A - Linac-based Light Sources
Paper Title Page
MOA1PL01
Latest Developments in X-Ray FELs and Future Perspectives  
 
  • W. Decking
    DESY, Hamburg, Germany
 
  The successful commissioning of the PAL-XFEL, SwissFEL and European XFEL in the last year has increased the number of operating hard X-Ray FELs together with SACLA and LCLS to five. This talk will try to summarize the status of the facilities, compare similarities and differences and give an outlook of what is to be expected in the coming years.  
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MOA1PL02
Review of Schemes for Improved Peak Power and Coherence in X-Ray FELs  
 
  • E. Prat
    PSI, Villigen PSI, Switzerland
 
  X-ray free-electron-lasers (FEL) are cutting-edge research instruments that produce transversely coherent radiation with peak powers of 10-100 gigawatts and pulse durations of the order of 10 femtoseconds or shorter. Standard FEL facilities based on the SASE mechanism have certain limitations concerning the properties of the produced radiation, namely the longitudinal coherence or bandwidth, the peak power and the pulse duration. In this talk a review of different schemes to enhance the peak power and the longitudinal coherence of FELs will be presented. The talk will cover well-established methods, such as tapering or seeding, as well as other promising but not yet demonstrated techniques, like the high-brightness SASE and some methods based on superradiance to generate terawatt-attosecond radiation. The progress of such schemes will be reviewed and, based on present limitations and challenges, areas for future development will be pointed out. Moreover, we will present how most of these schemes can be accommodated in the design of the next generation of FEL facilities.  
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MOP1WA01
The Shanghai Hard X-ray Free Electron Laser Project  
 
  • D. Wang
    SINAP, Shanghai, People's Republic of China
 
  This talk is about the Shanghai Hard X-ray Free Electron Laser Project.  
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MOP1WA02 The LCLS-II-HE, A High Energy Upgrade of the LCLS-II 6
 
  • T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
 
  The LCLS-II XFEL will be based on a 4 GeV CW SRF linac and will produce x-ray pulses at 1 MHz over the spectral range of 200 to 5,00 eV. The rf gun will be installed and tested in early 2018; cryomodules are being produced at Fermilab and Jefferson lab and shipped to SLAC; undulator segments are being fabricated at LBNL and measured at SLAC. In parallel, a High Energy upgrade will be described which would extend the linac to 8 GeV and increase the spectral range to 12.8 keV.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FLS2018-MOP1WA02  
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MOP1WA03
PAL-XFEL and Its Time-Resolved Experiment with sub-20-fs Timing Jitter  
 
  • C.-K. Min, I. Eom, J. Hu, S.H. Jung, H.-S. Kang, S.H. Kim, H.-S. Lee, S.S. Park
    PAL, Pohang, Kyungbuk, Republic of Korea
 
  A tunable femtosecond X-ray laser, PAL-XFEL have sub-20- fs timing jitter between XFEL pulses and optical laser pulses, which make this machine extremely useful for time-resolved experiments with high time resolution. We describe the effort made to minimize timing jitter of XFEL machine and to synchronize optical laser system to our low phase noise RF reference. Passively stabilized RF timing distribution system and phase-locked oscillators provide 1 fs level jitter, and carefully designed LLRF and modulator system provide 10-4 level energy stability of electron bunches. The electron bunch arrival jitter is measured less than 20 fs with a phase cavity. Cross correlation between XFEL and optical laser also showed less than 20 fs timing jitter.  
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MOP2WA01
Report on the First ICFA Mini-Workshop on Machine Learning for Particle Accelerators  
 
  • D.F. Ratner, X. Huang, C.E. Mayes, T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
 
  Machine learning techniques are playing a growing role in operation of particle accelerators around the world. To facilitate collaborations and discussions at this early stage, we have organized the first ICFA mini-workshop on machine learning applications at SLAC National Accelerator Laboratory: https://conf.slac.stanford.edu/icfa-ml-2018/. Here we report on the outcome of the meeting.  
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MOP2WA02
Automated Optimization of Machine Parameters at the European XFEL  
 
  • S.I. Tomin
    XFEL. EU, Hamburg, Germany
  • L. Fröhlich, M. Scholz
    DESY, Hamburg, Germany
 
