­length 1064 nm, 532nm, 266nm at a rep­e­ti­tion rate 54.167MHz. The av­er­age power of the dri­ving laser sys­tem is more than 25W, 8W, 1W at wave­length 1064nm, 532nm, 266nm re­spec­tively. The cath­ode ma­te­r­ial is GaAs. The sec­ond har­monic is used, of which av­er­age power is 8.55W, pulse width is about 12ps, power sta­bil­ity is 0.72% and point­ing sta­bil­ity is 46u­rad.  
 
WEPA23 DEVELOPMENT OF AN ITC-RF GUN FOR COMPACT THz FEL 385
 
  • W. Bai, Y. Chen, M. Li, L.J. Shan, X.M. Shen, H.B. Wang
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  
  An in­de­pen­dent tun­able cells thermionic rf gun (ITC-RF Gun) used for com­pact Tera-hertz (THz) free elec­tron laser(FEL) is de­vel­oped at In­sti­tute of Ap­plied Elec­tron­ics, China Acad­emy of En­gi­neer­ing Physics (CAEP). This RF-gun con­sists of a sin­gle cell and a 3-cells ac­cel­er­at­ing cav­ity which are ex­cited in­de­pen­dently, so the am­pli­tude and phase of the two parts can be ad­justed eas­ily. The paper in­tro­duces some re­sults of the sim­u­la­tion, cold test and pre­lim­i­nary hot test. The test re­sults agree well with the the­o­ret­i­cal de­sign.  
 
THPA13 A 54.167MHz Laser Wire System for Free Electron Laser in CAEP 493
 
  • D. Wu
    TUB, Beijing, People's Republic of China
  • W. Bai, M. Li, H.B. Wang, J. Wang
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  
  The laser wire (LW) method has been demon­strated as an ef­fec­tive non-in­ter­cep­tive tech­nique for mea­sur­ing trans­verse elec­tron beam size of CW FELs and ERLs. To mea­sure the beam size of a CW DC gun, which is built as an elec­tron source of THz FEL in China Acad­emy of En­gi­neer­ing Physics (CAEP), a high rep­e­ti­tion LW sys­tem is pro­posed. The first pro­posed sys­tem is going to be in­stalled at the exit of the DC gun, where the en­ergy of elec­tron beam is ex­tremely low. In this paper, the LW sys­tem adapted to the FEL beam pa­ra­me­ters is dis­cussed, and the main pa­ra­me­ters are given.  
 
THPA33 Bunch Length Measurement Based on the Beam Position Monitor 555
 
  • J. Wang, M. Li, H.B. Wang, D. Wu
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  
  BPM (Beam Po­si­tion Mon­i­tor) is the most basic in­stru­ment of the beam dy­nam­ics. The sig­nal of the BPM con­sist more in­for­ma­tion of the beam apart from the beam po­si­tion. By pro­cess­ing and an­a­lyz­ing of the BPM sig­nal, the in­for­ma­tion of the bunch length can be got. It's a chal­lenge to use this method when the en­ergy is low (<30 MeV) and the bunch length is es­pe­cially short(10 ps rms). In this paper, the BPM sys­tem which can be used to mea­sure the bunch length is dis­cussed. And the method of the sig­nal pro­cess­ing and an­a­lyz­ing is given.  
 
THPB20 DC High Voltage Photoemission Electron Gun for CAEP FEL 598
 
  • H.B. Wang, M. Li, X. Yang
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
  
  The re­search on high av­er­age power Ter­a­hertz free elec­tron laser re­quires more de­mand­ing spec­i­fi­ca­tions of elec­tron source. DC high volt­age elec­tron guns with pho­toe­mis­sion cath­odes are a nat­ural choice for gen­er­at­ing the crit­i­cal beams con­sid­er­ing the con­di­tion of tech­nol­ogy. Field emis­sion from the elec­trode struc­tures lim­its the op­er­at­ing volt­age and cath­ode field gra­di­ent in these guns. A ce­ramic in­su­la­tor de­ter­mines the level of op­er­at­ing volt­age. The pho­to­cath­ode op­er­a­tional life­time is lim­ited by the gun vac­uum and by ion back bom­bard­ment. The de­sign­ing thought and the tech­ni­cal so­lu­tion to afore­men­tioned is­sues are pre­sented. The re­sults of the beam dy­namic sim­u­la­tion based on the de­sign are dis­played, nor­mal­ized emit­tance at the lo­ca­tion 120 cm far from the cath­ode sur­face: x=1.335 π*mm*mrad, y=1.364 π*mm*mrad, z=4.81 π*keV-deg, using the fol­low­ing ini­tial beam pa­ra­me­ters: the laser spot 4 mm in di­am­e­ter, the laser pulse length FWHM 12 ps, the charge per bunch 35 pC and the ac­cel­er­at­ing volt­age 350 kV. Now the DC pho­toe­mis­sion gun is con­di­tion­ing.