Applied Sciences

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3 pages, 152 KiB

Open AccessEditorial

X-ray Free-Electron Laser

by Kiyoshi Ueda

Appl. Sci. 2018, 8(6), 879; https://doi.org/10.3390/app8060879 - 28 May 2018

Cited by 5 | Viewed by 3629

Abstract

During the last decades, the advent of the short-wavelength Free Electron Lasers (FELs) in the range from extreme ultraviolet (XUV) to hard X-rays has opened a new research avenue for the investigations of ultrafast electronic and structural dynamics in any form of matter[...] [...] Read more.

During the last decades, the advent of the short-wavelength Free Electron Lasers (FELs) in the range from extreme ultraviolet (XUV) to hard X-rays has opened a new research avenue for the investigations of ultrafast electronic and structural dynamics in any form of matter[...] Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

Research

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947 KiB

Open AccessFeature PaperArticle

The FLASH Facility: Advanced Options for FLASH2 and Future Perspectives

by Bart Faatz, Markus Braune, Olaf Hensler, Katja Honkavaara, Raimund Kammering, Marion Kuhlmann, Elke Ploenjes, Juliane Roensch-Schulenburg, Evgeny Schneidmiller, Siegfried Schreiber, Kai Tiedtke, Markus Tischer, Rolf Treusch, Mathias Vogt, Wilfried Wurth, Mikhail Yurkov and Johann Zemella

Appl. Sci. 2017, 7(11), 1114; https://doi.org/10.3390/app7111114 - 28 Oct 2017

Cited by 45 | Viewed by 5870

Abstract

Since 2016, the two free-electron laser (FEL) lines FLASH1 and FLASH2 have been run simultaneously for users at DESY in Hamburg. With the installation of variable gap undulators in the new FLASH2 FEL line, many new possibilities have opened up in terms of [...] Read more.

Since 2016, the two free-electron laser (FEL) lines FLASH1 and FLASH2 have been run simultaneously for users at DESY in Hamburg. With the installation of variable gap undulators in the new FLASH2 FEL line, many new possibilities have opened up in terms of photon parameters for experiments. What has been tested so far is post-saturation tapering, reverse tapering, harmonic lasing, harmonic lasing self-seeding and two-color lasing. At the moment, we are working on concepts to enhance the capabilities of the FLASH facility even further. A major part of the upgrade plans, known as FLASH2020, will involve the exchange of the fixed gap undulators in FLASH1 and the implementation of a new flexible undulator scheme aimed at providing coherent radiation for multi-color experiments over a broad wavelength range. The recent achievements in FLASH2 and the current status of plans for the further development of the facility are presented. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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2073 KiB

Open AccessArticle

A Dispersive Inelastic X-ray Scattering Spectrometer for Use at X-ray Free Electron Lasers

by Jakub Szlachetko, Maarten Nachtegaal, Daniel Grolimund, Gregor Knopp, Sergey Peredkov, Joanna Czapla–Masztafiak and Christopher J. Milne

Appl. Sci. 2017, 7(9), 899; https://doi.org/10.3390/app7090899 - 1 Sep 2017

Cited by 14 | Viewed by 5751

Abstract

We report on the application of a short working distance von Hamos geometry spectrometer to measure the inelastic X-ray scattering (IXS) signals from solids and liquids. In contrast to typical IXS instruments where the spectrometer geometry is fixed and the incoming beam energy [...] Read more.

We report on the application of a short working distance von Hamos geometry spectrometer to measure the inelastic X-ray scattering (IXS) signals from solids and liquids. In contrast to typical IXS instruments where the spectrometer geometry is fixed and the incoming beam energy is scanned, the von Hamos geometry allows measurements to be made using a fixed optical arrangement with no moving parts. Thanks to the shot-to-shot capability of the spectrometer setup, we anticipate its application for the IXS technique at X-ray free electron lasers (XFELs). We discuss the capability of the spectrometer setup for IXS studies in terms of efficiency and required total incident photon flux for a given signal-to-noise ratio. The ultimate energy resolution of the spectrometer, which is a key parameter for IXS studies, was measured to the level of 150 meV at short crystal radius thanks to the application of segmented crystals for X-ray diffraction. The short working distance is a key parameter for spectrometer efficiency that is necessary to measure weak IXS signals. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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2268 KiB

Open AccessArticle

Modeling Non-Equilibrium Dynamics and Saturable Absorption Induced by Free Electron Laser Radiation

by Keisuke Hatada and Andrea Di Cicco

Appl. Sci. 2017, 7(8), 814; https://doi.org/10.3390/app7080814 - 9 Aug 2017

Cited by 5 | Viewed by 4008

Abstract

Currently available X-ray and extreme ultraviolet free electron laser (FEL) sources provide intense ultrashort photon pulses. Those sources open new exciting perspectives for experimental studies of ultrafast non-equilibrium processes at the nanoscale in condensed matter. Theoretical approaches and computer simulations are being developed [...] Read more.

Currently available X-ray and extreme ultraviolet free electron laser (FEL) sources provide intense ultrashort photon pulses. Those sources open new exciting perspectives for experimental studies of ultrafast non-equilibrium processes at the nanoscale in condensed matter. Theoretical approaches and computer simulations are being developed to understand the complicated dynamical processes associated with the interaction of FEL pulses with matter. In this work, we present the results of the application of a simplified three-channel model to the non-equilibrium dynamics of ultrathin aluminum films excited by FEL radiation at 33.3, 37 and 92 eV photon energy. The model includes semi-classical rate equations coupled with the equation of propagation of the photon wave packets. X-ray transmission measurements are found to be in agreement with present simulations, which are also able to shed light on temporal dynamics (in the fs range) in nano-sized Al films strongly interacting with the photon pulse. We also expanded our non-linear model, explicitly including the two-photon absorption cross-section and the effect of including electron heating for reproducing transmission measurements. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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11933 KiB

