NAPAC2016 - List of Keywords (plasma)

Paper	Title	Other Keywords	Page
MOA4IO01	Performance of the Low Charge State Laser Ion Source in BNL	ion, laser, target, 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 MOA4IO01 [7.796 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOA4IO01
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MOPOB05	Tokamak Accelerator	ion, vacuum, ECR, experiment	76
	G. Li ASIPP, Hefei, People's Republic of China
	Tokamak accelerator within plasma is analyzed to be implemented in existing machines for speeding the development of fusion energy with seeding fast particles from high current accelerators - the so-called two-component reactor approach [J. M. Dawson, H. P. Furth, and F. H. Tenney, Phys. Rev. Lett. 26, 1156 (1971)]. All plasma particles are heated at the same time by inductively-coupled power transfer (IPT) within an energy confinement time. This could facilitate the attainment of ignition in tokamak by forming high-gain high-field (HGHF) fusion plasma suggested in [Li. G., Sci. Rep.5, 15790 (2015)]. HGHF mechanism is validated by the flux-conserving process existed in discharges of tokamak plasma at normal operation with long pulses or at compression process within an energy confinement time. Differences between HGHF plasma and former unity-beta plasma are discussed. Tokamak as an accelerator could scale down the design capacity of fusion power plant by simply inserting in-vacuum vertical field coils (IVC) within its vacuum vessel, such as China Fusion Engineering Test Reactor (CFETR).
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MOPOB52	Dielectric Loaded High Pressure Gas Filled RF Cavities for Use in Muon Cooling Channels	ion, cavity, solenoid, accelerating-gradient	177
	B.T. Freemire IIT, Chicago, Illinois, USA M. Backfish, D.L. Bowring, A. Moretti, D.W. Peterson, A.V. Tollestrup, K. Yonehara Fermilab, Batavia, Illinois, USA R.P. Johnson Muons, Inc, Illinois, USA A.V. Kochemirovskiy University of Chicago, Chicago, Illinois, USA Y. Torun Illinois Institute of Technology, Chicago, Illlinois, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. High brightness muon beams require significant six dimensional cooling. One cooling scheme, the Helical Cooling Channel, employs high pressure gas filled radio frequency cavities, which provide both the absorber needed for ionization cooling, and a means to mitigate RF breakdown. The cavities are placed along the beam's trajectory, and contained within the bores of superconducting solenoid magnets. Gas filled RF cavities have been shown to successfully operate within multi-Tesla external magnetic fields, and not be overcome with the loading resulting from beam-induced plasma. The remaining engineering hurdle is to find a way to fit 325 and 650 MHz single cell pillbox cavities within the bores of the magnets using modern technology. One method to accomplish this is to partially fill the cavities with a dielectric material. Alumina (Al2O3) is an ideal dielectric, and the experimental test program to determine its performance under high power in a gas filled cavity has concluded. The final results, and their implications for the design of a muon cooling channel based on gas filled RF cavities will be discussed.
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TUA2IO01	AWAKE - A Proton Driven Plasma Wakefield Acceleration Experiment at CERN	ion, proton, electron, wakefield	266
	A. Caldwell MPI-P, München, Germany
	It is the aim of the AWAKE project at CERN to demonstrate the acceleration of electrons in the wake created by a proton beam passing through plasma. The proton beam will be modulated as a result of the transverse two-stream instability into a series ofμbunches that will then drive strong wakefields. The wakefields will then be used to accelerate electrons with GV/m strength fields. The AWAKE experiment is currently being commissioned and first data taking is expected this year. The status of the experimental program is described as well as first thoughts on future steps.
	Slides TUA2IO01 [24.428 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUA2IO01
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TUPOA28	Feasibility of OTR Imaging for Laser-Driven Plasma Accelerator Electron-Beam Diagnostics	ion, electron, polarization, laser	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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TUPOA44	Future Prospects of RF Hadron Beam Profile Monitors for Intense Neutrino Beam	ion, cavity, radiation, proton	373
