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diagnostics

Paper Title Other Keywords Page
MOPPH004 Measurement and Analysis of CSR effects at FLASH simulation, space-charge, optics, acceleration 18
 
  • W. Decking, T. Limberg, M. Roehrs, B. Beutner
    DESY, Hamburg
  The vacuum-ultra-violet Free Electron Laser in Hamburg (FLASH) is a linac driven SASE-FEL. High peak currents are produced using magnetic bunch compression chicanes. In these magnetic chicanes, the energy distribution along an electron bunch is changed by effects of Coherent Synchrotron Radiation (CSR). Energy changes in dispersive bunch compressor chicanes lead to transverse displacements along the bunch. These CSR induced displacements are studied using a transverse deflecting rf-structure. Recent experiments and simulations concerning the charge dependence of such transverse displacements are presented and analyzed. In these experiments an over-compression scheme is used which reduces the peak current downstream the bunch compressor chicanes. Therefore other self interactions like space charge forces which might complicate the measurements are suppressed.  
 
MOPPH009 Undulator Radiation in a Waveguide undulator, resonance, radiation, vacuum 34
 
  • E. Saldin, E. Schneidmiller, M. V. Yurkov, G. Geloni
    DESY, Hamburg
  We propose an analytical approach to characterize undulator radiation near resonance, when the presence of the vacuum-pipe considerably affects radiation properties. This is the case of the far-infrared undulator beamline at the Free-electron LASer (FEL) in Hamburg (FLASH), that is designed to deliver pulses in the TeraHertz (THz) range. This undulator can be used for pump-probe experiments where THz pulses are naturally synchronized to the VUV pulse from the FEL, as well as the development of novel electron-beam diagnostics techniques. Since the THz radiation diffraction-size exceeds the vacuum-chamber dimensions, characterization of infrared radiation must be performed accounting for the presence of a waveguide. We developed a theory of undulator radiation in a waveguide based on paraxial and resonance approximation. We solved the field equation with a tensor Green's function technique, and extracted figure of merits describing in a simple way the influence of the vacuum-pipe on the radiation pulse as a function of the problem parameters. Our theory, that makes consistent use of dimensionless analysis, allows treatment and physical understanding of many asymptotes of the parameter space, together with their region of applicability. (See DESY 07-031)  
 
MOPPH031 Spectroscopy and Spectrally Resolved Radioscopy of Biological Substances Using Terahertz Free Electron Laser Radiation radiation, free-electron-laser, laser, electron 86
 
  • V. V. Gerasimov
    NSU, Novosibirsk
  • A. M. Gonchar
    ICG SB RAS, Novosibirsk
  • B. A. Knyazev
    BINP SB RAS, Novosibirsk
  High average power and monochromacity of terahertz Novosibirsk free electron laser are favorable for the development of time and space resolved spectroscopic and radioscopic techniques for study of highly absorbing substances, in particular, biological ones. To study highly absorbing objects we applied a homemade attenuated total reflection spectrometer, which enables operation in both conventional and imaging mode. By measuring the reflection coefficients for p- and s-polarized radiation, the real (n) and imaginary (k) parts of refractive index can be derived. Using a microbolometer matrix (see the paper by Esaev et al. at this conference), imaging radioscopy of the samples containing amino acids and DNA had been performed. The methods developed were applied also for examination of bones of intact and senescence-accelerated mice that, probably, would lead to study osteoporosis development.  
 
MOPPH034 Diagnostics of an Electron Beam using Coherent Cherenkov Radiation radiation, electron, laser, undulator 95
 
  • R. Tikhoplav
    UCLA, Los Angeles, California
  A comparison of coherent Cherenkov and transition radiations as a diagnostic tool for longitudinal distribution of an electron beam is studied in this paper. Two methods will be used for the 7th harmonic bunching experiment at Neptune linear accelerator facility at UCLA. Coherent Cherenkov radiation is produced in an aerogel with an index of refraction close to unity.  
 
MOPPH040 A Study of Detection Schemes in Electro-Optic Sampling Technique laser, electron, background, polarization 101
 
  • J. Y. Huang, C. Kim, I. S. Ko, Y. W. Parc
    PAL, Pohang, Kyungbuk
  Electro-Optic Sampling (EOS) is the ingenious tool for the measurement of the electron beam or Thz radiation. There are two traditional detection schemes: one is the crossed polarizer scheme and another is balanced detection one. A new detection scheme called Near Crossed Polarizer scheme in the EOS technique is developed to increase the Signal to Noise Ratio in the experiment. The new detection scheme is studied in detail and the 3D scanning result with electron beam in FLASH is compared with the detection scheme. The new detection scheme has an analytical problem which shows two solutions for the relative phase shift for specific measurement of the electron beam. That problem is also studied through the comparative study between simulation and the analyzed data from the TEO setup in FLASH.  
 
MOPPH043 Control and Diagnostic System of Novosibirsk FEL Radiation radiation, controls, undulator, linac 111
 
  • V. V. Kubarev, E. V. Makashov, K. S. Palagin, S. S. Serednyakov
    BINP SB RAS, Novosibirsk
  The architecture the main capabilities of control and diagnostic system of the Novosibirsk FEL coherent radiation are described. The client-server model is used for software, controlling this system. The developed software is capable to work both in client and server mode. Also it can control various equipment – from FEL optical cavity mirrors to local equipment of users stations. The mode of control program operation and controlled equipment are determinates by external configuration files. Some results of the system operation are also presented.  
 
