FEL2014 - List of Keywords (photon)

Paper	Title	Other Keywords	Page
MOA03	First Lasing at FLASH2	undulator, electron, operation, laser	7
	S. Schreiber, B. Faatz DESY, Hamburg, Germany
	FLASH, the free-electron laser user facility at DESY (Hamburg, Germany), has been upgraded with a second undulator beamline FLASH2. The installation of the FLASH2 electron beamline, including twelve variable gap undulators, was finalized early 2014, and beam commissioning of the new beamline started in March 2014. We announce first lasing at FLASH2 achieved at a wavelength of 40 nm on August 20, 2014.
	Slides MOA03 [3.896 MB]

MOP001	Particle Tracking Simulations for EXFEL Complex shape Collimators	electron, radiation, simulation, lattice	22
	V.G. Khachatryan, V.H. Petrosyan, T.L. Vardanyan CANDLE SRI, Yerevan, Armenia
	The study sets the objective to investigate through numerical simulation the produced secondary radiation properties when the electron beam particles hit collimator walls. Using particle tracking simulation code FLUKA, the European XFEL electron beam as well as beam halo interaction with the collimator were simulated. The complex geometrical shape and material composition of the collimator have been taken into account. Absorbed dose spatial distribution in the material of the collimators and particle fluencies from the downstream surface of the collimator were simulated for the total secondary radiation and its main components.

MOP010	The Photon Beam Loss Monitors as a Part of Equipment Protection System at European XFEL	detector, vacuum, radiation, beam-transport	37
	N. Gerasimova, H. Sinn XFEL. EU, Hamburg, Germany S. Dziarzhytski, R. Treusch DESY, Hamburg, Germany
	For the X-ray beam transport systems, the problem of potential damage to the equipment by mis-steered photon beam emerged with advent of powerful X-ray FELs. In particular high repetition rate machines as European XFEL, where not only focused beam can produce ablation, but even unfocused beam can melt the beamline components while machine operates in multibunch mode, demand for implementation of equipment protection. Here we report on development of photon beam loss monitors at European XFEL facility. The photon beam loss monitors will react on the mis-steered photon beam and interface the machine protection system. The prototype comprises the vacuum chamber with fluorescence crystals positioned outside the photon beampath. The fast sub-hundred ns fluorescence induced by mis-steered beam can be detected by photomultiplier tube allowing for intra-train reaction of machine protection system. First tests have been carried out at FLASH and shown the feasibility of detection based on PMT-detected fluorescence. In addition to efficient YAG:Ce crystal, the robust low-Z material as CVD microcrystalline diamonds has shown a potential to be used as fluorescence crystals.

MOP012	Implementation Phase of the European XFEL Photon Diagnostics	diagnostics, undulator, FEL, electron	41
	J. Grünert, J. Buck, F. Dietrich, W. Freund, A. Koch, M. Planas XFEL. EU, Hamburg, Germany
	The European XFEL facility with 3 undulators and initially 6 experimental end-stations requires an extensive set of photon beam diagnostics for commissioning and user operation, capable of handling the extreme brilliance and its inherent damage potential, and the high intra bunch train repetition rate of 4.5MHz, potentially causing additional damage by high heat loads and making shot-to-shot diagnostics very demanding [1]. After extensive design [2-4] and prototype studies, in 2014 the installation of the photon beam devices starts with the equipment in the first photon tunnel XTD2 which is where the SASE1 hard X-ray undulator is located. This contribution reports on the device construction progress by focusing on the XTD2 tunnel devices and their implementation into the tunnel environment. [1] J.Grünert, Framework for X-Ray Photon Diagnostics at the European XFEL, TR-2012-003, 04/2012 [2] J.Buck, Online Photoemission Time-of-Flight Spectrometer for X-ray Photon Diagnostics, TR-2012-002, 06/2012 [3] C.Ozkan, Conceptual design report for Imaging Stations at the European XFEL, TR-2012-004, 02/2012 [4] W.Freund, The European XFEL Undulator Commissioning Spectrometer, XFEL. EU 05/2011

MOP014	X-ray Photon Temporal Diagnostics for the European XFEL	diagnostics, brilliance, electron, laser	45
	J. Liu, J. Buck, F. Dietrich, W. Freund, J. Grünert, M. Meyer XFEL. EU, Hamburg, Germany
	European XFEL (XFEL. EU) that will commissioning in 2016 shows great features on its extremely high number of light bullets (27000 p/s) and extremely high average brilliance. The FEL pulses in XFEL. EU are produced in a 10 Hz bunch trains that contains 2700 sub-pulses within the 600 μs time intervals, corresponding to a 220 ns sub-pulse separation and 4.5 MHz repetition rate. Characterizing the temporal properties of the high repetition rate FEL pulses that implicitly different from shot to shot is important for “pump and probe” experiments and data interpretation. Here we report the concept and recent progress about temporal diagnostic for XFEL. EU. THz streaking technique and spectral encoding will be implemented considering the high repetition rate and high brilliance of XFEL. EU. Laser based THz generation, optimization and numerical simulation for streaking FEL electrons with different photon energies will be presented. High repetition rate diagnostic requirements and solutions will also be discussed.

MOP018	Conceptual Study of a Self-seeding Scheme at FLASH2	undulator, FEL, electron, simulation	53
	T. Plath, L.L. Lazzarino Uni HH, Hamburg, Germany K.E. Hacker DELTA, Dortmund, Germany
	Funding: Supported by Federal Ministry of Education and Research of Germany under contract No. 05K1GU4 and 05K10PE1 and the German Research Foundation program graduate school 1355. We present a conceptual study of a self-seeding installation at the new FEL beamline, FLASH2, at the free-electron laser at DESY, Hamburg. For self-seeding, light from a first set of undulators is filtered by a monochromator and thus acts as a seed for the gain process in the main undulator. This scheme has been tested at LCLS at SLAC with a diamond monochromator for hard X-rays and with a grating monochromator for soft X-rays covering energies between 700 and 1000 eV. For such a design to offer benefits at FLASH2, it must be modified to work with X-rays with wavelength of about 5 nm (248 eV) where the damage threshold of the monochromator in the setup and the divergence at longer wavelengths become an issue. An analysis of the potential performance and limitations of this setup is performed using GENESIS 1.3 and a method developed for the soft X-ray self-seeding experiment at the European XFEL. With a total of 9 undulators in the first stage and 8 undulators after the monochromator, a pulse energy contrast ratio of 4.5 was simulated with an initial peak current of 2.5 kA.

