FEL2019 - List of Authors (Scholz, M.)

Paper	Title	Page
MOA04	First Lasing at the SASE2 and SASE3 FELs of European XFEL
	M. Scholz DESY, Hamburg, Germany
	The European XFEL includes three Free Electron Lasers. We report on the first lasing at the soft X-ray SASE FEL SASE3 in February 2018 and at the second hard X-Ray SASE FEL SASE2 in May 2018.
	Slides MOA04 [7.499 MB]
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TUA01	Parallel Operation of SASE1 and SASE3 at the European XFEL	25
	S. Liu, F. Brinker, W. Decking, L. Fröhlich, R. Kammering, D. Nölle, F. Obier, E. Schneidmiller, M. Scholz, T. Wilksen, M.V. Yurkov DESY, Hamburg, Germany R. Boll, N. Gerasimova, T. Mazza, M. Meyer, A. Scherz, H. Sinn EuXFEL, Schenefeld, Germany
	At the European XFEL a hard X-Ray SASE FEL (SA-SE1) and a soft X-Ray SASE FEL (SASE3) share in series the same electron beamline. This configuration couples the operation conditions for both undulators and their subsequent user experiments in terms of SASE in-tensity and background. We report on our experience in parallel operation and discuss the solutions that enable the operation of both undulators as independently as possible.
	Slides TUA01 [13.809 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUA01
About •	paper received ※ 26 August 2019 paper accepted ※ 17 October 2019 issue date ※ 05 November 2019
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TUA04	Harmonic Lasing Experiment at the European XFEL	29
	E. Schneidmiller, F. Brinker, W. Decking, M.W. Guetg, S. Liu, D. Nölle, M. Scholz, M.V. Yurkov, I. Zagorodnov DESY, Hamburg, Germany G. Geloni, N. Gerasimova, J. Grünert, S. Karabekyan, N.G. Kujala, J. Laksman, Y. Li, J. Liu, Th. Maltezopoulos, I. Petrov, L. Samoylova, S. Serkez, H. Sinn, F. Wolff-Fabris EuXFEL, Hamburg, Germany
	Harmonic lasing is an opportunity to extend the photon energy range of existing and planned X-ray FEL user facilities. Contrary to nonlinear harmonic generation, harmonic lasing can provide a much more intense, stable, and narrow-band FEL beam. Another interesting application is Harmonic Lasing Self-Seeding (HLSS) that allows to improve the longitudinal coherence and spectral power of a Self-Amplified Spontaneous Emission (SASE) FEL. This concept was successfully tested at FLASH in the range of 4.5 - 15 nm and at PAL XFEL at 1 nm. In this contribution we present recent results from the European XFEL where we successfully demonstrated operation of HLSS FEL at 5.9 Angstrom and 2.8 Angstrom, in the latter case obtaining both 3rd and 5th harmonic lasing.
	Slides TUA04 [1.174 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUA04
About •	paper received ※ 20 August 2019 paper accepted ※ 29 August 2019 issue date ※ 05 November 2019
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TUP058	First Characterization of the Photon Beam at the European XFEL in July, 2017	180
	V. Balandin, B. Beutner, F. Brinker, W. Decking, M. Dohlus, L. Fröhlich, U. Jastrow, R. Kammering, T. Limberg, D. Nölle, M. Scholz, A.A. Sorokin, K.I. Tiedtke, M.V. Yurkov, I. Zagorodnov DESY, Hamburg, Germany U. Boesenberg, W. Freund, J. Grünert, A. Koch, N.G. Kujala, J. Liu, Th. Maltezopoulos, M. Messerschmidt, I. Petrov, L. Samoylova, H. Sinn EuXFEL, Schenefeld, Germany
	North branch of the European XFEL, SASE1, produced first light on May 3rd, 2017, and XFEL operation has been gradually improved then. First characterization of the photon beam has been performed in July / August 2017, just before an official starting date of user experiments (September 1st, 2017). Energy of the electron beam was 14 GeV, bunch charge was 500 pC, photon energy was 9.3 keV. With photon diagnostics available at that time (X-ray gas monitor (XGM) and FEL imager) we measured the gain curve and traced evolution of the FEL radiation mode along the undulator. An important conclusion is that experimental results demonstrate reasonable agreement with baseline parameters. Developed techniques of the photon beam characterization also provided solid base for identification of the problems and means for improving SASE FEL tuning and operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP058
About •	paper received ※ 20 August 2019 paper accepted ※ 27 August 2019 issue date ※ 05 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP062	Two Colors at the SASE3 Line of the European XFEL: Project Scope and First Measurements	195
	S. Serkez, G. Geloni, N. Gerasimova, J. Grünert, S. Karabekyan, A. Koch, J. Laksman, Th. Maltezopoulos, T. Mazza, M. Meyer, S. Tomin EuXFEL, Hamburg, Germany W. Decking, L. Fröhlich, V. Kocharyan, Y.A. Kot, E. Saldin, E. Schneidmiller, M. Scholz, M.V. Yurkov, I. Zagorodnov DESY, Hamburg, Germany M. Huttula University of Oulu, Oulu, Finland E. Kukk University of Turku, Turku, Finland
	The European XFEL is a high-repetition rate facility that generates high-power SASE radiation pulses in three beamlines. A joint upgrade project, with Finnish universities, to equip the SASE3 beamline with a chicane has been recently approved to generate two SASE pulses with different photon energies and temporal separation. In this work we report the status of the project, its expected performance, and recent experimental results. Additionally, we discuss methods to diagnose the properties of the generated radiation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP062
About •	paper received ※ 20 August 2019 paper accepted ※ 29 August 2019 issue date ※ 05 November 2019
