Keyword: resonance
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MOPOB29 Measurements of the Properties of Garnet Material for Tuning a 2nd Harmonic Cavity for the Fermilab Booster ion, cavity, solenoid, ISOL 134
 
  • R.L. Madrak, W. Pellico, G.V. Romanov, C.-Y. Tan, I. Terechkine
    Fermilab, Batavia, Illinois, USA
 
  A perpendicular biased 2nd harmonic cavity is being designed and built for the Fermilab Booster, to help with injection and transition. The frequency range is 76 - 106 MHz. The garnet material chosen for the tuner is AL800. To reliably model the cavity, its static permeability and loss tangent must be well known. We present our measurements of these properties.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB29  
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MOPOB53 Simulation of Ping-Pong Multipactor with Continuous Electron Seeding ion, simulation, electron, multipactoring 181
 
  • M. Siddiqi, R.A. Kishek
    UMD, College Park, Maryland, USA
 
  Funding: National Science Foundation grant No. PHY1535519
Multipactor is a discharge induced by the impact of electrons on a surface due to radio-frequency (RF) electromagnetic fields and secondary electron emission (SEE). Depending on the impact energy and RF phase of the incident electron, a growth in the electron density is possible. Multipactor can lead to device breakdown in many applications, such as particle accelerator structures and rf systems, satellite communication equipment, and microwave components. Multipactor can also be a precursor for electron cloud effects. Due to the critical need to mitigate multipactor, a more comprehensive theory has been introduced that views multipactor as a global effect that can be analyzed through the concepts of iterative maps and nonlinear dynamics *. In order to test this novel approach, multipactor is simulated in a parallel-plate waveguide using the WARP particle-in-cell code. Different parameters are varied in the simulation to determine the conditions that add to multipactor growth, such as geometry dimensions, electron seeding scenarios, and an applied DC electric field. These computational results and their implications on the further development of this theory will be presented.
*R.A. Kishek, Physics of Plasmas 20, 056702 (2013).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB53  
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TUPOB21 MuSim, A Graphical User Interface for Multiple Simulation Codes ion, simulation, interface, proton 535
 
  • T.J. Roberts, Y. Bao
    Muons, Inc, Illinois, USA
  • Y. Bao
    UCR, Riverside, California, USA
 
  MuSim is a user-friendly program designed to interface to many different particle simulation codes, regardless of their data formats or geometry descriptions. It presents the user with a compelling graphical user interface that includes a flexible 3-D view of the simulated world plus powerful editing and drag-and-drop capabilities. All aspects of the design can be parameterized so that parameter scans and optimizations are easy. It is simple to create plots and display events in the 3-D viewer, allowing for an effortless comparison of different simulation codes. Simulation codes: G4beamline 3.02, MCNP 6.1, and MAD-X; more are coming. Many accelerator design tools and beam optics codes were written long ago, with primitive user interfaces by today's standards. MuSim is specifically designed to make it easy to interface to such codes, providing a common user experience for all, and permitting the construction and exploration of models with very little overhead. For today's technology-driven students, graphical interfaces meet their expectations far better than text-based tools, and education in accelerator physics is one of our primary goals.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB21  
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TUPOB26 Dynamics of Intense Beam in Quadrupole-Duodecapole Lattice Near Sixth Order Resonance ion, quadrupole, focusing, lattice 552
 
  • Y.K. Batygin, T.T. Fronk
    LANL, Los Alamos, New Mexico, USA
 
  Funding: Work supported by US DOE under contract DE-AC52-06NA25396
The presence of duodecapole components in quadrupole focusing field results in excitation of sixth-order single-particle resonance if the phase advance of the particles transverse oscillation is close to 60 deg. This phenomenon results in intensification of beam losses. We present analytical and numerical treatment of particle dynamics in the vicinity of sixth-order resonance. The topology of resonance in phase space is analyzed. Beam emittance growth due to crossing of resonance islands is determined. Halo formation of intense beams in presence of resonance conditions is examined.
 
poster icon Poster TUPOB26 [3.523 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB26  
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TUPOB35 Progress on Skew Parametric Resonance Ionization Cooling Channel Design and Simulation ion, coupling, multipole, optics 565
 