  In today's single-pass free-electron lasers, a lot of time and effort is spent on the manual optimization of machine parameters with the goal of improving the photon beam. Identifying and automating these tuning procedures holds the promise of faster set-up times and higher machine efficiency. This talk gives an overview of various optimization routines used for this purpose at the European XFEL. Our first attempts at exploiting machine learning algorithms are also included.  
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MOP2WA03
The Feasibility of Neuron Network-based Beam-based Alignment  
 
  • L. Zeng
    SINAP, Shanghai, People's Republic of China
 
  Artificial neuron networks which inspired by biological neural networks have been widely used in various domains, including computer vision, machine translation, pattern/speech recognition, medical diagnosis and so on, due to its overwhelming superiorities. But it's not until recently that intelligent algorithms have been introduced in light source field. M.P. Ehrlichman, Yi Jiao, Juhao Wu and A. Sanchez-Gonzalez did some work in this respect and got commendable results. Considering Shanghai X-ray Free-Electron Laser (SXFEL) conditions, we are urgent to improve the FEL performance, and fundamental technique turns out to be beam-based alignment. But it's difficult to implement this means in SXFEL due to the low electron beam energy resulting in uncontrollable orbit disturbance. Thus, a new method which is suitable for SXFEL is an eager desire. Here, we discuss the feasibility of neuron network-based beam-based alignment, and try to take it into reality in SXFEL. In fact, Hornik have proved, as early as 1989, that a single hidden layer feedforward networks can approximate any measurable function arbitrarily well, which provides the theoretical evidence to our suggestion.  
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MOP2WA04
FEL Optimization Through BBA with Undulator Spectrum Analysis and Undulator Optics Matching  
 
  • H.-S. Kang, H. Yang
    PAL, Pohang, Kyungbuk, Republic of Korea
 
  The use of electron-beam-based alignment incorporating undulator radiation spectrum analysis has allowed reliable operation of PAL-XFEL with unprecedented stability in terms of orbit, energy, and timing. The hard XFEL operation procedure established using e-BBA and incorporating undulator radiation spectrum analysis proved to be highly reliable and robust, and essential for the variable-gap undulators. The undulator optics matching using the wire-scanner based emittance measurement is extensively used to maximize the FEL intensity even at higher photon energy up to 14.5 keV.  
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TUP1WA01
Generation of Atto-Second FELs  
 
  • A. Marinelli
    SLAC, Menlo Park, California, USA
 
  Sub-fs X-ray pump/probe capabilities hold great promise for understanding the role of coherent electron dynamics in molecules and solids. At the Linac Coherent Light Source (LCLS) for hard X-ray energies the sub-fs regime can be reached by shortening the electrong bunch and operating the FEL in the single-spike SASE FEL limit. In the soft X-ray region, achieving sub-fs pulses requires bandwidth broadening by means of an enhanced SASE scheme. In this talk I will present recent results on the generation of sub-fs X-ray pulses at LCLS and discuss the path to time-resolved experiments with attosecond time resolution  
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TUP1WA02
Ultrashort Pulse Generation and Superradiance in FELs  
 
  • X. Yang
    BNL, Upton, Long Island, New York, USA
  • L. Giannessi
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  The generation of a single X-ray isolated spike of radiation with peak power at multi-GW level and femtosecond temporal duration represents an almost unique opportunity in time resolved diffraction imaging of isolated molecules or non-periodic structures, for the possibility of acquiring single shot images before the Coulomb explosion of the sample takes place. Such a condition is met by an FEL operating in superradiant regime when the pulse has a self-similar shape deriving from the combined dynamics of saturation and slippage of the radiation over fresh electrons. We show that the peak of the pulse moves at superluminal speed similarly to the case of pulses propagation in anomalous dispersive active media and it is followed by a long pedestal resulting from the complex dynamics occurring in the tail after saturation. We analyze the dynamical conditions leading to the formation of the main pulse and the following tail and we study the correlation of the tail structure with the longitudinal phase space of the e-beam, providing recipes to partially suppress it.  
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TUP1WA03
Free-Electron Laser R&D in the UK - Steps Towards a National X-FEL Facility  
 