MOP020	Compact Spectrometer for Single Shot X-ray Emission and Photon Diagnostics	FEL, target, synchrotron, diagnostics	62
	F. Frassetto, P. Miotti, L. P. Poletto CNR-IFN, Padova, Italy M. Coreno CNR-IMIP, Monterotondo Stazione RM, Italy A. Di Cicco, F. Iesari Università di Camerino, Camerino, Italy P. Finetti, E. Giangrisostomi, R. Mincigrucci, E. Principi Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy C. Grazioli Universita Degli Studi di Trieste, Trieste, Italy A. Kivimaki IOM-CNR, Trieste, Italy S. Stagira CNR-IFN & Dipartimento di Fisica - Politecnico di Milano, Milano, Italy S. Stagira Politecnico/Milano, Milano, Italy
	The design and characterization of a compact spectrometer realized for photon in-photon out experiments (in particular X-Ray Emission Spectroscopy), conceived to be used at the FERMI free-electron-laser (FEL) at ELETTRA (Italy) is here presented. The instrument can be easily installed on different end stations at variable distances from the target area both at synchrotron and FEL beamlines. Different input sections can be accommodated in order to fit the experimental requests. The design is compact in order to realize a portable instrument within an overall size of less than one square meter. The spectrometer covers the 25-800 eV spectral range, with spectral resolution better than 0.2%. The characterization on Gas Phase @ ELETTRA as instrument for XES and some experimental data of the FEL emission acquired at EIS-TIMEX @ FERMI, where the instrument has been used for photon beam diagnostics, are introduced.

MOP038	Characterization of the Undulator Magnetic Field Quality by the Angle Averaged Radiation Spectrum	undulator, radiation, electron	100
	O.A. Shevchenko, N. Vinokurov BINP SB RAS, Novosibirsk, Russia N. Vinokurov KAERI, Daejon, Republic of Korea
	The real undulator magnetic field always contains errors which influence undulator performance. The effect of these errors is usually characterized by broadening of the spontaneous emission spectrum at zero angle and corresponding reduction of the spectral intensity. This approach works very well for the phase errors while it does not take into account transversal trajectory displacements. The integrated over the angles radiation spectrum contains more complete information about the undulator field quality but its calculation requires more effort. Therefore the spectral density of emitted radiation (the total number of emitted photons with given energy) can be considered as a figure of merit for an undulator. In this paper we derive analytical formula for this spectrum suitable for doing efficient numerical calculations and demonstrate its application to the case of some typical undulator field errors.

MOP040	General Strategy for the Commissioning of the ARAMIS Undulators with a 3 GeV Electron Beam	undulator, electron, alignment, quadrupole	107
	M. Calvi, M. Aiba, M. Brügger, S. Danner, R. Ganter, R. Ischebeck, L. Patthey, T. Schietinger, T. Schmidt PSI, Villigen PSI, Switzerland
	The commissioning of the first SwissFEL undulator line (Aramis) is planned for the beginning of 2017. Each undulator is equipped with a 5-axis camshaft system to remotely adjust its position in the micrometer range and a gap drive system to set K-values between 0.1 and 1.8. In the following paper the beam-based alignment of the undulator with respect to the golden orbit, the definition of look-up tables for the local correction strategy (minimization of undulator field errors), the fine-tuning of the K-values as well as the setting of the phase shifters are addressed. When applicable both electron beam and light based methods are presented and compared.

MOP041	Summary of the U15 Prototype Magnetic Performance	undulator, vacuum, electron, quadrupole	111
	M. Calvi, M. Aiba, M. Brügger, S. Danner, R. Ganter, C. Ozkan, T. Schmidt PSI, Villigen PSI, Switzerland
	The first undulator prototype (U15) was assembled and magnetically tested. The instrumentation and the algorithms developed for the undulator optimization are presented and a comparison among different approaches is reviewed. The magnetic measurement results before and after the installation of the vacuum components are discussed. The summary of the undulator test with 100 MeV electron beam is presented and the impact of the radiation on the magnetics is addressed.

MOP054	Harmonic Lasing Options for LCLS-II	undulator, electron, radiation, FEL	148
	G. Marcus, Y. Ding, Z. Huang, T.O. Raubenheimer SLAC, Menlo Park, California, USA G. Penn LBNL, Berkeley, California, USA
	Harmonic lasing can be a cheap and relatively efficient way to extend the photon energy range of a particular FEL beamline. Furthermore, in comparison to nonlinear harmonics, harmonic lasing can provide a beam that is more intense, stable, and narrow-band. This paper explores the application of the harmonic lasing concept at LCLS-II using various combinations of phase shifters and attenuators. In addition, a scheme by which individual undulator modules are tuned to amplify either the third or fifth harmonic in different configurations is presented in detail.

MOP056	SASE Characteristics from Baseline European XFEL Undulators in the Tapering Regime	electron, undulator, radiation, FEL	159
	I.V. Agapov, G. Geloni XFEL. EU, Hamburg, Germany G. Feng, V. Kocharyan, E. Saldin, S. Serkez, I. Zagorodnov DESY, Hamburg, Germany
	The output SASE characteristics of the baseline European XFEL, recently used in the TDRs of scientific instruments and X-ray optics, have been previously optimized assuming uniform undulators without considering the potential of undulator tapering in the SASE regime. Here we demonstrate that the performance of European XFEL sources can be significantly improved without additional hardware. The procedure consists in the optimization of the undulator gap configuration for each X-ray beamline. Here we provide a comprehensive description of the X-ray photon beam properties as a function of wavelength and bunch charge. Based on nominal parameters for the electron beam, we demonstrate that undulator tapering allows one to achieve up to a tenfold increase in peak power and photon spectral density in the conventional SASE regime.

MOP068	Suppression of the Fundamental Frequency for a Successful Harmonic Lasing in SASE FELs	undulator, FEL, electron, simulation	215
	E. Schneidmiller, M.V. Yurkov DESY, Hamburg, Germany
	Harmonic lasing in X-ray FELs has recently attracted a significant attention and is now seriously considered as a potential method for generation of brilliant photon beams at short wavelengths. It is clear, however, that for a successful harmonic lasing one has to suppress the fundamental. In this paper we discuss different methods for such a suppression: phase shifters, intraundulator spectral filtering, switching between the 3rd and the 5th harmonics etc.

MOP082	Perspectives for Imaging Single Protein Molecules with the Present Design of the European XFEL	electron, laser, free-electron-laser, FEL	238
	G. Geloni XFEL. EU, Hamburg, Germany V. Kocharyan, E. Saldin, S. Serkez, I. Zagorodnov DESY, Hamburg, Germany O. Yefanov CFEL, Hamburg, Germany
	European XFEL aims to support imaging and structure determination of biological specimens between less than 0.1 microns and 1 micron size with working photon energies between 3 keV and 16 keV. This wide operation range is a cause for challenges to the focusing optics. A long propagation distance of about 900 m between x-ray source and sample leads to a large lateral photon beam size at the optics. Due to the large divergence of nominal X-ray pulses with durations shorter than 10 fs, one suffers diffraction from mirror apertures, leading to a 100-fold decrease in fluence at photon energies around 4 keV, which seem ideal for imaging of single biomolecules. Moreover, the nominal SASE1 is very far from the level required for single particle imaging. Here we show how it may be possible to optimize the SPB instrument for single biomolecule imaging with minimal additional costs and time, achieving diffraction without destruction at near-atomic resolution with 10¹³ photons in a 4 fs pulse at 4 keV photon energy and in a 100 nm focus, corresponding to a fluence of 10²³ ph/cm². This result is exemplified using the RNA Pol II molecule as a case study.

