FEL2017 - List of Authors (Schreiber, S.)

Paper	Title	Page
MOP031	First Operation of a Harmonic Lasing Self-Seeded FEL	102
	E. Schneidmiller, B. Faatz, M. Kuhlmann, J. Rönsch-Schulenburg, S. Schreiber, M. Tischer, M.V. Yurkov DESY, Hamburg, Germany
	Harmonic lasing is a perspective mode of operation of X-ray FEL user facilities that allows it to provide brilliant beams of higher-energy photons for user experiments. Another useful application of harmonic lasing is so called Harmonic Lasing Self-Seeded Free Electron Laser (HLSS FEL), that allows it to improve spectral brightness of these facilities. In the past, harmonic lasing has been demonstrated in the FEL oscillators in infrared and visible wavelength ranges, but not in high-gain FELs and not at short wavelengths. In this paper, we report on the first evidence of the harmonic lasing and the first operation of the HLSS FEL at the soft X-ray FEL user facility FLASH in the wavelength range between 4.5 nm and 15 nm. Spectral brightness was improved in comparison with Self-Amplified Spontaneous emission (SASE) FEL by a factor of six in the exponential gain regime. A better performance of HLSS FEL with respect to SASE FEL in the post-saturation regime with a tapered undulator was observed as well. The first demonstration of harmonic lasing in a high-gain FEL and at a short wavelength paves the way for a variety of applications of this new operation mode in X-ray FELs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP031
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MOP043	Plasma Wakefield Accelerated Beams for Demonstration of FEL Gain at FLASHForward	140
	P. Niknejadi, A. Aschikhin, C. Behrens, S. Bohlen, R.T.P. D'Arcy, J. Dale, L. Di Lucchio, M. Felber, B. Foster, L. Goldberg, J.-N. Gruse, Z. Hu, S. Karstensen, A. Knetsch, O. S. Kononenko, V. Libov, K. Ludwig, A. Martinez de la Ossa, F. Marutzky, T.J. Mehrling, J. Osterhoff, C.A.J. Palmer, K. Poder, P. Pourmoussavi, M. Quast, J.-H. Röckemann, J. Schaffran, L. Schaper, H. Schlarb, B. Schmidt, S. Schreiber, S. Schröder, J.-P. Schwinkendorf, B. Sheeran, M.J.V. Streeter, G.E. Tauscher, V. Wacker, S. Weichert, S. Wesch, P. Winkler, S. Wunderlich, J. Zemella DESY, Hamburg, Germany A.R. Maier CFEL, Hamburg, Germany A.R. Maier, A. Martinez de la Ossa, M. Meisel, J.-H. Röckemann University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany C.B. Schroeder LBNL, Berkeley, California, USA V. Wacker University of Hamburg, Hamburg, Germany
	Funding: Work supported by Helmholtz ARD program and VH-VI-503 FLASHForward is the Future-ORiented Wakefield Accelerator Research and Development project at the DESY free-electron laser (FEL) facility FLASH. It aims to produce high-quality, GeV-energy electron beams over a plasma cell of a few centimeters. The plasma is created by means of a 25 TW Ti:Sapphire laser system. The plasma wakefield will be driven by high-current-density electron beams extracted from the FLASH accelerator. The project focuses on the advancement of plasma-based particle acceleration technology through the exploration of both external and internal witness-beam injection schemes. Multiple conventional and cutting-edge diagnostic tools, suitable for diagnosis of short electron beams, are under development. The design of the post-plasma beamline sections will be finalized based on the result of these aforementioned diagnostics. In this paper, the status of the project, as well as the progress towards achieving its overarching goal of demonstrating FEL gain via plasma wakefield acceleration, is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP043
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TUA01	Recent FEL Experiments at FLASH	210
	S. Schreiber, E. Schneidmiller, M.V. Yurkov DESY, Hamburg, Germany
	The FLASH free-electron laser user facility at DESY (Hamburg, Germany) provides high brilliance SASE FEL radiation in the XUV and soft X-ray wavelength range. With the recent installation of a second undulator beamline (FLASH2), variable-gap undulators are now available. They now allow various experiments not possible with the FLASH1 fixed gap undulators. We report on experiments on tapering, harmonic lasing, reverse tapering, frequency doubling at FLASH2 and experiments using double pulses for specific SASE and THz experiments at FLASH1.
	Slides TUA01 [4.124 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUA01
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WEP003	Update on the Lifetime of Cs2Te Photocathodes Operated at FLASH	415
	S. Schreiber, S. Lederer DESY, Hamburg, Germany P. Michelato, L. Monaco, D. Sertore INFN/LASA, Segrate (MI), Italy
	The photoinjector of the free-electron laser facility FLASH at DESY (Hamburg, Germany) uses Cs2Te photocathodes. We report on an update of the lifetime and quantum efficiency of cathodes operated at FLASH during the last years.
	Poster WEP003 [0.286 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-WEP003
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WEP006	Preliminary On-Table and Photoelectron Results from the PITZ Quasi-Ellipsoidal Photocathode Laser System	426
	J.D. Good, G. Asova, P. Boonpornprasert, Y. Chen, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D.M. Melkumyan, A. Oppelt, H.J. Qian, Y. Renier, T. Rublack, F. Stephan DESY Zeuthen, Zeuthen, Germany A.V. Andrianov, E. Gacheva, E. Khazanov, S. Mironov, A. Poteomkin, V. Zelenogorsky IAP/RAS, Nizhny Novgorod, Russia I. Hartl, S. Schreiber DESY, Hamburg, Germany E. Syresin JINR, Dubna, Moscow Region, Russia
	The optimization of photoinjectors is crucial for the successful operation of linac-based free electron lasers, and beam dynamics simulations have shown that ellipsoidal photocathode laser pulses result in significantly lower electron beam emittance than that of conventional cylindrical pulses. Therefore, in collaboration with the Institute of Applied Physics (Nizhny Novgorod, Russia) and the Joint Institute of Nuclear Research (Dubna, Russia), a laser system capable of generating quasi-ellipsoidal laser pulses has been developed and installed at the Photo Injector Test facility at DESY, Zeuthen site (PITZ). The pulse shaping has been realized using the spatial light modulator technique, characterized by cross-correlation and spectrographic measurements, and is demonstrated with electron beam measurements. In this contribution the overall setup, operating principles, and results of first regular electron beam measurements will be presented together with corresponding beam dynamics simulations. Furthermore, the numerous improvements of the simplified re-design currently under construction shall be detailed.
	Poster WEP006 [1.766 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-WEP006
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Paper

