Author: Kuhl, A.
Paper Title Page
TUPC076 Realization of a High Bandwidth Bunch Arrival-time Monitor with Cone-shaped Pickup Electrodes for FLASH and XFEL 1177
 
  • A. Angelovski, M. Hansli, R. Jakoby, A. Kuhl, A. Penirschke, S. Schnepp
    TU Darmstadt, Darmstadt, Germany
  • M. Bousonville, H. Schlarb
    DESY, Hamburg, Germany
  • T. Weiland
    TEMF, TU Darmstadt, Darmstadt, Germany
  
  Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA
In the Free Elec­tron Laser in Ham­burg (FLASH) an elec­tro-op­ti­cal sys­tem is used as a Bunch Ar­rival time Mon­i­tor (BAM). The time-of-ar­rival res­o­lu­tion is pro­por­tion­al to the steep­ness of the beam pick-up sig­nal at the first ze­ro-cross­ing*. Fu­ture ex­per­i­ments will be con­duct­ed using sig­nif­i­cant­ly lower bunch charges re­sult­ing in a re­duced sig­nal steep­ness. This re­quires BAM pick­up elec­trodes with in­creased band­width as in­tro­duced in **. This paper pre­sents the im­ple­men­ta­tion and mea­sure­ment re­sults of a high band­width cone-shaped pick­up ca­pa­ble of op­er­at­ing in the fre­quen­cy range up to 40 GHz. The slope steep­ness at the zero cross­ing is in­ves­ti­gat­ed for a sim­pli­fied equiv­a­lent cir­cuit model. RF-mea­sure­ments have been per­formed using a non-her­met­ic pro­to­type of the BAM pick­ups for as­sess­ing the in­flu­ence of man­u­fac­tur­ing tol­er­ances on the sen­sor per­for­mance. The mea­sure­ments are com­pared to sim­u­la­tion re­sults ob­tained by CST PAR­TI­CLE STU­DIO®.
* F. Loehl et al., Proc. of DIPAC2007, WEPB15, p. 262 (2007).
** A. Angelovski et al., "Pickup design for a high resolution Bunch Arrival time Monitor for FLASH and XFEL", DIPAC2011.
 		 
 
TUPC079 Sensitivity and Tolerance Analysis of a New Bunch Arrival-time Monitor Pickup Design for FLASH and XFEL 1186
 
  • A. Kuhl, A. Angelovski, R. Jakoby, A. Penirschke, S. Schnepp
    TU Darmstadt, Darmstadt, Germany
  • M. Bousonville, H. Schlarb
    DESY, Hamburg, Germany
  • T. Weiland
    TEMF, TU Darmstadt, Darmstadt, Germany
  
  Funding: Supported by the Graduate School of Computational Engineering at TU Darmstadt and the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors"
The Free Elec­tron Laser in Ham­burg (FLASH) is equipped with Bunch Ar­rival Time Mon­i­tors (BAM)*, which pro­vide for a time res­o­lu­tion of less than 10 fs for bunch charges high­er than 0.2 nC. Fu­ture ex­per­i­ments, how­ev­er, will aim at gen­er­at­ing FEL light puls­es from a broad range of bunch charges down to 10 pC. In these cir­cum­stances the re­quire­ments on the time res­o­lu­tion will no longer be ful­filled, which de­mands for a larg­er band­width of the pick­up sys­tem. A new cone-shaped pick­up, which has a band­width greater than 40 GHz has been pro­posed**. At high fre­quen­cies, small man­u­fac­tur­ing tol­er­ances might have great in­flu­ence on the pick­up sig­nal. A sen­si­tiv­i­ty anal­y­sis of sev­er­al man­u­fac­tur­ing tol­er­ances in the pick­up de­sign re­gard­ing their in­flu­ence on the out­put sig­nal was car­ried out (by means of CST PAR­TI­CLE STU­DIO®). These re­sults are uti­lized for set­ting lim­its to the man­u­fac­tur­ing tol­er­ances.
* M.K. Bock et al., IPAC2010, WEOCMH02, Kyoto, Japan, 2010.
** A. Kuhl et al., "Design eines hochauflösenden Ankunftszeitmonitor für FLASH", DPG Frühjahrstagung 2011, Karlsruhe, Germany.