FEL2017 - List of Authors (Decking, W.)

Paper	Title	Page
MOC03	Commissioning and First Lasing of the European XFEL	9
	H. Weise, W. Decking DESY, Hamburg, Germany
	Funding: Work supported by the respective funding agencies of the contributing institutes; for details please see http:www.xfel.eu The European X-ray Free-Electron Laser (XFEL) in Hamburg, Northern Germany, aims at producing X-rays in the range from 260 eV to 24 keV out of three undulators that can be operated simultaneously with up to 27,000 pulses per second. The XFEL is driven by a 17.5 GeV superconducting linac. This linac is the worldwide largest installation based on superconducting radio-frequency acceleration. The design is using the so-called TESLA technology which was developed for the superconducting version of an international electron positron linear collider. After eight years of construction the facility is now brought into operation. First lasing was demonstrated in May 2017. Experience with the super-conducting accelerator as well as beam commissioning results will be presented. The path to the first user experiments will be laid down.
	Slides MOC03 [5.418 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOC03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP008	Status of the Hard X-Ray Self-Seeding Project at the European XFEL	42
	G. Geloni, S. Karabekyan, L. Samoylova, S. Serkez, H. Sinn XFEL. EU, Hamburg, Germany V.D. Blank, S. Terentiev TISNCM, Troitsk, Russia W. Decking, C. Engling, N. Golubeva, V. Kocharyan, B. Krause, S. Lederer, S. Liu, A. Petrov, E. Saldin, T. Wohlenberg DESY, Hamburg, Germany X. Dong European X-Ray Free-Electron Laser Facility GmbH, Schelefeld, Germany D. Shu ANL, Argonne, Illinois, USA
	A Hard X-ray Self-Seeding setup is currently under realization at the European XFEL, and will be ready for installation in 2018. The setup consists of two single-crystal monochromators that will be installed at the SASE2 undulator line. In this contribution, after a short summary of the physical principles and of the design, we will discuss the present status of the project including both electron beam and X-ray optics hardware. We will also briefly discuss the expected performance of the setup, which is expected to produce nearly Fourier-limited pulses of X-ray radiation with increased brightness compared to the baseline of the European XFEL, as well as possible complementary uses of the two electron chicanes.
	Poster MOP008 [2.445 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP008
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP002	Numerical Studies on RF-Induced Trajectory Variations at the European XFEL	251
	T. Hellert, B. Beutner, W. Decking, N. Walker DESY, Hamburg, Germany
	At the European X-Ray Free-Electron Laser, superconducting TESLA-type cavities are used for acceleration of the driving electron bunches. Due to the high achievable duty cycle, a long radio frequency (RF) pulse structure can be provided, which allows to operate the machine with long bunch trains. The designated pointing stability of the FEL radiation places stringent restrictions on the acceptable trajectory variations of individual electron bunches. Therefore a transverse intra-bunch-train feedback system (IBFB) is located upstream of the undulator section. However, intra-bunch-train variations of RF parameters and misalignment of RF structures induce significant trajectory variations that may exceed the capability of the IBFB. In this paper we give an estimate of the expected RF-induced intra-bunch-train trajectory variations for different machine realizations and investigate methods for their limitation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUP002
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP003	First Beam Halo Measurements Using Wire Scanners at the European XFEL	255
	S. Liu, V. Balandin, B. Beutner, W. Decking, L. Fröhlich, N. Golubeva, T. Lensch DESY, Hamburg, Germany
	Beam halo measurements and collimations are of great importance at the European XFEL, especially for the operation at high repetition rates (27000 pulses/s). First beam halo measurements have been performed during the commissioning using the wire scanners installed before and after the ~200 m long post-linac collimation section. We present the measurement results and the comparison of beam halo distributions before and after the collimation section.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUP003
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP004	Longitudinal Phase Space Optimization for the Hard X-ray Self-Seeding	259
	S. Liu, W. Decking, G. Feng, V. Kocharyan, I. Zagorodnov DESY, Hamburg, Germany G. Geloni, S. Serkez XFEL. EU, Schenefeld, Germany
	For the implementation of Hard X-ray Self-Seeding (HXRSS) at European XFEL, short electron-beam bunches (FWHM ≤ 50 fs) are preferred to mitigate spatio-temperal coupling effect and to fit to the seeding bump width. Therefore, operations with low charges (< 250 pC) are preferred. Longitudinal phase-space optimization has been performed for the 100 pC case by flattening the current distribution. Start-to-end simulations show that, with the optimized distribution, for the photon energy of 14.4 keV, the HXRSS output power, pulse energy and spectral intensity can be increased by a factor of approximately 2 as compared to the nominal working point.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUP004
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Commissioning and First Lasing of the European XFEL