Title

Page

First Operation of a Harmonic Lasing Self-Seeded FEL

102

E. Schneidmiller, B. Faatz, M. Kuhlmann, J. Rönsch-Schulenburg, S. Schreiber, M. Tischer, M.V. Yurkov
DESY, Hamburg, Germany

Harmonic lasing is a perspective mode of operation of X-ray FEL user facilities that allows it to provide brilliant beams of higher-energy photons for user experiments. Another useful application of harmonic lasing is so called Harmonic Lasing Self-Seeded Free Electron Laser (HLSS FEL), that allows it to improve spectral brightness of these facilities. In the past, harmonic lasing has been demonstrated in the FEL oscillators in infrared and visible wavelength ranges, but not in high-gain FELs and not at short wavelengths. In this paper, we report on the first evidence of the harmonic lasing and the first operation of the HLSS FEL at the soft X-ray FEL user facility FLASH in the wavelength range between 4.5 nm and 15 nm. Spectral brightness was improved in comparison with Self-Amplified Spontaneous emission (SASE) FEL by a factor of six in the exponential gain regime. A better performance of HLSS FEL with respect to SASE FEL in the post-saturation regime with a tapered undulator was observed as well. The first demonstration of harmonic lasing in a high-gain FEL and at a short wavelength paves the way for a variety of applications of this new operation mode in X-ray FELs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP031

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP043

Plasma Wakefield Accelerated Beams for Demonstration of FEL Gain at FLASHForward

140

P. Niknejadi, A. Aschikhin, C. Behrens, S. Bohlen, R.T.P. D'Arcy, J. Dale, L. Di Lucchio, M. Felber, B. Foster, L. Goldberg, J.-N. Gruse, Z. Hu, S. Karstensen, A. Knetsch, O. S. Kononenko, V. Libov, K. Ludwig, A. Martinez de la Ossa, F. Marutzky, T.J. Mehrling, J. Osterhoff, C.A.J. Palmer, K. Poder, P. Pourmoussavi, M. Quast, J.-H. Röckemann, J. Schaffran, L. Schaper, H. Schlarb, B. Schmidt, S. Schreiber, S. Schröder, J.-P. Schwinkendorf, B. Sheeran, M.J.V. Streeter, G.E. Tauscher, V. Wacker, S. Weichert, S. Wesch, P. Winkler, S. Wunderlich, J. Zemella
DESY, Hamburg, Germany
A.R. Maier
CFEL, Hamburg, Germany
A.R. Maier, A. Martinez de la Ossa, M. Meisel, J.-H. Röckemann
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
C.B. Schroeder
LBNL, Berkeley, California, USA
V. Wacker
University of Hamburg, Hamburg, Germany

