Keyword: laser
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MOA4IO01 Performance of the Low Charge State Laser Ion Source in BNL ion, target, plasma, ion-source 49
 
  • M. Okamura, J.G. Alessi, E.N. Beebe, M.R. Costanzo, L. DeSanto, S. Ikeda, J.P. Jamilkowski, T. Kanesue, R.F. Lambiase, D. Lehn, C.J. Liaw, D.R. McCafferty, J. Morris, R.H. Olsen, A.I. Pikin, R. Schoepfer, A.N. Steszyn
    BNL, Upton, Long Island, New York, USA
  
  In March 2014, a Laser Ion Source (LIS) was commissioned which delivers high brightness low charge state heavy ions for the hadron accelerator complex in Brookhaven National Laboratory (BNL). Since then, the LIS has provided many heavy ion species successfully. The induced low charge state (mostly singly charged) beams are injected to the Electron Beam Ion Source (EBIS) where ions are then highly ionized to fit to the following accelerator's Q/M acceptance, like Au32+. Last year, we upgraded the LIS to be able to provide two different beams into EBIS on a pulse-to- pulse basis. Now the LIS is simultaneously providing beams for both the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory (NSRL). In the conference we present achieved performance and developed new techniques of the LIS.  
slides icon Slides MOA4IO01 [7.796 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOA4IO01  
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MOPOB08 Streak Camera Measurements of the APS PC Gun Drive Laser ion, factory, gun, optics 85
 
  • J.C. Dooling
    ANL, Argonne, Illinois, USA
  • A.H. Lumpkin
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357.
We report recent pulse-duration measurements of the APS PC Gun drive laser at both second harmonic (SH, 527 nm) and fourth harmonic (FH. 263 nm) wavelengths. The drive laser is a Nd:Glass-based CPA with the IR wavelength (1053 nm) twice doubled to obtain UV output for the gun. A Hamamatsu C5680 streak camera and an M5675 synchroscan unit are used for these measurements; the synchroscan unit is tuned to 119 MHz, the 24th subharmonic of the linac operating frequency. Calibration is accomplished both electronically and optically. Electronic calibration utilizes a programmable delay line in the 119 MHz rf path. The optical delay employs an etalon with known spacing between reflecting surfaces; this etalon is coated for the visible, SH wavelength. IR pulse duration is monitored with an autocorrelator. Fitting the streak camera image projected profiles with Gaussians, UV rms pulse durations are found to vary from 2.1 ps to 3.5 ps as the IR varies from 2.2 ps to 5.2 ps. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB08  
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MOPOB68 A New Method for Grain Texture Manipulation in Post-Deposition Niobium Films ion, niobium, controls, electron 221
 
  • J. Musson, K. Macha, H.L. Phillips
    JLab, Newport News, Virginia, USA
  • W. Cao, H. Elsayed-Ali
    ODU, Norfolk, Virginia, USA
  
  Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Old Dominion University
Niobium films are frequently grown using forms of energetic condensation, with modest substrate temperatures to control grain structure. As an alternative, energetic deposition onto a cold substrate results in a dense amorphous film, with a much larger energy density than the re-crystallized state. Re-crystallization is then performed using a pulsed UV (HIPPO) laser, with minimal damage to the substrate. In addition, a graded interface between the substrate and Nb film is created during the early stages of energetic deposition. Experimental approach and apparatus are described. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB68  
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TUB2IO02 Advanced Concepts for Seeded FELs ion, FEL, electron, controls 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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TUPOA05 Development of a Fiber Laser for Improving the Pulse Radiolysis System ion, electron, radiation, gun 299
 
  • Y. Saito, S.Y. Soeta, M. Washio
    Waseda University, Tokyo, Japan
  • Y. Hosaka, K. Sakaue
    RISE, Tokyo, Japan
  
  When material is irradiated by the ionizing radiation, short-lived and highly reactive substance intermediate active species are made and then react with substances. The chemical reaction is determined by intermediate active species in early process. Proving the behavior of intermediate active species is important for understanding and controlling radiation chemical reaction. In Waseda university we been developing a Pulse Radiolysis System, a method to measure the behavior of intermediate species, for radiation chemical analysis with RF electron gun. Currently we are developing a Supercontinuum ray(SC ray)as a probe ray to improve Pulse Radiolysis System. We have introduced a SC ray using Yb fiver laser and PCF(Photonic Crystal Fiber). But this type of prove light isn't stable enough in the visible light region. Therefore we started to study Er fiber laser oscillator as new prove ray source. We have succeeded to oscillate a Er fs laser pulse, second harmonic generation and measurement of hydrated electron in ns time resolution. In this presentation we will report current research about generation of SC ray, Er fiber laser system and dose rate effect against the hydrated electron.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA05  
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TUPOA25 Initial Demonstration of 9-MHz Framing Camera Rates on the FAST Drive Laser Pulse Trains* ion, electron, optics, radiation 333
 