	Q. Liu Case Western Reserve University, Cleveland, USA M. Backfish, A. Moretti, V. Papadimitriou, A.V. Tollestrup, K. Yonehara, R.M. Zwaska Fermilab, Batavia, Illinois, USA M.A. Cummings, R.P. Johnson, G.M. Kazakevich Muons, Inc, Illinois, USA B.T. Freemire IIT, Chicago, Illinois, USA
	Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013795. A novel beam monitor based on a gas-filled RF resonator is proposed to measure the precise profile of secondary particles downstream of a target in the LBNF beam line at high intensity. The RF monitor is so simple that it promises to be radiation robust in extremely high-radiation environment. When a charged beam passes through a gas-filled microwave RF cavity, it produces electron-ion pairs in the RF cavity. The induced plasma changes the gas permittivity in proportion to the beam intensity. The permittivity shift can be measured by the modulated RF frequency and quality factor. The beam profile can thus be reconstructed from the signals from individual RF cavity pixels built into the beam profile monitor. A demonstration test is underway, and the current results has shown technical feasibility. The next phase consists of two stages, (1) to build and test a new multi-cell 2.45 GHz RF cavity that can be used for the NuMI beamline, and (2) to build and test a new multi-cell 9.3 GHz RF cavity that can be put in service in a future beamline at the LBNF for spatial resolution. These two resonant frequencies are chosen since they are the standard frequencies for magnetron RF source.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA44
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TUPOA49	A General Model of Vacuum Arcs in Linacs	ion, experiment, laser, 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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TUA3CO03	Compact Ring-Based X-Ray Source With on-Orbit and on-Energy Laser-Plasma Injection	ion, electron, laser, 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 TUA3CO03 [8.411 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUA3CO03
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TUA4CO03	Loading of Wakefields in a Plasma Accelerator Section Driven by a Self-Modulated Proton Beam	ion, simulation, proton, wakefield	457
	V.K.B. Olsen, E. Adli University of Oslo, Oslo, Norway P. Muggli MPI-P, München, Germany J. Vieira Instituto Superior Tecnico, Lisbon, Portugal
	Using parameters from the AWAKE project and particle-in-cell simulations we investigate beam loading of a plasma wake driven by a self-modulated proton beam. Addressing the case of injection of an electron witness bunch after the drive beam has already experienced self-modulation in a previous plasma, we optimise witness bunch parameters of size, charge and injection phase to maximise energy gain and minimise relative energy spread and emittance of the accelerated bunch.
	Slides TUA4CO03 [3.103 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUA4CO03
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TUA4CO04	Simulation of High-Power Tunable THz Generation in Corrugated Plasma Waveguides	ion, laser, 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 TUA4CO04 [3.569 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUA4CO04
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TUPOB07	Considerations on Energy Frontier Colliders After LHC	ion, collider, luminosity, hadron	493
	V.D. Shiltsev Fermilab, Batavia, Illinois, USA
	The future of the world-wide HEP community critically depends on the feasibility of possible post-LHC colliders. The concept of the feasibility is complex and includes at least three factors: feasibility of energy, feasibility of luminosiity and feasibility of cost. The talk will give on overview of all current options for post-LHC colliders from such perspective (ILC, CLIC, Muon Collider, plasma colliders, CEPC, FCC, HE-LHC, etc) and discuss major challenges and accelerator R&D required to claim these machines feasible.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB07
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WEPOA01	Effect of Proton Bunch Parameter Variation on AWAKE	ion, wakefield, injection, electron	684
	N. Savard University of Victoria, Victoria BC, Canada P. Muggli MPI, Muenchen, Germany J. Vieira IPFN, Lisbon, Portugal