  • N. Thompson, J.A. Clarke, D.J. Dunning
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • J.A. Clarke, D.J. Dunning
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • B.W.J. MᶜNeil
    USTRAT/SUPA, Glasgow, United Kingdom
 
  In this contribution we present highlights of FEL R&D in the UK with a focus on progress towards a national X-Ray FEL user facility. We discuss the aims and status of CLARA, a dedicated FEL test facility under construction at STFC Daresbury Laboratory and present highlights of recent research into the development of novel FEL output possibilities.  
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TUP2WA01
EEHG Experiment at FERMI  
 
  • E. Allaria
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  Echo enabled harmonic generation (EEHG) has been recognized as a possible solution to extend the tuning range of externally seeded FELs to wavelength as short as few nm. Previous experiments have confirmed the capabilities to produce bunching at very high harmonic but they have been done only at long wavelength. An experiment to demonstrate EEHG operations at high harmonic and short wavelength is planned at FERMI. With few modifications to the FERMI FEL-2 layout, EEHG will be studied and performances will be compared to other seeding schemes such as high gain harmonic generation (HGHG). Attention will be focused to the spectral purity and to the sensitivity of EEHG and HGHG to microbunching instabilities.  
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TUP2WA02
An X-Ray FEL Oscillator for Novel Sciences  
 
  • K.-J. Kim
    ANL, Argonne, Illinois, USA
 
  Funding: This work was supported by U.S. Department of Energy, Office of Basic Energy Sciences, Contract No. DE-AC02-06CH11357
An X-ray FEL Oscillator (XFELO) is capable of producing fully coherent flux of ~1015 photons /s/ (meV bandwidth) over the hard X-ray spectral range 5 to 25 keV. This is higher by about three orders of magnitude than that from the self-amplified-spontaneous-emission (SASE) sources and about six orders magnitudes than the MBA sources. A CW, MHz rep rate, multi-GeV superconducting linac, such as planned at several laboratories is ideally suited for operating an XFELO. The XFELO pulses are also highly stable in contrast to the SASE pulses. In contrast to the ultrafast sciences probed by SASE, the XFELO is well-suited for sciences probing ultra fine spectral resolution. An XFELO can thus greatly extend the parameter space of the techniques established in third generation sources (IXS, XPCS, NRS) as well as opening up entirely new field, for example the nuclear physics of Mössbauer states and fundamental physics with X-ray spectral comb. The performance listed above is based on experimentally demonstrated level of X-ray power density on diamond reflectors and a fixed (4%) out-coupling efficiency. Further enhancement could be feasible if these constraints can be relaxed.
 
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TUP2WA03 Harmonic Lasing in X-Ray FELs: Theory and Experiment 68
 
  • E. Schneidmiller, B. Faatz, M. Kuhlmann, J. Rönsch-Schulenburg, S. Schreiber, M. Tischer, M.V. Yurkov
    DESY, Hamburg, Germany
 
  Harmonic lasing in XFELs is an opportunity to extend operating range of existing and planned X-ray FEL user facilities*. Contrary to nonlinear harmonic generation, harmonic lasing can provide much more intense, stable, and narrow-band FEL beam which is easier to handle due to the suppressed fundamental. Another interesting application of harmonic lasing is Harmonic Lasing Self-Seeded (HLSS) FEL*,** that allows to improve longitudinal coherence and spectral power of a SASE FEL. Recently*** this concept was successfully tested at FLASH2 in the range 4.5 - 15 nm. That was also the first experimental demonstration of harmonic lasing in a high-gain FEL and at a short wavelength (before it worked only in infrared FEL oscillators). In this contribution we describe the concepts of harmonic lasing and of HLSS FEL, and present the experimental results from FLASH2.
* E.Schneidmiller and M.Yurkov, Phys. Rev. ST-AB 15(2012)080702
** E.Schneidmiller and M.Yurkov, Proc. of FEL2013, p.700
*** E.Schneidmiller et al., Phys. Rev. Accel. Beams 20(2017)020705
 
slides icon Slides TUP2WA03 [3.378 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FLS2018-TUP2WA03  
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TUP2WA04
Simulations and Performance Study of an Optimized Longitudinal Phase Space for the Hard X-Ray Self-Seeding at the European XFEL  
 