  • A.H. Lumpkin, D.R. Edstrom, J. Ruan
    Fermilab, Batavia, Illinois, USA
  
  Funding: * Work at Fermilab supported by Fermi Research Alliance, LLC under Contract No. DE-AC02- 07CH11359 with the United States Department of Energy.
Although beam centroid information at the MHz-micropulse-repetition rate has routinely been achieved at various facilities with rf BPMS, the challenge of recording beam size information at that rate is more daunting. The Integrable Optics Test Accelerator (IOTA) ring being planned at Fermilab has ~8 MHz revolution rates. To simulate the IOTA synchrotron radiation source temporal structure, we have used the UV component of the drive laser of the Fermilab Accelerator Science and Technology (FAST) Facility. This laser is normally set at 3 MHz, but has also been run at 9 MHz. We have configured our Hamamatsu C5680 streak camera in a framing camera mode using a slow vertical sweep plugin unit with the dual axis horizontal sweep unit**. A two-dimensional array of images sampled at the MHz rate can then be displayed on the streak tube phosphor and recorded by the CCD readout camera at up to 10 Hz. As an example, by using the 10 microsecond vertical sweep with the 100 microsecond horizontal sweep ranges, 49 of the 300 micropulses at 3 MHz are displayed for a given trigger delay in each of six images. Example 2D image arrays with profiling examples will be presented.
**Hamamatsu C5680 product web page. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA25  
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TUPOA26 Initial Observations of Micropulse Elongation of Electron Beams in a SCRF Accelerator* ion, electron, gun, MMI 337
 
  • A.H. Lumpkin, D.R. Edstrom, J. Ruan, J.K. Santucci, R.M. Thurman-Keup
    Fermilab, Batavia, Illinois, USA
  
  Funding: * Work at Fermilab supported by Fermi Research Alliance, LLC under Contract No. DE-AC02- 07CH11359 with the United States Department of Energy
Commissioning at the SCRF accelerator at the Fermilab Accelerator Science and Technology (FAST) Facility has included the implementation of a versatile bunch-length monitor located after the 4-dipole chicane bunch compressor for electron beam energies of 20-50 MeV and integrated charges in excess of 10 nC. The team has initially used a Hamamatsu C5680 synchroscan streak camera. An Al-coated Si screen was used to generate optical transition radiation (OTR) resulting from the beam's interaction with the screen. The chicane bypass beamline allowed the measurements of the bunch length without the compression stage at the downstream beamline location using OTR and the streak camera. The UV component of the drive laser had previously been characterized with a Gaussian fit σ of 3.5-3.7 ps**. However, the uncompressed electron beam is expected to elongate due to space charge forces in an initial 1.5-m drift from the gun to the first SCRF accelerator cavity. We have observed electron beam bunch lengths from 5 to 14 ps (σ) for micropulse charges of 60 pC to 800 pC, respectively. Commissioning of the system and initial results with uncompressed and compressed beam will be presented.
**A.H. Lumpkin et al., Proceedings of FEL14, MOP021, Basel, Switzerland, www. JACoW.org 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA26  
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TUPOA28 Feasibility of OTR Imaging for Laser-Driven Plasma Accelerator Electron-Beam Diagnostics ion, electron, polarization, plasma 345
 
  • A.H. Lumpkin
    Fermilab, Batavia, Illinois, USA
  • M. Downer
    The University of Texas at Austin, Austin, Texas, USA
  • D.W. Rule
    Private Address, Silver Spring, USA
  
