Stephan, F and Boulware, CH and Krasilnikov, M and Bahr, J and Asova, G and Donat, A and Gensch, U and Grabosch, HJ and Hanel, M and Hakobyan, L and Henschel, H and Ivanisenko, Y and Jachmann, L and Khodyachykh, S and Khojoyan, M and Kohler, W and Korepanov, S and Koss, G and Kretzschmann, A and Leich, H and Ludecke, H and Meissner, A and Oppelt, A and Petrosyan, B and Pohl, M and Riemann, S and Rimjaem, S and Sachwitz, M and Schoneich, B and Scholz, T and Schulze, H and Schultze, J and Schwendicke, U and Shapovalov, A and Spesyvtsev, R and Staykov, L and Tonisch, F and Walter, T and Weisse, S and Wenndorff, R and Winde, M and von Vu, L and Durr, H and Kamps, T and Richter, D and Sperling, M and Ovsyannikov, R and Vollmer, A and Knobloch, J and Jaeschke, E and Boster, J and Brinkmann, R and Choroba, S and Flechsenhar, K and Flottmann, K and Gerdau, W and Katalev, V and Koprek, W and Lederer, S and Martens, C and Pucyk, P and Schreiber, S and Simrock, S and Vogel, E and Vogel, V and Rosbach, K and Bonev, I and Tsakov, I and Michelato, P and Monaco, L and Pagani, C and Sertore, D and Garvey, T and Will, I and Templin, I and Sandner, W and Ackermann, W and Arevalo, E and Gjonaj, E and Muller, WFO and Schnepp, S and Weiland, T and Wolfheimer, F and Ronsch, J and Rossbach, J (2010) Detailed characterization of electron sources yielding first demonstration of European X-ray Free-Electron Laser beam quality. PHYS REV SPEC TOP-AC , 13 (2) , Article 020704. 10.1103/PhysRevSTAB.13.020704.
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.
|Title:||Detailed characterization of electron sources yielding first demonstration of European X-ray Free-Electron Laser beam quality|
|Open access status:||An open access publication|
|Keywords:||CESIUM TELLURIDE PHOTOCATHODES, PHOTOEMISSION, FEL|
|UCL classification:||UCL > School of BEAMS > Faculty of Maths and Physical Sciences > Chemistry|
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