Open AccessFeature PaperArticle

SwissFEL: The Swiss X-ray Free Electron Laser

by Christopher J. Milne, Thomas Schietinger, Masamitsu Aiba, Arturo Alarcon, Jürgen Alex, Alexander Anghel, Vladimir Arsov, Carl Beard, Paul Beaud, Simona Bettoni, Markus Bopp, Helge Brands, Manuel Brönnimann, Ingo Brunnenkant, Marco Calvi, Alessandro Citterio, Paolo Craievich, Marta Csatari Divall, Mark Dällenbach, Michael D’Amico, Andreas Dax, Yunpei Deng, Alexander Dietrich, Roberto Dinapoli, Edwin Divall, Sladana Dordevic, Simon Ebner, Christian Erny, Hansrudolf Fitze, Uwe Flechsig, Rolf Follath, Franziska Frei, Florian Gärtner, Romain Ganter, Terence Garvey, Zheqiao Geng, Ishkhan Gorgisyan, Christopher Gough, Andreas Hauff, Christoph P. Hauri, Nicole Hiller, Tadej Humar, Stephan Hunziker, Gerhard Ingold, Rasmus Ischebeck, Markus Janousch, Pavle Juranić, Mario Jurcevic, Maik Kaiser, Babak Kalantari, Roger Kalt, Boris Keil, Christoph Kittel, Gregor Knopp, Waldemar Koprek, Henrik T. Lemke, Thomas Lippuner, Daniel Llorente Sancho, Florian Löhl, Carlos Lopez-Cuenca, Fabian Märki, Fabio Marcellini, Goran Marinkovic, Isabelle Martiel, Ralf Menzel, Aldo Mozzanica, Karol Nass, Gian Luca Orlandi, Cigdem Ozkan Loch, Ezequiel Panepucci, Martin Paraliev, Bruce Patterson, Bill Pedrini, Marco Pedrozzi, Patrick Pollet, Claude Pradervand, Eduard Prat, Peter Radi, Jean-Yves Raguin, Sophie Redford, Jens Rehanek, Julien Réhault, Sven Reiche, Matthias Ringele, Jochen Rittmann, Leonid Rivkin, Albert Romann, Marie Ruat, Christian Ruder, Leonardo Sala, Lionel Schebacher, Thomas Schilcher, Volker Schlott, Thomas Schmidt, Bernd Schmitt, Xintian Shi, Markus Stadler, Lukas Stingelin, Werner Sturzenegger, Jakub Szlachetko, Dhanya Thattil, Daniel M. Treyer, Alexandre Trisorio, Wolfgang Tron, Seraphin Vetter, Carlo Vicario, Didier Voulot, Meitian Wang, Thierry Zamofing, Christof Zellweger, Riccardo Zennaro, Elke Zimoch, Rafael Abela, Luc Patthey and Hans-Heinrich Braun Show full author list Hide full author list

Appl. Sci. 2017, 7(7), 720; https://doi.org/10.3390/app7070720 - 14 Jul 2017

Cited by 304 | Viewed by 24500

Abstract

The SwissFEL X-ray Free Electron Laser (XFEL) facility started construction at the Paul Scherrer Institute (Villigen, Switzerland) in 2013 and will be ready to accept its first users in 2018 on the Aramis hard X-ray branch. In the following sections we will summarize [...] Read more.

The SwissFEL X-ray Free Electron Laser (XFEL) facility started construction at the Paul Scherrer Institute (Villigen, Switzerland) in 2013 and will be ready to accept its first users in 2018 on the Aramis hard X-ray branch. In the following sections we will summarize the various aspects of the project, including the design of the soft and hard X-ray branches of the accelerator, the results of SwissFEL performance simulations, details of the photon beamlines and experimental stations, and our first commissioning results. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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1136 KiB

Open AccessArticle

Observing Femtosecond Fragmentation Using Ultrafast X-ray-Induced Auger Spectra

by Thomas J. A. Wolf, Fabian Holzmeier, Isabella Wagner, Nora Berrah, Christoph Bostedt, John Bozek, Phil Bucksbaum, Ryan Coffee, James Cryan, Joe Farrell, Raimund Feifel, Todd J. Martinez, Brian McFarland, Melanie Mucke, Saikat Nandi, Francesco Tarantelli, Ingo Fischer and Markus Gühr

Appl. Sci. 2017, 7(7), 681; https://doi.org/10.3390/app7070681 - 1 Jul 2017

Cited by 19 | Viewed by 8851

Abstract

Molecules often fragment after photoionization in the gas phase. Usually, this process can only be investigated spectroscopically as long as there exists electron correlation between the photofragments. Important parameters, like their kinetic energy after separation, cannot be investigated. We are reporting on a [...] Read more.

Molecules often fragment after photoionization in the gas phase. Usually, this process can only be investigated spectroscopically as long as there exists electron correlation between the photofragments. Important parameters, like their kinetic energy after separation, cannot be investigated. We are reporting on a femtosecond time-resolved Auger electron spectroscopy study concerning the photofragmentation dynamics of thymine. We observe the appearance of clearly distinguishable signatures from thymine′s neutral photofragment isocyanic acid. Furthermore, we observe a time-dependent shift of its spectrum, which we can attribute to the influence of the charged fragment on the Auger electron. This allows us to map our time-dependent dataset onto the fragmentation coordinate. The time dependence of the shift supports efficient transformation of the excess energy gained from photoionization into kinetic energy of the fragments. Our method is broadly applicable to the investigation of photofragmentation processes. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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1370 KiB

Open AccessArticle

State-Population Narrowing Effect in Two-Photon Absorption for Intense Hard X-ray Pulses

by Krzysztof Tyrała, Klaudia Wojtaszek, Marek Pajek, Yves Kayser, Christopher Milne, Jacinto Sá and Jakub Szlachetko

Appl. Sci. 2017, 7(7), 653; https://doi.org/10.3390/app7070653 - 24 Jun 2017

Cited by 3 | Viewed by 5241

Abstract

We report on studies of state-populations during the two-photon absorption process using intense X-ray pulses. The calculations were performed in a time-dependent manner using a simple three-level model expressed by coupled rate equations. We show that the proposed approach describes well the measured [...] Read more.

