THB —  FEL Technology (Electron Diagnostics, Timing, Synchronization and Controls)   (28-Aug-14   10:30—12:00)
Chair: R. Ischebeck, PSI, Villigen PSI, Switzerland
Paper Title Page
THB01 Simultaneous Measurement of Electron and Photon Pulse Duration at FLASH 654
  • S. Düsterer
    DESY, Hamburg, Germany
  One of the most challenging tasks for extreme ultraviolet, soft and hard X-ray free-electron laser photon diagnostics is the precise determination of the photon pulse duration, which is typically in the sub 100 fs range. In a larger campaign nine different methods, which are able to determine such ultrashort photon pulse durations were compared at FLASH. Radiation pulses at a wavelength of 13.5 nm and 24.0 nm together with the corresponding electron bunch duration were measured by indirect methods like analyzing spectral correlations, statistical fluctuations and energy modulations of the electron bunch, and also direct methods like autocorrelation techniques, THz streaking or reflectivity changes of solid state samples.  
slides icon Slides THB01 [4.520 MB]  
THB02 Experimental Results of Diagnostics Response for Longitudinal Phase Space 657
  • F. Frei, V.R. Arsov, H. Brands, R. Ischebeck, B. Kalantari, R. Kalt, B. Keil, W. Koprek, F. Löhl, G.L. Orlandi, Á. Saá Hernández, T. Schilcher, V. Schlott
    PSI, Villigen PSI, Switzerland
  At SwissFEL, electron bunches will be accelerated, shaped, and longitudinally compressed by different radio frequency (RF) structures (S-, C-, and X-band) in combination with magnetic chicanes. In order to meet the envisaged performance, it is planned to regulate the different RF parameters based on the signals from numerous electron beam diagnostics. Here we will present experimental results of the diagnostics response on RF phase and field amplitude variations that were obtained at the SwissFEL Injector Test Facility.  
slides icon Slides THB02 [6.110 MB]  
THB03 Femtosecond-Stability Delivery of Synchronized RF-Signals to the Klystron Gallery over 1-km Optical Fibers 663
  • J. Kim, K. Jung, J. Lim, J. Shin, H. Yang
    KAIST, Daejeon, Republic of Korea
  • H.-S. Kang, C.-K. Min
    PAL, Pohang, Kyungbuk, Republic of Korea
  Funding: This work was supported by the PAL-XFEL Project and the National Research Foundation (Grant number 2012R1A2A2A01005544) of South Korea.
We present our recent progress in optical frequency comb-based remote optical and RF distribution system at PAL-XFEL. A 238 MHz mode-locked Er-laser is used as an optical master oscillator (OMO), which is stabilized to a 2.856 GHz RF master oscillator (RMO) using a fiber- loop optical-microwave phase detector (FLOM-PD). We partly installed a pair of 1.15 km long fiber links through a cable duct to connect and OMO room to a klystron gallery in the PAL-XFEL Injector Test Facility (ITF). The fiber links are stabilized using balanced optical cross- correlators (BOC). A voltage controlled RF oscillator (VCO) is locked to the delivered optical pulse train using the second FLOM-PD. Residual timing jitter and drift between the two independently distributed optical pulse train and RF signal is measured at the klystron gallery. The results are 6.6 fs rms and 31 fs rms over 7 hours and 62 hours, respectively. This is the first comb-based optical/RF distribution and phase comparison in the klystron gallery environment.
slides icon Slides THB03 [7.478 MB]  
THB04 Electron Beam Diagnostics and Feedback for the LCLS-II 666
  • J.C. Frisch, P. Emma, A.S. Fisher, P. Krejcik, H. Loos, T.J. Maxwell, T.O. Raubenheimer, S.R. Smith
    SLAC, Menlo Park, California, USA
  Funding: work supported by DOE contract DE-AC02-76-SF00515
The LCLSII is a CW superconducting accelerator driven, hard and soft X-ray Free Electron Laser which is planned to be constructed at SLAC. It will operate with a variety of beam modes from single shot to approximately 1 MHz CW at bunch charges from 10pc to 300pC with average beam powers up to 1.2 MW. A variety of types of beam instrumentation will be used, including stripline and cavity BPMS, fluorescent and OTR based beam profile monitors, fast wire scanners and transverse deflection cavities. The beam diagnostics system is designed to allow tuning and continuous measurement of beam parameters, and to provide signals for fast beam feedbacks.
slides icon Slides THB04 [1.501 MB]