IBIC2014 - List of Keywords (FEL)

Paper	Title	Other Keywords	Page
MOPF22	Simultaneous Operation of Two FEL Undulator Beamlines at FLASH	undulator, laser, electron, operation	103
	S. Ackermann, V. Ayvazyan, B. Faatz, E. Hass, K. Klose, S. Pfeiffer, M. Scholz, S. Schreiber DESY, Hamburg, Germany
	The FLASH FEL User Facility at DESY (Hamburg) is driven by a Photocathode RF gun and superconducting RF structures, producing up to 800 electron bunches per train with a repetition rate of 10 Hz. Because not all user experiments need the full pulse train (8000 FEL pulses per second), part of the electron bunches can be deflected into a second beamline, which can simultaneously deliver FEL pulses with different parameters to a second user experiment. To realize this possibility, the FLASH facility has been upgraded with a second undulator line and a second experimental Hall. In this contribution, we will present the new layout of the FLASH facility and the first results to operate it with different parameter sets. We will show present results achieved during the commissioning of the new beamline. Finally, we will give an outlook of further commissioning plans and user operation. S. Ackermann for the FLASH II Team
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOPD06	Electron Beam Diagnostics for Short Pulse FEL Schemes at CLARA	electron, laser, diagnostics, simulation	147
	S. Spampinati, D. Newton Cockcroft Institute, Warrington, Cheshire, United Kingdom D. Newton The University of Liverpool, Liverpool, United Kingdom
	CLARA (Compact Linear Accelerator for Research and Applications) [1] is a proposed 250 MeV, 100-400 nm FEL test facility at Daresbury Laboratory. The purpose of CLARA is to test and validate new FEL schemes in areas such as ultra-short pulse generation, temporal coherence and pulse-tailoring. Some of the schemes that can be tested at CLARA depend on a manipulation of the electron beam properties with characteristic scales shorter than the electron beam and require a 30 - 50 μm modulation of the beam energy acquired via the interaction with an infrared laser beam in a short undulator. In this article we describe the electron beam diagnostics required to carry on these experiments.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOPD08	A Double-Prism Spectrometer for the Longitudinal Diagnosis of Femtosecond Electron Bunches with Mid-Infrared Transition Radiation	radiation, electron, detector, diagnostics	157
	S. Wunderlich, E. Hass, B. Schmidt, M. Yan DESY, Hamburg, Germany
	Funding: The project has been supported by the BMBF under contract 05K10GU2 & FS FLASH 301. Electron bunch lengths in the sub-10 fs regime and charges of a few tens of picocoulombs are parameters required for free-electron lasers [] and are also a consequence from the intrinsic process in laser-driven plasma wake field acceleration []. Since the coherent spectrum of transition radiation of these bunches carries the information on the longitudinal bunch profile in the form factor, the spectroscopy of transition radiation is an attractive method to determine the electron bunch length. A double-prism spectrometer has been developed and demonstrated for the single-stage measurement of mid-infrared transition radiation between 2 μm and 18 μm. The spectrometer facilitates single-shot spectral measurements with high signal-to-noise ratio utilising a line array of mercury cadmium telluride detectors. In this contribution, we present the spectrometer and measurements of electron bunches of the Free-Electron Laser in Hamburg (FLASH) at DESY. The results are compared to established bunch length monitors which are a multi-stage grating spectrometer for transition radiation and a transverse deflecting structure accessing the longitudinal phase space of the electron bunches directly. J. Rönsch-Schulenburg et al., Proceedings of FEL 2014, TUB04 (2014), to be published **O. Lundh et al., Nature Physics 7, 219–222 (2011)
	Poster MOPD08 [1.346 MB]
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOPD10	New Results Of FERMI FEL1 EOS Diagnostics With Full Optical Synchronization	laser, electron, diagnostics, electronics	165
	M. Veronese, E. Allaria, P. Cinquegrana, E. Ferrari, F. Rossi, P. Sigalotti, C. Spezzani Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy E. Ferrari Università degli Studi di Trieste, Trieste, Italy
	The Electro Optical Sampling diagnostics (EOS) of the FERMI FEL has been recently upgraded with a full optical synchronization of its dedicated femtosecond fiber laser to the ultra-stable optical pulsed timing system of FERMI. For this purpose a dual synchronization electronics has been developed and installed. It exploits a mixed error signal derived from both optical to electrical conversion and from a second harmonic generation based optical phase detection. For this second part a new optical setup including a cross correlator has been installed. The operation of the EOS has greatly benefited from the upgrade. The arrival time measurements have been compared with the ones from the bunch arrival monitor diagnostics (BAM) showing very good agreement. This new setup has also allowed to improve the bunch profile measurement. Some examples of measurement with ZnTe and GaP are presented. Finally, usability and operator friendliness of the new setup are also discussed.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUPF25	Characterization of the Laser Beam for HHG Seeding	simulation, electron, laser, undulator	380
	S. Ackermann, B. Faatz DESY, Hamburg, Germany V. Miltchev Uni HH, Hamburg, Germany
	Recently free-electron laser (FEL) facilities around the world have shown that the direct seeding approach can enhance the spectral, temporal and coherence properties of the emitted radiation as well as reducing the fluctuations in arrival time and output energy. To achieve this, a photon pulse of the desired wavelength ("seed") is overlapped transversely and temporally with the electrons in the undulator to start up the FEL process from a defined radiation pulse rather than from noise. To benefit from the advantages of this technique, the energy of the seed has to exceed the energy of the spontaneous emission. The ratio between these two energies is strongly influenced by the seed beam properties. In this contribution, we will present simulations on the achieveable power contrast in dependence on the beam quality of the seed, and compare the results to the experimental data of the seeded FEL experiment ("sFLASH") at DESY, Hamburg. Additionally we show up a way of creating FEL seed pulses for simulation purposes from Hermite-Gaussian generating functions.
Export •	reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPF22

