Keyword: betatron
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MOPMF010 Measurement and Simulation of Betatron Coupling Beam Transfer Function in RHIC coupling, simulation, experiment, quadrupole 99
 
  • Y. Luo, W. Fischer, A. Marusic, M.G. Minty
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Transfer function measurements are important for characterizing betatron tunes, betatron coupling, and beam spectrum in the routine operation of the Relativistic Heavy Ion Collider (RHIC). To counteract the linear betatron coupling, we developed a technique to continuously measure the betatron coupling coefficient with a base band phase lock loop tune meter in 2006. Based on this technique, we demonstrated and built a robust tune/coupling feedback in RHIC. In this article, we revisit the BTF measurement with betatron coupling to benchmark our BTF simulation code. We also compared the values of eigenmode projection ratios from BTF with those calculated with the single particle model.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF010  
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MOPMF038 Cleaning Performance of the Collimation System with Xe Beams at the Large Hadron Collider simulation, collimation, heavy-ion, proton 176
 
  • N. Fuster-Martínez, R. Bruce, P.D. Hermes, J.M. Jowett, D. Mirarchi, S. Redaelli
    CERN, Geneva, Switzerland
 
  The LHC heavy-ion program with Pb ions has delivered substantial physics results since the startup of the LHC. There was a Xe run in 2017 in which collimation losses and cleaning were assessed. These studies give a unique opportunity for very valuable benchmark of simulation models with measurements, which could also be very important to understand limitations for future runs with Pb and other species. In this paper, we present collimation loss maps measured in the first ever operation of the LHC with Xe ions. The measurements are compared with simulations and first conclusions are discussed for possible future operation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF038  
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MOPML021 Shorter Treatment Time by Intensity Modulation with a Betatron Core Extraction extraction, proton, radiation, synchrotron 439
 
  • M. G. Pullia, E. Bressi, G.M.A. Calvi, M. Donetti, L. Falbo, S. Foglio, V. Lante, A. Parravicini, C. Priano, E. Rojatti, S. Savazzi, C. Viviani
    CNAO Foundation, Pavia, Italy
 
  The CNAO (National Center for Oncological Hadrontherapy) main accelerator is a synchrotron capable to accelerate carbon ions up to 400 MeV/u and protons up to 250 MeV. Three treatment rooms are available and are equipped with horizontal beam lines; one of the treatment rooms also features a vertical treatment line to allow additional treatment ports. All of the beamlines are equipped with an active beam scanning system for dose delivery. With such a dose distribution technique, particles are sent to different depths by changing the energy from the synchrotron and are moved transversally by means of two scanning magnets. The number of particles to be deposited in each position varies strongly within the same iso-energetic layer. Part of the dose needed in a given position is in fact delivered by particles directed to deeper layers. In order to maintain the required precision on the number of particles delivered to each spot, the intensity is reduced when spots that require low number of particles are present in a layer. A method to shorten the irradiation time based on variable intensity within the same layer is presented that works also with a betatron based extraction scheme.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML021  
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MOPML035 Betatron Frequencies in Cotangential Trajectory Accelerator for Proton Beam Therapy alignment, cyclotron, resonance, extraction 485
 
  • T. Aoki, F. Ebina, C. Hori, Y. Nakashima, T. Seki
    Hitachi Ltd., Ibaraki-ken, Japan
  • T. Hae
    Hitachi Ltd., Hitachi Research Laboratory, Ibaraki-ken, Japan
 
  It is important that downsizing of an accelerator for spreading proton beam therapy. The synchrotron is the solution of accelerator of proton beam therapy system which can vary energy of extracted beam in the range of from 70 MeV to 235 MeV with a merit of requiring no energy selection system. In order to downsize accelerator with above merit, we suggested smaller variable energy accelerator which have cotangential trajectories. This new type accelerator is expected to realize variability of beam energy with static main magnetic field. One of technological problems of this new type accelerator is stability of betatron oscillation. We plan to utilize week focusing field as main magnetic field, which is decreasing on the radial direction outward and uniform in longitudinal direction, of this new type accelerator. We found the main magnetic field which realizes stable betaron oscillations in the range of from 70 MeV to 235 MeV as the result of estimating the betaron oscillations in this main field by numerical calculation. We report new type accelerator concept and results of analysis of betatron oscillation in cotangential trajectories.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML035  
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TUPAF029 Observation of Fast Losses in the LHC Operation in 2017 operation, detector, beam-losses, monitoring 740
 
  • A.A. Gorzawski, N. Fuster-Martínez, S. Redaelli, C. Xu, C. Zamantzas
    CERN, Geneva, Switzerland
  • R.B. Appleby
    UMAN, Manchester, United Kingdom
  • H. Garcia Morales
    Royal Holloway, University of London, Surrey, United Kingdom
 
  Four diamond detectors that provide beam loss measurements with time resolution in the nanosecond range were added in the vicinity of the primary collimators of the Large Hadron Collider (LHC). This is a powerful diagnostic tool that provides the unique chance to measure bunch-by-bunch losses. The operation of the LHC in 2017 presented several unusual events of fast, high intensity beam losses, many of them captured by the diamond detectors in the betatron cleaning region. In this paper we review some of the relevant loss cases that were analyzed in the wider scope of determining the source of the instability generating these losses. We show few of the possible applications of this detectors in daily operations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF029  
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TUPAF047 Systematic Studies of Transverse Emittance Measurements Along the CERN PS Booster Cycle emittance, scattering, brightness, proton 806
 
