Keyword: FEL
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MOPOB32 Design and Test of the Prototype Tuner for 3.9 GHz SRF Cavity for LCLS II Project cavity, ion, SRF, cryomodule 140
 
  • Y.M. Pischalnikov, E. Borissov, J.C. Yun
    Fermilab, Batavia, Illinois, USA
 
  Fermilab is responsible for the design of the 3.9GHz cryomodule for the LCLS-II that will operate in continuous wave (CW) mode. Bandwidth of the SRF cavities will be in the range of the 180Hz. In our tuner design, we adopted as the slow tuner-mechanism slim blade tuner originated by INFN for the European XFEL 3.9GHz. At the same time bandwidth of the SRF cavities for LCLS II will be in the range of the 180Hz and fine/fast tuning of the cavity frequency required. We added to the design fast/fine tuner made with 2 encapsulated piezos. First prototype tuner has been built and went through testing at warm conditions. Details of the design and summary of the tests will be presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB32  
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TUB1CO02 Operating Synchrotron Light Sources with a High Gain Free Electron Laser ion, undulator, electron, emittance 259
 
  • S. Di Mitri, M. Cornacchia
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  The peak current required by a high gain free electron laser (FEL) is not deemed to be compatible with the multi-bunch filling pattern of synchrotrons. We show that this problem can be overcome by virtue of magnetic bunch length compression in a ring section and that, after lasing, the beam returns to equilibrium conditions without beam quality disruption*. As a consequence of bunch length compression, the peak current stimulates a high gain FEL emission, while the large energy spread makes the beam less sensitive to the FEL heating and to the microwave instability. The beam large energy spread is matched to the FEL energy bandwidth through a transverse gradient undulator. Feasibility of lasing at 25 nm is shown for the Elettra synchrotron light source (SLS) at 1 GeV. Viable scenarios for the upgrade of existing or planned SLSs to the new hybrid insertion devices-plus-FEL operational mode are discussed, while ensuring little impact on the standard beamlines functionality.
* S. Di Mitri and M. Cornacchia, NJP 17 (2015) 113006
 
slides icon Slides TUB1CO02 [2.353 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB1CO02  
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TUB2IO02 Advanced Concepts for Seeded FELs ion, electron, controls, laser 284
 
  • E. Ferrari, E. Allaria
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  The use of an external laser to seed an electron beam at the beginning of the Free Electron Laser process has been proposed as a way to improve temporal coherence of modern short wavelength FELs. More recent studies and experiments have shown that electron beam manipulation through interaction with a seed laser can be exploited for tailoring FEL properties to specific users requests. Recently, experiment for phase control, multi-color emission and coherent control have been reported.  
slides icon Slides TUB2IO02 [15.975 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB2IO02  
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TUB2CO04 Corrugated Structure Insertion to Extend SASE Bandwidth Up to 3% at the European XFEL ion, radiation, undulator, electron 293
 
  • I. Zagorodnov, G. Feng, T. Limberg
    DESY, Hamburg, Germany
 
  The usage of x-ray free electron laser (XFEL) in femtosecond nanocrystallography involves sequential illumination of many small crystals of arbitrary orientation. Hence a wide radiation bandwidth could be useful in order to obtain and to index a larger number of Bragg peaks used for determination of crystal orientation. Considering the baseline configuration of the European XFEL in Hamburg, and based on beam dynamics simulations, we demonstrate here that usage of corrugated structures allows for a considerable increase in radiation bandwidth. It allows for data collection with a 3% bandwidth, a few micrjoule radiation pulse energy, a few fs pulse duration, and a photon energy 4.1 keV.  
slides icon Slides TUB2CO04 [5.848 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB2CO04  
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TUB3CO03 Demonstration of fresh slice self seeding in a hard X-ray free electron laser ion, electron, experiment, simulation 450
 
  • C. Emma, C. Pellegrini
    UCLA, Los Angeles, USA
  • M.W. Guetg, A.A. Lutman, A. Marinelli, J. Wu
    SLAC, Menlo Park, California, USA
 