MOPPH072 The IR-Beam Transport System from the ELBE-FELs to the User Labs laser, electron, radiation, focusing 171
 
  • M. Justus, K.-W. Leege, D. Proehl, R. Schlenk, A. Winter, D. Wohlfarth, R. Wuensch, W. Seidel
    FZD, Dresden
  In the Forschungszentrum Dresden-Rossendorf, two free-electron lasers (FELs) have been put into operation. They produce laser light in the medium and the far infrared wavelength range (4-200 microns). The IR light is transported to several laboratories in the same building and to the adjacent building of the High Magnetic Field Laboratory (HLD) as well. The latter is up to 70m away from the FELs. Constructional peculiarities, the large wavelength range (a factor of 50 between the shortest and the longest wavelengths), the high average power in cw regime, and the beam property requirements of the users pose a challenge to the beam line design. The transport system includes vacuum pipes, plane and toroidal gold-covered copper mirrors, exit windows, and diagnostic elements. The designed transport system produces a beam waist at selected spots in each laboratory representing an image of the outcoupling hole. Spot size and position are independent of the wavelength. In the HLD the beam is fed into a circulare waveguide, guiding the radiation to the sample inside of a cryostat. To ensure the desired beam properties, the transport system has been analyzed by means of various ray and wave optical models.  
 
TUPPH015 Diffraction Effects in the Coherent Transition Radiation Bunch Length Diagnostics electron, radiation, injection, photon 256
 
  • V. A. Lebedev, S. Nagaitsev, G. M. Kazakevich
    Fermilab, Batavia, Illinois
  Diffraction effects in the Coherent Transition Radiation (CTR) bunch length diagnostics were considered for the A0 Photoinjector and the ILC injection module. The effects can cause a noticeable distortion of the measured CTR spectra dependently on the experimental setup and the bunch parameters. The distortion results in the the errors of the bunch length determination. Presented calculations show possible errors in determination of the bunch length in assumed experiments based on the CTR spectra measurements at A0 Photo injector and the ILC injection module.  
 
WEPPH011 Photocathode Laser Pulse Diagnostics at PITZ laser, cathode, electron, emittance 346
 
  • J. W. Baehr, S. A. Korepanov, M. Krasilnikov, F. Stephan, M. Hänel
    DESY Zeuthen, Zeuthen
  • Ye. Ivanisenko
    KhNU, Kharkov
  The main objective of the Photo Injector Test facility at DESY in Zeuthen (PITZ) is the development of electron sources that meet the requirements for existing and future FELs such as FLASH or the European XFEL. The goal is the minimization of the transverse emittance of the produced electron bunches. In this respect one of the key issues is the cathode laser system, which should provide longitudinal and transversal flat-top pulses with an excellent long-term stability. In this work we present the full system of laser diagnostics that is currently used at PITZ to monitor the laser pulse parameters.  
 
WEPPH013 Status and Perspectives of the PITZ Facility Upgrade gun, emittance, cathode, booster 354
 
  • G. Asova, J. W. Baehr, C. H. Boulware, H.-J. Grabosch, L. H. Hakobyan, M. Hänel, S. Khodyachykh, S. A. Korepanov, M. Krasilnikov, S. Lederer, A. Oppelt, B. Petrosyan, S. Riemann, T. A. Scholz, L. Staykov, F. Stephan, S. Rimjaem
    DESY Zeuthen, Zeuthen
  • K. Boyanov
    INRNE, Sofia
  • K. Floettmann
    DESY, Hamburg
  • R. Richter
    BESSY GmbH, Berlin
  • J. Roensch
    Uni HH, Hamburg
  • K. Rosbach
    Humboldt University Berlin, Institut für Physik, Berlin
  • A. Shapovalov
    MEPhI, Moscow
  The Photo Injector Test facility at DESY in Zeuthen (PITZ) has been established to develop and optimize electron sources that cover requirements of FEL facilities such as FLASH and the European XFEL. A major upgrade of the facility is ongoing in steps, in parallel to the commissioning of the extended setup and first experiments. The new setup towards the final design mainly includes a photo cathode RF gun, a post acceleration booster cavity and several diagnostic systems. In order to fulfil the high brightness electron source characterization, the diagnostic systems will consist of three emittance measurement systems, two high-energy dispersive arms, an RF deflecting cavity and a longitudinal phase space tomography module as well as bunch length diagnostics. In this paper, results of the commissioning of the new RF gun, which has been installed and conditioned at PITZ in spring and summer of 2007, the current PITZ status and details of the future facility upgrade will be presented.  
 
WEPPH049 Test of a Wiresanner in the Diagnostic Section of PITZ electron, cathode, undulator, background 461
 
  • G. Asova, J. W. Baehr, J. H. Han, S. Khodyachykh, S. A. Korepanov, M. Krasilnikov, V. Miltchev, A. Oppelt, B. Petrosyan, M. Sachwitz, L. Staykov, F. Stephan, H.-J. Grabosch
    DESY Zeuthen, Zeuthen
  The Photo Injector Test facility at Zeuthen (PITZ) has been established to optimize electron beams of high brilliance needed for short wavelength FELs. In a first step one wire scanner station, developed and used in the undulator section of FLASH at DESY, was tested in the diagnostic section of PITZ. Measurements of the beam-profile and the beam-position were performed to test the useability of such type of wire scanner at PITZ. The obtained results are presented and discussed. The test has shown that wire scanners of this type can be used successfully as complementary measurement device for beam-profile measurements at PITZ. In the final state of extension of PITZ , two wire scanners are foreseen as standard diagnostic tools.