	In AWAKE, long proton bunches propagate through a plasma, generating wakefields through the self-modulation instability (SMI). The phase velocity of these wakefields changes during the first 4 m of propagation and growth of the SMI, after which it stabilizes at the proton bunch velocity. This means that the ideal injection point for electrons to be accelerated is after 4 m into the plasma. Using the PIC code OSIRIS, we study how small changes in the initial proton bunch parameters (such as charge, radial and longitudinal bunch length, etc) to be expected in the experiment affect the phase velocity of the wakefields, primarily by looking at the difference in the phase of the wakefields at the point of injection (along the bunch and along the plasma) when changing these parameters by a small amount (±5%). We also look for the region of optimal acceleration/focusing for electron injection. Ultimately, it is found that small changes in the initial proton bunch parameters are not expected to significantly impact electron injection experiments in the future.
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WEPOA02	Progress Toward an Experiment at AWAKE*	ion, laser, 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
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WEPOA04	Design of Front End for RF Synchronized Short Pulse Laser Ion Source	ion, laser, rfq, ion-source	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.
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WEPOA09	Proton Beam Defocusing as a Result of Self-Modulation in Plasma	proton, ion, wakefield, focusing	707
	M. Turner, E. Gschwendtner, A.V. Petrenko CERN, Geneva, Switzerland K.V. Lotov, A. Sosedkin Budker INP & NSU, Novosibirsk, Russia
	Funding: CERN The AWAKE experiment will use a 400 GeV/c proton beam with a longitudinal bunch length of sigmq_z = 12 cm to create and sustain GV/m plasma wakefields over 10 meters. A 12 cm long bunch can only drive strong wakefields in a plasma with n_pe = 7 x 10¹⁴ electrons/cm³ after the self-modulation instability (SMI) developed and microbunches formed, spaced at the plasma wavelength. The fields present during SMI focus and defocus the protons in the transverse plane. We show that by inserting two imaging screens downstream the plasma, we can measure the maximum defocusing angle of the defocused protons for plasma densities above n_pe = 5 x10¹⁴ electrons/cm³. Measuring maximum defocusing angles around 1 mrad indirectly proves that SMI developed successfully and that GV/m plasma wakefields were created. In this paper we present numerical studies on how and when the wakefields defocus protons in plasma, the expected measurement results of the two screen diagnostics and the physics we can deduce from it.
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WEPOA29	Recent Experiments at NDCX-II: Irradiation of Materials Using Short, Intense Ion Beams	ion, experiment, target, focusing	755
	P.A. Seidl, E. Feinberg, Q. Ji, B.A. Ludewigt, A. Persaud, T. Schenkel, M. Silverman, A.A. Sulyman, W.L. Waldron LBNL, Berkeley, California, USA J.J. Barnard, A. Friedman, D.P. Grote LLNL, Livermore, California, USA E.P. Gilson, I. Kaganovich, A.D. Stepanov PPPL, Princeton, New Jersey, USA F. Treffert, M. Zimmer TU Darmstadt, Darmstadt, Germany
	Funding: This work was supported by the Office of Science of the US Department of Energy under contracts DE-AC0205CH11231 (LBNL), DE-AC52- 07NA27344 (LLNL) and DE-AC02-09CH11466 (PPPL). We present an overview of the performance of the Neutralized Drift Compression Experiment-II (NDCX-II) accelerator at Berkeley Lab, and summarize recent studies of material properties created with nanosecond and millimeter-scale ion beam pulses. The scientific topics being explored include the dynamics of ion induced damage in materials, materials synthesis far from equilibrium, warm dense matter and intense beam-plasma physics. We summarize the improved accelerator performance, diagnostics and results of beam-induced irradiation of thin samples of, e.g., tin and silicon. Bunches with over 3x10¹⁰ ions, 1-mm radius, and 2-30 ns FWHM duration have been created. To achieve these short pulse durations and mm-scale focal spot radii, the 1.2 MeV He⁺ ion beam is neutralized in a drift compression section which removes the space charge defocusing effect during final compression and focusing. Quantitative comparison of detailed particle-in-cell simulations with the experiment play an important role in optimizing accelerator performance; these keep pace with the accelerator repetition rate of ~1/minute.
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WEPOA30	High-Performance Modeling of Plasma-Based Acceleration and Laser-Plasma Interactions.	ion, simulation, laser, 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.
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WEPOA34	Progress on Beam-Plasma Effect Simulations in Muon Ionization Cooling Lattices	ion, simulation, emittance, scattering	765
	J.S. Ellison IIT, Chicago, Illinois, USA P. Snopok Fermilab, Batavia, Illinois, USA P. Snopok Illinois Institute of Technology, Chicago, Illlinois, USA