  We discuss the first demonstration of fresh slice self seeding (FSSS) in a hard X-ray Free Electron Laser (XFEL). The FSSS method utilizes a single electron beam to generate a strong seed pulse and amplify it with a small energy spread electron slice. This extends the capability of self seeded XFELs by producing short pulses, not limited by the duration set by the self-seeding monochromator system, with high peak intensity. The scheme relies on using a parallel plate dechirper to impart a spatial chirp on the beam, and appropriate orbit control to lase with different electron beam slices before and after the self-seeding monochromator. The performance of the FSSS method is analyzed with start-to-end simulations for the Linac Coherent Light Source (LCLS). The simulations include the effect of the parallel plate dechirper and propagation of the radiation field through the monochromator. We also present results of the first successful demonstration of FSSS at LCLS. The radiation properties of FSSS X-ray pulses are compared with the Self-Amplified Spontaneous Emission (SASE) mode of FEL operation for the same electron beam parameters.  
slides icon Slides TUB3CO03 [10.423 MB]  
poster icon Poster TUB3CO03 [3.275 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB3CO03  
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TUB4IO01 Status of the Los Alamos Multi-Probe Facility for Matter-Radiation Interactions in Extremes ion, electron, experiment, linac 464
 
  • J.L. Erickson, R.W. Garnett
    LANL, Los Alamos, New Mexico, USA
 
  The Matter-Radiation Interactions in Extremes (MaRIE) project will provide capability that will address the control of performance and production of materials at the mesoscale. MaRIE will characterize the behavior of interfaces, defects, and microstructure between the spatial scales of atomic structures and those of the engineering continuum where there is a current capability gap. The mission need is well-met with an x-ray source, coherent to optimize disordered imaging capability, brilliant and high-rep-rate to provide time-dependent information, and high enough energy to see into and through the mesoscale of materials of interest. It will be designed for time-dependence from electronic motion (picosecond) through sound waves (nanosecond) through thermal diffusion (millisecond) to manufacturing (seconds and above). The mission need, the requirements, a plausible alternative reference design of a 12-GeV linac-based 42-keV x-ray free-electron laser, and the status of the project will be described.  
slides icon Slides TUB4IO01 [16.013 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB4IO01  
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TUB4IO02 Accelerator Technical Progress and First Commissioning Results from the European XFEL ion, linac, MMI, electron 469
 
  • R. Wichmann
    DESY, Hamburg, Germany
 
  The construction of the European XFEL is coming to an end. The linac tunnel will be closed and commissioning of the main linac will start. The status of the construction project is reviewed. Commissioning of the injector of the European XFEL was already performed in 2016 while construction of the main linac was continuing. The commissioning goals and achievements for the XFEL injector will be reviewed.
Proposed Speaker: W. Decking, DESY
 
slides icon Slides TUB4IO02 [13.428 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB4IO02  
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TUPOB19 FEL Wiggler Bussbar Field Compensation ion, wiggler, storage-ring, electron 532
 
  • B. Li, H. Hao, Y.K. Wu
    FEL/Duke University, Durham, North Carolina, USA
  • J.Y. Li
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  Abstract The Duke storage ring is a dedicated driver for the storage ring based free-electron laser (FEL) and the High Intensity Gamma-ray Source (HIGS). The high intensity gamma-ray beam is produced using Compton scattering between the electron and FEL photon beams. The beam displacement and angle at the collision point need to be maintained constant during the gamma-ray beam production. The magnetic field of the copper bussbars carrying the current to the FEL wigglers can impact the beam orbit. The compensation scheme in-general is complicated. In this work, we report preliminary results of a bussbar compensation scheme for one of the wiggler and power supply configurations. Significant reductions of the orbit distortions have been realized using this compensation.  
poster icon Poster TUPOB19 [3.693 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB19  
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WEA3IO02 Start-to-End Beam Dynamics Optimization of X-Ray FEL Light Source Accelerators ion, linac, controls, electron 838
 