9

H. Weise, W. Decking
DESY, Hamburg, Germany

Funding: Work supported by the respective funding agencies of the contributing institutes; for details please see http:www.xfel.eu
The European X-ray Free-Electron Laser (XFEL) in Hamburg, Northern Germany, aims at producing X-rays in the range from 260 eV to 24 keV out of three undulators that can be operated simultaneously with up to 27,000 pulses per second. The XFEL is driven by a 17.5 GeV superconducting linac. This linac is the worldwide largest installation based on superconducting radio-frequency acceleration. The design is using the so-called TESLA technology which was developed for the superconducting version of an international electron positron linear collider. After eight years of construction the facility is now brought into operation. First lasing was demonstrated in May 2017. Experience with the super-conducting accelerator as well as beam commissioning results will be presented. The path to the first user experiments will be laid down.

Slides MOC03 [5.418 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOC03

Export •

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

MOP008

Status of the Hard X-Ray Self-Seeding Project at the European XFEL

42

G. Geloni, S. Karabekyan, L. Samoylova, S. Serkez, H. Sinn
XFEL. EU, Hamburg, Germany
V.D. Blank, S. Terentiev
TISNCM, Troitsk, Russia
W. Decking, C. Engling, N. Golubeva, V. Kocharyan, B. Krause, S. Lederer, S. Liu, A. Petrov, E. Saldin, T. Wohlenberg
DESY, Hamburg, Germany
X. Dong
European X-Ray Free-Electron Laser Facility GmbH, Schelefeld, Germany
D. Shu
ANL, Argonne, Illinois, USA

A Hard X-ray Self-Seeding setup is currently under realization at the European XFEL, and will be ready for installation in 2018. The setup consists of two single-crystal monochromators that will be installed at the SASE2 undulator line. In this contribution, after a short summary of the physical principles and of the design, we will discuss the present status of the project including both electron beam and X-ray optics hardware. We will also briefly discuss the expected performance of the setup, which is expected to produce nearly Fourier-limited pulses of X-ray radiation with increased brightness compared to the baseline of the European XFEL, as well as possible complementary uses of the two electron chicanes.

Poster MOP008 [2.445 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP008

Export •

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

TUP002

Numerical Studies on RF-Induced Trajectory Variations at the European XFEL

251

T. Hellert, B. Beutner, W. Decking, N. Walker
DESY, Hamburg, Germany

At the European X-Ray Free-Electron Laser, superconducting TESLA-type cavities are used for acceleration of the driving electron bunches. Due to the high achievable duty cycle, a long radio frequency (RF) pulse structure can be provided, which allows to operate the machine with long bunch trains. The designated pointing stability of the FEL radiation places stringent restrictions on the acceptable trajectory variations of individual electron bunches. Therefore a transverse intra-bunch-train feedback system (IBFB) is located upstream of the undulator section. However, intra-bunch-train variations of RF parameters and misalignment of RF structures induce significant trajectory variations that may exceed the capability of the IBFB. In this paper we give an estimate of the expected RF-induced intra-bunch-train trajectory variations for different machine realizations and investigate methods for their limitation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUP002

Export •

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

TUP003

First Beam Halo Measurements Using Wire Scanners at the European XFEL

255

S. Liu, V. Balandin, B. Beutner, W. Decking, L. Fröhlich, N. Golubeva, T. Lensch
DESY, Hamburg, Germany

Beam halo measurements and collimations are of great importance at the European XFEL, especially for the operation at high repetition rates (27000 pulses/s). First beam halo measurements have been performed during the commissioning using the wire scanners installed before and after the ~200 m long post-linac collimation section. We present the measurement results and the comparison of beam halo distributions before and after the collimation section.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUP003

Export •

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

TUP004

Longitudinal Phase Space Optimization for the Hard X-ray Self-Seeding

259

S. Liu, W. Decking, G. Feng, V. Kocharyan, I. Zagorodnov
DESY, Hamburg, Germany
G. Geloni, S. Serkez
XFEL. EU, Schenefeld, Germany

For the implementation of Hard X-ray Self-Seeding (HXRSS) at European XFEL, short electron-beam bunches (FWHM ≤ 50 fs) are preferred to mitigate spatio-temperal coupling effect and to fit to the seeding bump width. Therefore, operations with low charges (< 250 pC) are preferred. Longitudinal phase-space optimization has been performed for the 100 pC case by flattening the current distribution. Start-to-end simulations show that, with the optimized distribution, for the photon energy of 14.4 keV, the HXRSS output power, pulse energy and spectral intensity can be increased by a factor of approximately 2 as compared to the nominal working point.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUP004

Export •

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