Paper | Title | Other Keywords | Page |
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TUPF19 | APPLE-II Undulator Magnetic Fields Characterised from Undulator Radiation | undulator, radiation, emittance, photon | 546 |
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The spatial profile of APPLE-II undulator radiation has been measured at high undulator deflection parameter, high harmonic and very small emittance. Undulators are typically designed to operate with small deflection parameter to push the fundamental mode to high photon energies. This unusual choice of parameters is desirable for measurement of vertical emittance with a vertical undulator. We present 1-D and 2-D measured profiles of undulator radiation, and show that this is reproduced in numerical models using the measured magnetic field of the insertion device. Importantly these measurements confirm that for these parameters, the spatial intensity distribution departs significantly from usual Gaussian approximations, instead resembling a double-slit diffraction pattern. This could be an important consideration for photon beamlines of ultimate storage ring light sources. | |||
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Poster TUPF19 [2.364 MB] | ||
WEPC41 | Comparative Analysis of Different Electro-Optical Intensity Modulator Candidates for the New 40 GHz Bunch Arrival Time Monitor System for FLASH and European XFEL | laser, pick-up, electron, free-electron-laser | 782 |
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Funding: The work is supported by Federal Ministry of Education and Research of Germany (BMBF) within FSP 301 under the contract numbers 05K10GU2 and 05K10RDA. The currently installed Bunch Arrival time Monitors (BAMs) at the Free electron LASer in Hamburg (FLASH) achieved a time resolution of less than 10 fs for bunch charges higher than 500 pC. In order to achieve single spike FEL pulses at FLASH, electron bunch charges down to 20 pC are of interest. With these BAMs the required time resolution is not reachable for bunch charges below 500 pC. Therefore new pickups with a bandwidth of up to 40 GHz are designed and manufactured*. The signal evaluation takes place with a time-stabilized reference laser pulse train which is modulated with an Electro-Optical intensity Modulator (EOM). The new BAM system also requires new EOMs for the electro-optical frontend. The available selection of commercial EOM candidates for the new frontend is very limited. In this paper we present a comparison between different EOM candidates for the new electro optical frontend. * A. Angelovski et al. Proceedings Phys. Rev ST AB, DOI:10.1103/PhysRevSTAB.15.112803 |
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Poster WEPC41 [0.619 MB] | ||