  • A.V. Sy, Y.S. Derbenev, V.S. Morozov
    JLab, Newport News, Virginia, USA
  • A. Afanasev
    GWU, Washington, USA
  • Y. Bao
    UCR, Riverside, California, USA
  • R.P. Johnson
    Muons, Inc, Illinois, USA
 
  Funding: This work was supported in part by U.S. DOE STTR Grant DE-SC0005589. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Skew Parametric-resonance Ionization Cooling (Skew PIC) is an extension of the Parametric-resonance Ionization Cooling (PIC) framework that has previously been explored as the final 6D cooling stage of a high-luminosity muon collider. The addition of skew quadrupoles to the PIC magnetic focusing channel induces coupled dynamic behavior of the beam that is radially periodic. The periodicity of the radial motion allows for the avoidance of unwanted resonances in the horizontal and vertical transverse planes, while still providing periodic locations at which ionization cooling components can be implemented. Properties of the linear beam dynamics have been previously reported and good agreement exists between theory, analytic solutions, and simulations. Progress on aberration compensation in the coupled correlated optics channel is presented and discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB35  
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TUPOB38 Implementation of MAD-X into MuSim ion, simulation, interface, detector 575
 
  • Y. Bao
    UCR, Riverside, California, USA
  • T.J. Roberts
    Muons, Inc, Illinois, USA
 
  Funding: This work is supported by Muons, Inc.
MuSim is a new and innovative graphical system that allows the user to design, optimize, analyze, and evaluate accelerator and particle systems efficiently. It is designed for both students and experienced physicists to use in dealing with the many modeling tools and their different description languages and data formats. G4beamline [1] and MCNP [2] have been implemented into MuSim in previous studies. In this work, we implement MAD-X [3] into MuSim so that the users can easily use the graphical interface to design beam lines with MAD-X and compare the modeling results of different codes.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB38  
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TUPOB54 Using Square Matrix to Realize Phase Space Manipulation and Dynamic Aperture Optimization ion, lattice, sextupole, dynamic-aperture 609
 
  • Y. Li, L. Yu
    BNL, Upton, Long Island, New York, USA
 
  We introduce a new method of using square matrix to realize phase space manipulation and dynamic aperture optimization in storage rings. Both the tracking simulation and the experimental observation in the NSLS-II ring lattice are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB54  
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WEA2IO01 Calculating Spin Lifetime ion, polarization, lattice, synchrotron 667
 
  • V.H. Ranjbar
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by the US Department of Energy under contract number DE-SC0012704.
We have extended a lattice independent code to integrate the Thomas-BMT equation over 2 hours of beam time in the presence of two orthogonal Siberian snakes. In tandem to this we have recast the Thomas-BMT equation in the presences of longitudinal dynamics, into the parametric resonance formalism recently developed to understand overlapping spin resonances *
* V. H. Ranjbar, "Approximations for crossing two nearby spin
resonances," Phys. Rev. ST Accel. Beams 18, no. 1, 014001
(2015). doi:10.1103/PhysRevSTAB.18.014001
 
slides icon Slides WEA2IO01 [2.252 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEA2IO01  
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WEPOA52 Modeling and Simulation of RFQs for Analysis of Fields and Frequency Deviations with Respect to Internal Dimensional Errors ion, rfq, simulation, operation 810
 
  • Y.W. Kang, S.W. Lee
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: This work was supported by SNS through UT­Battelle, LLC, under contract DE­AC05­00OR22725 for the U.S.DOE.
Performance of radio frequency quadrupole (RFQ) is sensitive to the errors in internal dimensions which shift resonance frequency and distort field distribution on the beam axis along the structure. The SNS RFQ has been retuned three times to compensate the deviations in frequency and field flatness with suspected dimensional changes since the start of the project for continuous operation with H ion beams. SNS now has a new RFQ as a spare that is installed in beam test facility (BTF), a low energy test accelerator. In order to understand and predict the performance deviation, full 3D modeling and simulation were performed for the SNS RFQs. Field and frequency errors from hypothetical transverse vane perturbations, and vane erosion (and metal deposition such as Cesium introduced by the ion source operation) at the low energy ends are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA52  
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WEPOA54 Simulation of a Skew Parametric Resonance Ionization Cooling Channel ion, simulation, cavity, collider 813
 