We report on studies of state-populations during the two-photon absorption process using intense X-ray pulses. The calculations were performed in a time-dependent manner using a simple three-level model expressed by coupled rate equations. We show that the proposed approach describes well the measured rates of X-rays excited in the one-photon and two-photon absorption processes, and allows detailed investigation of the state population dynamics during the course of the incident X-ray pulse. Finally, we demonstrate that the nonlinear interaction of X-ray pulses with atoms leads to a time-narrowing of state populations. This narrowing-effect is attributed to a quadratic incidence X-ray intensity dependence characteristic for nonlinear interactions of photons with matter. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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694 KiB

Open AccessArticle

Algorithm for Reconstruction of 3D Images of Nanorice Particles from Diffraction Patterns of Two Particles in Independent Random Orientations with an X-ray Laser

by Sung Soon Kim, Sandi Wibowo and Dilano Kerzaman Saldin

Appl. Sci. 2017, 7(7), 646; https://doi.org/10.3390/app7070646 - 23 Jun 2017

Cited by 1 | Viewed by 3855

Abstract

The method of angular correlations recovers quantities from diffraction patterns of randomly oriented particles, as expected to be measured with an X-ray free electron laser (XFEL), proportional to quadratic functions of the spherical harmonic expansion coefficients of the diffraction volume of a single [...] Read more.

The method of angular correlations recovers quantities from diffraction patterns of randomly oriented particles, as expected to be measured with an X-ray free electron laser (XFEL), proportional to quadratic functions of the spherical harmonic expansion coefficients of the diffraction volume of a single particle. We have previously shown that it is possible to reconstruct a randomly oriented icosahedral or helical virus from the average over all measured diffraction patterns of such correlations. We point out in this paper that a structure of even simpler particles of 50 Å or so in diameter and consisting of heavier atomic elements (to enhance scattering) that has been used as a test case for reconstructions from XFEL diffraction patterns can also be solved by this technique. Even though there has been earlier work on similar objects (prolate spheroids), one advantage of the present technique is its potential to also work with diffraction patterns not only due to single particles as has been suggested on the basis on nonoverlapping delta functions of angular scattering. Accordingly, we calculated from the diffraction patterns the angular momentum expansions of the pair correlations and triple correlations for general particle images and reconstructed those images in the standard way. Although the images looked pretty much the same, it is not totally clear to us that the angular correlations are exactly the same as different numbers of particles due to the possibility of constructive or destructive interference between the scattered waves from different particles. It is of course known that, for a large number of particles contributing to a diffraction parttern, the correlations converge to that of a single particle. It could be that the lack of perfect agreement between the images reconstructed with one and two particles is due to uncancelling constructive and destructive conditions that are not found in the case of solution scattering. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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3206 KiB

Open AccessFeature PaperArticle

FERMI: Present and Future Challenges

by Luca Giannessi and Claudio Masciovecchio

Appl. Sci. 2017, 7(6), 640; https://doi.org/10.3390/app7060640 - 21 Jun 2017

Cited by 16 | Viewed by 5301

Abstract

We present an overview of the FERMI (acronym of Free Electron laser Radiation for Multidisciplinary Investigations) seeded free electron laser (FEL) facility located at the Elettra laboratory in Trieste. FERMI is now in user operation with both the FEL lines FEL-1 and FEL-2, [...] Read more.

We present an overview of the FERMI (acronym of Free Electron laser Radiation for Multidisciplinary Investigations) seeded free electron laser (FEL) facility located at the Elettra laboratory in Trieste. FERMI is now in user operation with both the FEL lines FEL-1 and FEL-2, covering the wavelength range between 100 nm and 4 nm. The seeding scheme adopted for photon pulse production makes FERMI unique worldwide and allows the extension of table top laser experiments in the extreme ultraviolet/soft X-ray region. In this paper, we discuss how advances in the performance of the FELs, with respect to coherent control and multi-colour pulse production, may push the development of original experimental strategies to study non-equilibrium behaviour of matter at the attosecond-nanometer time-length scales. This will have a tremendous impact as an experimental tool to investigate a large array of phenomena ranging from nano-dynamics in complex materials to phenomena that are at the heart of the conversion of light into other forms of energy. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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419 KiB

Open AccessArticle

Application of Matched-Filter Concepts to Unbiased Selection of Data in Pump-Probe Experiments with Free Electron Lasers

by Carlo Callegari, Tsukasa Takanashi, Hironobu Fukuzawa, Koji Motomura, Denys Iablonskyi, Yoshiaki Kumagai, Subhendu Mondal, Tetsuya Tachibana, Kiyonobu Nagaya, Toshiyuki Nishiyama, Kenji Matsunami, Per Johnsson, Paolo Piseri, Giuseppe Sansone, Antoine Dubrouil, Maurizio Reduzzi, Paolo Carpeggiani, Caterina Vozzi, Michele Devetta, Davide Faccialà, Francesca Calegari, Mattea Carmen Castrovilli, Marcello Coreno, Michele Alagia, Bernd Schütte, Nora Berrah, Oksana Plekan, Paola Finetti, Eugenio Ferrari, Kevin Charles Prince and Kiyoshi Ueda Show full author list Hide full author list

Appl. Sci. 2017, 7(6), 621; https://doi.org/10.3390/app7060621 - 16 Jun 2017

Cited by 2 | Viewed by 4862

Abstract

Pump-probe experiments are commonly used at Free Electron Lasers (FEL) to elucidate the femtosecond dynamics of atoms, molecules, clusters, liquids and solids. Maximizing the signal-to-noise ratio of the measurements is often a primary need of the experiment, and the aggregation of repeated, rapid, [...] Read more.

Pump-probe experiments are commonly used at Free Electron Lasers (FEL) to elucidate the femtosecond dynamics of atoms, molecules, clusters, liquids and solids. Maximizing the signal-to-noise ratio of the measurements is often a primary need of the experiment, and the aggregation of repeated, rapid, scans of the pump-probe delay is preferable to a single long-lasting scan. The limited availability of beamtime makes it impractical to repeat measurements indiscriminately, and the large, rapid flow of single-shot data that need to be processed and aggregated into a dataset, makes it difficult to assess the quality of a measurement in real time. In post-analysis it is then necessary to devise unbiased criteria to select or reject datasets, and to assign the weight with which they enter the analysis. One such case was the measurement of the lifetime of Intermolecular Coulombic Decay in the weakly-bound neon dimer. We report on the method we used to accomplish this goal for the pump-probe delay scans that constitute the core of the measurement; namely we report on the use of simple auto- and cross-correlation techniques based on the general concept of “matched filter”. We are able to unambiguously assess the signal-to-noise ratio (SNR) of each scan, which then becomes the weight with which a scan enters the average of multiple scans. We also observe a clear gap in the values of SNR, and we discard all the scans below a SNR of 0.45. We are able to generate an average delay scan profile, suitable for further analysis: in our previous work we used it for comparison with theory. Here we argue that the method is sufficiently simple and devoid of human action to be applicable not only in post-analysis, but also for the real-time assessment of the quality of a dataset. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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Open AccessArticle

