Keyword: scattering
Paper Title Other Keywords Page
WEPOA34 Progress on Beam-Plasma Effect Simulations in Muon Ionization Cooling Lattices ion, plasma, simulation, emittance 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.
DOI • reference for this paper ※  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
WEPOA37 Hybrid Methods for Simulation of Muon Ionization Cooling Channels ion, simulation, collider, experiment 775
  • J.D. Kunz, P. Snopok
    IIT, Chicago, Illinois, USA
  • M. Berz
    MSU, East Lansing, Michigan, USA
  • J.D. Kunz
    Anderson University, Anderson, USA
  • P. Snopok
    Fermilab, Batavia, Illinois, USA
  Funding: Work supported by the U.S. Department of Energy
COSY Infinity is an arbitrary-order beam dynamics simulation and analysis code. It uses high-order transfer maps of combinations of particle optical elements of arbitrary field configurations. New features have been developed and implemented in COSY to follow charged particles through matter. To study in detail the properties of muons passing through a material, the transfer map approach alone is not sufficient. The interplay of beam optics and atomic processes must be studied by a hybrid transfer map–Monte Carlo approach in which transfer map methods describe the average behavior of the particles including energy loss, and Monte Carlo methods are used to provide small corrections to the predictions of the transfer map, accounting for the stochastic nature of scattering and straggling of particles. This way the vast majority of the dynamics is represented by fast application of the high-order transfer map of an entire element and accumulated stochastic effects. The gains in speed simplify the optimization of muon cooling channels which are usually very computationally demanding. Progress on the development of the required algorithms is reported.
DOI • reference for this paper ※  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
WEPOB20 Multiple Scattering Effects on a Short Pulse Electron Beam Travelling Through Thin Beryllium Foils ion, experiment, vacuum, simulation 937
  • E.E. Wisniewski, S.P. Antipov, M.E. Conde, D.S. Doran, W. Gai, Q. Gao, C.-J. Jing, W. Liu, J.G. Power, C. Whiteford
    ANL, Argonne, Illinois, USA
  • S.P. Antipov, C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • Q. Gao
    TUB, Beijing, People's Republic of China
  • G. Ha
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  Funding: Argonne, a U.S.A. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357.
The Argonne Wakefield Accelerator beamlines have stringent vacuum requirements (100 picotorr) necessitated by the Cesium telluride photoinjector. In direct conflict with this, the structures-based wakefield accelerator research program sometimes includes worthy but complex experimental installations with components or structures unable to meet the vacuum standards. A proposed chamber to sequester such experiments safely behind a thin beryllium (Be) window is described and the results of a study of beam-quality issues due to the multiple scattering of the beam through the window are presented and compared to GEANT4 simulations via G4beamline. Three thicknesses of Be foil were used: 30, 75 and 127 micron, probed by electron beams of three different energies: 25, 45, and 65 MeV. Multiple scattering effects were evaluated by comparing the measured transverse rms beam size for the scattered vs. unscattered beam. The experimental results are presented and compared to simulations. Results are discussed along with the implications and suggestions for the future sequestered vacuum chamber design.
DOI • reference for this paper ※  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
WEPOB21 Benchmarking of Touschek Beam Lifetime Calculations for the Advanced Photon Source ion, synchrotron, coupling, storage-ring 940
  • A. Xiao, B.X. Yang
    ANL, Argonne, Illinois, USA
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Particle loss from Touschek scattering is one of the most significant issues faced by present and future synchrotron light source storage rings. For example, the predicted, Touschek-dominated beam lifetime for the Advanced Photon Source (APS) Upgrade lattice in 48-bunch, 200-mA timing mode is only ~2 h. In order to understand the reliability of the predicted lifetime, a series of measurements with various beam parameters was performed on the present APS storage ring. This paper first describes the entire process of beam lifetime measurement, then compares measured lifetime with the calculated one by applying the measured beam parameters. The results show very good agreement.
DOI • reference for this paper ※  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
WEPOB35 LLNL Laser-Compton X-Ray Characterization ion, electron, laser, simulation 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 ※  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
THPOA42 3D Modeling and Simulations of Electron Emission From Photocathodes With Controlled Rough Surfaces ion, electron, simulation, cathode 1187
  • D.A. Dimitrov, G.I. Bell, D.N. Smithe, C.D. Zhou
    Tech-X, Boulder, Colorado, USA
  • I. Ben-Zvi, J. Smedley
    BNL, Upton, Long Island, New York, USA
  • S.S. Karkare, H.A. Padmore
    LBNL, Berkeley, California, USA
  Funding: This work is supported by the US DOE Office of Science, department of Basic Energy Sciences under grant DE-SC0013190.
Developments in materials design and synthesis have resulted in photocathodes that can have a high quantum efficiency (QE), operate at visible wavelengths, and are robust enough to operate in high electric field gradient photoguns, for application to free electron lasers and in dynamic electron microscopy and diffraction. However, synthesis often results in roughness, ranging from the nano to the microscale. The effect of this roughness in a high gradient accelerator is to produce a small transverse accelerating gradient, which therefore results in emittance growth. Although analytical formulations of the effects of roughness have been developed, a full theoretical model and experimental verification are lacking, and our work aims to bridge this gap. We report results on electron emission modeling and 3D simulations from photocathodes with controlled surface roughness similar to grated surfaces that have been fabricated by nanolithography. The simulations include both charge carrier dynamics in the photocathode material and a general electron emission modeling that includes field enhancement effects at rough surfaces. The models are being implemented in the VSim code.
DOI • reference for this paper ※  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
FRA2CO03 Study of the Electrical Center of a Resonant Cavity Beam Position Monitor (RF-BPM) and Its Integration With the Main Beam Quadrupole for Alignment Purposes ion, cavity, alignment, quadrupole 1297
  • S. Zorzetti, M. Wendt
    CERN, Geneva, Switzerland
  • L. Fanucci
    Università di Pisa, Pisa, Italy
  To achieve the luminosity goals in a next generation linear collider, acceleration and preservation of ultra-low emittance particle beams is mission critical and requires a precise alignment between the main accelerator components. PACMAN is an innovative doctoral training program, hosted by CERN, with the goal of developing high accuracy metrology and alignment methods and tools to integrate those components in a standalone, automatic test bench. The method will be validated on CLIC components, a proposed Compact Linear Collider currently studied at CERN. The alignment between the electrical center of the Beam Position Monitor (BPM) and the magnetic center of the associated Main Beam Quadrupole (MBQ) is of particular importance to minimize the emittance blow-up, and therefore in the focus of the PACMAN project. The two components have been independently characterized on separated test benches by stretched and vibrating wire techniques. Preliminary conclusions are presented in this paper, with emphasis on the characterization of the electrical center of the BPM.
The PACMAN project is funded by the European Union' s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 606839
slides icon Slides FRA2CO03 [7.920 MB]  
poster icon Poster FRA2CO03 [1.570 MB]  
DOI • reference for this paper ※  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)