WEPLO —  Wednesday Poster Session-Lake Ontario   (04-Sep-19   16:30—18:00)
Paper Title Page
WEPLO02 Progress on Muon Ionization Cooling Demonstration with MICE -1
  • P. Snopok
    Illinois Institute of Technology, Chicago, Illinois, USA
  Funding: STFC, NSF, DOE, INFN, CHIPP andd more
The Muon Ionization Cooling Experiment (MICE) at the Rutherford Appleton Laboratory has collected extensive data to study the ionization cooling of muons. Several million individual particle tracks have been recorded passing through a series of focusing magnets in a number of different configurations and a liquid hydrogen or lithium hydride absorber. Measurement of the tracks upstream and downstream of the absorber has shown the expected effects of the 4D emittance reduction. Further studies are providing more and deeper insight.
poster icon Poster WEPLO02 [0.514 MB]  
Laser-Ionized Thin Plasma Lenses  
  • C.E. Doss, R.A. Ariniello, J.R. Cary, K.D. Hunt-Stone
    CIPS, Boulder, Colorado, USA
  • J.R. Cary
    Tech-X, Boulder, Colorado, USA
  • M.D. Litos
    Colorado University at Boulder, Boulder, Colorado, USA
  Future plasma wakefield accelerators (PWFA) operating at higher densities will demand smaller electron beam sizes in order to match the beam divergence to the focusing force of the plasma ion column to preserve the transverse emittance. These requirements can be met by using thin, passive plasma lenses to focus the relativistic electron beams at strengths many times greater than conventional quadrupole magnets. To achieve the precise plasma density profiles necessary for thin plasma lenses, we propose using laser ionization by focusing a pulsed laser with peak power 10 - 100s GW into a gas jet outflow. Fluid simulations from a typical nozzle show that sufficient gas density uniformity can be achieved over the necessary volume in space. PIC simulations are used to simulate drive and witness beams interacting with such a lens and show agreement with analytical theory. We discuss plans to implement thin passive plasma lenses at SLAC’s FACET-II facility for use in PWFA future experiments.  
poster icon Poster WEPLO03 [1.213 MB]  
Recent Progress and Future Plans for the Accelerator Test Facility at Brookhaven National Laboratory  
  • M.A. Palmer, M. Babzien, C. Cullen, M.G. Fedurin, K. Kusche, R. Malone, M.A. Montemagno, I. Pogorelsky, M.N. Polyanskiy
    BNL, Upton, New York, USA
  Funding: Work supported by the US Department of Energy Office of Science under contract DE-SC0012704.
The Accelerator Test Facility (ATF) at Brookhaven National Laboratory operates as a National User Facility supported by the Accelerator Stewardship Program in the US DOE’s Office of High Energy Physics. The facility presently provides high brightness 80 MeV electron beams, terawatt-class CO2 laser and Ultrafast Electron Diffraction beamline capabilities to support a vibrant program in advanced accelerator R&D. Recent updates to our capabilities include the commissioning of an experimental chamber for electron beam-laser interactions in plasma, the demonstration of >5 TW peak laser power in a single <2 ps pulse at a wavelength of 9.2 microns, and the commissioning of new electron beam diagnostics based on an x-band deflecting cavity. The facility currently supports over 20 active experimental efforts in advanced accelerator research. We describe the current operating status of the facility as well as our future plans.
Developing Criteria for Laser Transverse Instability in LWFA Simulations  
SUPLE07   use link to see paper's listing under its alternate paper code  
  • Y. Yan, L.D. Amorim, P. Iapozzuto, V. Litvinenko, N. Vafaei-Najafabadi
    Stony Brook University, Stony Brook, USA
  • M. Babzien, M.G. Fedurin, Y.C. Jing, K. Kusche, M.A. Palmer, I. Pogorelsky, M.N. Polyanskiy
    BNL, Upton, New York, USA
  • M. Downer, J.R. Welch, R. Zgadzaj
    The University of Texas at Austin, Austin, Texas, USA
  • C. Joshi, W.B. Mori
    UCLA, Los Angeles, California, USA
  • P. Kumar, V. Samulyak
    SBU, Stony Brook, USA
  Funding: We acknowledge resources of NERSC facility, operated under Contract No. DE-AC02-5CH11231, and of SEAWULF at Stony Brook University as well as funding from SBU-BNL Seed Grants.