  Funding: * Work at Fermilab partly supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. DoE. ** Work at the Univ. of Texas supported by DoE grant DE-SC0011617.
Recent measurements of betatron x-ray emission from quasi-monoenergetic electrons accelerating to 500 MeV within a laser plasma accelerator (LPA) enabled estimates of normalized transverse emittance well below 1 mm-mrad and divergences of order 1/gamma [1]. Such unprecedented LPA beam parameters can, in principle, be addressed by utilizing the properties of linearly polarized optical transition radiation (OTR) that provide additional beam parameter sensitivity. We propose a set of complementary measurements of beam size and divergence with near-field and far-field OTR imaging, respectively, on LPA electron beams ranging in energy from 100 MeV [2] to 2 GeV [3]. The feasibility is supported by analytical modeling for beam size sensitivity and divergence sensitivity. In the latter case, the calculations indicate that the parallel polarization component of the far-field OTR pattern is sensitive to divergences from 0.1 to 0.4 mrad (σ) at 2 GeV, and it is similarly sensitive to divergences from 1 to 5 mrad (σ) at 100 MeV. We anticipate the signal levels from charges of 100 pC will require a 16-bit cooled CCD camera. Other practical challenges in the LPA will also be discussed.
1.G. R. Plateau et al., Phys. Rev. Lett. 109, 064802 (2012).
2.Hai-EnTsai, Chih-Hao Pai, and M.C. Downer, AIP Proc. 1507, 330 (2012)
3.Xiaoming Wang et al., Nature Communications 4,1988(2013).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA28  
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TUPOA42 Multicavity Coherent Pulse Stacking Using Herriott Cells cavity, ion, controls, experiment 370
 
  • Y. Yang, J.M. Byrd, L.R. Doolittle, G. Huang, W. Leemans, Q. Qiang, R.B. Wilcox
    LBNL, Berkeley, California, USA
  • J. Dawson
    LLNL, Livermore, California, USA
  • A. Galvanauskas, J.M. Ruppe
    University of Michigan, Ann Arbor, Michigan, USA
  • Y.L. Xu
    TUB, Beijing, People's Republic of China
  
  Coherent Pulse Stacking provides a promising way to generate a single high-intensity laser pulse by stacking a sequence of phase and amplitude modulated laser pulses using multiple optical cavities. Optical misalignment and phase stability are two critical issues that need to be addressed. Herriott cells are implemented for their relaxed alignment tolerance and a phase stabilization method based on cavity output pattern matching has been developed. A single pulse with intensity enhancement factor over 7.4 has been generated by stacking 13 modulated pules through a four-cavity stacking system. This can be a possible path for generating TW KHz laser pulses for a future laser-driven plasma accelerator.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA42  
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TUPOA47 Development of Short Undulators for Electron-Beam-Radiation Interaction Studies ion, undulator, radiation, electron 380
 
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  • M.B. Andorf, G. Fagerberg, M. Figora
    Northern Illinois University, DeKalb, Illinois, USA
  
  Funding: Work supported by the US DOE contract DE-SC0013761 with Northern Illinois University
Interaction of an electron beam with external field or its own radiation has widespread applications ranging from coherent radiation generation, phase space cooling or formation of time-structured beam. An efficient coupling mechanism between an electron beam and radiation field relies on the use of a magnetic undulator. In this contribution we detail the construction and magnetic measurements of short (11 period) undulators with 7-cm period built using parts of the ALADDIN U3 undulator*. Possible use of these undulators at two accelerator test facilities to support experiment relevant to cooling techniques and radiation souces are discussed.
* F. C. Younger, W. Jorge Pearce, B. Ng, Nucl. Instrum. Meth Phys. Res. A 347, pp. 96-101 (1994). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA47  
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TUPOA49 A General Model of Vacuum Arcs in Linacs ion, plasma, experiment, vacuum 387
 
  • J. Norem
    Nano Synergy, Inc., Downers Grove, Illinois, USA
  • Z. Insepov
    Purdue University, West Lafayette, Indiana, USA
  
  We are developing a general model of breakdown and gradient limits that applies to accelerators, along with other high field applications such as power grids and laser ablation. Our recent efforts have considered failure modes of integrated circuits, sheath properties of dense, non-Debye plasmas and applications of capillary wave theory to rf breakdown in linacs. In contrast to much of the rf breakdown effort that considers one physical mechanism or on e experimental geometry, we are finding that there is an enormous volume of relevant material in the literature that helps to constrain our model and suggest experimental tests.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA49  
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TUPOA61 Integrated Control System for an X-Band-Based Laser-Compton X-Ray Source ion, controls, FPGA, LabView 408
 
  • D.J. Gibson, G.G. Anderson, C.P.J. Barty, R.A. Marsh
    LLNL, Livermore, California, USA
  
  Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
LLNL's compact, tunable, laser-Compton x-ray source has been built around an advanced X-band photogun and accelerator sections and two independent laser systems. In support of this source, the control system has evolved from a minimal, isolated control points to an integrated architecture that continues to grow to simplify operation of the system and to meet new needs of this research capability. In addition to a PLC-based machine protection component, a custom, LabView-based suite of control software monitors systems including low level and high power RF, vacuum, magnets, and beam imaging cameras. This system includes a comprehensive operator interface, automated arc detection and rf processing to optimize rf conditioning of the high-gradient structures, and automated quad-scan-based emittance measurements to explore the beam tuning parameter space. The latest upgrade to the system includes a switch from real-time OS to FPGA-based low-level RF generation and arc detection. This offloads processing effort from the main processor allowing for arbitrary expansion of the monitored points. It also allows the possibility of responding to arcs before the pulse is complete. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA61  
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TUA3CO03 Compact Ring-Based X-Ray Source With on-Orbit and on-Energy Laser-Plasma Injection ion, electron, plasma, radiation 435
 
  • M. Turner
    CERN, Geneva, Switzerland
  • J.R. Cheatam, A.L. Edelen
    CSU, Fort Collins, Colorado, USA
  • J. Gerity
    Texas A&M University, College Station, USA
  • A. Lajoie, C.Y. Wong
    NSCL, East Lansing, Michigan, USA
  • G. Lawler
    UCLA, Los Angeles, California, USA
  • O. Lishilin
    DESY Zeuthen, Zeuthen, Germany
  • K. Moon
    UNIST, Ulsan, Republic of Korea
  • A. A. Sahai, A. Seryi
    JAI, London, United Kingdom
  • K. Shih
    SBU, Stony Brook, New York, USA
  • B. Zerbe
    MSU, East Lansing, Michigan, USA
  
  Funding: We acknowledge the stimulating atmosphere and support of US Particle Accelerator School, class of June 2016, where this design study was performed.
We report here the results of a one week long investigation into the conceptual design of an X-ray source based on a compact ring with on-orbit and on-energy laser-plasma accelerator (mini-project 10.4 from [1]). We performed these studies during the June 2016 USPAS class "Physics of Accelerators, Lasers, and Plasma…" applying the art of inventiveness TRIZ. We describe three versions of the light source with the constraints of the electron beam with energy 1 GeV or 3 GeV and a magnetic lattice design being normal conducting (only for the 1 GeV beam) or superconducting (for either beam). The electron beam recirculates in the ring, to increase the effective photon flux. We describe the design choices, present relevant parameters, and describe insights into such machines.
[1] Unifying physics of accelerators, lasers and plasma, A. Seryi, CRC Press, 2015. 		 
slides icon Slides TUA3CO03 [8.411 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUA3CO03  
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TUA4CO04 Simulation of High-Power Tunable THz Generation in Corrugated Plasma Waveguides ion, plasma, radiation, GUI 460
 
  • C.M. Miao, T.M. Antonsen
    UMD, College Park, Maryland, USA
  • J. Palastro
    NRL, Washington,, USA
  
  Intense, short laser pulses propagating through inhomogeneous plasmas generate terahertz (THz) radiation. We consider the excitation of THz radiation by the interaction between an ultra short laser pulse and a miniature plasma waveguide. Such corrugated plasma waveguides support electromagnetic (EM) channel modes with subluminal phase velocities, thus allowing the phasing matching between the generated THz modes and the ponderomotive potential associated with laser pulse, making significant THz generation possible. Full format PIC simulations and theoretical analysis are conducted to investigate this slow wave phase matching mechanism. We find the generated THz is characterized by lateral emission and a coherent, narrow band spectrum. A range of realistic laser pulse and plasma profile parameters are considered with the goal of increasing the conversion efficiency of optical energy to THz radiation. As an example, a fixed driver pulse (1.66 J) with spot size of 15 μ m and pulse duration of 50 fs excites approximately 83.7 μ J of THz radiation in a 500-μ m-long corrugated waveguide with on axis average density of 1018 cm-3.  
slides icon Slides TUA4CO04 [3.569 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUA4CO04  
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WEPOA02 Progress Toward an Experiment at AWAKE* ion, plasma, diagnostics, experiment 687
 
  • P. Muggli
    MPI, Muenchen, Germany
  
  The AWAKE experimental program is scheduled to start at the end of 2016. The aim of the first experiments is to detect and study the self-modulation instability (SMI) of the long proton bunch ~12cm in a plasma with wakefields of period of ~1.2mm. The occurrence of SMI results in the formation of a charge core surrounded by a halo in the time-integrated images of the proton bunch transverse profile. Transverse profiles are obtained from scintillator screens and from optical transition radiation (OTR). The OTR is time resolved using a ps-resolution streak camera to determine the start of the wakefields along the bunch on a slow time scale (~ns), i.e., the location of the seeding of the SMI generated by the ionizing laser pulse. The modulation period is measured using the faster time scale (~ps). Coherent transition radiation (CTR) is analyzed by a heterodyne system to also yield the modulation frequency. Later experiments will sample the wakefields generated by externally injecting low-energy (~15MeV) electrons expected to be accelerated to the GeV energy level over the 10m-long plasma. Progress toward the completion of the experimental set-up will be presented.
*for the AWAKE Collaboration 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA02  
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WEPOA04 Design of Front End for RF Synchronized Short Pulse Laser Ion Source ion, rfq, ion-source, plasma 693
 