MOP092	X-ray Monochromators for Self-seeding XFELs in the Photon Energy Range Starting from 1.5 keV	FEL, scattering, electron, radiation	269
	Yu. Shvyd'ko ANL, Argonne, Ilinois, USA
	Self-seeding of XFELs below 1 keV can be performed using grating monochromators [1]. Forward-Bragg diffraction (wake) monochromators [2] were instrumental for achieving self-seeding in hard x-ray FELs in the photon energy range from 5 to 10 keV [3]. Large photo-absorption makes extension into the lower photon range difficult. Here alternative schemes of x-ray monochromators are introduced and discussed for achieving self-seeding in a yet inaccessible spectral range starting from 1.5 keV. [1] J. Feldhaus, et al., Opt. Commun. 140, 341 (1997). [2]. G. Geloni, V. Kocharyan, and E. Saldin, J. Mod. Opt. 58, 1391 (2011). [3] J. Amann, et al., Nat. Photonics 6, 693 (2012).

TUP002	Characterization of Partially Coherent Ultrashort FEL Pulses	FEL, laser, electron, free-electron-laser	346
	C. Bourassin-Bouchet, M.-E. Couprie SOLEIL, Gif-sur-Yvette, France C. Evain PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
	Temporal metrology is a major need for free-electron lasers. However, the lack of longitudinal coherence, that is shot-to-shot fluctuations, of these sources has prevented so far the full amplitude and phase temporal characterization of FEL pulses. To sort out this issue, we propose a solution inspired from attosecond metrology, where XUV pulse measurement techniques already exist, and from coherent diffraction imaging, where numerical solutions have been developed for processing partially coherent diffraction patterns. The experimental protocole implies the measurement of photoelectron spectra obtained through XUV-laser photoionisation. The spectra are then processed with an algorithm in order to retrieve the partially coherent FEL pulse. When applied to SASE FELs, the technique gives access to the full statistics of the emitted pulses. With seeded-FELs, the pulse shape becomes stable from shot-to-shot, but an XUV-laser time jitter remains. In that case, the technique enables the joint measurement of the FEL pulse shape (in amplitude and phase) and of the laser/FEL jitter envelope. The concept has been validated with numerical simulations in the context of the LUNEX5 FEL project.

TUP003	Quantum FEL II: Many-electron Theory	electron, FEL, laser, resonance	348
	P. Kling, R. Sauerbrey HZDR, Dresden, Germany R. Endrich, E.A. Giese, W.P. Schleich Uni Ulm, Ulm, Germany
	We investigate the emergence of the quantum regime of the FEL when many electrons interact simultaneously with the wiggler and the laser field. We find the Quantum FEL as the limit where only two momentum states are populated by the electrons. Moreover, we obtain exponential gain-per-pass and start-up from vacuum.

TUP004	Quantum FEL I: Multi-mode Theory	electron, resonance, coupling, FEL	353
	R. Endrich, E.A. Giese, W.P. Schleich Uni Ulm, Ulm, Germany P. Kling, R. Sauerbrey HZDR, Dresden, Germany
	The quantum regime of the FEL in a single-mode, single-particle approximation is characterized by a two-level behaviour of the center-of-mass motion of the electrons. We extend this model to include all modes of the radiation field and analyze the effect of spontaneous emission. In particular, we investigate this scattering mechanism to derive experimental conditions for realizing an FEL in the quantum regime.

TUP054	Status of Electron Beam Slicing Project at NSLS-II, BNL	electron, radiation, storage-ring, linac	496
	A. He, F.J. Willeke, L.-H. Yu BNL, Upton, Long Island, New York, USA
	The Electron Beam Slicing (e-beam slicing) at NSLS-II, Brookhaven National Laboratory, supported by the Laboratory Directed Research and Development (LDRD) Program, is focused on the development of the new method to generate ultra-short x-ray pulses using focused short low energy (∼20 MeV) electron bunches to create short slices of electrons from the circulating electron bunches in a synchrotron radiation storage ring. The e-beam slicing activities are staged in 3 main phases. In Phases 0, the theory of e-beam slicing is developed, the low energy linac compressor is simulation designed, the radiation separation between the satellite and core is analyzed by simulation and the properties of the e-beam slicing system are discussed and compared with other ultra-short x- ray sources. Phase 0 has completed successfully, Phase 1 is under way. This paper presents an update on the status of Phase 0.

TUP097	Fast, Multi-band Photon Detectors based on Quantum Well Devices for Beam-monitoring in New Generation Light Sources	detector, laser, monitoring, electron	600
	T. Ganbold University of Trieste, School of Nanotechnology, Trieste, Italy M. Antonelli, G. Cautero, R. Cucini, D.M. Eichert, W.H. Jark, R.H. Menk Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy G. Biasiol IOM-CNR, Trieste, Italy
	In order to monitor the photon-beam position for both diagnostics and calibration purposes, we have investigated the possibility to use InGaAs/InAlAs Quantum Well (QW) devices as position-sensitive photon detectors for Free-Electron Laser (FEL) or Synchrotron Radiation (SR). Owing to their direct, low-energy band gap and high electron mobility, such QW devices may be used also at Room Temperature (RT) as fast multi-band sensors for photons ranging from visible light to hard X-rays. Moreover, internal charge-amplification mechanism can be applied for very low signal levels, while the high carrier mobility allows the design of very fast photon detectors with sub-nanosecond response times. Segmented QW sensors have been preliminary tested with 100-fs-wide UV laser pulses and X-ray SR. The reported results indicate that these devices respond with 100-ps rise-times to ultra-fast UV laser pulses. Besides, X-ray tests have shown that these detectors are sensitive to beam position and exhibit a good efficiency in the collection of photo-generated carriers.

TUC01	Hard X-ray Self-Seeding Setup and Results at SACLA	undulator, electron, FEL, radiation	603
	T. Inagaki, N. Adumi, T. Hara, T. Ishikawa, R. Kinjo, H. Maesaka, Y. Otake, H. Tanaka, T. Tanaka, K. Togawa, M. Yabashi RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan S. Goto, Y. Inubushi, T.K. Kameshima, T. Ohata, K. Tono JASRI/SPring-8, Hyogo, Japan T. Hasegawa, S. Tanaka SES, Hyogo-pref., Japan H. Kimura, A. Miura, H. Ohashi, H. Yamazaki Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), Hyogo, Japan
	In order to improve the spectral and temporal properties of XFEL, the self-seeding option based on the transmission crystal optics has been implemented in SACLA since 2012. The self-seeding setup composed of four dipole magnets that can generate up to 50 fs temporal delay and a diamond single crystal with the thickness of 180 micro-m has been installed at the position of the 9th undulator segment, which has been moved downstream. In 2013, the installation of all the components has been completed in August and the commissioning has been started in October. After a number of tuning processes such as the beam collimation and undulator K-value optimization, significant spectral narrowing has been confirmed at 10 keV with the C(400) Bragg reflection. The spectral bandwidth of seeded FEL is about 3 eV, which is nearly one order narrower than that of SASE measured without the diamond crystal. The peak spectral intensity of seeded FEL is about 5 times higher than that of SASE. Systematic optimization on beam properties is now in progress towards experimental use of seeded XFELs. This talk gives the overview of the plan, achieved results and ongoing R&D.
	Slides TUC01 [20.337 MB]