  • S. Liu, W. Decking, V. Kocharyan
    DESY, Hamburg, Germany
  • G. Geloni, S. Serkez
    XFEL. EU, Hamburg, Germany
 
  A two-stage Hard X-ray Self-Seeding (HXRSS) set-up will be implemented at European XFEL in late 2018. For the demonstration of the HXRSS, short electron beam bunches (FWHM ≤ 50 fs) are preferred to mitigate spatio-temperal coupling effect and to fit to the seeding bump width. In preparation for the commissioning of the HXRSS, beam dynamics simulations have been performed to optimize the longitudinal phase space for a 100 pC electron beam with 5 kA peak current. Performance of the optimized longitudinal phase space will be studied using a transverse deflecting structure in early 2018. With the optimized electron beam, HXRSS simulations have been performed for the lower (~3 keV) and the upper (~14 keV) photon energy range planned for the HXRSS operation. The locations of the two HXRSS stages have been studied and chosen to optimize the performance of the upper photon energy with an insignificant effect on the lower one. We will present the longitudinal phase space optimization for the 100 pC case as well as the expected performance of the HXRSS with the optimized set-up.  
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WEP2PT003 Undulator Phase Matching for the the European XFEL 103
 
  • Y. Li, J. Pflüger
    XFEL. EU, Hamburg, Germany
 
  The undulator system in the European XFEL is mainly comprised 5-m long undulator segments and 1.1 m long intersections in between. In intersections the electron velocity is faster than it inside an undulator and the optical phase is detuned. The detune effect is also from the undulator fringe field where electron longitudinal speed also deviates from the oscillation condition. The total detune effect is compensated by a magnetic device called phase shifter, which is correspondingly set for a specific undulator gap. In this paper we introduce the method to set the phase shifter gap for each K parameter according to the measured magnetic field.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FLS2018-WEP2PT003  
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WEP2PT008 Microbunching Instability Study in the Linac-Driven FERMI FEL Spreader Beam Line 108
 
  • S. Di Mitri, S. Spampinati
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  Suppression of microbunching instability (MBI) along high brightness electron beam delivery systems is a priority for Free Electron lasers (FELs) aiming at very narrow bandwidth. The impact of MBI on FEL spectral brilliance is aggravated by the growing demand for multi-user FEL facilities, which adopt multi-bend switchyard lines traversed by high charge density electron beams. This study provides practical guidelines to switchyards design largely immune to MBI, by focusing on the FERMI FEL Spreader line. First, two MBI analytical models [1, 2] are successfully benchmarked along the accelerator. Being the second model flexible enough to describe an arbitrary multi-bend line, and found it in agreement with particle tracking and experimental results, it was used to demonstrate that a newly proposed Spreader optics provides unitary MBI gain while preserving the electron beam brightness.
[1] Z. Huang and K.-J. Kim, Phys. Rev. Special Topics - Accel. Beams 5, 074401 (2002)
[2] R.A. Bosch, K.J. Kleman, and J. Wu, Phys. Rev. Special Topics - Accel. Beams 11, 090702 (2008)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FLS2018-WEP2PT008  
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WEP2PT050 Status of CAEP THz Free Electron Laser Oscillator 154
 
  • M. Li, T.H. He, C.L. Lao, P. Li, S.F. Lin, X. Luo, Q. Pan, L.J. Shan, X. Shen, H. Wang, J. Wang, D. Wu, D.X. Xiao, Y. Xu, X. Yang, P. Zhang, K. Zhou
    CAEP/IAE, Mianyang, Sichuan, People's Republic of China
 
  China Academy of Engineering Physics tera-hertz free electron laser (CAEP THz FEL, CTFEL) is the first THz FEL oscillator in China, which was jointly built by CAEP, Peking university and Tsinghua university. The stimulated saturation of the CTFEL was reached in August, 2017. This THz FEL facility consists of a GaAs photocathode high-voltage DC gun, a superconducting RF linac, a planar undulator and a quasi-concentric optical resonator. The terahertz laser's frequency is continuous adjustable from 2 THz to 3 THz. The average power is more than 10 W and the micro-pulse power is more than 0.1 MW.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FLS2018-WEP2PT050  
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THA1WA01
Fast Simulation of FEL Linacs with Collective Effects  
 