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WEB01	Identification and Mitigation of Smoke-Ring Effects in Scintillator-Based Electron Beam Images at the European XFEL	301
	G. Kube, S. Liu, A.I. Novokshonov, M. Scholz DESY, Hamburg, Germany
	Standard transverse beam profile measurements at the European XFEL are based on scintillating screen monitors using LYSO:Ce. While it is possible to resolve beam sizes down to a few micrometers with this scintillator, the experience during the XFEL commissioning showed that the measured emittance values were significantly larger than the expected ones. In addition, beam profiles measured at bunch charges of a few hundred pC showed a ’smoke ring’ structure. While coherent OTR emission and beam dynamical influence can be excluded, it is assumed that the profile distortions are caused by effects from the scintillator material. Following the experience in high energy physics, a simple model was developed which takes into account quenching effects of excitonic carriers inside a scintillator in a heuristic way. Based on this model, the observed beam profiles can be understood qualitatively. Together with the model description, first comparisons with experimental results will be shown. Possible new scintillator materials suitable for beam profile diagnostics and first test results from beam measurements will be presented.
	Slides WEB01 [5.057 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WEB01
About •	paper received ※ 20 August 2019 paper accepted ※ 28 August 2019 issue date ※ 05 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP008	Multi-Beamline Operation at the European XFEL	335
	L. Fröhlich, A. Aghababyan, V. Balandin, B. Beutner, F. Brinker, W. Decking, N. Golubeva, O. Hensler, Y. Janik, R. Kammering, H. Kay, T. Limberg, S. Liu, D. Nölle, F. Obier, M. Omet, M. Scholz, T. Wamsat, T. Wilksen, J. Wortmann DESY, Hamburg, Germany
	The European XFEL uses a unique beam distribution scheme to direct electron bunches to its three undulator lines. The accelerator delivers up to 600 microsecond long bunch trains, out of which parts or individual bunches can be selected for photon production in any of the FELs. This contribution gives a brief overview of the kicker-septum scheme facilitating this and highlights how even complex bunch patterns can easily be configured via the timing system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WEP008
About •	paper received ※ 19 August 2019 paper accepted ※ 29 August 2019 issue date ※ 05 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THP001	Steffen Hard-Edge Model for Quadrupoles with Extended Fringe-Fields at the European XFEL	588
	N. Golubeva, V. Balandin, W. Decking, L. Fröhlich, M. Scholz DESY, Hamburg, Germany
	For modeling of linear focusing properties of quadrupole magnets the conventional rectangular model is commonly used for the design and calculations of the linear beam optics for accelerators. At the European XFEL the quadrupole magnets are described using a more accurate Steffen hard-edge model. In this paper we discuss the application of the Steffen approach for the European XFEL quadrupoles and present the examination of the model with the orbit response matrix technique.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THP001
About •	paper received ※ 20 August 2019 paper accepted ※ 25 August 2019 issue date ※ 05 November 2019
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THP002	Beam Based Alignment in all Undulator Beamlines at European XFEL	592
	M. Scholz, W. Decking DESY, Hamburg, Germany Y. Li EuXFEL, Hamburg, Germany
	The Free Electron Laser European XFEL aims at delivering X-rays from 0.25 keV up to 25 keV out of three SASE undulators. A good overlap of photon and electron beams is indispensable to obtain good lasing performance, especially for the higher photon energies. Thus the quadrupole magnets in the undulators must be aligned as good as possible on a straight line. This can only be realized with a beam based alignment procedure. In this paper we will report on the method that was performed at the European XFEL. We will also discuss our results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THP002
About •	paper received ※ 20 August 2019 paper accepted ※ 12 September 2019 issue date ※ 05 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THD03	FEL Optimization: From Model-Free to Model-Dependent Approaches and ML Prospects	762
	S. Tomin, G. Geloni EuXFEL, Schenefeld, Germany M. Scholz DESY, Hamburg, Germany
	Users beam-time at modern FEL sources is an extremely valuable commodity. Moreover, maximization of FEL up-time must always be performed accounting for stringent requirements on the photon pulse characteristics. These may vary widely depending on the users requests, which poses issues to parallel operation of high-repetition rate facilities like the European XFEL. Therefore, both model-free or model-dependent optimization schemes, where the model might be given, or provided by machine-learning approaches, are of high importance for the overall efficiency of FEL facilities. In this contribution, we review our previous activities and we report on current efforts and progress in FEL optimization schemes at the European XFEL. Finally, we provide an outlook on future developments.
	Slides THD03 [13.636 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THD03
About •	paper received ※ 21 August 2019 paper accepted ※ 12 September 2019 issue date ※ 05 November 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

