Keyword: space-charge
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MOPRC007 Status of and Plans for the Beam Dynamics Program DYNAC rfq, target, beam-transport, proton 80
 
  • E. Tanke, M. Eshraqi, Y.I. Levinsen, A. Ponton
    ESS, Lund, Sweden
  • S. Valero
    CEA, Gif-sur-Yvette, France
 
  A short introduction to the linac beam dynamics code DYNAC will be given. Recently implemented features, such as a Graphical User Interface (GUI), will be presented and benchmarking of the Radio Frequency Quadrupole (RFQ) model will be discussed. Additional planned features to DYNAC and the GUI will be touched upon.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPRC007  
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MOPRC009 Simulating Apertures in the Uniform Equivalent Beam Model simulation, quadrupole, optics, software 87
 
  • G.H. Gillespie
    G.H. Gillespie Associates, Inc., Del Mar, California, USA
 
  The uniform equivalent beam model is useful for simulating particle beam envelopes. Beam root-mean-square (rms) sizes, divergences, and emittances of an equivalent uniform beam approximate well the rms properties of more realistic beam distributions, even in the presence of space charge. Envelope simulation codes for high current beams using the model, such as TRACE 3-D, are central to particle optics design. However, the modeling of apertures has required multi-particle simulation codes. Multi-particle codes do not typically have the fitting and optimization capabilities common to envelope codes, so the evaluation of aperture effects is often a secondary study that may result in further design iteration. To incorporate aperture effects into the optics design at the start, a method has been developed for simulating apertures in the context of a uniform equivalent beam. The method is described and its TRACE 3-D implementation is outlined. Comparisons with multi-particle simulations are used to validate the method and examine regions of applicability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPRC009  
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MOPRC013 Tracking Based Courant-Snyder Parameter Matching in a Linac with a Strong Space-Charge Force linac, DTL, emittance, quadrupole 93
 
  • R. Miyamoto
    ESS, Lund, Sweden
 
  During the design of a hadron linac, matching at the interfaces of different structures or lattice periods is often performed with the linear approximation of the space-charge force. When space-charge is extremely strong, like in the low energy part of the proton linac of the European Spallation Source, such a matching method is not always good enough and could lead to a residual mismatch at the design level. To avoid this, a matching scheme based on iterations of tracking, thus including the full effect of the space-charge force, is developed. This paper presents the scheme itself as well as its application to the ESS linac.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPRC013  
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MOPRC016 RF-Track: Beam Tracking in Field Maps Including Space-Charge Effects, Features and Benchmarks linac, ion, rfq, simulation 104
 
  • A. Latina
    CERN, Geneva, Switzerland
 
  RF-Track is a novel tracking code developed at CERN for the optimization of low-energy ion linacs in presence of space-charge effects. RF-Track features great flexibility and rapid simulation speed. It can transport beams of particles with arbitrary mass and charge even mixed together, solving fully relativistic equations of motion. It implements direct space-charge effects in a physically consistent manner, using parallel algorithms. It can simulate bunched beams as well as continuous ones, and transport through conventional elements as well as through maps of oscillating radio-frequency fields. RF-Track is written in optimized and parallel C++, and it uses the scripting languages Octave and Python as user interfaces. RF-Track has been tested successfully in several cases. The main features of the code and the results of its benchmark studies are presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPRC016  
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MOPRC023 Semi-3D Beam-Tracking Code for Electron Injectors Using Bulk-to-Point Calculation Technique for Space Charge Fields emittance, electron, simulation, gun 120
 
  • A. Mizuno, H. Hanaki
    JASRI/SPring-8, Hyogo-ken, Japan
 
  A new semi-three-dimensional beam-tracking simulation code for electron injectors using bulk-to-point calculation technique for space charge fields is developed. The calculated space charge fields are not produced by a point charge but a doughnut which has the volume and whose cross-section is ellipsoid. Since the calculation noise which is usually caused by distributions of positions of point charge can be minimized, high accuracy calculation on emittance is realized with small number of electrons. Simultaneously, the calculation time becomes markedly shortened. In this paper, calculation examples for asymmetrical beams are demonstrated by the new code. The accuracy of emittance is also discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPRC023  
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TUOP11 Methods for Bunch Shape Monitor Phase Resolution Improvement electron, linac, focusing, quadrupole 408
 
  • A. Feschenko, S.A. Gavrilov
    RAS/INR, Moscow, Russia
 
  Bunch shape monitors, based on secondary electrons emission, are widely used for measurements of longitudinal bunch profiles during a linac commissioning and initial optimization of beam dynamics. A typical phase resolution of these devices is about 1°. However it becomes insufficient for new modern linacs, which require a better resolution. Some developed methods for a phase resolution improvement are discussed.  
slides icon Slides TUOP11 [21.248 MB]  
poster icon Poster TUOP11 [1.888 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP11  
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TUPRC006 Phase-Space Transformation for a Uniform Target Irradiation at DONES target, octupole, neutron, simulation 424
 
  • C. Oliver, A. Ibarra
    CIEMAT, Madrid, Spain
  • P. Cara
    Fusion for Energy, Garching, Germany
  • N. Chauvin
    CEA/DSM/IRFU, France
  • A. Gallego
    Universidad Complutense Madrid, Madrid, Spain
 