WEB03	European XFEL Construction Status	undulator, electron, laser, diagnostics	623
	W. Decking DESY, Hamburg, Germany F. Le Pimpec XFEL. EU, Hamburg, Germany
	The European XFEL is presently constructed in the Hamburg region, Germany. It aims at producing X-rays in the range from 260 eV up to 24 keV out of three undulators that can be operated simultaneously with up to 27000 pulses/second. The FEL is driven by a 17.5 GeV linear accelerator based on TESLA-type superconducting accelerator modules. This paper presents the status of major components, the present project schedule and a summary of beam parameters that are adapted to the evolving needs of the users.
	Slides WEB03 [12.982 MB]

WEB05	FLASH: First Soft X-ray FEL Operating Two Undulator Beamlines Simultaneously	electron, operation, laser, undulator	635
	K. Honkavaara, B. Faatz, J. Feldhaus, S. Schreiber, R. Treusch, M. Vogt DESY, Hamburg, Germany
	FLASH, the free electron laser user facility at DESY (Hamburg, Germany), has been upgraded with a second undulator beamline FLASH2. After a shutdown to connect FLASH2 to the FLASH linac, FLASH1 is back in user operation since February 2014. Installation of the FLASH2 electron beamline has been completed early 2014, and the first electron beam was transported into the new beamline in March 2014. The commissioning of FLASH2 takes place in 2014 parallel to FLASH1 user operation. This paper reports the status of the FLASH facility, and the first experience of operating two FEL beamlines.
	Slides WEB05 [2.481 MB]

THA01	THz Streak Camera for FELTemporal Diagnostics: Concepts and Considerations	electron, FEL, laser, free-electron-laser	640
	P.N. Juranic, R. Abela, I. Gorgisyan, C.P. Hauri, R. Ischebeck, B. Monoszlai, L. Patthey, C. Pradervand, M. Radovic, L. Rivkin, V. Schlott, A.G. Stepanov PSI, Villigen PSI, Switzerland I. Gorgisyan, C.P. Hauri, L. Rivkin EPFL, Lausanne, Switzerland R. Ivanov, P. Peier DESY, Hamburg, Germany J. Liu XFEL. EU, Hamburg, Germany B. Monoszlai University of Pecs, Pécs, Hungary K. Ogawa, T. Togashi, M. Yabashi RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan S. Owada JASRI/RIKEN, Hyogo, Japan
	The accurate, non-destructive measurements of FEL pulse length and arrival time relative to an experimental laser are necessary for operators and users alike. The FEL operators can get a better understanding of their machine and the optics of an FEL by examining the pulse length changes of the photons coming to the user stations, and the users can use the arrival time and pulse length information to better understand their data. PSI has created the pulse arrival and length monitor (PALM) based on the THz-streak camera concept for measurement at x-ray FELs, meant to be used at the upcoming SwissFEL facility. The first results from the experimental beamtime at SACLA will be presented, showcasing the accuracy and reliability of the device. Further plans for improvement and eventual integration into SwissFEL will also be presented.
	Slides THA01 [5.798 MB]

THB01	Simultaneous Measurement of Electron and Photon Pulse Duration at FLASH	electron, laser, free-electron-laser, FEL	654
	S. Düsterer DESY, Hamburg, Germany
	One of the most challenging tasks for extreme ultraviolet, soft and hard X-ray free-electron laser photon diagnostics is the precise determination of the photon pulse duration, which is typically in the sub 100 fs range. In a larger campaign nine different methods, which are able to determine such ultrashort photon pulse durations were compared at FLASH. Radiation pulses at a wavelength of 13.5 nm and 24.0 nm together with the corresponding electron bunch duration were measured by indirect methods like analyzing spectral correlations, statistical fluctuations and energy modulations of the electron bunch, and also direct methods like autocorrelation techniques, THz streaking or reflectivity changes of solid state samples.
	Slides THB01 [4.520 MB]

THP060	Design of a Spatio-temporal 3-D Ellipsoidal Photo Cathode Laser System for the High Brightness Photo Injector PITZ	laser, electron, cathode, simulation	878
	T. Rublack, J.D. Good, M. Khojoyan, M. Krasilnikov, F. Stephan DESY Zeuthen, Zeuthen, Germany A.V. Andrianov, E. Gacheva, E. Khazanov, S. Mironov, A. Poteomkin, V. Zelenogorsky IAP/RAS, Nizhny Novgorod, Russia I. Hartl, S. Schreiber DESY, Hamburg, Germany E. Syresin JINR, Dubna, Moscow Region, Russia
	Funding: German Federal Ministry of education and Research, project 05K10CHE “Development and experimental test of a laser system for producing quasi 3D ellipsoidal laser pulses” and RFBR grant 13-02-91323. Minimized emittance is crucial for improved operation of linac-based free electron lasers. Simulations have thus shown 3-D ellipsoidal photocathode laser pulses are superior to the standard Gaussian or cylindrical laser pulses in this manner. Therefore, in collaboration with the Joint Institute of Nuclear Research (JINR, Dubna, Russia) and the Photo Injector Test facility at DESY, Zeuthen (PITZ), a prototype system capable of producing spatio-temporal 3-D ellipsoidal pulses has been constructed at the Institute of Applied Physics (IAP, Nizhny Novgorod, Russia). The system consists of a dual-output, 1030 nm fiber laser coupled with disc amplifiers, a scheme based on Spatial Light Modulators for spatial and temporal pulse shaping of the primary output, a cross-correlator set up utilizing the secondary output to characterize the primary output, and finally frequency conversion to the UV. A preliminary, temporal ellipsoidal shaped IR pulse has been observed and measured so far at IAP RAS. As of writing, improvements and refinements of the system are ongoing and it is expected to replicate the finalized prototype at PITZ soon.

FRA02	Wave-Mixing Experiments with Multi-colour Seeded FEL Pulses	experiment, FEL, laser, polarization	985
	F. Bencivenga, A. Battistoni, F. Capotondi, R. Cucini, M.B. Danailov, G. De Ninno, M. Kiskinova, C. Masciovecchio Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	The extension of wave-mixing experiments in the extreme ultraviolet (EUV) and x-ray spectral range represents one of the major breakthroughs for ultrafast x-ray science. Essential prerequisites to develop such kind of non-linear coherent methods are the strength of the input fields, comparable with the atomic field one, as well as the high temporal coherence and stability of the photon source(s). These characteristics are easily achievable by optical lasers. Seeded free-electron-lasers (FELs) are similar in many respects to conventional lasers, hence calling for the development of wave-mixing methods. At the FERMI seeded FEL facility this ambitious task is tackled by the TIMER project, which includes the realization of a dedicated experimental end-station. The wave-mixing approach will be initially used to study collective atomic dynamics in disordered systems and nanostructures, through transient grating (TG) experiments. However, the wavelength and polarization tunability of FERMI, as well as the possibility to radiate multi-colour seeded FEL pulses, would allow to expand the range of possible scientific applications.
	Slides FRA02 [7.731 MB]

Paper

Title

Other Keywords

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MOA03

First Lasing at FLASH2

undulator, electron, operation, laser

7

S. Schreiber, B. Faatz
DESY, Hamburg, Germany

FLASH, the free-electron laser user facility at DESY (Hamburg, Germany), has been upgraded with a second undulator beamline FLASH2. The installation of the FLASH2 electron beamline, including twelve variable gap undulators, was finalized early 2014, and beam commissioning of the new beamline started in March 2014. We announce first lasing at FLASH2 achieved at a wavelength of 40 nm on August 20, 2014.