Terawatt-Isolated Attosecond X-ray Pulse Using a Tapered X-ray Free Electron Laser

by Sandeep Kumar, Alexandra S. Landsman and Dong Eon Kim

Appl. Sci. 2017, 7(6), 614; https://doi.org/10.3390/app7060614 - 13 Jun 2017

Cited by 4 | Viewed by 4952

Abstract

High power attosecond (as) X-ray pulses are in great demand for ultrafast dynamics and high resolution microscopy. We numerically demonstrate the generation of a ~230 attosecond, 1.5 terawatt (TW) pulse at a photon energy of 1 keV, and a 115 attosecond, 1.2 TW [...] Read more.

High power attosecond (as) X-ray pulses are in great demand for ultrafast dynamics and high resolution microscopy. We numerically demonstrate the generation of a ~230 attosecond, 1.5 terawatt (TW) pulse at a photon energy of 1 keV, and a 115 attosecond, 1.2 TW pulse at a photon energy of 12.4 keV, using the realistic electron beam parameters such as those of Korean X-ray free electron laser (XFEL) in a tapered undulator configuration. To compensate the energy loss of the electron beam and maximize its radiation power, a tapering is introduced in the downstream section of the undulator. It is found that the tapering helps in not only amplifying a target radiation pulse but also suppressing the growth of satellite radiation pulses. Tapering allows one to achieve a terawatt-attosecond pulse only with a 60 m long undulator. Such an attosecond X-ray pulse is inherently synchronized to a driving optical laser pulse; hence, it is well suited for the pump-probe experiments for studying the electron dynamics in atoms, molecules, and solids on the attosecond time-scale. For the realization of these experiments, a high level of synchronization up to attosecond precision between optical laser and X-ray pulse is demanded, which can be possible by using an interferometric feedback loop. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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Open AccessFeature PaperArticle

Photon Beam Transport and Scientific Instruments at the European XFEL

by Thomas Tschentscher, Christian Bressler, Jan Grünert, Anders Madsen, Adrian P. Mancuso, Michael Meyer, Andreas Scherz, Harald Sinn and Ulf Zastrau

Appl. Sci. 2017, 7(6), 592; https://doi.org/10.3390/app7060592 - 9 Jun 2017

Cited by 242 | Viewed by 14359

Abstract

European XFEL is a free-electron laser (FEL) user facility providing soft and hard X-ray FEL radiation to initially six scientific instruments. Starting user operation in fall 2017 European XFEL will provide new research opportunities to users from science domains as diverse as physics, [...] Read more.

European XFEL is a free-electron laser (FEL) user facility providing soft and hard X-ray FEL radiation to initially six scientific instruments. Starting user operation in fall 2017 European XFEL will provide new research opportunities to users from science domains as diverse as physics, chemistry, geo- and planetary sciences, materials sciences or biology. The unique feature of European XFEL is the provision of high average brilliance in the soft and hard X-ray regime, combined with the pulse properties of FEL radiation of extreme peak intensities, femtosecond pulse duration and high degree of coherence. The high average brilliance is achieved through acceleration of up to 27,000 electron bunches per second by the super-conducting electron accelerator. Enabling the usage of this high average brilliance in user experiments is one of the major instrumentation drivers for European XFEL. The radiation generated by three FEL sources is distributed via long beam transport systems to the experiment hall where the scientific instruments are located side-by-side. The X-ray beam transport systems have been optimized to maintain the unique features of the FEL radiation which will be monitored using build-in photon diagnostics. The six scientific instruments are optimized for specific applications using soft or hard X-ray techniques and include integrated lasers, dedicated sample environment, large area high frame rate detector(s) and computing systems capable of processing large quantities of data. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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971 KiB

Open AccessCommunication

Measurement of the X-ray Spectrum of a Free Electron Laser with a Wide-Range High-Resolution Single-Shot Spectrometer

by Yuichi Inubushi, Ichiro Inoue, Jangwoo Kim, Akihiko Nishihara, Satoshi Matsuyama, Hirokatsu Yumoto, Takahisa Koyama, Kensuke Tono, Haruhiko Ohashi, Kazuto Yamauchi and Makina Yabashi

Appl. Sci. 2017, 7(6), 584; https://doi.org/10.3390/app7060584 - 6 Jun 2017

Cited by 34 | Viewed by 5582

Abstract

We developed a single-shot X-ray spectrometer for wide-range high-resolution measurements of Self-Amplified Spontaneous Emission (SASE) X-ray Free Electron Laser (XFEL) pulses. The spectrometer consists of a multi-layer elliptical mirror for producing a large divergence of 22 mrad around 9070 eV and a silicon [...] Read more.

We developed a single-shot X-ray spectrometer for wide-range high-resolution measurements of Self-Amplified Spontaneous Emission (SASE) X-ray Free Electron Laser (XFEL) pulses. The spectrometer consists of a multi-layer elliptical mirror for producing a large divergence of 22 mrad around 9070 eV and a silicon (553) analyzer crystal. We achieved a wide energy range of 55 eV with a fine spectral resolution of 80 meV, which enabled the observation of a whole SASE-XFEL spectrum with fully-resolved spike structures. We found that a SASE-XFEL pulse has around 60 longitudinal modes with a pulse duration of 7.7 ± 1.1 fs. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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3108 KiB

Open AccessArticle

Split-And-Delay Unit for FEL Interferometry in the XUV Spectral Range

by Sergey Usenko, Andreas Przystawik, Leslie Lamberto Lazzarino, Markus Alexander Jakob, Florian Jacobs, Christoph Becker, Christian Haunhorst, Detlef Kip and Tim Laarmann

Appl. Sci. 2017, 7(6), 544; https://doi.org/10.3390/app7060544 - 25 May 2017

Cited by 10 | Viewed by 6183

Abstract

In this work we present a reflective split-and-delay unit (SDU) developed for interferometric time-resolved experiments utilizing an (extreme ultraviolet) XUV pump–XUV probe scheme with focused free-electron laser beams. The developed SDU overcomes limitations for phase-resolved measurements inherent to conventional two-element split mirrors by [...] Read more.

