1. Detailed characterization of electron sources yielding first demonstration of European X-ray Free-Electron Laser beam quality
- Author
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Sascha Schnepp, M. Sperling, I. Bonev, Erion Gjonaj, Roman Spesyvtsev, C. Martens, Frank Stephan, I. Tsakov, Ruslan Ovsyannikov, Thomas Weiland, M. Pohl, W. Köhler, Mikhail Krasilnikov, E. Vogel, Sven Lederer, P. Pucyk, Wolfgang Sandner, Felix Wolfheimer, T.A.Scholz, A. Kretzschmann, I. Templin, A. Shapovalov, Jörg Rossbach, M. Hänel, L. Staykov, U. Schwendicke, R. Wenndorff, E. Jaeschke, F. Tonisch, Anne Oppelt, V. Katalev, Wolfgang Franz Otto Müller, T. Garvey, Sakhorn Rimjaem, Wolfgang Ackermann, S. Weisse, Carlo Pagani, L. Jachmann, Jens Knobloch, E. Arevalo, Waldemar Koprek, G. Asova, J. Rönsch, L. v. Vu, H. Schulze, D. Richter, M. Sachwitz, T. Walter, H. Lüdecke, V. Vogel, L. Hakobyan, S. Korepanov, J. Bähr, Antje Vollmer, Y. Ivanisenko, A. Donat, K. Rosbach, A. Meissner, K. Flechsenhar, Paolo Michelato, Bagrat Petrosyan, Hermann A. Dürr, R. Brinkmann, B. Schöneich, Ingo Will, Sabine Riemann, Siegfried Schreiber, S. Simrock, H. Henschel, H.-J. Grabosch, M. Winde, U. Gensch, Klaus Flöttmann, C. H. Boulware, S. Khodyachykh, J. Boster, G. Koss, S. Choroba, Thorsten Kamps, Laura Monaco, W. Gerdau, Martin Khojoyan, Daniele Sertore, H. Leich, J. Schultze, Deutsches Elektronen-Synchrotron [Zeuthen] (DESY), Helmholtz-Gemeinschaft = Helmholtz Association, Deutsches Elektronen-Synchrotron [Hamburg] (DESY), Laboratoire de l'Accélérateur Linéaire (LAL), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Nuclear and High Energy Physics ,Physics and Astronomy (miscellaneous) ,[PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph] ,29.25.Bx, 52.59.Sa, 41.60.Cr ,7. Clean energy ,01 natural sciences ,law.invention ,Optics ,law ,0103 physical sciences ,ddc:530 ,Thermal emittance ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,010306 general physics ,Electron gun ,Physics ,010308 nuclear & particles physics ,business.industry ,Free-electron laser ,DESY ,Surfaces and Interfaces ,Laser ,lcsh:QC770-798 ,Physics::Accelerator Physics ,Laser beam quality ,business ,Lasing threshold ,Beam (structure) - Abstract
The photoinjector test facility at DESY, Zeuthen site (PITZ), was built to develop and optimize photoelectron sources for superconducting linacs for high-brilliance, short-wavelength free-electron laser (FEL) applications like the free-electron laser in Hamburg (FLASH) and the European x-ray free-electron laser (XFEL). In this paper, the detailed characterization of two laser-driven rf guns with different operating conditions is described. One experimental optimization of the beam parameters was performed at an accelerating gradient of about 43 MV/m at the photocathode and the other at about 60 MV/m. In both cases, electron beams with very high phase-space density have been demonstrated at a bunch charge of 1 nC and are compared with corresponding simulations. The rf gun optimized for the lower gradient has surpassed all the FLASH requirements on beam quality and rf parameters (gradient, rf pulse length, repetition rate) and serves as a spare gun for this facility. The rf gun studied with increased accelerating gradient at the cathode produced beams with even higher brightness, yielding the first demonstration of the beam quality required for driving the European XFEL: The geometric mean of the normalized projected rms emittance in the two transverse directions was measured to be 1.26±0.13 mm mrad for a 1-nC electron bunch. When a 10% charge cut is applied excluding electrons from those phase-space regions where the measured phase-space density is below a certain level and which are not expected to contribute to the lasing process, the normalized projected rms emittance is about 0.9 mm mrad.
- Published
- 2010