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SUPAF05 Polarized Proton Beams From Laser-Induced Plasmas laser, proton, polarization, plasma 46
  • M. Büscher, J. Böker, R. Engels, I. Engin, R. Gebel, A. Hützen, A. Lehrach
    FZJ, Jülich, Germany
  • A.M. Pukhov, J. Thomas
    HHUD, Dusseldorf, Germany
  • T. P. Rakitzis, D. Sofikitis
    University of Crete, Heraklion, Crete, Greece
  Laser-driven particle acceleration has undergone impressive progress in recent years. Nevertheless, one unexplored issue is how the particle spins are influenced by the huge magnetic fields inherently present in the plasmas. In the framework of the JuSPARC (Jülich Short-Pulse Particle and Radiation Center) facility and of the ATHENA consortium, the laser-driven generation of polarized particle beams in combination with the development of advanced target technologies is being pursued. In order to predict the degree of beam polarization from a laser-driven plasma accelerator, particle-in-cell simulations including spin effects have been carried out for the first time. For this purpose, the Thomas-BMT equation, describing the spin precession in electromagnetic fields, has been implemented into the VLPL (Virtual Laser Plasma Lab) code. A crucial result of our simulations is that a target containing pre-polarized hydrogen nuclei is needed for producing highly polarized relativistic proton beams. For the experimental realization, a polarized HCl gas-jet target is under construction the Forschungszentrum Jülich where the degree of hydrogen polarization is measured with a Lamb-shift polarimeter. The final experiments, aiming at the first observation of a polarized particle beam from laser-generated plasmas, will be carried out at the 10 PW laser system SULF at SIOM/Shanghai.  
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About • paper received ※ 19 October 2018       paper accepted ※ 24 October 2018       issue date ※ 26 January 2019  
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SUPAF09 Sparse Grid Particle-in-Cell Scheme for Noise Reduction in Beam Simulations simulation, electron, plasma, damping 71
  • A.J. Cerfon
    Courant Institute of Mathematical Sciences, New York University, New York, USA
  • L.F. Ricketson
    LLNL, Livermore, California, USA
  The complexity of standard solvers grows exponentially with the number of dimensions of the underlying equations. This issue is particularly acute for continuum solvers, which need to discretize the six-dimensional phase-space distribution function, and whose run times are consequently large even for a moderate number of grid points for each dimension. Particle-in-Cell (PIC) schemes are a popular alternate approach to continuum methods, because they only discretize the three-dimensional physical space and are therefore less subject to the curse of dimensionality. Even if so, PIC solvers still have large run times, because of the statistical error which is inherent to particle methods and which decays slowly with the number of particles per cell. In this talk, we will present a new scheme to address the curse of dimensionality and at the same time reduce the numerical noise of PIC simulations. Our PIC scheme is inspired by the sparse grids combination technique, a method invented to reduce grid based error when solving high dimensional partial differential equations [1]. The technique, when applied to the PIC method, has two benefits: 1) it almost eliminates the dependence of the grid based error on dimensionality, just like in a standard sparse grids application; 2) it lowers the statistical error significantly, because the sparse grids have larger cells, and thus a larger number of particles per cell for a given total number of particles. We will analyze the performance of our scheme for standard test problems in beam physics. We will demonstrate remarkable speed up for a certain class of problems, and less impressive performance for others. The latter will allow us to identify the limitations of our scheme and explore ideas to address them.
[1] Griebel M et al. 1990 A combination technique for the solution of sparse grid problems Iterative Methods in Linear Algebra ed R Bequwens and P de Groen (Amsterdam: Elsevier) pp 263-81
slides icon Slides SUPAF09 [1.848 MB]  
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About • paper received ※ 19 October 2018       paper accepted ※ 19 November 2018       issue date ※ 26 January 2019  
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SUPAG05 Muon Background Studies for Beam Dump Operation of the K12 Beam Line at CERN proton, experiment, background, simulation 93
  • M.S. Rosenthal, D. Banerjee, J. Bernhard, M. Brugger, N. Charitonidis, B. Döbrich, L. Gatignon, A. Gerbershagen, E. Montbarbon, B. Rae, M.W.U. Van Dijk
    CERN, Geneva, Switzerland
  • T. Spadaro
    INFN/LNF, Frascati, Italy
  In the scope of the Physics Beyond Colliders study at CERN a future operation of the NA62 experiment in beam dump mode is discussed, enabling the search for dark sector particles, e.g. heavy neutral leptons, dark photons and axions. For this purpose, the 400 GeV/c primary proton beam, extracted from the SPS, will be dumped on a massive dump collimator located in the front end of the K12 beam line. Muons originating from interactions and decays form a potential background for this kind of experiment. To reduce this background, magnetic sweeping within the beam line is employed. In this contribution, the muon production and transport has been investigated with the simulation framework G4beamline. The high computational expense of the muon production has been reduced by implementing sampling methods and parametrizations to estimate the amount of high-energy muons and efficiently study optimizations of the magnetic field configuration. These methods have been benchmarked with measured data, showing a good qualitative agreement. Finally, first studies to reduce the muon background by adapting the magnetic field configuration are presented, promising a potential background reduction by a factor four.  
slides icon Slides SUPAG05 [1.885 MB]  
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About • paper received ※ 19 October 2018       paper accepted ※ 28 January 2019       issue date ※ 26 January 2019  
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MOPAF02 Realistic Modeling of the Muon g-2 Experiment Beamlines at Fermilab simulation, storage-ring, experiment, proton 134
  • D. Tarazona, M. Berz, K. Makino
    MSU, East Lansing, Michigan, USA
  • D. Stratakis, M.J. Syphers
    Fermilab, Batavia, Illinois, USA
  • M.J. Syphers
    Northern Illinois University, DeKalb, Illinois, USA
  Funding: This work is supported by the U.S. Department of Energy under Award No. DE-FG02-08ER41546, by the PhD Accelerator Program at Fermilab, and by a Strategic Partnership Grant from the MSU Foundation.
The main goal of the Muon g-2 Experiment at Fermilab (E989) is to measure the muon anomalous magnetic moment (a, also dubbed as the "anomaly’’) to unprecedented precision. This new measurement will allow to test the completeness of the Standard Model (SM) and to validate other theoretical models beyond the SM. Simulations of the beamlines from the pion production target to the entrance of the g-2 Storage Ring using COSY INFINITY contribute to the understanding and characterization of the muon beam production in relation to the statistical and systematics uncertainties of the E989 measurement. The effect of nonlinearites from fringe fields and high-order contributions on the beam delivery system performance are considered, as well as interactions with the beamline elements apertures, particle decay channels, spin dynamics, and beamline misalignments.
slides icon Slides MOPAF02 [14.110 MB]  
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About • paper received ※ 22 October 2018       paper accepted ※ 28 January 2019       issue date ※ 26 January 2019  
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