In this work we present a reflective split-and-delay unit (SDU) developed for interferometric time-resolved experiments utilizing an (extreme ultraviolet) XUV pump–XUV probe scheme with focused free-electron laser beams. The developed SDU overcomes limitations for phase-resolved measurements inherent to conventional two-element split mirrors by a special design using two reflective lamellar gratings. The gratings produce a high-contrast interference signal controlled by the grating displacement in every diffraction order. The orders are separated in the focal plane of the focusing optics, which enables one to avoid phase averaging by spatially selective detection of a single interference state of the two light fields. Interferometry requires a precise relative phase control of the light fields, which presents a challenge at short wavelengths. In our setup the phase delay is determined by an in-vacuum white light interferometer (WLI) that monitors the surface profile of the SDU in real time and thus measures the delay for each laser shot. The precision of the WLI is 1 nm as determined by optical laser interferometry. In the presented experimental geometry it corresponds to a time delay accuracy of 3 as, which enables phase-resolved XUV pump–XUV probe experiments at free-electron laser (FEL) repetition rates up to 60 Hz. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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Open AccessArticle

Fundamental Limits on Spatial Resolution in Ultrafast X-ray Diffraction

by Adam Kirrander and Peter M. Weber

Appl. Sci. 2017, 7(6), 534; https://doi.org/10.3390/app7060534 - 23 May 2017

Cited by 25 | Viewed by 5984

Abstract

X-ray Free-Electron Lasers have made it possible to record time-sequences of diffraction images to determine changes in molecular geometry during ultrafast photochemical processes. Using state-of-the-art simulations in three molecules (deuterium, ethylene, and 1,3-cyclohexadiene), we demonstrate that the nature of the nuclear wavepacket initially [...] Read more.

X-ray Free-Electron Lasers have made it possible to record time-sequences of diffraction images to determine changes in molecular geometry during ultrafast photochemical processes. Using state-of-the-art simulations in three molecules (deuterium, ethylene, and 1,3-cyclohexadiene), we demonstrate that the nature of the nuclear wavepacket initially prepared by the pump laser, and its subsequent dispersion as it propagates along the reaction path, limits the spatial resolution attainable in a structural dynamics experiment. The delocalization of the wavepacket leads to a pronounced damping of the diffraction signal at large values of the momentum transfer vector q, an observation supported by a simple analytical model. This suggests that high-q measurements, beyond 10–15 Å

^{- 1}

, provide scant experimental payback, and that it may be advantageous to prioritize the signal-to-noise ratio and the time-resolution of the experiment as determined by parameters such as the repetition-rate, the photon flux, and the pulse durations. We expect these considerations to influence future experimental designs, including source development and detection schemes. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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Open AccessArticle

X-ray Pump–Probe Investigation of Charge and Dissociation Dynamics in Methyl Iodine Molecule

by Li Fang, Hui Xiong, Edwin Kukk and Nora Berrah

Appl. Sci. 2017, 7(5), 529; https://doi.org/10.3390/app7050529 - 19 May 2017

Cited by 9 | Viewed by 5759

Abstract

Molecular dynamics is of fundamental interest in natural science research. The capability of investigating molecular dynamics is one of the various motivations for ultrafast optics. We present our investigation of photoionization and nuclear dynamics in methyl iodine (CH₃I) molecule with an [...] Read more.

Molecular dynamics is of fundamental interest in natural science research. The capability of investigating molecular dynamics is one of the various motivations for ultrafast optics. We present our investigation of photoionization and nuclear dynamics in methyl iodine (CH₃I) molecule with an X-ray pump X-ray probe scheme. The pump–probe experiment was realized with a two-mirror X-ray split and delay apparatus. Time-of-flight mass spectra at various pump–probe delay times were recorded to obtain the time profile for the creation of high charge states via sequential ionization and for molecular dissociation. We observed high charge states of atomic iodine up to 29+, and visualized the evolution of creating these high atomic ion charge states, including their population suppression and enhancement as the arrival time of the second X-ray pulse was varied. We also show the evolution of the kinetics of the high charge states upon the timing of their creation during the ionization-dissociation coupled dynamics. We demonstrate the implementation of X-ray pump–probe methodology for investigating X-ray induced molecular dynamics with femtosecond temporal resolution. The results indicate the footprints of ionization that lead to high charge states, probing the long-range potential curves of the high charge states. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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Open AccessArticle

Probing Dynamics in Colloidal Crystals with Pump-Probe Experiments at LCLS: Methodology and Analysis

by Nastasia Mukharamova, Sergey Lazarev, Janne-Mieke Meijer, Matthieu Chollet, Andrej Singer, Ruslan P. Kurta, Dmitry Dzhigaev, Oleg Yu. Gorobtsov, Garth Williams, Diling Zhu, Yiping Feng, Marcin Sikorski, Sanghoon Song, Anatoly G. Shabalin, Tatiana Gurieva, Elena A. Sulyanova, Oleksandr M. Yefanov and Ivan A. Vartanyants

Appl. Sci. 2017, 7(5), 519; https://doi.org/10.3390/app7050519 - 19 May 2017

Cited by 4 | Viewed by 6381

Abstract

We present results of the studies of dynamics in colloidal crystals performed by pump-probe experiments using an X-ray free-electron laser (XFEL). Colloidal crystals were pumped with an infrared laser at a wavelength of 800 nm with varying power and probed by XFEL pulses [...] Read more.