  • Y. Bao
    UCR, Riverside, California, USA
  • A. Afanasev
    GWU, Washington, USA
  • Y.S. Derbenev, V.S. Morozov, A.V. Sy
    JLab, Newport News, Virginia, USA
  • R.P. Johnson
    Muons, Inc, Illinois, USA
 
  Skew Parametric-resonance Ionization Cooling (Skew-PIC) is designed for the final 6D cooling of a high-luminosity muon collider. Tracking of muons in such a channel has been modeled in MAD-X in previous studies. However, the ionization cooling process has to be simulated with a code that can handle matter dominated beam lines. In this paper we present the simulation of a Skew-PIC channel using G4beamline. We implemented the required magnetic field components into G4beamline and compare the tracking of muons by the two different codes. We optimize the cooling channel and present the muon cooling effect in the Skew-PIC channel for the first time.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA54  
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WEA4CO03 Intrinsic Landau Damping of Space Charge Modes at Coupling Resonance ion, damping, coupling, ECR 863
 
  • A. Macridin, J.F. Amundson, A.V. Burov, P. Spentzouris, E.G. Stern
    Fermilab, Batavia, Illinois, USA
 
  Funding: This work was performed at Fermilab, operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Using Synergia accelerator modeling package and Dynamic Mode Decomposition technique, the properties of the first transverse dipole mode in Gaussian bunches with space charge are compared at transverse coupling resonance and off-resonance. The Landau damping at coupling resonance and in the strong space charge regime is a factor of two larger, while the mode's tune and shape are nearly the same. While the damping mechanism in the off-resonance case fits well with the classical Landau damping paradigm, the enhancement at coupling resonance is due to a higher order mode-particle coupling term which is modulated by the amplitude oscillation of the resonance trapped particles.
 
slides icon Slides WEA4CO03 [3.422 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEA4CO03  
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WEPOB65 Experiments of Lossless Crossing - Resonance With Tune Modulation by Synchrotron Oscillations ion, lattice, experiment, quadrupole 1036
 
  • G.M. Wang, B. Holub, Y. Li, J. Rose, T.V. Shaftan, V.V. Smaluk
    BNL, Upton, Long Island, New York, USA
 
  It had become a standard practice to constrain particle's tune footprint while designing the storage ring lattice so that the tunes fit between harmful resonances that limit ring dynamic aperture (DA). However, in recent ultra-bright light source design, the nonlinearities of storage ring lattices are much enhanced as compared with the 3rd generation light source one. It is becoming more and more difficult to keep the off-momentum tune footprint confined and even more, the solution cannot be found to confine off-energy tune footprint in certain cases. The questions have been asked whether crossing of a resonance stopband from off-momentum particle will necessarily lead to particle loss. In NSLS-II, we modified the lattice working point to mimic machine tune footprint crossing half integer with beam synchrotron oscillation excitation and demonstrated that beam can cross a resonance without loss with control of stopband width and high order chromaticity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB65  
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THPOA15 Adaptive Space Charge Calculations in MADX-SC ion, emittance, simulation, optics 1126
 
  • Y.I. Alexahin, V.V. Kapin, A. Valishev
    Fermilab, Batavia, Illinois, USA
  • F. Schmidt, R. Wasef
    CERN, Geneva, Switzerland
 
  Funding: Work supported by Fermi Research Alliance, LLC under Contract DE-AC02-07CH11359 with the U.S. DOE
Since a few years MAD-X allows to simulate beam dynamics with frozen space charge à la Basseti-Erskine. The limitation of simulation with a fixed distribution is somewhat overcome by an adaptive approach that consists of updating the emittances once per turn and by recalculating the Twiss parameters after certain intervals, typically every 1,000 turns to avoid an excessive slowdown of the simulations. The technique has been benchmarked for the PS machines over 800, 000 turns. MADX-SC code developments are being discussed that include the re-introduction of acceleration into MAD-X and more advanced beam σ calculations that will avoid code interruptions for the Twiss parameters calculation.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA15  
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