  • Y. Fuwa, Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  
  A short pulse laser ion source is under development. In this ion source, ions are produced by femto-second laser in RF electric field and produced ion bunch with a few nanosecond pulse length. This feature can eliminate bunching section of RFQ and beam can be accelerated from the first cell of RFQ. In this presentation, results of design study for the RFQ without bunching section will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA04  
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WEPOA30 High-Performance Modeling of Plasma-Based Acceleration and Laser-Plasma Interactions. ion, plasma, simulation, GPU 758
 
  • J.-L. Vay, G. Blaclard, R. Lehé, M. Lobet, H. Vincenti
    LBNL, Berkeley, California, USA
  • B.B. Godfrey
    UMD, College Park, Maryland, USA
  • M. Kirchen
    University of Hamburg, Hamburg, Germany
  • P. Lee
    CNRS LPGP Univ Paris Sud, Orsay, France
  
  Funding: Work supported by US-DOE Contracts DE-AC02-05CH11231 and by the European Commission through the Marie Slowdoska-Curie actions. Used resources of NERSC, supported by US-DOE Contract DE-AC02-05CH11231.
Large-scale numerical simulations are essential to the design of plasma-based accelerators and laser-plasma interations for ultra-high intensity (UHI) physics. The electromagnetic Particle-In-Cell (PIC) approach is the method of choice for self-consistent simulations, as it is based on first principles, and captures all kinetic effects, and also scales easily (for uniform plasmas) to many cores on supercomputers. The standard PIC algorithm relies on second-order finite-difference discretizations of the Maxwell and Newton-Lorentz equations. We present here novel PIC formulations, based on the use of very high-order pseudo-spectral Maxwell solvers, which enable near-total elimination of the numerical Cherenkov instability and increased accuracy over the standard PIC method. We also discuss the latest implementations in the PIC modules Warp-PICSAR and FBPIC on the Intel Xeon Phi and GPU architectures. Examples of applications are summarized on the simulation of laser-plasma accelerators and high-harmonic generation with plasma mirrors. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA30  
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WEPOA39 Theoretical and Numerical Study on Plasmon-Assisted Channeling Interactions in Nanostructures ion, plasma, target, acceleration 782
 
  • Y.-M. Shin
    Northern Illinois University, DeKalb, Illinois, USA
  
  Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC.
A plasmon-assisted channeling acceleration can be realized with a large channel possibly in a nanometer scale. Carbon nanotubes are the most typical example of nano-channels that can confine a large amount of channeled particles and confined plasmon in a coupling condition. This paper presents theoretical and numerical study on the concept of the laser-driven surface-plasmon (SP) acceleration in a carbon nanotube (CNT) channel. Analytic description of the SP-assisted laser acceleration is detailed with practical acceleration parameters, in particular with specifications of a typical tabletop femto-second laser system. The maximally achievable acceleration gradients and energy gains within dephasing lengths and CNT lengths are discussed with respect to laser-incident angles and CNT-filling ratios. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA39  
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WEPOA57 Stabilized Operation Mode of Laser Ion Source Using Pulsed Magnetic Field ion, ion-source, solenoid, electron 823
 
  • S. Ikeda, M.R. Costanzo, T. Kanesue, R.F. Lambiase, C.J. Liaw, M. Okamura
    BNL, Upton, Long Island, New York, USA
  
  A laser ion source (LIS) provides several types of singly charged ions into an electron beam ion source (EBIS) followed by linear accelerator injectors for the Relativistic Heavy Ion Collider (RHIC) and the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory. In the present set-up of the LIS, beam current shape varies with time drastically. It is expected that the present current shape is not optimal for the ion trap of the EBIS. However, there are no knobs to modify the shape flexibly. Therefore, as an upgrade of the LIS, we install a coil and a pulsed circuit* that generates a fast-rising pulsed magnetic field to tailor the beam current shape. In this presentation, the effect of the magnetic field on the beam profile from the LIS and the performance of the injectors, such as the transmission and the charge injected into an accelerator downstream, are described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA57  
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WEPOB30 Simulation of the Shot-Noise Driven Microbunching Instability Experiment at the LCLS ion, simulation, electron, bunching 967
 