We present results of the studies of dynamics in colloidal crystals performed by pump-probe experiments using an X-ray free-electron laser (XFEL). Colloidal crystals were pumped with an infrared laser at a wavelength of 800 nm with varying power and probed by XFEL pulses at an energy of 8 keV with a time delay up to 1000 ps. The positions of the Bragg peaks, and their radial and azimuthal widths were analyzed as a function of the time delay. The spectral analysis of the data did not reveal significant enhancement of frequencies expected in this experiment. This allowed us to conclude that the amplitude of vibrational modes excited in colloidal crystals was less than the systematic error caused by the noise level. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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3230 KiB

Open AccessFeature PaperArticle

Construction and Commissioning of PAL-XFEL Facility

by In Soo Ko, Heung-Sik Kang, Hoon Heo, Changbum Kim, Gyujin Kim, Chang-Ki Min, Haeryong Yang, Soung Youl Baek, Hyo-Jin Choi, Geonyeong Mun, Byoung Ryul Park, Young Jin Suh, Dong Cheol Shin, Jinyul Hu, Juho Hong, Seonghoon Jung, Sang-Hee Kim, KwangHoon Kim, Donghyun Na, Soung Soo Park, Yong Jung Park, Young Gyu Jung, Seong Hun Jeong, Hong Gi Lee, Sangbong Lee, Sojeong Lee, Bonggi Oh, Hyung Suck Suh, Jang-Hui Han, Min Ho Kim, Nam-Suk Jung, Young-Chan Kim, Mong-Soo Lee, Bong-Ho Lee, Chi-Won Sung, Ik-Su Mok, Jung-Moo Yang, Yong Woon Parc, Woul-Woo Lee, Chae-Soon Lee, Hocheol Shin, Ji Hwa Kim, Yongsam Kim, Jae Hyuk Lee, Sang-Youn Park, Jangwoo Kim, Jaeku Park, Intae Eom, Seungyu Rah, Sunam Kim, Ki Hyun Nam, Jaehyun Park, Jaehun Park, Sangsoo Kim, Soonnam Kwon, Ran An, Sang Han Park, Kyung Sook Kim, Hyojung Hyun, Seung Nam Kim, Seonghan Kim, Chung-Jong Yu, Bong-Soo Kim, Tai-Hee Kang, Kwang-Woo Kim, Seung-Hwan Kim, Hee-Seock Lee, Heung-Soo Lee, Ki-Hyeon Park, Tae-Yeong Koo, Dong-Eon Kim and Ki Bong Lee Show full author list Hide full author list

Appl. Sci. 2017, 7(5), 479; https://doi.org/10.3390/app7050479 - 17 May 2017

Cited by 117 | Viewed by 11032

Abstract

The construction of Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL), a 0.1-nm hard X-ray free-electron laser (FEL) facility based on a 10-GeV S-band linear accelerator (LINAC), is achieved in Pohang, Korea by the end of 2016. The construction of the 1.11 km-long building [...] Read more.

The construction of Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL), a 0.1-nm hard X-ray free-electron laser (FEL) facility based on a 10-GeV S-band linear accelerator (LINAC), is achieved in Pohang, Korea by the end of 2016. The construction of the 1.11 km-long building was completed by the end of 2014, and the installation of the 10-GeV LINAC and undulators started in January 2015. The installation of the 10-GeV LINAC, together with the undulators and beamlines, was completed by the end of 2015. The commissioning began in April 2016, and the first lasing of the hard X-ray FEL line was achieved on 14 June 2016. The progress of the PAL-XFEL construction and its commission are reported here. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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375 KiB

Open AccessArticle

Two- and Three-Photon Partial Photoionization Cross Sections of Li⁺, Ne⁸⁺ and Ar¹⁶⁺ under XUV Radiation

by William Hanks, John T. Costello and Lampros A. A. Nikolopoulos

Appl. Sci. 2017, 7(3), 294; https://doi.org/10.3390/app7030294 - 17 Mar 2017

Cited by 3 | Viewed by 5935

Abstract

In this work, we present the photon energy dependence of the two- and three-photon cross sections of the two-electron Li⁺, Ne⁸⁺ and Ar¹⁶⁺ ions, following photoionization from their ground state. The expressions for the cross sections are based on [...] Read more.

In this work, we present the photon energy dependence of the two- and three-photon cross sections of the two-electron Li⁺, Ne⁸⁺ and Ar¹⁶⁺ ions, following photoionization from their ground state. The expressions for the cross sections are based on the lowest-order (non-vanishing) perturbation theory for the electric field, while the calculations are made with the use of an ab initio configuration interaction method. The ionization cross section is dominated by pronounced single photon resonances in addition to peaks associated with doubly excited resonances. In the case of two-photon ionization, and in the non-resonant part of the cross section, we find that the ¹D ionization channel overwhelms the ¹S one. We also observe that, as one moves from the lowest atomic number ion, namely Li⁺, to the highest atomic number ion, namely Ar¹⁶⁺, the cross sections generally decrease. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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Review

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28 pages, 4353 KiB

Open AccessReview

Current Status of Single Particle Imaging with X-ray Lasers

by Zhibin Sun, Jiadong Fan, Haoyuan Li and Huaidong Jiang

Appl. Sci. 2018, 8(1), 132; https://doi.org/10.3390/app8010132 - 22 Jan 2018

Cited by 33 | Viewed by 9392

Abstract

The advent of ultrafast X-ray free-electron lasers (XFELs) opens the tantalizing possibility of the atomic-resolution imaging of reproducible objects such as viruses, nanoparticles, single molecules, clusters, and perhaps biological cells, achieving a resolution for single particle imaging better than a few tens of [...] Read more.

The advent of ultrafast X-ray free-electron lasers (XFELs) opens the tantalizing possibility of the atomic-resolution imaging of reproducible objects such as viruses, nanoparticles, single molecules, clusters, and perhaps biological cells, achieving a resolution for single particle imaging better than a few tens of nanometers. Improving upon this is a significant challenge which has been the focus of a global single particle imaging (SPI) initiative launched in December 2014 at the Linac Coherent Light Source (LCLS), SLAC National Accelerator Laboratory, USA. A roadmap was outlined, and significant multi-disciplinary effort has since been devoted to work on the technical challenges of SPI such as radiation damage, beam characterization, beamline instrumentation and optics, sample preparation and delivery and algorithm development at multiple institutions involved in the SPI initiative. Currently, the SPI initiative has achieved 3D imaging of rice dwarf virus (RDV) and coliphage PR772 viruses at ~10 nm resolution by using soft X-ray FEL pulses at the Atomic Molecular and Optical (AMO) instrument of LCLS. Meanwhile, diffraction patterns with signal above noise up to the corner of the detector with a resolution of ~6 Ångström (Å) were also recorded with hard X-rays at the Coherent X-ray Imaging (CXI) instrument, also at LCLS. Achieving atomic resolution is truly a grand challenge and there is still a long way to go in light of recent developments in electron microscopy. However, the potential for studying dynamics at physiological conditions and capturing ultrafast biological, chemical and physical processes represents a tremendous potential application, attracting continued interest in pursuing further method development. In this paper, we give a brief introduction of SPI developments and look ahead to further method development. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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10966 KiB