  Funding: "This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053."
In the framework of the EU Roadmap, a DEMO Oriented Neutron Source (DONES) [*] has been proposed to provide a high neutron intense neutron source with a suitable neutron spectrum to understand the degradation of advanced materials under DEMO and future fusion plants irradiation conditions. DONES will be based on the International Fusion Materials Irradiation Facility IFMIF [**], being only one accelerator considered. The HEBT will be devoted to the transport, bending and shaping of the 40 MeV, 125 mA CW deuteron beam to the free surface of the rapidly flowing lithium target. To produce a forward peaked source of fusion-like neutrons, which stream through the target into the test cell, a rectangular uniform distribution across the flat top of the beam profile is required, being the footprint tailored in both the vertical and horizontal directions according to the target design. Different methods for beam uniformization in IFMIF accelerator has been proposed in the past [***]. Two main concerns in DONES will be the minimization of particle losses over the whole HEBT and the effect of the different shaping techniques on such strong space charge regime, specially on the beam halo modulation. A review of the different methods for the beam shaping of the high power, high space charge DONES HEBT beam will be depicted. A final solution will be proposed.
[*] DONES Conceptual Design Report, April 2014
[**] IFMIF Comprehensive Design Report, CDR, IFMIF International Team, January 2004
[***] IFMIF Intermediate Engineering Design Report
 
poster icon Poster TUPRC006 [2.546 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPRC006  
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TUPRC010 Multispecies Simulation of the FRIB Frontend Near the ECR Sources with the Warp Code dipole, simulation, ECR, solenoid 434
 
  • K. Fukushima, S.M. Lund
    FRIB, East Lansing, USA
  • C.Y. Wong
    NSCL, East Lansing, Michigan, USA
 
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 and the National Science Foundation under Grant No. PHY-1102511.
The linear accelerator in the Facility for Rare Isotope Beams (FRIB) will use Electron Cyclotron Resonance (ECR) sources. ECR sources can generate a high-brightness DC beam with high charge states. However, the ECR sources produce numerous species that must be collimated to one or two target species with minimal degradation to beam quality. The first stage of this collimation is accomplished in a tight 90 degree dipole bend with a wide aperture and slanted pole faces to provide additional focusing. We report on simulations for the high-rigidity U ion operation using linked 2D xy-slice runs in the straight section upstream of the bend and steady-state 3D simulations in the dipole bend comparing simulations with both ideal (sector) and full 3D field maps of the dipole magnet. Issues associated with placing a 3D dipole field with fringe on a bent simulation coordinate system are addressed. Placement of the dipole bend is optimized consistent with the 3D field and is found to closely correspond to the ideal field center. Minimal problems are found (small centroid shift and distribution distortions) due to 3D space-charge effects in the species separation within the bend when using simple fractional neutralization factors.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPRC010  
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TUPRC014 Self-Consistent PIC Modeling of Near Source Transport of FRIB lattice, ion, simulation, ECR 441
 
  • C.Y. Wong
    NSCL, East Lansing, Michigan, USA
  • K. Fukushima, S.M. Lund
    FRIB, East Lansing, USA
 
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 and the National Science Foundation under Grant No. PHY-1102511.
Self-consistent simulation studies of the FRIB low energy beam transport (LEBT) system are conducted with the PIC code Warp. Transport of the many-species DC ion beam emerging from an Electron Cyclotron Resonance (ECR) ion source is examined in a realistic lattice through the Charge Selection System (CSS) which employs two 90-degree bends, two quadrupole triplets, and slits to collimate non-target species. Simulation tools developed will support commissioning activities on the FRIB front end which begins early operations in 2017. Efficient transverse (xy) slice simulation models using 3D lattice fields are employed within a scripted framework that is readily adaptable to analyze many ion cases and levels of model detail. Effects from large canonical angular momentum (magnetized beam emerging from ECR), thermal spread, nonlinear focusing, and electron neutralization are examined for impact on collimated beam quality.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPRC014  
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THPRC026 Optical Design of the PI-Test MEBT Beam Scraping System SRF, focusing, linac, emittance 827
 
  • A. Saini, A.V. Shemyakin
    Fermilab, Batavia, Illinois, USA
 
  PI-Test [1] is an accelerator facility under construction at Fermilab that will provide a platform to demonstrate critical technologies and concept of front-end of the PIP-II superconducting radio frequency (SRF) linac. It will be capable to accelerate an H ion beam with average current of 2 mA up to 25 MeV in continuous wave (CW) regime. To protect the SRF components from beam irradiation, the Medium Energy Beam Transport (MEBT) section of PI-Test includes an elaborated beam scraping system. It consists of four assemblies spread along the MEBT, with each assembly composed of four radiation-cooled, electrically isolated plates that can be moved into the beam in horizontal and vertical direction. The primary objectives of scraping system are to intercept particles with large transverse action and to protect the beamline elements and SRF linac in case of errors with beam focusing or steering. In this paper we formulate requirements for the scraping system and discuss factors affecting its efficiency. An optical design compatible with PI-Test MEBT is also presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC026  
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FR1A01 Fast Envelope Tracking for Space Charge Dominated Injectors linac, TRIUMF, GUI, optics 1017
 
  • R.A. Baartman
    TRIUMF, Vancouver, Canada
 
  High brightness injectors are increasingly pushing against space charge effects. Usually, particle tracking codes such as ASTRA, GPT, or PARMELA are used to model these systems however these can be slow to use for detailed optimization. It becomes increasingly challenging in future projects such as LCLS-II where space charge effects are still significant after BC1 and BC2 at 250 and 1600 MeV respectively. This talk will describe an envelope tracking approach that compares well against the particle tracking codes and could facilitate much faster optimization.  
slides icon Slides FR1A01 [0.786 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-FR1A01  
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