	Funding: Work supported by the U.S. Department of Energy. New computational tools are essential for accurate modeling and simulation of the next generation of muon-based accelerators. One of the crucial physics processes specific to muon accelerators that has not yet been simulated in detail is beam-induced plasma effect in liquid, solid, and gaseous absorbers. We report here on the progress of developing the required simulation tools and applying them to study the properties of plasma and its effects on the beam in muon ionization cooling channels.
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WEPOA39	Theoretical and Numerical Study on Plasmon-Assisted Channeling Interactions in Nanostructures	ion, laser, 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.
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WEPOA45	Positive and Negative Ions Radio Frequency Sources with Solenoidal Magnetic Field	ion, solenoid, ion-source, electron	799
	V.G. Dudnikov, R.P. Johnson Muons, Inc, Illinois, USA G. Dudnikova ICT SB RAS, Novosibirsk, Russia B. Han, S. Murrey, C. Stinson ORNL RAD, Oak Ridge, Tennessee, USA T.R. Pennisi, C. Piller, M. Santana, M.P. Stockli, R.F. Welton ORNL, Oak Ridge, Tennessee, USA
	Funding: The work was supported in part by US DOE Contract DE-AC05-00OR22725 and by STTR grant, DE-SC0011323. Operation of Radio Frequency surfaces plasma sources (RF SPS) with a solenoidal magnetic field are described. RF SPS with solenoidal and saddle antennas are discussed. Dependences of beam current and extraction current on RF power, gas flow, solenoidal magnetic field and filter magnetic field are presented.
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WEPOA55	Modulator Simulations for Coherent Electron Cooling	ion, electron, simulation, quadrupole	816
	J. Ma, X. Wang SBU, Stony Brook, New York, USA V. Litvinenko, V. Samulyak, G. Wang, K. Yu BNL, Upton, Long Island, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA V. Samulyak SUNY SB, Stony Brook, New York, USA
	Highly resolved numerical simulations of the modulator, the first section of the proposed coherent electron cooling (CEC) device, have been performed using the code SPACE. The beam parameters for simulations are relevant to the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Numerical convergence has been studied using various numbers of macro-particles and mesh refinements of computational domain. A good agreement of theory and simulations has been obtained for the case of stationary and moving ions in uniform electron clouds with realistic distribution of thermal velocities. The main result of the paper is the prediction of modulation processes for ions with reference and off-reference coordinates in realistic Gaussian electron bunches with quadrupole field.
	Poster WEPOA55 [1.510 MB]
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THB2IO03	Fulfilling the Mission of Brookhaven ATF as DOE's Flagship User Facility in Accelerator Stewardship	ion, laser, electron, acceleration	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 THB2IO03 [49.425 MB]
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FRA1CO05	Progress of Gas-Filled Multi-RF-Cavity Beam Profile Monitor for Intense Neutrino Beams	ion, electron, cavity, experiment	1275
	K. Yonehara, M. Backfish, A. Moretti, A.V. Tollestrup, A.C. Watts, R.M. Zwaska Fermilab, Batavia, Illinois, USA M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer Muons, Inc, Illinois, USA B.T. Freemire IIT, Chicago, Illinois, USA Q. Liu Case Western Reserve University, Cleveland, USA
	Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013795. A novel pressurized gas-filled multi-RF-cavity beam profile monitor has been studied that is simple and robust in high-radiation environments. Charged particles passing through each RF-cavity in the monitor produce intensity-dependent ionized plasma, which changes the gas permittivity. The sensitivity to beam intensity is adjustable using gas pressure and RF gradient. The performance of the gas-filled beam profile monitor has been numerically simulated to evaluate the sensitivity of permittivity measurements. The result indicates that the RF resonator will be useful to measure the beam profile with a charged beam intensity range from 10⁶ to 10¹³ protons/bunch. The range covers the expected beam intensities in NuMI and LBNF. The demonstration of the monitor with intense proton beams are taken place at Fermilab to validate the simulation result. The result will be given in this presentation.
	Slides FRA1CO05 [3.750 MB]
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Paper