Funding: Work supported by Helmholtz ARD program and VH-VI-503
FLASHForward is the Future-ORiented Wakefield Accelerator Research and Development project at the DESY free-electron laser (FEL) facility FLASH. It aims to produce high-quality, GeV-energy electron beams over a plasma cell of a few centimeters. The plasma is created by means of a 25 TW Ti:Sapphire laser system. The plasma wakefield will be driven by high-current-density electron beams extracted from the FLASH accelerator. The project focuses on the advancement of plasma-based particle acceleration technology through the exploration of both external and internal witness-beam injection schemes. Multiple conventional and cutting-edge diagnostic tools, suitable for diagnosis of short electron beams, are under development. The design of the post-plasma beamline sections will be finalized based on the result of these aforementioned diagnostics. In this paper, the status of the project, as well as the progress towards achieving its overarching goal of demonstrating FEL gain via plasma wakefield acceleration, is discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP043

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUA01

Recent FEL Experiments at FLASH

210

S. Schreiber, E. Schneidmiller, M.V. Yurkov
DESY, Hamburg, Germany

The FLASH free-electron laser user facility at DESY (Hamburg, Germany) provides high brilliance SASE FEL radiation in the XUV and soft X-ray wavelength range. With the recent installation of a second undulator beamline (FLASH2), variable-gap undulators are now available. They now allow various experiments not possible with the FLASH1 fixed gap undulators. We report on experiments on tapering, harmonic lasing, reverse tapering, frequency doubling at FLASH2 and experiments using double pulses for specific SASE and THz experiments at FLASH1.

Slides TUA01 [4.124 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP003

Update on the Lifetime of Cs2Te Photocathodes Operated at FLASH

415

S. Schreiber, S. Lederer
DESY, Hamburg, Germany
P. Michelato, L. Monaco, D. Sertore
INFN/LASA, Segrate (MI), Italy

The photoinjector of the free-electron laser facility FLASH at DESY (Hamburg, Germany) uses Cs2Te photocathodes. We report on an update of the lifetime and quantum efficiency of cathodes operated at FLASH during the last years.

Poster WEP003 [0.286 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-WEP003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP006

Preliminary On-Table and Photoelectron Results from the PITZ Quasi-Ellipsoidal Photocathode Laser System

426

J.D. Good, G. Asova, P. Boonpornprasert, Y. Chen, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, D.M. Melkumyan, A. Oppelt, H.J. Qian, Y. Renier, T. Rublack, F. Stephan
DESY Zeuthen, Zeuthen, Germany
A.V. Andrianov, E. Gacheva, E. Khazanov, S. Mironov, A. Poteomkin, V. Zelenogorsky
IAP/RAS, Nizhny Novgorod, Russia
I. Hartl, S. Schreiber
DESY, Hamburg, Germany
E. Syresin
JINR, Dubna, Moscow Region, Russia

The optimization of photoinjectors is crucial for the successful operation of linac-based free electron lasers, and beam dynamics simulations have shown that ellipsoidal photocathode laser pulses result in significantly lower electron beam emittance than that of conventional cylindrical pulses. Therefore, in collaboration with the Institute of Applied Physics (Nizhny Novgorod, Russia) and the Joint Institute of Nuclear Research (Dubna, Russia), a laser system capable of generating quasi-ellipsoidal laser pulses has been developed and installed at the Photo Injector Test facility at DESY, Zeuthen site (PITZ). The pulse shaping has been realized using the spatial light modulator technique, characterized by cross-correlation and spectrographic measurements, and is demonstrated with electron beam measurements. In this contribution the overall setup, operating principles, and results of first regular electron beam measurements will be presented together with corresponding beam dynamics simulations. Furthermore, the numerous improvements of the simplified re-design currently under construction shall be detailed.

Poster WEP006 [1.766 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-WEP006

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)