Laser-driven plasma wakefield acceleration (LWFA) is considered as a potential technology for future colliders and light sources. To make the best use of a laser’s power, the laser is expected to maintain a stable propagation. A transverse instability is observed in our previous simulations when a long, intense CO2 laser propagates inside a plasma*. This unstable motion is accompanied by strong transverse diffraction of the laser power and results in the disruption of the ion channel typically used for radiation generation**. We investigated the hosing-like instability using the Particle-in-Cell code OSIRIS*** by modeling the laser portion where this instability is seeded and then evolves. In this proceeding, a criteria will be described that allows for the characterization of the temporal and spatial evolution of this instability.
*J. Yan, et al. , AAC, IEEE, 2018.
** L. Nemos et al., PPCF, 58(3), 2016.
***R. A. Fonseca et al., Lecture Notes Computation Science (2331) 342, 2002.
WEPLO06 Start-to-End Simulation of the Drive-Beam Longitudinal Dynamics for Beam-Driven Wakefield Acceleration -1
SUPLE03   use link to see paper's listing under its alternate paper code  
  • W.H. Tan, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  • A. Zholents, A. Zholents
    ANL, Lemont, Illinois, USA
  Funding: This work is supported by the U.S. Department of Energy, Office of Science under contracts No. DE-AC02-06CH11357 (via a laboratory- directed R&D program at ANL) and No. DE-SC0018656 at NIU.
Collinear beam-driven wakefield acceleration (WFA) relies on shaped driver beam to provide higher accelerating gradient at a smaller cost and physical footprint. This acceleration scheme is currently envisioned to accelerate electron beams capable of driving free-electron laser *. Start-to-end simulation of drive-bunch beam dynamics is crucial for the evaluation of the design of accelerators built upon WFA. We report the start-to-end longitudinal beam dynamics simulations of an accelerator beamline capable of producing high charge drive beam. The generated wakefield when it passes through a corrugated waveguide results in a transformer ratio of 5. This paper especially discusses the challenges and criteria associated with the generation of temporally-shaped driver beam, including the beam formation in the photoinjector, and the influence of energy chirp control on beam transport stability.
A. Zholents et al., "A Conceptual Design of a Compact Wakefield Accelerator for a High Repetition Rate Multi User X-ray Free-Electron Laser Facility"
Ion Motion and Hosing Suppression in Plasma-Based Accelerators  
  • C.B. Schroeder, C. Benedetti, E. Esarey, T.J. Mehrling
    LBNL, Berkeley, California, USA
  Funding: Supported by the U.S. DOE under Contract No. DE-AC02-05CH11231.
Plasma accelerators can produce extremely high fields, enabling compact accelerators. The transverse wakefields in a plasma accelerator will drive the hosing instability (growth in beam misalignment). We show that hosing in plasma accelerators can be mitigated by plasma ion motion. For high-energy beams with low emittance, the focusing in the plasma will pinch the beam to a density that is orders of magnitude above the ion density, leading to ion motion over the bunch duration, resulting in nonlinear focusing fields and emittance growth. However, such ion motion will generate a head-to-tail variation in the focusing experienced by the beam, which can suppress hosing. By analyzing the response of the ions to a high-density beam, including the coupling to the hosing instability, it is shown that the ion motion results in hosing suppression. A class of beam distributions are identified that are equilibrium solutions in the plasma wakefield, including ion motion. Using these distributions enables ion motion without emittance growth. Hence, stable acceleration in plasma accelerators is possible and, by beam shaping, both the emittance may be preserved and the energy spread minimized.