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Other Keywords

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MOA4IO01

Performance of the Low Charge State Laser Ion Source in BNL

ion, laser, target, 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 MOA4IO01 [7.796 MB]

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MOPOB05

Tokamak Accelerator

ion, vacuum, ECR, experiment

76

G. Li
ASIPP, Hefei, People's Republic of China

Tokamak accelerator within plasma is analyzed to be implemented in existing machines for speeding the development of fusion energy with seeding fast particles from high current accelerators - the so-called two-component reactor approach [J. M. Dawson, H. P. Furth, and F. H. Tenney, Phys. Rev. Lett. 26, 1156 (1971)]. All plasma particles are heated at the same time by inductively-coupled power transfer (IPT) within an energy confinement time. This could facilitate the attainment of ignition in tokamak by forming high-gain high-field (HGHF) fusion plasma suggested in [Li. G., Sci. Rep.5, 15790 (2015)]. HGHF mechanism is validated by the flux-conserving process existed in discharges of tokamak plasma at normal operation with long pulses or at compression process within an energy confinement time. Differences between HGHF plasma and former unity-beta plasma are discussed. Tokamak as an accelerator could scale down the design capacity of fusion power plant by simply inserting in-vacuum vertical field coils (IVC) within its vacuum vessel, such as China Fusion Engineering Test Reactor (CFETR).

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MOPOB52

Dielectric Loaded High Pressure Gas Filled RF Cavities for Use in Muon Cooling Channels

ion, cavity, solenoid, accelerating-gradient

177

B.T. Freemire
IIT, Chicago, Illinois, USA
M. Backfish, D.L. Bowring, A. Moretti, D.W. Peterson, A.V. Tollestrup, K. Yonehara
Fermilab, Batavia, Illinois, USA
R.P. Johnson
Muons, Inc, Illinois, USA
A.V. Kochemirovskiy
University of Chicago, Chicago, Illinois, USA
Y. Torun
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
High brightness muon beams require significant six dimensional cooling. One cooling scheme, the Helical Cooling Channel, employs high pressure gas filled radio frequency cavities, which provide both the absorber needed for ionization cooling, and a means to mitigate RF breakdown. The cavities are placed along the beam's trajectory, and contained within the bores of superconducting solenoid magnets. Gas filled RF cavities have been shown to successfully operate within multi-Tesla external magnetic fields, and not be overcome with the loading resulting from beam-induced plasma. The remaining engineering hurdle is to find a way to fit 325 and 650 MHz single cell pillbox cavities within the bores of the magnets using modern technology. One method to accomplish this is to partially fill the cavities with a dielectric material. Alumina (Al2O3) is an ideal dielectric, and the experimental test program to determine its performance under high power in a gas filled cavity has concluded. The final results, and their implications for the design of a muon cooling channel based on gas filled RF cavities will be discussed.

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TUA2IO01

AWAKE - A Proton Driven Plasma Wakefield Acceleration Experiment at CERN

ion, proton, electron, wakefield

266

A. Caldwell
MPI-P, München, Germany

It is the aim of the AWAKE project at CERN to demonstrate the acceleration of electrons in the wake created by a proton beam passing through plasma. The proton beam will be modulated as a result of the transverse two-stream instability into a series ofμbunches that will then drive strong wakefields. The wakefields will then be used to accelerate electrons with GV/m strength fields. The AWAKE experiment is currently being commissioned and first data taking is expected this year. The status of the experimental program is described as well as first thoughts on future steps.

Slides TUA2IO01 [24.428 MB]

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TUPOA28

Feasibility of OTR Imaging for Laser-Driven Plasma Accelerator Electron-Beam Diagnostics

ion, electron, polarization, laser

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).