Simultaneous Operation of Two FEL Undulator Beamlines at FLASH

undulator, laser, electron, operation

103

S. Ackermann, V. Ayvazyan, B. Faatz, E. Hass, K. Klose, S. Pfeiffer, M. Scholz, S. Schreiber
DESY, Hamburg, Germany

The FLASH FEL User Facility at DESY (Hamburg) is driven by a Photocathode RF gun and superconducting RF structures, producing up to 800 electron bunches per train with a repetition rate of 10 Hz. Because not all user experiments need the full pulse train (8000 FEL pulses per second), part of the electron bunches can be deflected into a second beamline, which can simultaneously deliver FEL pulses with different parameters to a second user experiment. To realize this possibility, the FLASH facility has been upgraded with a second undulator line and a second experimental Hall. In this contribution, we will present the new layout of the FLASH facility and the first results to operate it with different parameter sets. We will show present results achieved during the commissioning of the new beamline. Finally, we will give an outlook of further commissioning plans and user operation.
S. Ackermann for the FLASH II Team

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOPD06

Electron Beam Diagnostics for Short Pulse FEL Schemes at CLARA

electron, laser, diagnostics, simulation

147

S. Spampinati, D. Newton
Cockcroft Institute, Warrington, Cheshire, United Kingdom
D. Newton
The University of Liverpool, Liverpool, United Kingdom

CLARA (Compact Linear Accelerator for Research and Applications) [1] is a proposed 250 MeV, 100-400 nm FEL test facility at Daresbury Laboratory. The purpose of CLARA is to test and validate new FEL schemes in areas such as ultra-short pulse generation, temporal coherence and pulse-tailoring. Some of the schemes that can be tested at CLARA depend on a manipulation of the electron beam properties with characteristic scales shorter than the electron beam and require a 30 - 50 μm modulation of the beam energy acquired via the interaction with an infrared laser beam in a short undulator. In this article we describe the electron beam diagnostics required to carry on these experiments.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOPD08