Open AccessReview

Ultrashort Free-Electron Laser X-ray Pulses

by Wolfram Helml, Ivanka Grguraš, Pavle N. Juranić, Stefan Düsterer, Tommaso Mazza, Andreas R. Maier, Nick Hartmann, Markus Ilchen, Gregor Hartmann, Luc Patthey, Carlo Callegari, John T. Costello, Michael Meyer, Ryan N. Coffee, Adrian L. Cavalieri and Reinhard Kienberger

Appl. Sci. 2017, 7(9), 915; https://doi.org/10.3390/app7090915 - 6 Sep 2017

Cited by 31 | Viewed by 12436

Abstract

For the investigation of processes happening on the time scale of the motion of bound electrons, well-controlled X-ray pulses with durations in the few-femtosecond and even sub-femtosecond range are a necessary prerequisite. Novel free-electron lasers sources provide these ultrashort, high-brightness X-ray pulses, but [...] Read more.

For the investigation of processes happening on the time scale of the motion of bound electrons, well-controlled X-ray pulses with durations in the few-femtosecond and even sub-femtosecond range are a necessary prerequisite. Novel free-electron lasers sources provide these ultrashort, high-brightness X-ray pulses, but their unique aspects open up concomitant challenges for their characterization on a suitable time scale. In this review paper we describe progress and results of recent work on ultrafast pulse characterization at soft and hard X-ray free-electron lasers. We report on different approaches to laser-assisted time-domain measurements, with specific focus on single-shot characterization of ultrashort X-ray pulses from self-amplified spontaneous emission-based and seeded free-electron lasers. The method relying on the sideband measurement of X-ray electron ionization in the presence of a dressing optical laser field is described first. When the X-ray pulse duration is shorter than half the oscillation period of the streaking field, few-femtosecond characterization becomes feasible via linear streaking spectroscopy. Finally, using terahertz fields alleviates the issue of arrival time jitter between streaking laser and X-ray pulse, but compromises the achievable temporal resolution. Possible solutions to these remaining challenges for single-shot, full time–energy characterization of X-ray free-electron laser pulses are proposed in the outlook at the end of the review. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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5424 KiB

Open AccessFeature PaperReview

The Linac Coherent Light Source: Recent Developments and Future Plans

by R. W. Schoenlein, S. Boutet, M. P. Minitti and A.M. Dunne

Appl. Sci. 2017, 7(8), 850; https://doi.org/10.3390/app7080850 - 18 Aug 2017

Cited by 41 | Viewed by 7958

Abstract

The development of X-ray free-electron lasers (XFELs) has launched a new era in X-ray science by providing ultrafast coherent X-ray pulses with a peak brightness that is approximately one billion times higher than previous X-ray sources. The Linac Coherent Light Source (LCLS) facility [...] Read more.

The development of X-ray free-electron lasers (XFELs) has launched a new era in X-ray science by providing ultrafast coherent X-ray pulses with a peak brightness that is approximately one billion times higher than previous X-ray sources. The Linac Coherent Light Source (LCLS) facility at the SLAC National Accelerator Laboratory, the world’s first hard X-ray FEL, has already demonstrated a tremendous scientific impact across broad areas of science. Here, a few of the more recent representative highlights from LCLS are presented in the areas of atomic, molecular, and optical science; chemistry; condensed matter physics; matter in extreme conditions; and biology. This paper also outlines the near term upgrade (LCLS-II) and motivating science opportunities for ultrafast X-rays in the 0.25–5 keV range at repetition rates up to 1 MHz. Future plans to extend the X-ray energy reach to beyond 13 keV (<1 Å) at high repetition rate (LCLS-II-HE) are envisioned, motivated by compelling new science of structural dynamics at the atomic scale. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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1912 KiB

Open AccessReview

Probing Physics in Vacuum Using an X-ray Free-Electron Laser, a High-Power Laser, and a High-Field Magnet

by Toshiaki Inada, Takayuki Yamazaki, Tomohiro Yamaji, Yudai Seino, Xing Fan, Shusei Kamioka, Toshio Namba and Shoji Asai

Appl. Sci. 2017, 7(7), 671; https://doi.org/10.3390/app7070671 - 29 Jun 2017

Cited by 37 | Viewed by 5770

Abstract

A nonlinear interaction between photons is observed in a process that involves charge sources. To observe this process in a vacuum, there are a growing number of theoretical and experimental studies. This process may contain exotic contribution from new physics beyond the Standard [...] Read more.

A nonlinear interaction between photons is observed in a process that involves charge sources. To observe this process in a vacuum, there are a growing number of theoretical and experimental studies. This process may contain exotic contribution from new physics beyond the Standard Model of particle physics, and is probed by experiments using a high-power laser or a high-field magnet, and more recently using an X-ray free-electron laser (XFEL). Here, we review the present status of our experiments testing various vacuum processes. We describe four experiments with a focus on those using an XFEL: (i) photon–photon scattering in the X-ray region, (ii) laser-induced birefringence and diffraction of X rays, (iii) vacuum birefringence induced by a high-field magnet, and (iv) a dedicated search for axion-like particles using the magnet and X rays. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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1080 KiB

Open AccessReview

Measurement of the Resonant Magneto-Optical Kerr Effect Using a Free Electron Laser

by Shingo Yamamoto and Iwao Matsuda

Appl. Sci. 2017, 7(7), 662; https://doi.org/10.3390/app7070662 - 27 Jun 2017

Cited by 25 | Viewed by 17231

Abstract

We present a new experimental magneto-optical system that uses soft X-rays and describe its extension to time-resolved measurements using a free electron laser (FEL). In measurements of the magneto-optical Kerr effect (MOKE), we tune the photon energy to the material absorption edge and [...] Read more.