Slides MOA03 [3.896 MB]

MOP001

Particle Tracking Simulations for EXFEL Complex shape Collimators

electron, radiation, simulation, lattice

22

V.G. Khachatryan, V.H. Petrosyan, T.L. Vardanyan
CANDLE SRI, Yerevan, Armenia

The study sets the objective to investigate through numerical simulation the produced secondary radiation properties when the electron beam particles hit collimator walls. Using particle tracking simulation code FLUKA, the European XFEL electron beam as well as beam halo interaction with the collimator were simulated. The complex geometrical shape and material composition of the collimator have been taken into account. Absorbed dose spatial distribution in the material of the collimators and particle fluencies from the downstream surface of the collimator were simulated for the total secondary radiation and its main components.

MOP010

The Photon Beam Loss Monitors as a Part of Equipment Protection System at European XFEL

detector, vacuum, radiation, beam-transport

37

N. Gerasimova, H. Sinn
XFEL. EU, Hamburg, Germany
S. Dziarzhytski, R. Treusch
DESY, Hamburg, Germany

For the X-ray beam transport systems, the problem of potential damage to the equipment by mis-steered photon beam emerged with advent of powerful X-ray FELs. In particular high repetition rate machines as European XFEL, where not only focused beam can produce ablation, but even unfocused beam can melt the beamline components while machine operates in multibunch mode, demand for implementation of equipment protection. Here we report on development of photon beam loss monitors at European XFEL facility. The photon beam loss monitors will react on the mis-steered photon beam and interface the machine protection system. The prototype comprises the vacuum chamber with fluorescence crystals positioned outside the photon beampath. The fast sub-hundred ns fluorescence induced by mis-steered beam can be detected by photomultiplier tube allowing for intra-train reaction of machine protection system. First tests have been carried out at FLASH and shown the feasibility of detection based on PMT-detected fluorescence. In addition to efficient YAG:Ce crystal, the robust low-Z material as CVD microcrystalline diamonds has shown a potential to be used as fluorescence crystals.

MOP012

Implementation Phase of the European XFEL Photon Diagnostics

diagnostics, undulator, FEL, electron

41

J. Grünert, J. Buck, F. Dietrich, W. Freund, A. Koch, M. Planas
XFEL. EU, Hamburg, Germany

The European XFEL facility with 3 undulators and initially 6 experimental end-stations requires an extensive set of photon beam diagnostics for commissioning and user operation, capable of handling the extreme brilliance and its inherent damage potential, and the high intra bunch train repetition rate of 4.5MHz, potentially causing additional damage by high heat loads and making shot-to-shot diagnostics very demanding [1]. After extensive design [2-4] and prototype studies, in 2014 the installation of the photon beam devices starts with the equipment in the first photon tunnel XTD2 which is where the SASE1 hard X-ray undulator is located. This contribution reports on the device construction progress by focusing on the XTD2 tunnel devices and their implementation into the tunnel environment. [1] J.Grünert, Framework for X-Ray Photon Diagnostics at the European XFEL, TR-2012-003, 04/2012 [2] J.Buck, Online Photoemission Time-of-Flight Spectrometer for X-ray Photon Diagnostics, TR-2012-002, 06/2012 [3] C.Ozkan, Conceptual design report for Imaging Stations at the European XFEL, TR-2012-004, 02/2012 [4] W.Freund, The European XFEL Undulator Commissioning Spectrometer, XFEL. EU 05/2011

MOP014

X-ray Photon Temporal Diagnostics for the European XFEL

diagnostics, brilliance, electron, laser

45

J. Liu, J. Buck, F. Dietrich, W. Freund, J. Grünert, M. Meyer
XFEL. EU, Hamburg, Germany

European XFEL (XFEL. EU) that will commissioning in 2016 shows great features on its extremely high number of light bullets (27000 p/s) and extremely high average brilliance. The FEL pulses in XFEL. EU are produced in a 10 Hz bunch trains that contains 2700 sub-pulses within the 600 μs time intervals, corresponding to a 220 ns sub-pulse separation and 4.5 MHz repetition rate. Characterizing the temporal properties of the high repetition rate FEL pulses that implicitly different from shot to shot is important for “pump and probe” experiments and data interpretation. Here we report the concept and recent progress about temporal diagnostic for XFEL. EU. THz streaking technique and spectral encoding will be implemented considering the high repetition rate and high brilliance of XFEL. EU. Laser based THz generation, optimization and numerical simulation for streaking FEL electrons with different photon energies will be presented. High repetition rate diagnostic requirements and solutions will also be discussed.

MOP018

Conceptual Study of a Self-seeding Scheme at FLASH2

undulator, FEL, electron, simulation

53

T. Plath, L.L. Lazzarino
Uni HH, Hamburg, Germany
K.E. Hacker
DELTA, Dortmund, Germany

Funding: Supported by Federal Ministry of Education and Research of Germany under contract No. 05K1GU4 and 05K10PE1 and the German Research Foundation program graduate school 1355.
We present a conceptual study of a self-seeding installation at the new FEL beamline, FLASH2, at the free-electron laser at DESY, Hamburg. For self-seeding, light from a first set of undulators is filtered by a monochromator and thus acts as a seed for the gain process in the main undulator. This scheme has been tested at LCLS at SLAC with a diamond monochromator for hard X-rays and with a grating monochromator for soft X-rays covering energies between 700 and 1000 eV. For such a design to offer benefits at FLASH2, it must be modified to work with X-rays with wavelength of about 5 nm (248 eV) where the damage threshold of the monochromator in the setup and the divergence at longer wavelengths become an issue. An analysis of the potential performance and limitations of this setup is performed using GENESIS 1.3 and a method developed for the soft X-ray self-seeding experiment at the European XFEL. With a total of 9 undulators in the first stage and 8 undulators after the monochromator, a pulse energy contrast ratio of 4.5 was simulated with an initial peak current of 2.5 kA.

