3 results
Search Results
Now showing 1 - 3 of 3
- ItemCharacterization of self-modulated electron bunches in an argon plasma(Bristol : IOP Publ., 2018) Gross, M.; Lishilin, O.; Loisch, G.; Boonpornprasert, P.; Chen, Y.; Engel, J.; Good, J.; Huck, H.; Isaev, I.; Krasilnikov, M.; Li, X.; Niemczyk, R.; Oppelt, A.; Qian, H.; Renier, Y.; Stephan, F.; Zhao, Q.; Brinkmann, R.; Martinez de la Ossa, A.; Osterhoff, J.; Grüner, F.J.; Mehrling, T.; Schroeder, C.B.; Will, I.The self-modulation instability is fundamental for the plasma wakefield acceleration experiment of the AWAKE (Advanced Wakefield Experiment) collaboration at CERN where this effect is used to generate proton bunches for the resonant excitation of high acceleration fields. Utilizing the availability of flexible electron beam shaping together with excellent diagnostics including an RF deflector, a supporting experiment was set up at the electron accelerator PITZ (Photo Injector Test facility at DESY, Zeuthen site), given that the underlying physics is the same. After demonstrating the effect [1] the next goal is to investigate in detail the self-modulation of long (with respect to the plasma wavelength) electron beams. In this contribution we describe parameter studies on self-modulation of a long electron bunch in an argon plasma. The plasma was generated with a discharge cell with densities in the 1013 cm-3 to 1015 cm-3 range. The plasma density was deduced from the plasma wavelength as indicated by the self-modulation period. Parameter scans were conducted with variable plasma density and electron bunch focusing.
- ItemDetailed characterization of electron sources yielding first demonstration of European x-ray free-electron laser beam quality(College Park, Md. : APS, 2010) Stephan, F.; Boulware, C.H.; Krasilnikov, M.; Bähr, J.; Asova, G.; Donat, A.; Gensch, U.; Grabosch, H.J.; Hänel, M.; Hakobyan, L.; Henschel, H.; Ivanisenko, Y.; Jachmann, L.; Khodyachykh, S.; Khojoyan, M.; Kohler, W.; Korepanov, S.; Koss, G.; Kretzschmann, A.; Leich, H.; Ludecke, H.; Meissner, A.; Oppelt, A.; Petrosyan, B.; Pohl, M.; Riemann, S.; Rimjaem, S.; Sachwitz, M.; Schoneich, B.; Scholz, T.; Schulze, H.; Schultze, J.; Schwendicke, U.; Shapovalov, A.; Spesyvtsev, R.; Staykov, L.; Tonisch, F.; Walter, T.; Weisse, S.; Wenndorff, R.; Winde, M.; Vu, L.V.; Durr, H.; Kamps, T.; Richter, D.; Sperling, M.; Ovsyannikov, R.; Vollmer, A.; Knobloch, J.; Jaeschke, E.; Boster, J.; Brinkmann, R.; Choroba, S.; Flechsenhar, K.; Flottmann, K.; Gerdau, W.; Katalev, V.; Koprek, W.; Lederer, S.; Martens, C.; Pucyk, P.; Schreiber, S.; Simrock, S.; Vogel, E.; Vogel, V.; Rosbach, K.; Bonev, I.; Tsakov, I.; Michelato, P.; Monaco, L.; Pagani, C.; Sertore, D.; Garvey, T.; Will, I.; Templin, I.; Sandner, W.; Ackermann, W.; Arévalo, E.; Gjonaj, E.; Muller, W.F.O.; Schnepp, S.; Weiland, T.; Wolfheimer, F.; Ronsch, J.; Rossbach, J.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 1.260±13 mmmrad 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 mmmrad. © 2010 The American Physical Society.
- ItemPhotocathode laser based bunch shaping for high transformer ratio plasma wakefield acceleration(Amsterdam : North-Holland Publ. Co., 2018) Loisch, G.; Good, J.; Gross, M.; Huck, H.; Isaev, I.; Krasilnikov, M.; Lishilin, O.; Oppelt, A.; Renier, Y.; Stephan, F.; Brinkmann, R.; Grüner, F.; Will, I.Beam driven plasma acceleration is one of the most promising candidates for future compact particle accelerator technologies. In this scheme a particle bunch drives a wake in a plasma medium. The fields inside of the wake can be used to accelerate a trailing witness bunch. To maximise the ratio between acceleration of the witness to deceleration of the drive bunch, the so called transformer ratio, several methods have been proposed. The ones yielding the most favorable results are based on shaped drive bunches that are long in terms of the plasma wavelength. We present here methods to create such drive bunches employing temporally shaped UV-laser pulses for the extraction of electron bunches from a photo-electron gun. Theoretical considerations, experimental results and possibilities for further improvements are discussed.