IBIC2014 - List of Authors (Hass, E.)

Paper	Title	Page
MOPF22	Simultaneous Operation of Two FEL Undulator Beamlines at FLASH	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
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MOPD08	A Double-Prism Spectrometer for the Longitudinal Diagnosis of Femtosecond Electron Bunches with Mid-Infrared Transition Radiation	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]
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Paper

Title

Page

Simultaneous Operation of Two FEL Undulator Beamlines at FLASH

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

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MOPD08

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

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]

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