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TUPOA44

Future Prospects of RF Hadron Beam Profile Monitors for Intense Neutrino Beam

ion, cavity, radiation, proton

373

Q. Liu
Case Western Reserve University, Cleveland, USA
M. Backfish, A. Moretti, V. Papadimitriou, A.V. Tollestrup, K. Yonehara, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
M.A. Cummings, R.P. Johnson, G.M. Kazakevich
Muons, Inc, Illinois, USA
B.T. Freemire
IIT, Chicago, Illinois, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013795.
A novel beam monitor based on a gas-filled RF resonator is proposed to measure the precise profile of secondary particles downstream of a target in the LBNF beam line at high intensity. The RF monitor is so simple that it promises to be radiation robust in extremely high-radiation environment. When a charged beam passes through a gas-filled microwave RF cavity, it produces electron-ion pairs in the RF cavity. The induced plasma changes the gas permittivity in proportion to the beam intensity. The permittivity shift can be measured by the modulated RF frequency and quality factor. The beam profile can thus be reconstructed from the signals from individual RF cavity pixels built into the beam profile monitor. A demonstration test is underway, and the current results has shown technical feasibility. The next phase consists of two stages, (1) to build and test a new multi-cell 2.45 GHz RF cavity that can be used for the NuMI beamline, and (2) to build and test a new multi-cell 9.3 GHz RF cavity that can be put in service in a future beamline at the LBNF for spatial resolution. These two resonant frequencies are chosen since they are the standard frequencies for magnetron RF source.

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TUPOA49

A General Model of Vacuum Arcs in Linacs

ion, experiment, laser, 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.

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TUA3CO03

Compact Ring-Based X-Ray Source With on-Orbit and on-Energy Laser-Plasma Injection

ion, electron, laser, 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 TUA3CO03 [8.411 MB]

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TUA4CO03

Loading of Wakefields in a Plasma Accelerator Section Driven by a Self-Modulated Proton Beam

ion, simulation, proton, wakefield

457

V.K.B. Olsen, E. Adli
University of Oslo, Oslo, Norway
P. Muggli
MPI-P, München, Germany
J. Vieira
Instituto Superior Tecnico, Lisbon, Portugal

Using parameters from the AWAKE project and particle-in-cell simulations we investigate beam loading of a plasma wake driven by a self-modulated proton beam. Addressing the case of injection of an electron witness bunch after the drive beam has already experienced self-modulation in a previous plasma, we optimise witness bunch parameters of size, charge and injection phase to maximise energy gain and minimise relative energy spread and emittance of the accelerated bunch.

Slides TUA4CO03 [3.103 MB]

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TUA4CO04

Simulation of High-Power Tunable THz Generation in Corrugated Plasma Waveguides

ion, laser, 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 TUA4CO04 [3.569 MB]

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TUPOB07

Considerations on Energy Frontier Colliders After LHC

ion, collider, luminosity, hadron

493

V.D. Shiltsev
Fermilab, Batavia, Illinois, USA

The future of the world-wide HEP community critically depends on the feasibility of possible post-LHC colliders. The concept of the feasibility is complex and includes at least three factors: feasibility of energy, feasibility of luminosiity and feasibility of cost. The talk will give on overview of all current options for post-LHC colliders from such perspective (ILC, CLIC, Muon Collider, plasma colliders, CEPC, FCC, HE-LHC, etc) and discuss major challenges and accelerator R&D required to claim these machines feasible.

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WEPOA01

Effect of Proton Bunch Parameter Variation on AWAKE

ion, wakefield, injection, electron

684

N. Savard
University of Victoria, Victoria BC, Canada
P. Muggli
MPI, Muenchen, Germany
J. Vieira
IPFN, Lisbon, Portugal

In AWAKE, long proton bunches propagate through a plasma, generating wakefields through the self-modulation instability (SMI). The phase velocity of these wakefields changes during the first 4 m of propagation and growth of the SMI, after which it stabilizes at the proton bunch velocity. This means that the ideal injection point for electrons to be accelerated is after 4 m into the plasma. Using the PIC code OSIRIS, we study how small changes in the initial proton bunch parameters (such as charge, radial and longitudinal bunch length, etc) to be expected in the experiment affect the phase velocity of the wakefields, primarily by looking at the difference in the phase of the wakefields at the point of injection (along the bunch and along the plasma) when changing these parameters by a small amount (±5%). We also look for the region of optimal acceleration/focusing for electron injection. Ultimately, it is found that small changes in the initial proton bunch parameters are not expected to significantly impact electron injection experiments in the future.

