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| MOAAU01 |
First Lasing below 7 nm Wavelength at FLASH/DESY, Hamburg
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- J. Rossbach
Uni HH, Hamburg
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After installation of a further superconducting accelerator module in 2007, the Free-Electron Laser in Hamburg, FLASH,reaches its original design value of up to 1 GeV electron energy. With this electron beam, FLASH has now achieved its design wavelength of 6.5 nm and delivers radiation at saturation level down to below 7 nm routinely to users. The radiation pulse length is in the 10 fs range. The talk will present some key features of the FEL performance at this wavelength.
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Slides
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| TUPPH051 |
Conceptual Ideas for the Temporal Overlap of the Electron Beam and the Seed Laser for sFLASH
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363 |
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- R. Tarkeshian, J. Boedewadt, M. Drescher, J. Rossbach
Uni HH, Hamburg
- R. Ischebeck
PSI, Villigen
- H. Schlarb, S. Schreiber
DESY, Hamburg
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sFLASH is a seeding FEL experiment at FLASH/DESY, to introduce a 30nm HHG-based XUV-beam laser to the electron bunches of FLASH at the entrance of a 10m variable-gap undulator. The temporal overlap between the electron beam and HHG is important for the FEL process. The installation of a 3rd harmonic cavity at FLASH will provide a long high current electron beam (at kA level) over ~600fs (FWHM) bunch duration. The duration of the HHG laser pulse will be about 30fs (FWHM).The desired overlap can be achieved in steps. One approach will be to synchronize the drive laser (Ti:Sapphire, 800nm) of HHG and the incoherent spontaneous synchrotron radiation of the undulator at a sub-picosecond precision. In a following step the overlap can be improved by scanning within the sub-picosecond uncertainty. The possibility of using a streak camera to detect both the 800nm laser and the spontaneous undulator radiation pulses without perturbing FLASH user operation is investigated. To match the power levels, the laser beam has to be attenuated by several orders in magnitude. The layout of the experiment and preliminary simulation results of generation and transport of both light pulses are presented.
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| TUPPH003 |
Tolerance Studies on the High Harmonic Laser Seeding at Flash
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235 |
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- V. Miltchev, A. Azima, J. Boedewadt, H. Delsim-Hashemi, M. Drescher, S. Khan, Th. Maltezopoulos, M. Mittenzwey, J. Rossbach, R. Tarkeshian, M. Wieland
Uni HH, Hamburg
- S. Düsterer, J. Feldhaus, T. Laarmann, H. Schlarb
DESY, Hamburg
- R. Ischebeck
PSI, Villigen
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Currently, the Free-electron-LASer at Hamburg (FLASH) operates in the Self-Amplified Spontaneous Emission (SASE) mode, delivering to users photon beams with wavelengths between 6.5 nm and 40 nm. In order to improve the temporal coherence of the generated radiation, it is planned to externally seed FLASH with higher harmonics of an optical laser. The project aims at seeding in the 30-13 nm range with stability suitable for user operation. In this contribution the performance of the seeded FEL is studied in simulations. Emphasis is placed on the tolerances of the most critical parameters such as transverse offset and angle between the electron beam and the external seed, timing jitter, energy of the seed pulse and the influence of the electron optics.
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| TUPPH038 |
First Measurement Results from the Upgraded Low Energy Longgitudinal Phase Space Diagnostics at PITZ
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330 |
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- J. Roensch, J. Rossbach
Uni HH, Hamburg
- G. Asova, J. W. Baehr, C. H. Boulware, H.-J. Grabosch, L. Hakobyan, M. Hänel, Ye. Ivanisenko, M. K. Khojoyan, M. Krasilnikov, B. Petrosyan, S. Rimjaem, T. A. Scholz, A. Shapovalov, R. Spesyvtsev, F. Stephan
DESY Zeuthen, Zeuthen
- S. Lederer, D. Lipka
DESY, Hamburg
- R. Richter
BESSY GmbH, Berlin
- K. Rosbach
Humboldt University Berlin, Institut für Physik, Berlin
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The Photo Injector Test facility at DESY, Zeuthen site (PITZ) was built to optimize electron sources and to study electron beam characteristics for short wavelength Free-Electron Lasers (FELs). In addition, using a further accelerating ('booster') RF cavity, the so-called emittance compensation mechanism is under investigation at PITZ. Due to the upgrade of the PITZ facility the gap width of the dipole spectrometer downstream the RF gun cavity was too small and had to be modified. A slit was added in front of the spectrometer to improve the momentum resolution. Design considerations are discussed and first measurement results are presented. Furthermore, the bunch length measurements downstream the gun has been adapted to higher energies.