  • J. Qiang
    LBNL, Berkeley, California, USA
  • Y. Ding, P. Emma, Z. Huang, D.F. Ratner, T.O. Raubenheimer, F. Zhou
    SLAC, Menlo Park, California, USA
  
  The shot-noise driven microbunching instability can significantly degrade electron beam quality in next generation light sources. Experiments were carried out at the Linac Coherent Light Source (LCLS) to study this instability. In this paper, we will present start-to-end simulation of the shot-noise driven microbunching instability experiment at the LCLS.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB30  
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WEPOB32 Performance of a Combined System Using an X-Ray FEL Oscillator and a High-Gain FEL Amplifier ion, FEL, radiation, simulation 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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WEPOB35 LLNL Laser-Compton X-Ray Characterization ion, electron, simulation, scattering 977
 
  • Y. Hwang, T. Tajima
    UCI, Irvine, California, USA
  • G.G. Anderson, C.P.J. Barty, D.J. Gibson, R.A. Marsh
    LLNL, Livermore, California, USA
  
  Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52- 07NA27344
30 keV Compton-scattered X-rays have been produced at LLNL. The flux, bandwidth, and X-ray source focal spot size have been characterized using an X-ray ICCD camera and results agree very well with modeling predictions. The RMS source size inferred from direct electron beam spot size measurement is 17 um , while imaging of the penumbra yields an upper bound of 42 um. The accuracy of the latter method is limited by the spatial resolution of the imaging system, which has been characterized as well, and is expected to improve after the upgrade of the X-ray camera later this year. 		 
poster icon Poster WEPOB35 [37.648 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB35  
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WEPOB49 LCLS Injector Laser Profile Shaping Using Digital Micromirror Device ion, electron, cathode, target 1001
 
  • S. Li
    Stanford University, Stanford, California, USA
  • S.C. Alverson, D.K. Bohler, A.R. Fry, S. Gilevich, Z. Huang, A. Miahnahri, D.F. Ratner, J. Robinson, F. Zhou
    SLAC, Menlo Park, California, USA
  
  In the Linear Coherent Light Source (LCLS) at SLAC, the injector laser plays an important role as the source of the electron beam for the Free Electron Laser (FEL). The emittance of the beam is highly related to the transverse profile of the injector laser. Currently the LCLS injector laser has undesired features, such as hot spots, which carry over to the electron beam. These undesired features increase electron emittance, degrade the FEL performance, and complicate operations. The injector laser shaping project at LCLS aims to produce arbitrary electron beam profiles, such as cut-Gaussian, uniform, and parabolic, and to study the effect of spatial profiles on beam emittance and FEL performance. Effectively it also allows easy transition between the two spare lasers, where the operators can use the spatial shaper to achieve identical profiles for the two lasers. In this paper, we describe the experimental methods to achieve laser profile shaping and electron beam profile shaping respectively, and demonstrate promising results.  
poster icon Poster WEPOB49 [1.850 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB49  
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WEPOB54 DC Photogun Gun Test for RHIC Low Energy Electron Cooler (LEReC). ion, gun, electron, cavity 1008
 
  • D. Kayran, Z. Altinbas, D.R. Beavis, S. Bellavia, D. Bruno, M.R. Costanzo, A.V. Fedotov, D.M. Gassner, J. Halinski, K. Hamdi, J.P. Jamilkowski, J. Kewisch, C.J. Liaw, G.J. Mahler, T.A. Miller, S.K. Nayak, T. Rao, S. Seletskiy, B. Sheehy, J.E. Tuozzolo, Z. Zhao
    BNL, Upton, Long Island, New York, USA
  
  Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
Non-magnetized bunched electron cooling of low-energy RHIC requires electron beam energy in range of 1.6-2.6 MeV, with average current up to 45 mA, very small energy spread, and low emittance [1]. A 400 kV DC gun equipped with photocathode and laser delivery system will serve as a source of high-quality electron beam. Acceleration will be achieved by an SRF 704 MHz booster cavity and other RF components that are scheduled to be operational in early 2018. The DC gun testing in its installed location in RHIC will start in early 2017. During this stage we plan to test the critical equipment in close to operation conditions: laser beam delivery system, cathode QE lifetime, DC gun, beam instrumentation, high power beam dump system, and controls. In this paper, we describe the gun test set up, major components, and parameters to be achieved and measured during the gun beam test.
[1] A. Fedotov. Bunched beam electron cooling for Low Energy RHIC operation. ICFA Beam Dynamics letter, No. 65, p. 22 (December 2014) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB54  
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WEPOB59 Performance of CEC Pop Gun During Commissioning ion, cathode, gun, cavity 1024
 