MOA04

First Lasing at the SASE2 and SASE3 FELs of European XFEL

M. Scholz
DESY, Hamburg, Germany

The European XFEL includes three Free Electron Lasers. We report on the first lasing at the soft X-ray SASE FEL SASE3 in February 2018 and at the second hard X-Ray SASE FEL SASE2 in May 2018.

Slides MOA04 [7.499 MB]

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

TUA01

Parallel Operation of SASE1 and SASE3 at the European XFEL

25

S. Liu, F. Brinker, W. Decking, L. Fröhlich, R. Kammering, D. Nölle, F. Obier, E. Schneidmiller, M. Scholz, T. Wilksen, M.V. Yurkov
DESY, Hamburg, Germany
R. Boll, N. Gerasimova, T. Mazza, M. Meyer, A. Scherz, H. Sinn
EuXFEL, Schenefeld, Germany

At the European XFEL a hard X-Ray SASE FEL (SA-SE1) and a soft X-Ray SASE FEL (SASE3) share in series the same electron beamline. This configuration couples the operation conditions for both undulators and their subsequent user experiments in terms of SASE in-tensity and background. We report on our experience in parallel operation and discuss the solutions that enable the operation of both undulators as independently as possible.

Slides TUA01 [13.809 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUA01

About •

paper received ※ 26 August 2019 paper accepted ※ 17 October 2019 issue date ※ 05 November 2019

Export •

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

TUA04

Harmonic Lasing Experiment at the European XFEL

29

E. Schneidmiller, F. Brinker, W. Decking, M.W. Guetg, S. Liu, D. Nölle, M. Scholz, M.V. Yurkov, I. Zagorodnov
DESY, Hamburg, Germany
G. Geloni, N. Gerasimova, J. Grünert, S. Karabekyan, N.G. Kujala, J. Laksman, Y. Li, J. Liu, Th. Maltezopoulos, I. Petrov, L. Samoylova, S. Serkez, H. Sinn, F. Wolff-Fabris
EuXFEL, Hamburg, Germany

