# MFL

 2018-09-1211:54 [PUBDB-2018-03460] Journal Article et al Precision Feedback Control of a Normal Conducting Standing Wave Resonator Cavity   In this paper, the system identification and feedback controller design for a normal conducting Standing wave radio frequency cavity operated in pulsed mode of a free electron laser is presented. The system identification, essential to achieve high performance control, is based on a grey box model, with a priori knowledge about the physical behavior. [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext 2018-08-3114:57 [PUBDB-2018-03325] Report et al Transverse Phase Space Studies in TTF Photoinjector During Run 00-01. A Comparison between Simulation and Experiment. [ TESLA FEL 2000-04 ] 21 pp. (2000) Experimental data on transverse emittance and beam density measurements for avariety of injector settings (photocathode drive-laser phase w.r.t. to peak electric fieldin the RF-gun cavity, magnetic elds settings of solenoids ) are compared along withnumerical simulations performed using the particle tracking code Astra.. Restricted: PDF PDF (PDFA); 2018-08-1706:32 [PUBDB-2018-02985] Contribution to a conference proceedings/Contribution to a book Schreiber, S. Cs$_2$Te Photocathode Lifetime at FLASH and European XFEL 9th International Particle Accelerator Conference, IPAC’18, VancouverVancouver, Canada, 29 Apr 2018 - 4 May 2018 2496-2498 (2018) [doi:10.18429/JACoW-IPAC2018-WEPMF056]   The photoinjectors of FLASH and the European XFEL at DESY (Hamburg, Germany) use Cs$_2$Te photocathodes. In this contribution we give an update on the lifetime and quantum efficiency of the cathodes operated in both facilities. [...] OpenAccess: PDF PDF (PDFA); 2018-08-1310:05 [PUBDB-2018-02900] Contribution to a conference proceedings et al Temporal X-ray Reconstruction Using Temporal and Spectral Measurements 9th International Particle Accelerator Conference, IPAC’18, Vancouver, BCVancouver, BC, Canada, 29 Apr 2018 - 4 May 2018 1440-1443 (2018) [10.3204/PUBDB-2018-02900]   Transverse deflecting structures (TDS) are widely used inaccelerator physics to measure the longitudinal density ofparticle bunches. When used in combination with a dispersivesection, the whole longitudinal phase space density canbe imaged. [...] OpenAccess: PDF PDF (PDFA); 2018-07-2619:20 [PUBDB-2018-02704] Book/Report/Master Thesis Moortgat-Pick, G. Vlasov Simulation of Exotic Phase-Space Densities via Tree-Based Domain-Decomposition [DESY-THESIS-2018-022] Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-THESIS 77 pp. (2018) [10.3204/PUBDB-2018-02704] = Masterarbeit, Universität Hamburg, 2018   Magnetic bunch compression is used to produce the high-brightness electron bunches needed for the operation of a free-electron laser. A longitudinal energy chirp -- imprinted on the bunch via off-crest acceleration -- results in the compression of the bunch in a subsequent dispersive section of the accelerator in form of a magnetic chicane.Such a setup sets the stage for the self-interaction of charge-density in homogeneities via the space-charge fields they generate within the bunch.This can potentially lead to an enhancement of initially present charge-densitymodulations; an effect known as microbunching amplification.Numerical simulation of this dynamics is encumbered by the fact that phase-space densities of electron bunches encountered at free-electron lasers typically exhibit an exotic'' structure, as they form a thin, hair-like bandmeandering through phase-space.In this thesis, a Vlasov-simulation approach based on tree domain-decomposition is presented, that allows for the efficient simulation of these phase-space densities despite their exoticness.Further, a