  • M. Dohlus
    DESY, Hamburg, Germany
 
  The demands of FELs on beam quality are a challenge. From the source via accelerators, bunch compressors, collimation system to and through undulators, self effects play an important role for the design and operation of such machines. Unfortunately it is not possible to solve the coupled problem of Maxwell's equations and equations of motion for bunches of 10-6 to 10-3 meter length in machines with a dimension of 100 to 1000 meters. Therefore simplifying concepts as space charge fields, space charge optics, wakes and coherent synchrotron radiation are widely in use. There are even models for parasitic micro-bunch instabilities for wavelengths clearly below one micrometer. Although the individual models are well developed and efficient, it is still difficult to combine them in single program that simulates a machine from the source to the end.  
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THA1WA02
Eliminating the Microbunching-Instability-Induced Sideband in a Soft X-Ray Self-Seeding Free-Electron Laser  
 
  • K.Q. Zhang, C. Feng, D. Wang
    SINAP, Shanghai, People's Republic of China
 
  Soft x-ray self-seeding has been proved to be a feasible method to improve the longitudinal coherence of high gain free-electron laser. However, a pedestal-like sideband in the spectrum has been observed in the experiment, which generally limits the purity of the radiation pulse and the user's application. The previous theoretical study indicates that the pedestal-like sideband is mainly induced by microbunching instability generated from LINAC. In this paper, three dimensional simulations have been performed to confirm the analytical results and show the formation process of the spectral sideband. A probable method is proposed to eliminate the pedestal-like sideband by simply inserting a magnetic chicane before the self-seeding FEL undulator. Theoretical and numerical simulations have been performed and the results show that the proposed method can efficiently eliminate the microbunching-instability-induced sideband in a soft x-ray self-seeding FEL  
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THA1WA03 GPT-CSR: A New Simulation Code for CSR Effects 157
 
  • S.B. van der Geer, M.J. de Loos
    Pulsar Physics, Eindhoven, The Netherlands
  • I. Setija, P.W. Smorenburg
    ASML Netherlands B.V., Veldhoven, The Netherlands
  • P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
 
  For future applications of high-brightness electron beams, including the design of next generation FEL's, correct correct simulation of Coherent Synchrotron Radiation (CSR) is essential as it potentially degrades beam quality to unacceptable levels. However, the long interaction lengths compared to the bunch length, numerical cancellation, and difficult 3D retardation conditions make accurate simulation of CSR effects notoriously difficult. To ease the computational burden, CSR codes often make severe simplifications such as an ultra relativistic bunch travelling on a prescribed reference trajectory. Here we report on a new CSR model, implemented in the General Particle Tracer (GPT) code, that avoids most of the usual assumptions: It directly evaluates the Lienard-Wiechert potentials based on the stored history of the beam, it makes no assumptions about reference trajectories, while also taking into account the transverse size of the beam. First results demonstrating microbunching gain in a chicane are presented.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FLS2018-THA1WA03  
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THA1WA04
A Staged, Multi-User X-Ray Free Electron Laser & Nuclear Physics Facility Based on a Multi-Pass Recirculating Superconducting CW Linac  
 
  • P.H. Williams, D. Angal-Kalinin, A.D. Brynes, J.A. Clarke, L.S. Cowie, D.J. Dunning, P. Goudket, F. Jackson, J.K. Jones, P.A. McIntosh, B.L. Militsyn, A.J. Moss, B.D. Muratori, S.L. Smith, M. Surman, N. Thompson, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • J.A.G. Akkermans
    ASML Netherlands B.V., Veldhoven, The Netherlands
  • D. Angal-Kalinin, I.R. Bailey, A.D. Brynes, J.A. Clarke, L.S. Cowie, D.J. Dunning, P. Goudket, F. Jackson, J.K. Jones, P.A. McIntosh, B.W.J. MᶜNeil, B.L. Militsyn, A.J. Moss, B.D. Muratori, H.L. Owen, S.L. Smith, M. Surman, N. Thompson, A.E. Wheelhouse, P.H. Williams
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • I.R. Bailey
    Lancaster University, Lancaster, United Kingdom
  • S.V. Benson, D. Douglas, Y. Roblin, T. Satogata, M. F. Spata, C. Tennant
    JLab, Newport News, Virginia, USA
  • T.K. Charles
    The University of Melbourne, Melbourne, Victoria, Australia
  • T.K. Charles
    CERN, Geneva, Switzerland
  • B.W.J. MᶜNeil
    USTRAT/SUPA, Glasgow, United Kingdom
  • H.L. Owen
    UMAN, Manchester, United Kingdom
  • R.C. York
    FRIB, East Lansing, Michigan, USA
 