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| TUPPH048 |
Recent Results of the SPARC Project
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359 |
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- M. Ferrario, D. Alesini, M. Bellaveglia, R. Boni, M. Boscolo, M. Castellano, E. Chiadroni, A. Clozza, L. Cultrera, G. Di Pirro, A. Drago, A. Esposito, L. Ficcadenti, D. Filippetto, V. Fusco, A. Gallo, G. Gatti, A. Ghigo, A. Marcelli, B. Marchetti, M. Migliorati, A. Mostacci, E. Pace, L. Palumbo, L. Pellegrino, R. Ricci, U. Rotundo, C. Sanelli, F. Sgamma, B. Spataro, F. Tazzioli, S. Tomassini, C. Vaccarezza, M. Vescovi, C. Vicario
INFN/LNF, Frascati (Roma)
- A. Bacci, I. Boscolo, F. Broggi, F. Castelli, S. Cialdi, C. De Martinis, D. Giove, C. Maroli, V. Petrillo, A. R. Rossi, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano
- M. Bougeard, B. Carré, D. Garzella, M. Labat, G. Lambert, H. Merdji, P. Salieres, O. Tchebakoff
CEA, Gif-sur-Yvette
- L. Catani
INFN-Roma II, Roma
- A. Cianchi
Università di Roma II Tor Vergata, Roma
- F. Ciocci, G. Dattoli, M. Del Franco, A. Dipace, A. Doria, G. P. Gallerano, L. Giannessi, E. Giovenale, G. L. Orlandi, S. Pagnutti, A. Petralia, M. Quattromini, C. Ronsivalle, E. Sabia, I. P. Spassovsky, V. Surrenti
ENEA C. R. Frascati, Frascati (Roma)
- M.-E. Couprie
SOLEIL, Gif-sur-Yvette
- A. Marinelli, J. B. Rosenzweig
UCLA, Los Angeles, California
- M. Mattioli, M. Petrarca, M. Serluca
INFN-Roma, Roma
- J. Rossbach
Uni HH, Hamburg
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The SPARC project foresees the realization of a high brightness photo-injector to produce a 150-200 MeV electron beam to drive 500 nm FEL experiments in various configurations. The SPARC photoinjector is also the test facility for the recently approved VUV FEL project named SPARX. The second stage of the commissioning, that is currently underway, foresees a detailed analysis of the beam matching with the linac in order to confirm the theoretically prediction of emittance compensation based on the “invariant envelope” matching , the demonstration of the “velocity bunching” technique in the linac and the characterisation of the spontaneous emission radiation in the SPARC undulators. In this paper we report the experimental results obtained so far.
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| TUPPH072 |
sFLASH: An Experiment for Seeding VUV Radiation at FLASH
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405 |
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- S. Khan, A. Azima, J. Boedewadt, H. Delsim-Hashemi, M. Drescher, V. Miltchev, M. Mittenzwey, J. Rossbach, R. Tarkeshian, M. Wieland
Uni HH, Hamburg
- S. Düsterer, J. Feldhaus, T. Laarmann, Th. Maltezopoulos, H. Schlarb
DESY, Hamburg
- A. Meseck
BESSY GmbH, Berlin
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The paper describes an FEL seeding experiment at VUV wavelengths,to be installed at the existing SASE FEL user facility FLASH. Beyond a proof-of-principle demonstration in the VUV, the emphasis will be on high stability in terms of intensity and timing thus providing a future alternative operation mode of FLASH for users. The seed laser generates high harmonics (HHG) by focusing a near-infrared laser into a noble gas jet. The efficient transport of the short wavelength (30nm) radiation and the spatial and temporal overlap with the electron beam are among the challenging tasks. The interaction of the seed laser and the electron beam takes place in a new undulator section to be installed in front of the existing FLASH undulator. Four hybrid variable-gap undulators are foreseen with a total length of 10 meters. In the space between undulator sections there are diagnostics devices for both the electron beam and the seed laser. After the undulators there is a weak magnetic chicane as a separator of the electron beam and the seeded FEL radiation. Finally a VUV beamline transports the radiation to an experimental hutch where the temporal characterization of the amplified pulses takes place.
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| THDAU01 |
Light Field Driven Streak-camera: Towards a Single Pulse Time Structure Measurement at FLASH
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524 |
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- U. Fruehling, M. Gensch, E. Plönjes
DESY, Hamburg
- F. Budzyn, M. Drescher, T. Gebert, O. Grimm, R. Kalms, M. Krikunova, J. Rossbach, M. Wieland
Uni HH, Hamburg
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The Free-Electron Laser in Hamburg (FLASH) produces short intense XUV light pulses using Self-Amplified Spontaneous Emission (SASE). Because the lasing in a SASE-FEL starts from shot noise energy, wavelength and time-structure fluctuate from shot to shot. Thus, a single shot measurement of the FLASH temporal profile is of significant interest. For this purpose, the XUV pulses from FLASH are superimposed with far infrared (FIR) light pulses, that are generated by the same electron bunch in a second undulator* and therefore are expected to be intrinsically synchronized to the XUV pulse. In contrast to a conventional streak camera, the solid state photocathode is substituted by free noble gas atoms, which are ionized by the XUV pulses. The created photoelectrons are accelerated by the time-dependent electric field of the infrared light pulse, where the momentum gain depends on the FIR electric field at the ionization time. By measuring the photoelectron momenta we are able to sample the FIR light field. Moreover, single-shot spectra have been obtained that deliver information on the temporal profile of individual XUV pulses.
* M. Gensch et al., Infrared Phys. Techn.,(2008)
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Slides
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