Harmonic lasing is an opportunity to extend the photon energy range of existing and planned X-ray FEL user facilities. Contrary to nonlinear harmonic generation, harmonic lasing can provide a much more intense, stable, and narrow-band FEL beam. Another interesting application is Harmonic Lasing Self-Seeding (HLSS) that allows to improve the longitudinal coherence and spectral power of a Self-Amplified Spontaneous Emission (SASE) FEL. This concept was successfully tested at FLASH in the range of 4.5 - 15 nm and at PAL XFEL at 1 nm. In this contribution we present recent results from the European XFEL where we successfully demonstrated operation of HLSS FEL at 5.9 Angstrom and 2.8 Angstrom, in the latter case obtaining both 3rd and 5th harmonic lasing.

Slides TUA04 [1.174 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUA04

About •

paper received ※ 20 August 2019 paper accepted ※ 29 August 2019 issue date ※ 05 November 2019

Export •

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

TUP058

First Characterization of the Photon Beam at the European XFEL in July, 2017

180

V. Balandin, B. Beutner, F. Brinker, W. Decking, M. Dohlus, L. Fröhlich, U. Jastrow, R. Kammering, T. Limberg, D. Nölle, M. Scholz, A.A. Sorokin, K.I. Tiedtke, M.V. Yurkov, I. Zagorodnov
DESY, Hamburg, Germany
U. Boesenberg, W. Freund, J. Grünert, A. Koch, N.G. Kujala, J. Liu, Th. Maltezopoulos, M. Messerschmidt, I. Petrov, L. Samoylova, H. Sinn
EuXFEL, Schenefeld, Germany

North branch of the European XFEL, SASE1, produced first light on May 3rd, 2017, and XFEL operation has been gradually improved then. First characterization of the photon beam has been performed in July / August 2017, just before an official starting date of user experiments (September 1st, 2017). Energy of the electron beam was 14 GeV, bunch charge was 500 pC, photon energy was 9.3 keV. With photon diagnostics available at that time (X-ray gas monitor (XGM) and FEL imager) we measured the gain curve and traced evolution of the FEL radiation mode along the undulator. An important conclusion is that experimental results demonstrate reasonable agreement with baseline parameters. Developed techniques of the photon beam characterization also provided solid base for identification of the problems and means for improving SASE FEL tuning and operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP058

About •

paper received ※ 20 August 2019 paper accepted ※ 27 August 2019 issue date ※ 05 November 2019

Export •

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

TUP062

Two Colors at the SASE3 Line of the European XFEL: Project Scope and First Measurements

195

S. Serkez, G. Geloni, N. Gerasimova, J. Grünert, S. Karabekyan, A. Koch, J. Laksman, Th. Maltezopoulos, T. Mazza, M. Meyer, S. Tomin
EuXFEL, Hamburg, Germany
W. Decking, L. Fröhlich, V. Kocharyan, Y.A. Kot, E. Saldin, E. Schneidmiller, M. Scholz, M.V. Yurkov, I. Zagorodnov
DESY, Hamburg, Germany
M. Huttula
University of Oulu, Oulu, Finland
E. Kukk
University of Turku, Turku, Finland

The European XFEL is a high-repetition rate facility that generates high-power SASE radiation pulses in three beamlines. A joint upgrade project, with Finnish universities, to equip the SASE3 beamline with a chicane has been recently approved to generate two SASE pulses with different photon energies and temporal separation. In this work we report the status of the project, its expected performance, and recent experimental results. Additionally, we discuss methods to diagnose the properties of the generated radiation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP062

About •

paper received ※ 20 August 2019 paper accepted ※ 29 August 2019 issue date ※ 05 November 2019

Export •

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

WEB01

Identification and Mitigation of Smoke-Ring Effects in Scintillator-Based Electron Beam Images at the European XFEL

301

G. Kube, S. Liu, A.I. Novokshonov, M. Scholz
DESY, Hamburg, Germany

Standard transverse beam profile measurements at the European XFEL are based on scintillating screen monitors using LYSO:Ce. While it is possible to resolve beam sizes down to a few micrometers with this scintillator, the experience during the XFEL commissioning showed that the measured emittance values were significantly larger than the expected ones. In addition, beam profiles measured at bunch charges of a few hundred pC showed a ’smoke ring’ structure. While coherent OTR emission and beam dynamical influence can be excluded, it is assumed that the profile distortions are caused by effects from the scintillator material. Following the experience in high energy physics, a simple model was developed which takes into account quenching effects of excitonic carriers inside a scintillator in a heuristic way. Based on this model, the observed beam profiles can be understood qualitatively. Together with the model description, first comparisons with experimental results will be shown. Possible new scintillator materials suitable for beam profile diagnostics and first test results from beam measurements will be presented.