  A multi-pass recirculating superconducting CW linac offers a cost effective path to a multi-user facility with unprecedented scientific and industrial reach over a wide range of disciplines. We propose such a facility to be constructed in stages. The first stage constitutes an option for a potential UK-XFEL; the linac will simultaneously drive a suite of short wavelength Free Electron Lasers (FELs) capable of providing high average power (MHz repetition rate) at up to 10 keV photons and high pulse energy (3 mJ) 25 keV photons. The system architecture is chosen to enable additional coherent sources at longer wavelengths, depending on community need. In later stages the scope of the project expands; we propose beam transport modifications to enable operation in Energy Recovery mode. This enables multi-MHz FEL sources, e.g. an X-ray FEL oscillator. Combining with lasers and / or self-interaction will provide access to MeV and GeV gamma-rays via inverse Compton scattering at high average power. Opportunities are also created for internal target and fixed target experiments. We explore possible system architectures and outline a path to confirm feasibility through experiments.  
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THA2WA01
Experience and future plans for running concurrently multiple experiments with a single FEL  
 
  • A.R. Robert
    SLAC, Menlo Park, California, USA
 
  Experience and future plans for running concurrently multiple experiments with a single FEL  
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THA2WA02
Two-Bunch Operation With ns Temporal Separation at FERMI  
 
  • G. Penco
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  In the last decade a continuous effort has been spent to improve the capability of existing free-electron lasers (FELs) operating in the X-ray and VUV regimes. Together with the possibility to provide sub-ps and fs photon pulses with an intensity ten order of magnitude larger than the past generation light sources, new modes of operation have been conceived. In this framework, generation of two-color (or multi-colour) FEL pulses, temporally separated, had an unprecedented impact on the scientic community, pave the way for new pump-and-probe experiments. A number of two-color two-pulse schemes have been already implemented in several labs but with a limited time-separation from 0 to few hundreds of fs. We present a new design tested at the FERMI FEL machine, able to produce two independent electron bunches temporally separated from hundreds of ps to few ns. Measurements and characterisation of this two-bunch mode operation are presented, including trajectory control, impact of longitudinal and transverse wakefields, manipulation of the longitudinal phase space and finally a demonstration of suitability of the scheme to provide extreme ultra-violet light by using both bunches.  
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THA2WA03
Optimizing of Electron Beam Distribution at European XFEL and FLASH  
 
  • B. Faatz
    DESY, Hamburg, Germany
 
  As a rule, FELs have been single user machines. To distribute the electron beam with a fast kicker system between different undulators enables delivering beam to several users simultaneously. If it is done from RF pulse to RF pulse, it would decrease the number of bunches for each user. Therefore, it is planned at the European XFEL and already practice for several years at FLASH, to kick entire bunch trains within an RF pulse, thus delivering to both users the 10 Hz trains. It will be shown how the system has allowed long pulse trains for two users simultaneously and what has been done to keep the full flexibility within a bunch train not only in terms of wavelength, number of bunches and bunch separation, but also in bunch length needed to allow different users different FEL-pulse duration.  
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FRA1PL01 Summary Report: Linac-Based Light Sources 199
 
  • T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
  • W. Decking
    DESY, Hamburg, Germany
  • L. Giannessi
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • H.-S. Kang
    PAL, Pohang, Kyungbuk, Republic of Korea
 
  This is the summary report of the linac-based light sources working group.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FLS2018-FRA1PL01  
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