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WEPOA02

Progress Toward an Experiment at AWAKE*

ion, laser, 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

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WEPOA04

Design of Front End for RF Synchronized Short Pulse Laser Ion Source

ion, laser, rfq, ion-source

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.

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WEPOA09

Proton Beam Defocusing as a Result of Self-Modulation in Plasma

proton, ion, wakefield, focusing

707

M. Turner, E. Gschwendtner, A.V. Petrenko
CERN, Geneva, Switzerland
K.V. Lotov, A. Sosedkin
Budker INP & NSU, Novosibirsk, Russia

Funding: CERN
The AWAKE experiment will use a 400 GeV/c proton beam with a longitudinal bunch length of sigmq_z = 12 cm to create and sustain GV/m plasma wakefields over 10 meters. A 12 cm long bunch can only drive strong wakefields in a plasma with n_pe = 7 x 10¹⁴ electrons/cm³ after the self-modulation instability (SMI) developed and microbunches formed, spaced at the plasma wavelength. The fields present during SMI focus and defocus the protons in the transverse plane. We show that by inserting two imaging screens downstream the plasma, we can measure the maximum defocusing angle of the defocused protons for plasma densities above n_pe = 5 x10¹⁴ electrons/cm³. Measuring maximum defocusing angles around 1 mrad indirectly proves that SMI developed successfully and that GV/m plasma wakefields were created. In this paper we present numerical studies on how and when the wakefields defocus protons in plasma, the expected measurement results of the two screen diagnostics and the physics we can deduce from it.

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WEPOA29

Recent Experiments at NDCX-II: Irradiation of Materials Using Short, Intense Ion Beams

ion, experiment, target, focusing

755

P.A. Seidl, E. Feinberg, Q. Ji, B.A. Ludewigt, A. Persaud, T. Schenkel, M. Silverman, A.A. Sulyman, W.L. Waldron
LBNL, Berkeley, California, USA
J.J. Barnard, A. Friedman, D.P. Grote
LLNL, Livermore, California, USA
E.P. Gilson, I. Kaganovich, A.D. Stepanov
PPPL, Princeton, New Jersey, USA
F. Treffert, M. Zimmer
TU Darmstadt, Darmstadt, Germany

Funding: This work was supported by the Office of Science of the US Department of Energy under contracts DE-AC0205CH11231 (LBNL), DE-AC52- 07NA27344 (LLNL) and DE-AC02-09CH11466 (PPPL).
We present an overview of the performance of the Neutralized Drift Compression Experiment-II (NDCX-II) accelerator at Berkeley Lab, and summarize recent studies of material properties created with nanosecond and millimeter-scale ion beam pulses. The scientific topics being explored include the dynamics of ion induced damage in materials, materials synthesis far from equilibrium, warm dense matter and intense beam-plasma physics. We summarize the improved accelerator performance, diagnostics and results of beam-induced irradiation of thin samples of, e.g., tin and silicon. Bunches with over 3x10¹⁰ ions, 1-mm radius, and 2-30 ns FWHM duration have been created. To achieve these short pulse durations and mm-scale focal spot radii, the 1.2 MeV He⁺ ion beam is neutralized in a drift compression section which removes the space charge defocusing effect during final compression and focusing. Quantitative comparison of detailed particle-in-cell simulations with the experiment play an important role in optimizing accelerator performance; these keep pace with the accelerator repetition rate of ~1/minute.

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WEPOA30

High-Performance Modeling of Plasma-Based Acceleration and Laser-Plasma Interactions.

ion, simulation, laser, 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.