  • J. Qiang
    LBNL, Berkeley, California, USA
 
  State-of-the-art tools have been developed that allow start-to-end modeling of the beam formation at the cathode, to its transport, acceleration, and delivery to the undulator. Algorithms are based on first principles, enabling the capture of detailed physics such as shot-noise driven micro-bunching instabilities. The most recent generation of the IMPACT code, using multi-level parallelization on massively parallel supercomputers, now enables multi-objective parametric optimization. This is facilitated by recent advances such as the unified differential evolution algorithm*. The most recent developments will be described, together with applications to the modeling of LCLS-II**.
*J. Qiang, et al, http://www.optimization-online.org/DBFILE/2015/03/4796.pdf, submitted
**J. Qiang, et al, in preparation
 
slides icon Slides WEA3IO02 [10.928 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEA3IO02  
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WEPOB23 Performance of the Full-Length Vertical Polarizing Undulator Prototype for LCLS-II ion, undulator, operation, electron 946
 
  • N.O. Strelnikov, E. Gluskin, I. Vasserman, J.Z. Xu
    ANL, Argonne, Illinois, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
As part of the LCLS-II R&D program, a novel 3.4-meter long undulator prototype with horizontal main magnetic field and dynamic force compensation - called the horizontal gap vertical polarization undulator (HGVPU) - has recently been developed at the Advanced Photon Source (APS). Initial steps of the project included designing, building, and a testing 0.8-meter long prototype. Extensive mechanical testing of the HGVPU has been carried out. The magnetic tuning was accomplished by applying a set of magnetic shims. As a result, the performance of the HGVPU meets all the stringent requirements for the LCLS-II insertion device, which includes limits on the field integrals and phase errors for all operational gaps, as well as the reproducibility and accuracy of the gap settings. The HGVPU has been included in the baseline of the LCLS-II project for the hard x-ray undulator line.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB23  
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WEPOB27 Modification of 3rd Harmonic Cavity for CW Operation in LCLS-II Accelerator ion, HOM, cavity, linac 960
 
  • T.N. Khabiboulline, M.H. Awida, I.V. Gonin, A. Lunin, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
 
  A 3.9 GHz 3rd harmonic cavity was developed at FNAL and it is currently used in the FLASH accelerator at DESY in order to improve FEL operation. The European XFEL accelerator in Hamburg also adapted the same cavity design for a pulsed linac operation. The 3rd harmonic cavity for the LCLS-II accelerator at SLAC will operate in a continuous wave (CW) regime. A CW operation and a high average current in the LCLS-II linac result in in-creased heat loads to main and HOM couplers of the cavity. Several cavity design modifications were pro-posed and investigated for improving a cavity perfor-mance in the CW regime. In this paper we present results of the design review for proposed modifications  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB27  
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WEPOB32 Performance of a Combined System Using an X-Ray FEL Oscillator and a High-Gain FEL Amplifier ion, radiation, simulation, laser 974
 
  • L. Gupta
    University of Chicago, Chicago, Illinois, USA
  • K.-J. Kim, R.R. Lindberg
    ANL, Argonne, Illinois, USA
 
  Funding: [5] R. R. Lindberg, K.-J. Kim, "Intense, coherent x-rays at 40 keV or higher by combining an XFELO and a high-gain harmonic generation," (in prep) US DOE contract DE-AC02-06CH11357 & NSF PHY-1535639
The LCLS-II at SLAC will feature a 4 GeV CW superconducting (SC) RF linac [1] that can potentially drive a 5th harmonic X-Ray FEL Oscillator to produce fully coherent, 1 MW photon pulses with a 5 meV bandwidth at 14.4 keV [2]. The XFELO output can serve as the input seed signal for a high-gain FEL amplifier employing fs electron beams from the normal conducting SLAC linac, thereby generating coherent, fs x-ray pulses with ~TW peak powers using a tapered undulator after saturation [3]. Coherent, intense output at several tens of keV will also be feasible if one considers a harmonic generation scheme. Thus, one can potentially reach the 42 keV photon energy required for the MaRIE project [4] by beginning with an XFELO operating at the 5th harmonic to produce 8.4 keV photons using a 3.1 GeV SCRF linac, and then subsequently using the high-gain harmonic generation scheme to generate and amplify the 5th harmonic at 42 keV [5]. We report extensive GINGER simulations that determine an optimized parameter set for the combined system. [1] "Linac Coherent Light Source-II Conceptual Design Report," SLAC-R-978 (2011)
[2] T. J. Maxwell, et al., "Feasibility Study for an X-Ray FEL Oscillator at the LCLS-II," IPAC, Richmond, VA (May, 2015)
[3] K.-J. Kim, et al., IPAC 2016
[4] http://www.lanl.gov
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB32  
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WEPOB39 Photo-Injector Optimization and Validation Study with the OPAL Beam Simulation Code ion, emittance, simulation, booster 984
 