A Double-Prism Spectrometer for the Longitudinal Diagnosis of Femtosecond Electron Bunches with Mid-Infrared Transition Radiation

radiation, electron, detector, diagnostics

157

S. Wunderlich, E. Hass, B. Schmidt, M. Yan
DESY, Hamburg, Germany

Funding: The project has been supported by the BMBF under contract 05K10GU2 & FS FLASH 301.
Electron bunch lengths in the sub-10 fs regime and charges of a few tens of picocoulombs are parameters required for free-electron lasers [*] and are also a consequence from the intrinsic process in laser-driven plasma wake field acceleration [**]. Since the coherent spectrum of transition radiation of these bunches carries the information on the longitudinal bunch profile in the form factor, the spectroscopy of transition radiation is an attractive method to determine the electron bunch length. A double-prism spectrometer has been developed and demonstrated for the single-stage measurement of mid-infrared transition radiation between 2 μm and 18 μm. The spectrometer facilitates single-shot spectral measurements with high signal-to-noise ratio utilising a line array of mercury cadmium telluride detectors. In this contribution, we present the spectrometer and measurements of electron bunches of the Free-Electron Laser in Hamburg (FLASH) at DESY. The results are compared to established bunch length monitors which are a multi-stage grating spectrometer for transition radiation and a transverse deflecting structure accessing the longitudinal phase space of the electron bunches directly.
*J. Rönsch-Schulenburg et al., Proceedings of FEL 2014, TUB04 (2014), to be published
**O. Lundh et al., Nature Physics 7, 219–222 (2011)

Poster MOPD08 [1.346 MB]

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOPD10

New Results Of FERMI FEL1 EOS Diagnostics With Full Optical Synchronization

laser, electron, diagnostics, electronics

165

M. Veronese, E. Allaria, P. Cinquegrana, E. Ferrari, F. Rossi, P. Sigalotti, C. Spezzani
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
E. Ferrari
Università degli Studi di Trieste, Trieste, Italy

The Electro Optical Sampling diagnostics (EOS) of the FERMI FEL has been recently upgraded with a full optical synchronization of its dedicated femtosecond fiber laser to the ultra-stable optical pulsed timing system of FERMI. For this purpose a dual synchronization electronics has been developed and installed. It exploits a mixed error signal derived from both optical to electrical conversion and from a second harmonic generation based optical phase detection. For this second part a new optical setup including a cross correlator has been installed. The operation of the EOS has greatly benefited from the upgrade. The arrival time measurements have been compared with the ones from the bunch arrival monitor diagnostics (BAM) showing very good agreement. This new setup has also allowed to improve the bunch profile measurement. Some examples of measurement with ZnTe and GaP are presented. Finally, usability and operator friendliness of the new setup are also discussed.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUPF25

Characterization of the Laser Beam for HHG Seeding

simulation, electron, laser, undulator

380

S. Ackermann, B. Faatz
DESY, Hamburg, Germany
V. Miltchev
Uni HH, Hamburg, Germany

Recently free-electron laser (FEL) facilities around the world have shown that the direct seeding approach can enhance the spectral, temporal and coherence properties of the emitted radiation as well as reducing the fluctuations in arrival time and output energy. To achieve this, a photon pulse of the desired wavelength ("seed") is overlapped transversely and temporally with the electrons in the undulator to start up the FEL process from a defined radiation pulse rather than from noise. To benefit from the advantages of this technique, the energy of the seed has to exceed the energy of the spontaneous emission. The ratio between these two energies is strongly influenced by the seed beam properties. In this contribution, we will present simulations on the achieveable power contrast in dependence on the beam quality of the seed, and compare the results to the experimental data of the seeded FEL experiment ("sFLASH") at DESY, Hamburg. Additionally we show up a way of creating FEL seed pulses for simulation purposes from Hermite-Gaussian generating functions.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)