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WEPOA34

Progress on Beam-Plasma Effect Simulations in Muon Ionization Cooling Lattices

ion, simulation, emittance, scattering

765

J.S. Ellison
IIT, Chicago, Illinois, USA
P. Snopok
Fermilab, Batavia, Illinois, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: Work supported by the U.S. Department of Energy.
New computational tools are essential for accurate modeling and simulation of the next generation of muon-based accelerators. One of the crucial physics processes specific to muon accelerators that has not yet been simulated in detail is beam-induced plasma effect in liquid, solid, and gaseous absorbers. We report here on the progress of developing the required simulation tools and applying them to study the properties of plasma and its effects on the beam in muon ionization cooling channels.

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WEPOA39

Theoretical and Numerical Study on Plasmon-Assisted Channeling Interactions in Nanostructures

ion, laser, 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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA39

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WEPOA45

Positive and Negative Ions Radio Frequency Sources with Solenoidal Magnetic Field

ion, solenoid, ion-source, electron

799

V.G. Dudnikov, R.P. Johnson
Muons, Inc, Illinois, USA
G. Dudnikova
ICT SB RAS, Novosibirsk, Russia
B. Han, S. Murrey, C. Stinson
ORNL RAD, Oak Ridge, Tennessee, USA
T.R. Pennisi, C. Piller, M. Santana, M.P. Stockli, R.F. Welton
ORNL, Oak Ridge, Tennessee, USA

Funding: The work was supported in part by US DOE Contract DE-AC05-00OR22725 and by STTR grant, DE-SC0011323.
Operation of Radio Frequency surfaces plasma sources (RF SPS) with a solenoidal magnetic field are described. RF SPS with solenoidal and saddle antennas are discussed. Dependences of beam current and extraction current on RF power, gas flow, solenoidal magnetic field and filter magnetic field are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA45

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WEPOA55

Modulator Simulations for Coherent Electron Cooling

ion, electron, simulation, quadrupole

816

J. Ma, X. Wang
SBU, Stony Brook, New York, USA
V. Litvinenko, V. Samulyak, G. Wang, K. Yu
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA
V. Samulyak
SUNY SB, Stony Brook, New York, USA

Highly resolved numerical simulations of the modulator, the first section of the proposed coherent electron cooling (CEC) device, have been performed using the code SPACE. The beam parameters for simulations are relevant to the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Numerical convergence has been studied using various numbers of macro-particles and mesh refinements of computational domain. A good agreement of theory and simulations has been obtained for the case of stationary and moving ions in uniform electron clouds with realistic distribution of thermal velocities. The main result of the paper is the prediction of modulation processes for ions with reference and off-reference coordinates in realistic Gaussian electron bunches with quadrupole field.

Poster WEPOA55 [1.510 MB]

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THB2IO03

Fulfilling the Mission of Brookhaven ATF as DOE's Flagship User Facility in Accelerator Stewardship

ion, laser, electron, acceleration

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 THB2IO03 [49.425 MB]

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FRA1CO05

Progress of Gas-Filled Multi-RF-Cavity Beam Profile Monitor for Intense Neutrino Beams

ion, electron, cavity, experiment

1275

K. Yonehara, M. Backfish, A. Moretti, A.V. Tollestrup, A.C. Watts, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer
Muons, Inc, Illinois, USA
B.T. Freemire
IIT, Chicago, Illinois, USA
Q. Liu
Case Western Reserve University, Cleveland, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013795.
A novel pressurized gas-filled multi-RF-cavity beam profile monitor has been studied that is simple and robust in high-radiation environments. Charged particles passing through each RF-cavity in the monitor produce intensity-dependent ionized plasma, which changes the gas permittivity. The sensitivity to beam intensity is adjustable using gas pressure and RF gradient. The performance of the gas-filled beam profile monitor has been numerically simulated to evaluate the sensitivity of permittivity measurements. The result indicates that the RF resonator will be useful to measure the beam profile with a charged beam intensity range from 10⁶ to 10¹³ protons/bunch. The range covers the expected beam intensities in NuMI and LBNF. The demonstration of the monitor with intense proton beams are taken place at Fermilab to validate the simulation result. The result will be given in this presentation.

Slides FRA1CO05 [3.750 MB]

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