  • I. Pinayev, W. Fu, Y. Hao, M. Harvey, T. Hayes, J.P. Jamilkowski, Y.C. Jing, P. K. Kankiya, D. Kayran, R. Kellermann, V. Litvinenko, G.J. Mahler, M. Mapes, K. Mernick, K. Mihara, T.A. Miller, G. Narayan, M.C. Paniccia, W.E. Pekrul, T. Rao, F. Severino, B. Sheehy, J. Skaritka, K.S. Smith, J.E. Tuozzolo, E. Wang, G. Wang, W. Xu, A. Zaltsman, Z. Zhao
    BNL, Upton, Long Island, New York, USA
  • I. Petrushina
    SUNY SB, Stony Brook, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The Coherent Electron Cooling Proof-of-Principle (CeC PoP) experiment employs a high-gradient CW photo-injector based on the superconducting RF cavity. Such guns operating at high accelerating gradients promise to revolutionize many sciences and applications. They can establish the basis for super-bright monochromatic X-ray and gamma ray sources, high luminosity hadron colliders, nuclear waste transmutation or a new generation of microchip production. In this paper we report on our operation of a superconducting RF electron gun with a high accelerating gradient at the CsK2Sb photo-cathode (i.e. ~ 20 MV/m) generating a record-high bunch charge (above 4 nC). We give short description of the system and then detail our experimental results. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB59  
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THA2CO03 New 1.4 Cell RF Photoinjector Design for High Brightness Beam Generation ion, cathode, brightness, electron 1083
 
  • E. Pirez, P. Musumeci
    UCLA, Los Angeles, California, USA
  • D. Alesini
    INFN/LNF, Frascati (Roma), Italy
  • J.M. Maxson
    Cornell University, Ithaca, New York, USA
  
  Funding: This work was partially funded by NSF grant 145583
The new electromagnetic and mechanical designs of the S-band 1.4 cell photoinjector are discussed. A novel fabrication method is adopted to replace the brazing process with a clamping technique achieving lower breakdown probability. The photoinjector is designed to operate at a 120 MV/m gradient and an optimal injection phase of 70 degrees to improve the extraction field by a factor of 1.9 compared to standard 1.6 cell designs with the same peak field. New geometries and features are implemented to improve beam quality for the demand of high brightness beam applications. 		 
slides icon Slides THA2CO03 [2.444 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THA2CO03  
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THB2IO03 Fulfilling the Mission of Brookhaven ATF as DOE's Flagship User Facility in Accelerator Stewardship ion, electron, acceleration, plasma 1096
 
  • I. Pogorelsky, I. Ben-Zvi, M.A. Palmer
    BNL, Upton, Long Island, New York, USA
  
  Funding: DOE
25 years ago, Brookhaven Accelerator Test Facility (ATF), sponsored by the U.S. Department of Energy's (DOE's) Office of High-Energy Physics (HEP), pioneered a concept of a proposal-driven user facility for advanced accelerator research using lasers and electron beams. Since then, the ATF became an internationally recognized destination for researchers to benefit from free access to unique equipment not affordable otherwise to individual institutions and businesses. We will show by examples how collaborative user research achieves high productivity when supported by the ATF's capabilities. Researchers from academia, industry and national laboratories coming to ATF successfully investigate wide range of topics. Recently endorsed as an Office of Science National User Facility and a flagship in Accelerator Stewardship, ATF continues broadening its user community. DOE is now planning a considerable expansion of the ATF's capabilities via simultaneously upgrading the parameters of the e-beam and laser. 		 
slides icon Slides THB2IO03 [49.425 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THB2IO03  
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THPOA50 Development of an Optical Cavity for LCS Sources at the Compact ERL cavity, ion, electron, photon 1204
 
  • T. Akagi, S. Araki, Y. Honda, A. Kosuge, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  • R. Hajima, M. Mori, R. Nagai, T. Shizuma
    QST, Tokai, Japan
  
  High-energy photons from the laser Compton scattering (LCS) sources are expected to be applied in various fields in a wide range photon energies from keV to GeV. High-flux and narrow-bandwidth LCS photon beam is realized in an energy recovery linac (ERL). An electron beam of high-average current and small-emittance collides with accumulating laser pulses in an enhancement cavity for generating high-flux LCS photon beam. We have developed the high-finesse bow-tie ring cavity for the LCS experiment at the Compact ERL (cERL) in KEK. In this presentation, we will report the detail of the optical cavity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA50  
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THPOA51 Improvement of X-Ray Generation by Using Laser Compton Scattering in Laser Undulator Compact X-Ray Source(LUCX) ion, gun, electron, photon 1207
 