MOP020

Compact Spectrometer for Single Shot X-ray Emission and Photon Diagnostics

FEL, target, synchrotron, diagnostics

62

F. Frassetto, P. Miotti, L. P. Poletto
CNR-IFN, Padova, Italy
M. Coreno
CNR-IMIP, Monterotondo Stazione RM, Italy
A. Di Cicco, F. Iesari
Università di Camerino, Camerino, Italy
P. Finetti, E. Giangrisostomi, R. Mincigrucci, E. Principi
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
C. Grazioli
Universita Degli Studi di Trieste, Trieste, Italy
A. Kivimaki
IOM-CNR, Trieste, Italy
S. Stagira
CNR-IFN & Dipartimento di Fisica - Politecnico di Milano, Milano, Italy
S. Stagira
Politecnico/Milano, Milano, Italy

The design and characterization of a compact spectrometer realized for photon in-photon out experiments (in particular X-Ray Emission Spectroscopy), conceived to be used at the FERMI free-electron-laser (FEL) at ELETTRA (Italy) is here presented. The instrument can be easily installed on different end stations at variable distances from the target area both at synchrotron and FEL beamlines. Different input sections can be accommodated in order to fit the experimental requests. The design is compact in order to realize a portable instrument within an overall size of less than one square meter. The spectrometer covers the 25-800 eV spectral range, with spectral resolution better than 0.2%. The characterization on Gas Phase @ ELETTRA as instrument for XES and some experimental data of the FEL emission acquired at EIS-TIMEX @ FERMI, where the instrument has been used for photon beam diagnostics, are introduced.

MOP038

Characterization of the Undulator Magnetic Field Quality by the Angle Averaged Radiation Spectrum

undulator, radiation, electron

100

O.A. Shevchenko, N. Vinokurov
BINP SB RAS, Novosibirsk, Russia
N. Vinokurov
KAERI, Daejon, Republic of Korea

The real undulator magnetic field always contains errors which influence undulator performance. The effect of these errors is usually characterized by broadening of the spontaneous emission spectrum at zero angle and corresponding reduction of the spectral intensity. This approach works very well for the phase errors while it does not take into account transversal trajectory displacements. The integrated over the angles radiation spectrum contains more complete information about the undulator field quality but its calculation requires more effort. Therefore the spectral density of emitted radiation (the total number of emitted photons with given energy) can be considered as a figure of merit for an undulator. In this paper we derive analytical formula for this spectrum suitable for doing efficient numerical calculations and demonstrate its application to the case of some typical undulator field errors.

MOP040

General Strategy for the Commissioning of the ARAMIS Undulators with a 3 GeV Electron Beam

undulator, electron, alignment, quadrupole

107

M. Calvi, M. Aiba, M. Brügger, S. Danner, R. Ganter, R. Ischebeck, L. Patthey, T. Schietinger, T. Schmidt
PSI, Villigen PSI, Switzerland

The commissioning of the first SwissFEL undulator line (Aramis) is planned for the beginning of 2017. Each undulator is equipped with a 5-axis camshaft system to remotely adjust its position in the micrometer range and a gap drive system to set K-values between 0.1 and 1.8. In the following paper the beam-based alignment of the undulator with respect to the golden orbit, the definition of look-up tables for the local correction strategy (minimization of undulator field errors), the fine-tuning of the K-values as well as the setting of the phase shifters are addressed. When applicable both electron beam and light based methods are presented and compared.

MOP041

Summary of the U15 Prototype Magnetic Performance

undulator, vacuum, electron, quadrupole

111

M. Calvi, M. Aiba, M. Brügger, S. Danner, R. Ganter, C. Ozkan, T. Schmidt
PSI, Villigen PSI, Switzerland

The first undulator prototype (U15) was assembled and magnetically tested. The instrumentation and the algorithms developed for the undulator optimization are presented and a comparison among different approaches is reviewed. The magnetic measurement results before and after the installation of the vacuum components are discussed. The summary of the undulator test with 100 MeV electron beam is presented and the impact of the radiation on the magnetics is addressed.

MOP054

Harmonic Lasing Options for LCLS-II

undulator, electron, radiation, FEL

148

G. Marcus, Y. Ding, Z. Huang, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
G. Penn
LBNL, Berkeley, California, USA

Harmonic lasing can be a cheap and relatively efficient way to extend the photon energy range of a particular FEL beamline. Furthermore, in comparison to nonlinear harmonics, harmonic lasing can provide a beam that is more intense, stable, and narrow-band. This paper explores the application of the harmonic lasing concept at LCLS-II using various combinations of phase shifters and attenuators. In addition, a scheme by which individual undulator modules are tuned to amplify either the third or fifth harmonic in different configurations is presented in detail.

MOP056

SASE Characteristics from Baseline European XFEL Undulators in the Tapering Regime

electron, undulator, radiation, FEL

159

I.V. Agapov, G. Geloni
XFEL. EU, Hamburg, Germany
G. Feng, V. Kocharyan, E. Saldin, S. Serkez, I. Zagorodnov
DESY, Hamburg, Germany

The output SASE characteristics of the baseline European XFEL, recently used in the TDRs of scientific instruments and X-ray optics, have been previously optimized assuming uniform undulators without considering the potential of undulator tapering in the SASE regime. Here we demonstrate that the performance of European XFEL sources can be significantly improved without additional hardware. The procedure consists in the optimization of the undulator gap configuration for each X-ray beamline. Here we provide a comprehensive description of the X-ray photon beam properties as a function of wavelength and bunch charge. Based on nominal parameters for the electron beam, we demonstrate that undulator tapering allows one to achieve up to a tenfold increase in peak power and photon spectral density in the conventional SASE regime.

MOP068

Suppression of the Fundamental Frequency for a Successful Harmonic Lasing in SASE FELs

undulator, FEL, electron, simulation

215

E. Schneidmiller, M.V. Yurkov
DESY, Hamburg, Germany

Harmonic lasing in X-ray FELs has recently attracted a significant attention and is now seriously considered as a potential method for generation of brilliant photon beams at short wavelengths. It is clear, however, that for a successful harmonic lasing one has to suppress the fundamental. In this paper we discuss different methods for such a suppression: phase shifters, intraundulator spectral filtering, switching between the 3rd and the 5th harmonics etc.

MOP082

Perspectives for Imaging Single Protein Molecules with the Present Design of the European XFEL

electron, laser, free-electron-laser, FEL

238

G. Geloni
XFEL. EU, Hamburg, Germany
V. Kocharyan, E. Saldin, S. Serkez, I. Zagorodnov
DESY, Hamburg, Germany
O. Yefanov
CFEL, Hamburg, Germany

European XFEL aims to support imaging and structure determination of biological specimens between less than 0.1 microns and 1 micron size with working photon energies between 3 keV and 16 keV. This wide operation range is a cause for challenges to the focusing optics. A long propagation distance of about 900 m between x-ray source and sample leads to a large lateral photon beam size at the optics. Due to the large divergence of nominal X-ray pulses with durations shorter than 10 fs, one suffers diffraction from mirror apertures, leading to a 100-fold decrease in fluence at photon energies around 4 keV, which seem ideal for imaging of single biomolecules. Moreover, the nominal SASE1 is very far from the level required for single particle imaging. Here we show how it may be possible to optimize the SPB instrument for single biomolecule imaging with minimal additional costs and time, achieving diffraction without destruction at near-atomic resolution with 10¹³ photons in a 4 fs pulse at 4 keV photon energy and in a 100 nm focus, corresponding to a fluence of 10²³ ph/cm². This result is exemplified using the RNA Pol II molecule as a case study.

