Paper | Title | Page |
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TUA01 | Parallel Operation of SASE1 and SASE3 at the European XFEL | 25 |
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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. | ||
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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 |
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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. | ||
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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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TUP056 | Feasibility Studies of the 100 keV Undulator Line of the European XFEL | 172 |
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The European XFEL is a multi-user X-ray FEL facility based on superconducting linear accelerator. Presently, three undulators (SASE1, SASE2, SASE3) deliver high-brightness soft- and hard- X-ray beams for users. There are two empty undulator tunnels that were originally designed to operate with spontaneous radiators. We consider instead a possible installation of two FEL undulators. One of them (SASE4) is proposed for the operation in ultrahard X-ray regime, up to the photon energy of 100 keV. In this contribution we present the results of the first feasibility studies of this option. | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP056 | |
About • | paper received ※ 20 August 2019 paper accepted ※ 27 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 |
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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 | |
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WEP008 | Multi-Beamline Operation at the European XFEL | 335 |
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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 | |
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WED02 | Absorbed Radiation Doses on the European XFEL Undulator Systems During Early User Experiments | 569 |
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The EuXFEL is a FEL user facility based on a superconducting accelerator with high duty cycle. Three gap movable SASE Undulator Systems using hybrid NdFeB permanent magnet segments are operated. Radiation damage on undulators can impact the quality of the SASE process and ultimately threaten user operation. We observed [1] in the commissioning phase doses up to 4 kGy and 3% demagnetization effect in a diagnostic undulator. Currently all SASE systems are used for user photon delivery and in this work we present characteristics of the absorbed radiation doses on undulators under stable conditions. Doses on the upstream segments are found to be originated in the event of occasional high energy electron losses. In contrast, towards the downstream end of a SASE system, individual segments show persistent absorbed doses which are proportional to the transmitted charge and are dominated by low energy radiation. This energy-dependence depiction shall result in distinct radiation damage thresholds for individual segments. Portable magnetic flux measurement systems allow in-situ tunnel assessment of undulator properties in order to estimate radiation dose limits for future user operation.
[1] F. Wolff-Fabris et al., J. of Phys. - Conf. Series 1067, 032025 (2018) |
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Slides WED02 [7.344 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WED02 | |
About • | paper received ※ 19 August 2019 paper accepted ※ 27 August 2019 issue date ※ 05 November 2019 | |
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WED04 |
Undulator Adjustment with the K-Monochromator System at the European XFEL | |
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The SASE1 and SASE2 undulator systems of the European XFEL consist of 35 segments with variable-gap planar undulators which are initially tuned to precise on-axis magnetic field strengths in a magnetic measurement lab. After tunnel installation only photon based methods can determine the K-values of undulator segments with a similar accuracy. The spontaneous radiation of single or few undulator cells is spectrally filtered with the K-monochromator (K-mono) and recorded with a sensitive spontaneous radiation imager (SR-imager). By processing the images from the SR-imager and geometrical fitting of the spatial distribution of the spontaneous radiation we obtain very fast the K-parameter and the beam pointing of single segments. This information is used for adjustments of the gap settings and vertical offset positions of the single undulator segments. In this presentation we describe the K-mono system at the European XFEL, the measurement principle, and the measurements that were performed [1].
[1] "First measurements with the K-Monochromator at European XFEL", proceedings of PhotonDiag 2018, JSR (in publication) |
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Slides WED04 [13.278 MB] | |
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FRA01 | FEL Operation at the European XFEL Facility | 766 |
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The European XFEL is a SASE FEL based user facility in the metropole region of Hamburg providing hard and soft X-ray photons with extremely high brilliance. The three FEL lines are operated simultaneously and are powered by a superconducting LINAC based on TESLA technology. Average power levels of up to several W have been demonstrated as well for soft and hard X-rays and can be requested by user experiments on day by day basis. The contribution will report on the results of the commissioning within the last two years as well as on the transition to user operation. Typical operation conditions for parallel operation of 3 SASE lines will be discussed. The perspective for the operation with an extended photon energy range, as well as for full power operation with up to 27000 pulses per second will be presented. | ||
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Slides FRA01 [27.196 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-FRA01 | |
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) | |