Slides WEB01 [5.057 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WEB01

About •

paper received ※ 20 August 2019 paper accepted ※ 28 August 2019 issue date ※ 05 November 2019

Export •

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

WEP008

Multi-Beamline Operation at the European XFEL

335

L. Fröhlich, A. Aghababyan, V. Balandin, B. Beutner, F. Brinker, W. Decking, N. Golubeva, O. Hensler, Y. Janik, R. Kammering, H. Kay, T. Limberg, S. Liu, D. Nölle, F. Obier, M. Omet, M. Scholz, T. Wamsat, T. Wilksen, J. Wortmann
DESY, Hamburg, Germany

The European XFEL uses a unique beam distribution scheme to direct electron bunches to its three undulator lines. The accelerator delivers up to 600 microsecond long bunch trains, out of which parts or individual bunches can be selected for photon production in any of the FELs. This contribution gives a brief overview of the kicker-septum scheme facilitating this and highlights how even complex bunch patterns can easily be configured via the timing system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WEP008

About •

paper received ※ 19 August 2019 paper accepted ※ 29 August 2019 issue date ※ 05 November 2019

Export •

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

THP001

Steffen Hard-Edge Model for Quadrupoles with Extended Fringe-Fields at the European XFEL

588

N. Golubeva, V. Balandin, W. Decking, L. Fröhlich, M. Scholz
DESY, Hamburg, Germany

For modeling of linear focusing properties of quadrupole magnets the conventional rectangular model is commonly used for the design and calculations of the linear beam optics for accelerators. At the European XFEL the quadrupole magnets are described using a more accurate Steffen hard-edge model. In this paper we discuss the application of the Steffen approach for the European XFEL quadrupoles and present the examination of the model with the orbit response matrix technique.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THP001

About •

paper received ※ 20 August 2019 paper accepted ※ 25 August 2019 issue date ※ 05 November 2019

Export •

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

THP002

Beam Based Alignment in all Undulator Beamlines at European XFEL

592

M. Scholz, W. Decking
DESY, Hamburg, Germany
Y. Li
EuXFEL, Hamburg, Germany

The Free Electron Laser European XFEL aims at delivering X-rays from 0.25 keV up to 25 keV out of three SASE undulators. A good overlap of photon and electron beams is indispensable to obtain good lasing performance, especially for the higher photon energies. Thus the quadrupole magnets in the undulators must be aligned as good as possible on a straight line. This can only be realized with a beam based alignment procedure. In this paper we will report on the method that was performed at the European XFEL. We will also discuss our results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THP002

About •

paper received ※ 20 August 2019 paper accepted ※ 12 September 2019 issue date ※ 05 November 2019

Export •

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

THD03

FEL Optimization: From Model-Free to Model-Dependent Approaches and ML Prospects

762

S. Tomin, G. Geloni
EuXFEL, Schenefeld, Germany
M. Scholz
DESY, Hamburg, Germany

Users beam-time at modern FEL sources is an extremely valuable commodity. Moreover, maximization of FEL up-time must always be performed accounting for stringent requirements on the photon pulse characteristics. These may vary widely depending on the users requests, which poses issues to parallel operation of high-repetition rate facilities like the European XFEL. Therefore, both model-free or model-dependent optimization schemes, where the model might be given, or provided by machine-learning approaches, are of high importance for the overall efficiency of FEL facilities. In this contribution, we review our previous activities and we report on current efforts and progress in FEL optimization schemes at the European XFEL. Finally, we provide an outlook on future developments.

Slides THD03 [13.636 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THD03

About •

paper received ※ 21 August 2019 paper accepted ※ 12 September 2019 issue date ※ 05 November 2019

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