MOP092

X-ray Monochromators for Self-seeding XFELs in the Photon Energy Range Starting from 1.5 keV

FEL, scattering, electron, radiation

269

Yu. Shvyd'ko
ANL, Argonne, Ilinois, USA

Self-seeding of XFELs below 1 keV can be performed using grating monochromators [1]. Forward-Bragg diffraction (wake) monochromators [2] were instrumental for achieving self-seeding in hard x-ray FELs in the photon energy range from 5 to 10 keV [3]. Large photo-absorption makes extension into the lower photon range difficult. Here alternative schemes of x-ray monochromators are introduced and discussed for achieving self-seeding in a yet inaccessible spectral range starting from 1.5 keV.
[1] J. Feldhaus, et al., Opt. Commun. 140, 341 (1997).
[2]. G. Geloni, V. Kocharyan, and E. Saldin, J. Mod. Opt. 58, 1391 (2011).
[3] J. Amann, et al., Nat. Photonics 6, 693 (2012).

TUP002

Characterization of Partially Coherent Ultrashort FEL Pulses

FEL, laser, electron, free-electron-laser

346

C. Bourassin-Bouchet, M.-E. Couprie
SOLEIL, Gif-sur-Yvette, France
C. Evain
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France

Temporal metrology is a major need for free-electron lasers. However, the lack of longitudinal coherence, that is shot-to-shot fluctuations, of these sources has prevented so far the full amplitude and phase temporal characterization of FEL pulses. To sort out this issue, we propose a solution inspired from attosecond metrology, where XUV pulse measurement techniques already exist, and from coherent diffraction imaging, where numerical solutions have been developed for processing partially coherent diffraction patterns. The experimental protocole implies the measurement of photoelectron spectra obtained through XUV-laser photoionisation. The spectra are then processed with an algorithm in order to retrieve the partially coherent FEL pulse. When applied to SASE FELs, the technique gives access to the full statistics of the emitted pulses. With seeded-FELs, the pulse shape becomes stable from shot-to-shot, but an XUV-laser time jitter remains. In that case, the technique enables the joint measurement of the FEL pulse shape (in amplitude and phase) and of the laser/FEL jitter envelope. The concept has been validated with numerical simulations in the context of the LUNEX5 FEL project.

TUP003

Quantum FEL II: Many-electron Theory

electron, FEL, laser, resonance

348

P. Kling, R. Sauerbrey
HZDR, Dresden, Germany
R. Endrich, E.A. Giese, W.P. Schleich
Uni Ulm, Ulm, Germany

We investigate the emergence of the quantum regime of the FEL when many electrons interact simultaneously with the wiggler and the laser field. We find the Quantum FEL as the limit where only two momentum states are populated by the electrons. Moreover, we obtain exponential gain-per-pass and start-up from vacuum.

TUP004

Quantum FEL I: Multi-mode Theory

electron, resonance, coupling, FEL

353

R. Endrich, E.A. Giese, W.P. Schleich
Uni Ulm, Ulm, Germany
P. Kling, R. Sauerbrey
HZDR, Dresden, Germany

The quantum regime of the FEL in a single-mode, single-particle approximation is characterized by a two-level behaviour of the center-of-mass motion of the electrons. We extend this model to include all modes of the radiation field and analyze the effect of spontaneous emission. In particular, we investigate this scattering mechanism to derive experimental conditions for realizing an FEL in the quantum regime.

TUP054

Status of Electron Beam Slicing Project at NSLS-II, BNL

electron, radiation, storage-ring, linac

496

A. He, F.J. Willeke, L.-H. Yu
BNL, Upton, Long Island, New York, USA

The Electron Beam Slicing (e-beam slicing) at NSLS-II, Brookhaven National Laboratory, supported by the Laboratory Directed Research and Development (LDRD) Program, is focused on the development of the new method to generate ultra-short x-ray pulses using focused short low energy (∼20 MeV) electron bunches to create short slices of electrons from the circulating electron bunches in a synchrotron radiation storage ring. The e-beam slicing activities are staged in 3 main phases. In Phases 0, the theory of e-beam slicing is developed, the low energy linac compressor is simulation designed, the radiation separation between the satellite and core is analyzed by simulation and the properties of the e-beam slicing system are discussed and compared with other ultra-short x- ray sources. Phase 0 has completed successfully, Phase 1 is under way. This paper presents an update on the status of Phase 0.

TUP097

Fast, Multi-band Photon Detectors based on Quantum Well Devices for Beam-monitoring in New Generation Light Sources

detector, laser, monitoring, electron

600

T. Ganbold
University of Trieste, School of Nanotechnology, Trieste, Italy
M. Antonelli, G. Cautero, R. Cucini, D.M. Eichert, W.H. Jark, R.H. Menk
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
G. Biasiol
IOM-CNR, Trieste, Italy

In order to monitor the photon-beam position for both diagnostics and calibration purposes, we have investigated the possibility to use InGaAs/InAlAs Quantum Well (QW) devices as position-sensitive photon detectors for Free-Electron Laser (FEL) or Synchrotron Radiation (SR). Owing to their direct, low-energy band gap and high electron mobility, such QW devices may be used also at Room Temperature (RT) as fast multi-band sensors for photons ranging from visible light to hard X-rays. Moreover, internal charge-amplification mechanism can be applied for very low signal levels, while the high carrier mobility allows the design of very fast photon detectors with sub-nanosecond response times. Segmented QW sensors have been preliminary tested with 100-fs-wide UV laser pulses and X-ray SR. The reported results indicate that these devices respond with 100-ps rise-times to ultra-fast UV laser pulses. Besides, X-ray tests have shown that these detectors are sensitive to beam position and exhibit a good efficiency in the collection of photo-generated carriers.

TUC01

Hard X-ray Self-Seeding Setup and Results at SACLA

undulator, electron, FEL, radiation

603

T. Inagaki, N. Adumi, T. Hara, T. Ishikawa, R. Kinjo, H. Maesaka, Y. Otake, H. Tanaka, T. Tanaka, K. Togawa, M. Yabashi
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
S. Goto, Y. Inubushi, T.K. Kameshima, T. Ohata, K. Tono
JASRI/SPring-8, Hyogo, Japan
T. Hasegawa, S. Tanaka
SES, Hyogo-pref., Japan
H. Kimura, A. Miura, H. Ohashi, H. Yamazaki
Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), Hyogo, Japan

In order to improve the spectral and temporal properties of XFEL, the self-seeding option based on the transmission crystal optics has been implemented in SACLA since 2012. The self-seeding setup composed of four dipole magnets that can generate up to 50 fs temporal delay and a diamond single crystal with the thickness of 180 micro-m has been installed at the position of the 9th undulator segment, which has been moved downstream. In 2013, the installation of all the components has been completed in August and the commissioning has been started in October. After a number of tuning processes such as the beam collimation and undulator K-value optimization, significant spectral narrowing has been confirmed at 10 keV with the C(400) Bragg reflection. The spectral bandwidth of seeded FEL is about 3 eV, which is nearly one order narrower than that of SASE measured without the diamond crystal. The peak spectral intensity of seeded FEL is about 5 times higher than that of SASE. Systematic optimization on beam properties is now in progress towards experimental use of seeded XFELs. This talk gives the overview of the plan, achieved results and ongoing R&D.