  • L.D. Duffy, K. Bishofberger, J.W. Lewellen, S.J. Russell, D.Y. Shchegolkov
    LANL, Los Alamos, New Mexico, USA
 
  A 42 keV x-ray free electron laser (XFEL) is a plausible technology alternative for the Matter Radiation Interactions in Extremes (MaRIE) experimental project, a concept developed by Los Alamos National Laboratory. An early pre-conceptual design for such an XFEL calls for 100 pC electron bunches with very low emittance and energy spread. High fidelity simulations that capture all beamline physics will be required to ensure a successful design. We expect to use the beam simulation code OPAL as one of the tools in this process. In this study, we validate OPAL as a photo-injector design tool by comparing its performance with published PITZ experimental data and simulations.  
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THPOA37 Study of 2D CSR Effects in a Compression Chicane ion, simulation, dipole, electron 1181
 
  • C.C. Hall
    RadiaSoft LLC, Boulder, Colorado, USA
  • S. Biedron, S.V. Milton
    CSU, Fort Collins, Colorado, USA
 
  The study of coherent synchrotron radiation (CSR) has been an area of great interest because of its negative impact on FEL performance. The modeling of CSR is frequently performed using a 1D approximation*, as 2D and 3D models can become extremely computational intensive. While experimental evidence is lacking in this area most studies show reasonable agreement between 1D and 2D CSR models for beam parameters in existing accelerators. In this work we focus on 2D modeling of CSR in a four­-dipole chicane lattice based on the Jefferson Lab FEL. Comparison is shown between several models and measurement for energy loss due to CSR in the chicane. While good agreement is generally observed we also present investigation of several key differences observed in simulation. In particular, showing how the 1D and 2D CSR models deviate in regards to CSR and beam interaction within the drift spaces of the chicane and the downstream drift at the chicane end.
*E. Saldin, E. Schneidmiller, and M. Yurkov, Nucl. Instr. Meth. A398, 373 (1997).
 
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FRA1CO03 An Ultra-High Resolution Pulsed-Wire Magnet Measurement System ion, undulator, radiation, experiment 1268
 
  • A. D'Audney, S. Biedron, S.V. Milton
    CSU, Fort Collins, Colorado, USA
 
  The performance of a Free-Electron Laser (FEL) depends in part on the quality of the magnetic field in the undulator. Imperfections in the magnetic field of an undulator lead to an imperfect electron trajectory, both offset and angle, as well as a relative phase error between the oscillation phase of the electrons and the generated electromagnetic field. The result of such errors is a reduction of laser gain impacting overall FEL performance. A pulsed-wire method can be used to determine the profile of the magnetic field. This is achieved by sending a square-current pulse through a wire placed along the length of the axis that will induce a Lorentz-force interaction with the magnetic field. Measurement of the resulting displacement in the wire over time using a motion detector yields the first or second integrals of the magnetic field and so provides a measure of the local magnetic field strength. Dispersion in the wire can be corrected using algorithms, with a resulting increase in overall accuracy of the measurement. We have designed, constructed and tested a pulsed-wire magnetic measurement system and used this system to characterize the CSU FEL undulator.  
slides icon Slides FRA1CO03 [4.318 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-FRA1CO03  
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