Physics Studies for High Intensity Proton Beams at the Fermilab Booster  
THZBA1   use link to access more material from this paper's primary paper code  
  • J.S. Eldred
    Fermilab, Batavia, Illinois, USA
  We present the results of the studies of the physics of high intensity proton seams at the 8 GeV Fermilab Booster RCS carried out in Spring 2019. The Booster studies span a variety of beam physics topics ’ The discovery of a new convective beam instability, an investigation of power-supply ripple in the Booster gradient dipoles, a characterization of space-charge induced emittance growth, optimization of adiabatic capture, a study of periodicity in the Booster, nonlinear chromaticity measurements, and transverse impedance measurements. The results will help prepare the Booster for the upcoming PIP-II intensity upgrades and inform next-generation RCS design.  
slides icon Slides WEPLO10 [7.566 MB]  
WEPLO11 Single Cycle THz Acceleration Structures -1
  • S.V. Kuzikov, A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  • S.P. Antipov, E. Gomez
    Euclid TechLabs, LLC, Solon, Ohio, USA
  Funding: This work was supported by the Russian Science Foundation under grant 19-42-04133 in the part of CST simulations for THz structures.
Recently, gradients on the order of 1 GV/m level have been obtained in a form of single cycle (~1 ps) THz pulses produced by conversion of a high peak power laser radiation in nonlinear crystals (~1 mJ, 1 ps, up to 3% conversion efficiency). These pulses however are broadband (0.1-5 THz) and therefore a new accelerating structure type is required. For electron beam acceleration with such pulses we propose arrays of parabolic focusing micro-mirrors with common central. These novel structures could be produced by a femtosecond laser ablation system developed at Euclid Techlabs. This technology had already been tested for production of several millimeters long, multi-cell structure which has been testing with electron beam. We also propose using of structures where necessary GV/m E-fields are excited by a drive bunch travelling in the corrugated waveguide. The radiated by drive bunch sequence of short range delayed wakes are guided in this case by metallic disks and reflected back being focused exactly at time when the witness bunch arrives.
poster icon Poster WEPLO11 [2.123 MB]  
WEPLO12 Design of a PIP-II Era Mu2e Experiment -1
  • M.A. Cummings, R.J. Abrams, T.J. Roberts
    Muons, Inc, Illinois, USA
  • D.V. Neuffer
    Fermilab, Batavia, Illinois, USA
  We present an alternative Mu2e-II production scheme for the Fermilab PIP-II era based on production schemes we devised for muon-collider and neutrino-factory front ends. Bright muon beams generated from sources designed for muon collider and neutrino factory facilities have been shown to generate two orders of magnitude more muons per proton than the current Mu2e production target and solenoid. In contrast to the current Mu2e, the muon collider design has forward-production of muons from the target. Forward production from 8 GeV protons would include high energy antiprotons, pions and muons, which would provide too much background for the Mu2e system. In contrast, the 800 MeV PIP-II beam does not have sufficient energy to produce antiprotons, and other secondaries will be at a low enough energy that they can be ranged out with an affordable shield of ~ 2 meters of concrete.  
Modeling of Capillary Discharge Plasmas for Plasma Wakefield Accelerators and Beam Transport  
  • N.M. Cook, J.A. Carlsson, P. Moeller, R. Nagler
    RadiaSoft LLC, Boulder, Colorado, USA
  • P. Tzeferacos
    Flash Center for Computational Science, Chicago, USA
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0018719.
Discharge capillary plasmas have been shown to increase both the peak energy and beam quality of laser wakefield accelerator, enabling the guiding of intense laser pulses over many Rayleigh lengths. They are also promising candidates for active plasma lenses, featuring peak magnetic fields hundreds of times larger than traditional magnets. For next-generation accelerators, these plasma sources are especially sensitive to plasma density profile evolution, and require careful consideration of heat transfer and magnetic field penetration to resolve the dynamics on relevant time scales. We present simulations of capillary discharge waveguides and active plasma lenses in 2D geometries using FLASH, a publicly-available multi-physics code in development at the University of Chicago. We report on boundary condition challenges for capturing realistic conductivities and magnetic field evolution. We then illustrate the use of laser deposition to model low density channel formation. Lastly, we discuss simulations of active capillary plasmas with different fill species, which show agreement with experimental observations of nonlinearities in the current density profile and magnetic field.