Slides TUC01 [20.337 MB]

WEB03

European XFEL Construction Status

undulator, electron, laser, diagnostics

623

W. Decking
DESY, Hamburg, Germany
F. Le Pimpec
XFEL. EU, Hamburg, Germany

The European XFEL is presently constructed in the Hamburg region, Germany. It aims at producing X-rays in the range from 260 eV up to 24 keV out of three undulators that can be operated simultaneously with up to 27000 pulses/second. The FEL is driven by a 17.5 GeV linear accelerator based on TESLA-type superconducting accelerator modules. This paper presents the status of major components, the present project schedule and a summary of beam parameters that are adapted to the evolving needs of the users.

Slides WEB03 [12.982 MB]

WEB05

FLASH: First Soft X-ray FEL Operating Two Undulator Beamlines Simultaneously

electron, operation, laser, undulator

635

K. Honkavaara, B. Faatz, J. Feldhaus, S. Schreiber, R. Treusch, M. Vogt
DESY, Hamburg, Germany

FLASH, the free electron laser user facility at DESY (Hamburg, Germany), has been upgraded with a second undulator beamline FLASH2. After a shutdown to connect FLASH2 to the FLASH linac, FLASH1 is back in user operation since February 2014. Installation of the FLASH2 electron beamline has been completed early 2014, and the first electron beam was transported into the new beamline in March 2014. The commissioning of FLASH2 takes place in 2014 parallel to FLASH1 user operation. This paper reports the status of the FLASH facility, and the first experience of operating two FEL beamlines.

Slides WEB05 [2.481 MB]

THA01

THz Streak Camera for FELTemporal Diagnostics: Concepts and Considerations

electron, FEL, laser, free-electron-laser

640

P.N. Juranic, R. Abela, I. Gorgisyan, C.P. Hauri, R. Ischebeck, B. Monoszlai, L. Patthey, C. Pradervand, M. Radovic, L. Rivkin, V. Schlott, A.G. Stepanov
PSI, Villigen PSI, Switzerland
I. Gorgisyan, C.P. Hauri, L. Rivkin
EPFL, Lausanne, Switzerland
R. Ivanov, P. Peier
DESY, Hamburg, Germany
J. Liu
XFEL. EU, Hamburg, Germany
B. Monoszlai
University of Pecs, Pécs, Hungary
K. Ogawa, T. Togashi, M. Yabashi
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
S. Owada
JASRI/RIKEN, Hyogo, Japan

The accurate, non-destructive measurements of FEL pulse length and arrival time relative to an experimental laser are necessary for operators and users alike. The FEL operators can get a better understanding of their machine and the optics of an FEL by examining the pulse length changes of the photons coming to the user stations, and the users can use the arrival time and pulse length information to better understand their data. PSI has created the pulse arrival and length monitor (PALM) based on the THz-streak camera concept for measurement at x-ray FELs, meant to be used at the upcoming SwissFEL facility. The first results from the experimental beamtime at SACLA will be presented, showcasing the accuracy and reliability of the device. Further plans for improvement and eventual integration into SwissFEL will also be presented.

Slides THA01 [5.798 MB]

THB01

Simultaneous Measurement of Electron and Photon Pulse Duration at FLASH

electron, laser, free-electron-laser, FEL

654

S. Düsterer
DESY, Hamburg, Germany

One of the most challenging tasks for extreme ultraviolet, soft and hard X-ray free-electron laser photon diagnostics is the precise determination of the photon pulse duration, which is typically in the sub 100 fs range. In a larger campaign nine different methods, which are able to determine such ultrashort photon pulse durations were compared at FLASH. Radiation pulses at a wavelength of 13.5 nm and 24.0 nm together with the corresponding electron bunch duration were measured by indirect methods like analyzing spectral correlations, statistical fluctuations and energy modulations of the electron bunch, and also direct methods like autocorrelation techniques, THz streaking or reflectivity changes of solid state samples.

Slides THB01 [4.520 MB]

THP060

Design of a Spatio-temporal 3-D Ellipsoidal Photo Cathode Laser System for the High Brightness Photo Injector PITZ

laser, electron, cathode, simulation

878

T. Rublack, J.D. Good, M. Khojoyan, M. Krasilnikov, F. Stephan
DESY Zeuthen, Zeuthen, Germany
A.V. Andrianov, E. Gacheva, E. Khazanov, S. Mironov, A. Poteomkin, V. Zelenogorsky
IAP/RAS, Nizhny Novgorod, Russia
I. Hartl, S. Schreiber
DESY, Hamburg, Germany
E. Syresin
JINR, Dubna, Moscow Region, Russia

Funding: German Federal Ministry of education and Research, project 05K10CHE “Development and experimental test of a laser system for producing quasi 3D ellipsoidal laser pulses” and RFBR grant 13-02-91323.
Minimized emittance is crucial for improved operation of linac-based free electron lasers. Simulations have thus shown 3-D ellipsoidal photocathode laser pulses are superior to the standard Gaussian or cylindrical laser pulses in this manner. Therefore, in collaboration with the Joint Institute of Nuclear Research (JINR, Dubna, Russia) and the Photo Injector Test facility at DESY, Zeuthen (PITZ), a prototype system capable of producing spatio-temporal 3-D ellipsoidal pulses has been constructed at the Institute of Applied Physics (IAP, Nizhny Novgorod, Russia). The system consists of a dual-output, 1030 nm fiber laser coupled with disc amplifiers, a scheme based on Spatial Light Modulators for spatial and temporal pulse shaping of the primary output, a cross-correlator set up utilizing the secondary output to characterize the primary output, and finally frequency conversion to the UV. A preliminary, temporal ellipsoidal shaped IR pulse has been observed and measured so far at IAP RAS. As of writing, improvements and refinements of the system are ongoing and it is expected to replicate the finalized prototype at PITZ soon.

FRA02

Wave-Mixing Experiments with Multi-colour Seeded FEL Pulses

experiment, FEL, laser, polarization

985

F. Bencivenga, A. Battistoni, F. Capotondi, R. Cucini, M.B. Danailov, G. De Ninno, M. Kiskinova, C. Masciovecchio
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The extension of wave-mixing experiments in the extreme ultraviolet (EUV) and x-ray spectral range represents one of the major breakthroughs for ultrafast x-ray science. Essential prerequisites to develop such kind of non-linear coherent methods are the strength of the input fields, comparable with the atomic field one, as well as the high temporal coherence and stability of the photon source(s). These characteristics are easily achievable by optical lasers. Seeded free-electron-lasers (FELs) are similar in many respects to conventional lasers, hence calling for the development of wave-mixing methods. At the FERMI seeded FEL facility this ambitious task is tackled by the TIMER project, which includes the realization of a dedicated experimental end-station. The wave-mixing approach will be initially used to study collective atomic dynamics in disordered systems and nanostructures, through transient grating (TG) experiments. However, the wavelength and polarization tunability of FERMI, as well as the possibility to radiate multi-colour seeded FEL pulses, would allow to expand the range of possible scientific applications.

Slides FRA02 [7.731 MB]