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WEPPH007 MCP-based Photon Detector with Extended Wavelength Range for FLASH radiation, photon, undulator, background 334
 
  • O. I. Brovko, D. Kharlamov, E. A. Matyushevskiy, A. V. Shabunov
    JINR/LHE, Moscow
  • J. Feldhaus, U. Hahn, M. Hesse, U. Jastrow, V. Kocharyan, P. Radcliffe, E. Saldin, E. Schneidmiller, K. I. Tiedtke, R. Treusch, M. V. Yurkov, N. von Bargen, L. Bittner
    DESY, Hamburg
  • V. I. Lokhmatov, E. Syresin
    JINR, Dubna, Moscow Region
  Experimental experience gained at the extreme ultraviolet SASE FEL FLASH (DESY, Hamburg) has shown that successful operation of the facility strongly depends on the quality of the radiation detectors. Here key issues are: wide wavelength range (6 to 100 nm for FLASH), wide dynamic range (from the level of spontaneous emission to the saturation level), and high relative accuracy of measurements which is crucial for detection of a signature of amplification and characterization of statistical properties of the radiation. In this report we describe MCP-based radiation detector for FLASH which meets these requirements. Key element of the detector is wide dynamic range micro-channel plate (MCP) which detects scattered radiation from a target. With five different targets and MCPs in combination with optical attenuators present detector covers operating wavelength range from 6 to 100 nm, and dynamic range of the radiation intensities, from the level of spontaneous emission up to the saturation level of SASE FEL.  
 
WEPPH032 Electron-Linac Based Femtosecond THz Radiation Source at PAL radiation, electron, linac, simulation 421
 
  • J. Choi, Y. G. Jung, C. Kim, H.-G. Kim, S.-C. Kim, I. S. Ko, W. W. Lee, B. R. Park, H. S. Suh, I. H. Yu, H.-S. Kang
    PAL, Pohang, Kyungbuk
  A 60-MeV electron linac for intense femto-second THz radiation is under construction at PAL, which is the beamline construction project to be completed by 2008. To get intense femto-second THz radiation up to 100 cm-1, the electron beam should be compressed down to below 100 fs. The linac will use an S-band photocathode RF-gun as an electron beam source, two S-band accelerating structures to accelerate the beam to 60 MeV, a chicane-type bunch compressor to get femto-second electron bunch, and an optical transition radiation (OTR) target as a radiator. The PARMELA code simulation result shows that the 0.2 nC beam can be compressed down to a few tens of femto-seconds, and even the higher charge of 0.5nC to about one hundred femto-seconds. Also, the linac will be able to provide a femto-second electron beam for electron pulse radiolysis and compton-scattering experiment for fs X-ray.  
 
WEPPH033 Stabilization of a Klystron Voltage at 100 PPM Level for PAL XFEL controls, feedback, power-supply, klystron 424
 
  • S. D. Jang, S. J. Kwon, Y. G. Son, J.-H. Suh, J.-S. Oh
    PAL, Pohang, Kyungbuk
  • E. H. Song
    CNU, Changwon
  The PAL XFEL needs a stable electron beam. The stable charging of PFN (pulse forming network) of a klystron-modulator is essential to provide the stable acceleration field for an electron beam. For PAL XFEL, stabilization of klystron voltage pulses at 100 PPM level is required. Short-term stability is determined by a minimum resolution of a charging system. Long-term stability is determined by a thermal stability due to the temperature drift. This paper shows details of hardware R&D and test results to achieve the target stability.  
 
WEPPH055 Experimental Investigation of Smith-Purcell Radiation From Gratings of Different Profile radiation, electron, vacuum, microtron 480
 
  • V. A. Cha, D. V. Karlovets, Yu. A. Popov, A. Potylitsyn, L. G. Sukhikh, G. A. Naumenko
    TPU, Tomsk
  • B. N. Kalinin, G. A. Saruev
    INPR, Tomsk
  Smith-Purcell radiation (SPR) is widely considered as the spontaneous mechanism for FEL. There are a few theoretical SPR models, which predict large difference between radiation intensity from relativistic electrons for grating with different profile. To choose the most effective grating we carried out the absolute coherent SPR intensity measurements on the 6.2 MeV electron beam. The coherent SPR spectra and angular distributions were investigated. Gratings with lamellar, triangular and so-called "flat" gratings were studied. It was shown the grating consisted of the conductive strips is more preferable target for SPR generation.