WEPLO16 Energy Spread Measurements for 400 MeV LINAC Beam at Fermilab Booster using a LASER Notcher System -1
  • C.M. Bhat, D.E. Johnson
    Fermilab, Batavia, Illinois, USA
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
To mitigate 8 GeV beam losses at extraction in the Fermilab Booster synchrotron, a LASER notcher system for multi-turn injection that produces notches at 720 keV is used. These notches synchronize with the revolution period of the beam [ref. HB2018, page 416] at injection in the Booster. Recently, a dedicated notching pattern that keeps a single 201 MHz LINAC bunch untouched in the middle of a notch is developed to measure the beam energy spread by studying the time evolution of this bunch in the Booster. A complementary to this method, recently, it has been realized that one can also measure energy spread of the LINAC beam by injecting <2 Booster turn beam and studying the time evolution of the multiple 201 MHz LINAC bunches. In this paper we present the general principle of the method and results from our measurements.
poster icon Poster WEPLO16 [0.198 MB]  
Ultrashort Laser Pulse Shaping and Characterization for Tailored Electron Bunch Generation  
SUPLE06   use link to see paper's listing under its alternate paper code  
  • T. Xu, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • M.E. Conde, G. Ha, J.G. Power
    ANL, Lemont, Illinois, USA
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  Temporally shaped laser pulses are desirable in various applications including emittance reduction and beam-driven acceleration. Pulse shaping techniques enable flexible controls over the longitudinal distribution of electron bunches emitted from the photocathode. While direct manipulation and measurement of an ultrashort pulse can be challenging in the time domain, both actions can be performed in the frequency domain. In this paper, we report the study and development of laser shaper and diagnostics at Argonne Wakefield Accelerator (AWA). Simulations of the shaping process for several sought-after shapes are presented along with the temporal diagnosis. Status of the experiment at the AWA facility is also discussed.  
WEPLO18 Numerical Study of Coherent Radiation from Induced Plasma Dipole Oscillation by Detuned Laser Pulses -1
  • P.C. Castillo, S.D. Rodriguez, D.A. Wan
    SUNY Farmingdale State College, State University of New York, Farmingdale, New York, USA
  • B. Gross
    City College of The City University of New York, New York, USA
  • M.S. Hur, S. Kylychbekov, H.S. Song
    UNIST, Ulsan, Republic of Korea
  • D.G. Lee
    SBU, Stony Brook, New York, USA
  • K. Yu
    BNL, Upton, New York, USA
  The study of intense laser-plasma interactions is a growing field of both theoretical and applied research. This research focuses on simulating the cross/self-interactions between high-intense short laser pulses and an initial target for preliminary ionization. Unlike our previous studies of laser-matter interaction over preformed plasma, we will explore the injection of laser pulses to induce background plasma driven by the self-guided laser wakefield mechanism, which is used to perturb the plasma for induced dipole oscillations followed by radiation. Inducing a cylindrical spatial plasma column within the laser beam radius regime, it is expected that a stable spatially localized plasma channel will result and the emitted radiation from the plasma dipole oscillation (PDO) will not be affected by surrounding absorption, resulting in effective radiation. We will depict the injection of laser pulses accounting for parameters such as field intensity, profile and phase difference defining the coordinated pulses to assess the potential of enhancing the efficiency and spectral properties of the transverse emitted radiation due to the counter-propagating pulses interaction in plasma.  
WEPLO19 Probing Multiperiod Plasma Response Regimes using Single Shot Wakefield Measurements -1
  • R.J. Roussel, G. Andonian, W.J. Lynn, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • M.E. Conde, D.S. Doran, G. Ha, J.G. Power, C. Whiteford, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  • J. Seok
    UNIST, Ulsan, Republic of Korea
  Funding: DE-SC0017648
Systematic differences between the linear and nonlinear regimes of plasma wakefield acceleration from electron beams are manifested in the plasma response. Typically, the ratio of peak beam density to nominal plasma density determines operation in the linear or nonlinear regime. Previous reports have shown that a the cross-over into the nonlinear regime is associated with an increase in the wakefield amplitude, as well as sawtooth-like shape. In this paper, we present preliminary measurements of quasi-nonlinear wakefields driven by a linearly ramped beam, with a maximum charge close to the unperturbed plasma density. We also demonstrate nonlinear wakefield behavior in a probe bunch using a single shot, multi-period wakefield measurement and its dependency on plasma density.