  • M.K. Fukuda, S. Araki, Y. Honda, Y. Sumitomo, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  • K. Sakaue
    Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
  • M. Washio
    RISE, Tokyo, Japan
  
  Funding: This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
We have been developing a compact X-ray source based on the laser Compton scattering(LCS) at Laser Undulator Compact X-ray source(LUCX) accelerator in KEK. We have started to take X-ray images such as refraction contrast images and phase contrast imaging with Talbot interferometer. In this accelerator, 6-10keV X-rays are generated by LCS. An electron beam is produced by a 3.6cell RF-gun and accelerated to 18-24MeV by a 12cell accelerating tube. A laser pulse is stored in a 4-mirror planar optical cavity to enhance the power. To increase the flux of LCS X-rays, we perform an optimization of the beam-loading compensation, improvement of the intensity of an electron beam and a laser light at the collision point. We report the result of the X-ray generation in this accelerator. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA51  
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THPOA53 Luminosity Increase in Laser-Compton Scattering by Crab Crossing Method ion, electron, luminosity, photon 1213
 
  • Y. Koshiba, D. Igarashi, S. Ota, T. Takahashi, M. Washio
    RISE, Tokyo, Japan
  • K. Sakaue
    Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
  • J. Urakawa
    KEK, Ibaraki, Japan
  
  In collider experiments such as KEKB, crab crossing method is a promising way to increase the luminosity and KEK (High Energy Accelerator Research Organization) has achieved the luminosity record in 2009. We are planning to apply crab crossing to laser-Compton scattering, which is a collision of electron beam and laser, to gain a higher luminosity leading to a higher brightness X-ray source. It is well known that the collision angle between electron beam and laser affects the luminosity. It is the best when the collision angle is zero, head-on collision, to get a higher luminosity but difficult to construct such system especially when using an optical cavity for laser. Concerning this difficulty, we are planning crab crossing by tilting the electron beam using an rf-deflector. Although crab crossing in laser-Compton scattering has been already proposed*, nowhere has demonstrated yet. We are going to demonstrate and conduct experimental study at our compact accelerator system in Waseda University. In this conference, we will report about our compact accelerator system, laser system for laser-Compton scattering, and expected results of crab crossing laser-Compton scattering.
*V. Alessandro, et al. "Luminosity optimization schemes in Compton experiments based on Fabry-Perot optical resonators." Physical Review Special Topics-Accelerators and Beams 14.3 (2011): 031001.
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA53  
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THPOA56 Primary Study of the Photocathode Electron Gun With a Cone Cathode and Radial Polarization Laser cathode, ion, gun, emittance 1216
 
  • R. Huang, Q.K. Jia
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Funding: This work is partly supported by the National Nature Science Foundation of China under Grant No. 11375199.
The linearly polarized laser with oblique incidence can achieve a higher quantum efficiency (QE) of metal cathodes than that with the normal incidence, which however requires the wavefront shaping for better performance. To maintain the high QE and simplify the system, we propose a cone cathode electron gun with a radial polarization laser at normal incidence. The primary analytical estimation and numerical simulations are explored for its effect on the emittance of the electron beam. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA56  
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FRA1CO06 Measurement of Coherent Transition Radiation Using Interferometer and Photoconductive Antenna ion, electron, linac, polarization 1279
 
  • K. Kan, M. Gohdo, T. Kondoh, I. Nozawa, J. Yang, Y. Yoshida
    ISIR, Osaka, Japan
  
  Ultrashort electron beams are essential for light sources and time-resolved measurements. Electron beams can emit terahertz (THz) pulses using coherent transition radiation (CTR). Michelson interferometer* is one of candidates for analyzing the pulse width of an electron beam based on frequency-domain analysis. Recently, electron beam measurement using a photoconductive antenna (PCA)** based on time-domain analysis has been investigated. In this presentation, measurement of femtosecond electron beam with 35 MeV energy and < 1 nC from a photocathode based linac will be reported. Frequency- and time- domain analysis of THz pulse of CTR by combining the interferometer and PCA will be carried out.
* I. Nozawa, K. Kan et al., Phys. Rev. ST Accel. Beams 17, 072803 (2014).
** K. Kan et al., Appl. Phys. Lett. 102, 221118 (2013). 		 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-FRA1CO06  
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