beam-dynamics model is presented, which most notably enables the time-discrete treatment of collective space-charge effects in drift regions of the accelerator.Based on this model an arbitrary-order perturbation theory for the microbunching gain in a bunch-compressor is conceived and applied to the case of a long bunch with monochromatic density modulation.Finally, the results from theory and simulation are compared as part of thebenchmarking of the simulation code.. OpenAccess: mthesis_amstutz - PDF PDF (PDFA); desy-thesis-18-022-title - PDF PDF (PDFA); 2018-07-1117:56 [PUBDB-2018-02583] Conference Presentation et al PolariX TDS - Applications at DESY High Gradient Workshop 2018, HG2018, SINAPShanghai, SINAP, China, 4 Jun 2018 - 8 Jun 2018   OpenAccess: PolariX_TDS_Applications_at_DESY-PDF - PDF PDF (PDFA); PolariX_TDS_Applications_at_DESY - PPTX; 2018-05-2911:22 [PUBDB-2018-02128] Poster Schreiber, S. Cs$_2$Te Photocathode Lifetime at FLASH and European XFEL The 9th International Particle Accelerator Conference, IPAC'18, VancouverVancouver, Canada, 29 Apr 2018 - 4 May 2018   The photoinjectors of FLASH and the European XFEL at DESY (Hamburg, Germany) use Cs$_2$ Te photocathodes. In this contribution we give an update on the lifetime and quantum efficiency of the cathodes operated in both facilities [...] OpenAccess: PDF PDF (PDFA); 2018-05-0914:08 [PUBDB-2018-01937] Book/Report/Dissertation / PhD Thesis Rönsch-Schulenburg, J. Generation of ultra-short low-charge electron bunches for single-spike SASE radiation at the Free-Electron Laser in Hamburg [DESY-THESIS-2018-015] Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-THESIS 144 pp. (2018) [10.3204/PUBDB-2018-01937] = Dissertation, Universität Hamburg, 2017   High-gain Free-Electron Lasers (FEL) constitute a powerful source of intense, short radiation pulses in the XUV and X-ray range that are used in a wide variety of research fields. They typically work in the Self-Amplified Spontaneous Emission (SASE) Mode. [...] OpenAccess: desy-thesis-18-015.title - PDF PDF (PDFA); PhDThesis_RehdersMarie - PDF PDF (PDFA); 2018-03-2913:22 [PUBDB-2018-01601] Contribution to a conference proceedings/Contribution to a book et al Operation of a seeded XUV free electron laser at DESY with high-gain harmonic generation seeding Conference on Lasers and Electro-Optics : [Proceedings] - OSA Washington, D.C., 2017. - ISBN 978-1-943580-27-9 - doi:10.1364/CLEO_AT.2017.JTu4L.5CLEO: Applications and Technology, CLEO 2017, San JoseSan Jose, California, 14 May 2017 - 19 May 2017 Washington, DC : OSA, OSA technical digest (online) JTu4L.5 (2017) [10.1364/CLEO_AT.2017.JTu4L.5]   The XUV free electron laser FLASH has been recently operated in the high-gain harmonic generation (HGHG) mode. We characterized the laser-induced energy modulation, as well as the temporal profile of the seeded FEL pulses. [...] 2017-12-2214:09 [PUBDB-2017-14061] Contribution to a conference proceedings Vogt, M. A Time-Discrete Vlasov Approach to LSC Driven Microbunching in FEL-like Beam Lines International ICFA Mini-Workshop on Nonlinear Dynamics and Collective Effects in Particle Beam Physics, NOCE2017, ArcidossoArcidosso, Italy, 19 Sep 2017 - 22 Sep 2017 10 pp. (2017) [10.3204/PUBDB-2017-14061]   Multi-stage bunch compression setups which are commonplace in Free-Electron Laser (FEL) beam lines have shown to be the source of a collective beam instability, the so-called microbunching instability. Collective forces can, in conjunction with the dispersive effect of the magnetic chicane present in such a compressor stage, lead to an amplification of inhomogeneities in the longitudinal charge density of an electron bunch. [...] OpenAccess: PDF PDF (PDFA);