WEPLO20 High Gradient High Efficiency C-Band Accelerator Structure Research at LANL -1
  • E.I. Simakov, A.W. Garmon, T.C. Germann, M.F. Kirshner, F.L. Krawczyk, J.W. Lewellenpresenter, D. Perez, G. Wang
    LANL, Los Alamos, New Mexico, USA
  • A. Fukasawa, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  Funding: Los Alamos National Laboratory LDRD Program
This poster will report on the status of the new high gradient C-band accelerator project at LANL. Modern applications such as X-ray sources require accelerators with optimized cost of construction and operation, naturally calling for high-gradient acceleration. Our goal is to use a multi-disciplinary approach that includes accelerator design, molecular dynamics simulations, and advanced manufacturing to develop high gradient, high efficiency RF structures for both compact and facility-size accelerator systems. We considered common operation frequencies for accelerators and identified C-band as the optimal frequency band for high gradient operations based on achievable gradients and means to control wakefields. We are putting together a high gradient C-band test facility that includes a 50 MW Toshiba klystron and cryo-coolers for operating copper NCRF accelerator cavities at long pulse duration. We plan to conduct high gradient testing of the optimized RF structures made of copper and novel copper alloys. LANL modeling capabilities will be used to systematically study the formation of breakdown precursors at high fields to develop basic theoretical understanding of the breakdown.
AWAKE Run 2 Plans  
  • P. Muggli
    MPI, Muenchen, Germany
  AWAKE very successfully demonstrated self-modulation (SM) of the long proton bunch in plasma and the acceleration of externally injected electrons from 19MeV to 2GeV. We are developing plans for Run 2. These include density step in a first plasma , the self-modulator. Simulation results show that with the step the amplitude of the wakefields remains at a large fraction of its saturation value for long plasma lengths. After a short gap, the self-modulated proton bunch drives wakefields in the accelerator plasma. In the gap, the electron bunch, short when compared to the wakefields period, is injected on-axis. Its parameters are such that it causes full blow-out of the plasma electrons, is matched the pure ion column focusing fields at its waist, and optimally loads the walkefields. In this case, a significant fraction of the bunch charge (~70%) is accelerated with a narrow energy spread (<1%) and retains its incoming emittance. At the same time, we are developing new plasma sources (e.,g., helicon, discharge) that can be very long (100s m). We explore possible applications of this acceleration scheme to high-energy physics. The overall plan for Run 2 and beyond will be presented.
For the AWAKE Collaboration
Magnetized Electron Source for JLEIC Cooler  
MOZBB5   use link to access more material from this paper's primary paper code  
  • R. Suleiman, P.A. Adderley, J.F. Benesch, D.B. Bullard, J.M. Grames, J. Guo, F.E. Hannon, J. Hansknecht, C. Hernandez-Garcia, R. Kazimi, G.A. Krafft, M.A. Mamun, M. Poelker, M.G. Tiefenback, Y.W. Wang, S. Zhang
    JLab, Newport News, Virginia, USA
  • J.R. Delayen, G.A. Krafft, S.A.K. Wijethunga, J.T. Yoskowitz
    ODU, Norfolk, Virginia, USA
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and supported by Laboratory Directed Research and Development funding.
Magnetized bunched-beam electron cooling is a critical part of the Jefferson Lab Electron Ion Collider (JLEIC). Strong cooling of ion beams will be accomplished inside a cooling solenoid where the ions co-propagate with an electron beam generated from a source immersed in magnetic field. This contribution describes the production and characterization of magnetized electron beam using a compact 300 kV DC high voltage photogun and bialkali-antimonide photocathodes. Beam magnetization was studied using a diagnostic beamline that includes viewer screens for measuring the shearing angle of the electron beamlet passing through a narrow upstream slit. Correlated beam emittance with magnetic field at the photocathode was measured for various laser spot sizes. Measurements of photocathode lifetime were carried out at different magnetized electron beam currents up to 28 mA and high bunch charge up to 0.7 nano-Coulomb was demonstrated.
slides icon Slides WEPLO22 [6.626 MB]