We present a new experimental magneto-optical system that uses soft X-rays and describe its extension to time-resolved measurements using a free electron laser (FEL). In measurements of the magneto-optical Kerr effect (MOKE), we tune the photon energy to the material absorption edge and thus induce the resonance effect required for the resonant MOKE (RMOKE). The method has the characteristics of element specificity, large Kerr rotation angle values when compared with the conventional MOKE using visible light, feasibility for M-edge, as well as L-edge measurements for 3d transition metals, the use of the linearly-polarized light and the capability for tracing magnetization dynamics in the subpicosecond timescale by the use of the FEL. The time-resolved (TR)-RMOKE with polarization analysis using FEL is compared with various experimental techniques for tracing magnetization dynamics. The method described here is promising for use in femtomagnetism research and for the development of ultrafast spintronics. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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2140 KiB

Open AccessFeature PaperReview

Status of the SACLA Facility

by Makina Yabashi, Hitoshi Tanaka, Kensuke Tono and Tetsuya Ishikawa

Appl. Sci. 2017, 7(6), 604; https://doi.org/10.3390/app7060604 - 10 Jun 2017

Cited by 32 | Viewed by 5825

Abstract

This article reports the current status of SACLA, SPring-8 Angstrom Compact free electron LAser, which has been producing stable X-ray Free Electron Laser (XFEL) light since 2012. A unique injector system and a short-period in-vacuum undulator enable the generation of ultra-short coherent X-ray [...] Read more.

This article reports the current status of SACLA, SPring-8 Angstrom Compact free electron LAser, which has been producing stable X-ray Free Electron Laser (XFEL) light since 2012. A unique injector system and a short-period in-vacuum undulator enable the generation of ultra-short coherent X-ray pulses with a wavelength shorter than 0.1 nm. Continuous development of accelerator technologies has steadily improved XFEL performance, not only for normal operations but also for fast switching operation of the two beamlines. After upgrading the broadband spontaneous-radiation beamline to produce soft X-ray FEL with a dedicated electron beam driver, it is now possible to operate three FEL beamlines simultaneously. Beamline/end-station instruments and data acquisition/analyzation systems have also been upgraded to allow advanced experiments. These efforts have led to the production of novel results and will offer exciting new opportunities for users from many fields of science. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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3016 KiB

Open AccessReview

Molecular Dynamics of XFEL-Induced Photo-Dissociation, Revealed by Ion-Ion Coincidence Measurements

by Edwin Kukk, Koji Motomura, Hironobu Fukuzawa, Kiyonobu Nagaya and Kiyoshi Ueda

Appl. Sci. 2017, 7(5), 531; https://doi.org/10.3390/app7050531 - 19 May 2017

Cited by 17 | Viewed by 6065

Abstract

X-ray free electron lasers (XFELs) providing ultrashort intense pulses of X-rays have proven to be excellent tools to investigate the dynamics of radiation-induced dissociation and charge redistribution in molecules and nanoparticles. Coincidence techniques, in particular multi-ion time-of-flight (TOF) coincident experiments, can provide detailed [...] Read more.

X-ray free electron lasers (XFELs) providing ultrashort intense pulses of X-rays have proven to be excellent tools to investigate the dynamics of radiation-induced dissociation and charge redistribution in molecules and nanoparticles. Coincidence techniques, in particular multi-ion time-of-flight (TOF) coincident experiments, can provide detailed information on the photoabsorption, charge generation, and Coulomb explosion events. Here we review several such recent experiments performed at the SPring-8 Angstrom Compact free electron LAser (SACLA) facility in Japan, with iodomethane, diiodomethane, and 5-iodouracil as targets. We demonstrate how to utilize the momentum-resolving capabilities of the ion TOF spectrometers to resolve and filter the coincidence data and extract various information essential in understanding the time evolution of the processes induced by the XFEL pulses. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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Other

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5175 KiB

Open AccessFeature PaperProject Report

Status of the SXFEL Facility

by Zhentang Zhao, Dong Wang, Qiang Gu, Lixin Yin, Ming Gu, Yongbin Leng and Bo Liu

Appl. Sci. 2017, 7(6), 607; https://doi.org/10.3390/app7060607 - 12 Jun 2017

Cited by 59 | Viewed by 7465

Abstract

The Shanghai soft X-ray Free-Electron Laser facility (SXFEL) is being developed in two steps; the SXFEL test facility (SXFEL-TF), and the SXFEL user facility (SXFEL-UF). The SXFEL-TF is a critical development step towards the construction a soft X-ray FEL user facility in China, [...] Read more.

The Shanghai soft X-ray Free-Electron Laser facility (SXFEL) is being developed in two steps; the SXFEL test facility (SXFEL-TF), and the SXFEL user facility (SXFEL-UF). The SXFEL-TF is a critical development step towards the construction a soft X-ray FEL user facility in China, and is under commissioning at the Shanghai Synchrotron Radiation Facility (SSRF) campus. The test facility is going to generate 8.8 nm FEL radiation using an 840 MeV electron linac passing through the two-stage cascaded HGHG-HGHG or EEHG-HGHG (high-gain harmonic generation, echo-enabled harmonic generation) scheme. The construction of the SXFEL-TF started at the end of 2014. Its accelerator tunnel and klystron gallery were ready for equipment installation in April 2016, and the installation of the SXFEL-TF linac and radiator undulators were completed by the end of 2016. In the meantime, the SXFEL-UF, with a designated wavelength in the water window region, began construction in November 2016. This was based on upgrading the linac energy to 1.5 GeV, and the building of a second undulator line and five experimental end-stations. Construction status and the future plans of the SXFEL are reported in this paper. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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136 KiB

Open AccessMeeting Report

Nobel Symposium on Free Electron Laser Research

by Mats Larsson

Appl. Sci. 2017, 7(4), 408; https://doi.org/10.3390/app7040408 - 18 Apr 2017

Cited by 2 | Viewed by 3942

Abstract

This meeting report describes the Nobel Symposium on Free Electron Laser Research, which was organized in Sigtuna, Sweden, 14–18 June 2015. Full article

(This article belongs to the Special Issue X-Ray Free-Electron Laser)

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