  • A. Santamaría García, S.C.P. Albright, H. Bartosik, J.A. Briz Monago, G.P. Di Giovanni, V. Forte, B. Mikulec, F. Roncarolo, V. Vlachoudis
    CERN, Geneva, Switzerland
 
  The CERN Proton Synchrotron Booster (PSB) will need to deliver 2 times the current brightness to the Large Hadron Collider (LHC) after the LHC Injectors Upgrade (LIU) to meet the High-Luminosity-LHC beam requirements. Beam intensity and transverse emittance are the key parameters to increase brightness, the latter being more difficult to manipulate. It is, therefore, crucial to monitor not only the emittance evolution between the different injectors but also along each acceleration cycle. To this end, detailed emittance measurements were carried out for the four rings of the PSB at various times in the cycle with different beam types. A thorough analysis of systematic error sources was conducted including multiple Coulomb scattering happening during profile measurements with wire scanners, where experimental and analytical treatments of the emittance blow-up were compared to FLUKA simulations. In order to properly account for the dispersive contribution, the full momentum spread profile was considered using a deconvolution method. We conclude with an assessment of this first comprehensive emittance evolution measurement along the PSB cycle.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF047  
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TUPAL018 Pulse-by-Pulse Switching of Operational Parameters in J-PARC 3-GeV RCS emittance, operation, injection, extraction 1041
 
  • H. Hotchi, H. Harada, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, Y. Watanabe, M. Yoshimoto
    JAEA/J-PARC, Tokai-mura, Japan
 
  J-PARC 3-GeV RCS (rapid cycling synchrotron) provides a high-power beam both to MLF (materials and life science experimental facility) and MR (main ring synchrotron) by switching the beam destination pulse by pulse. The beam properties required from MLF and MR are different; MLF needs a wide-emittance beam with less charge density, while MR requires a low-emittance beam with less beam halo. To meet the antithetic requirements while keeping beam loss at permissible levels, RCS has recently initiated pulse-by-pulse switching of operational parameters (betatron tune, chromaticity, painting emittance, etc.). This paper presents the recent efforts toward the performance upgrade of RCS while discussing the related beam dynamics issues.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL018  
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TUPAL028 New Feature of the Oscillating Synchrotron Motion Derived from the Hamiltonian Composed of Three Motions synchrotron, closed-orbit, experiment, storage-ring 1060
 
  • K. Jimbo
    Kyoto University, Kyoto, Japan
 
  The equation for the synchrotron motion was derived from the Hamiltonian, which was composed of coasting, betatron and synchrotron motions*. The betatron oscillation is the horizontal oscillation. The synchrotron oscillation is not only an oscillation of the revolution frequency but also an oscillation of the average radius. The synchrotron oscillation is both longitudinal and horizontal oscillations and it is possible to exchange energy with the betatron oscillation. The synchrotron oscillation occurs under a constant particle velocity and the Hamiltonian is conserved.
*K.Jimbo, Physical Review Special Topics - Accelerator and Beams 19, 010102 (2016).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL028  
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TUZGBF3 Betatron Core Slow Extraction at CNAO extraction, synchrotron, cavity, acceleration 1237
 
  • L. Falbo, E. Bressi, S. Foglio, C. Priano
    CNAO Foundation, Milan, Italy
 
  CNAO is the only Italian hadrontherapy facility able to treat tumors with beams of protons and carbon ions. Beam is extracted with a momentum selection scheme in which beam enters the third order resonance driven by a betatron core. When irradiating a tumor, it is thought as divided in the longitudinal plane in several slices while each slice is divided in the transverse plane in several spots called voxels. Considering the dose uniformity that can be obtained during extraction, the machine must extract an average intensity related to the voxel that requires less dose. Therefore during a treatment, for some slices, a technique is needed to lower the extracted beam intensity with respect to the nominal one. A way to guarantee the correct average intensity according to the treatment planning requirements, is to introduce a mechanical filter (a degrader) that reduces the intensity of the accelerated particles. However this method used in the first treatments at CNAO showed some disadvantages and it has been replaced by what has been called the "dynamic betatron" method. The paper shows the implementations and the advantages of this method in the CNAO treatments.  
slides icon Slides TUZGBF3 [2.151 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUZGBF3  
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WEPAK007 Slow Extraction Spill Characterization From Micro to Milli-Second Scale extraction, power-supply, resonance, experiment 2095
 
  • R. Singh, P. Boutachkov, P. Forck, S. Sorge, H. Welker
    GSI, Darmstadt, Germany
 
  This contribution deals with the topic of slow extraction spill quality characterization based on the measurements performed at GSI SIS-18. The sensitivity of the spill to power supply ripples are studied by introducing external ripples. An estimate of sources of inherent power supply ripples along with ripple magnitude are thus obtained. Spill characterization in time and frequency domain are discussed and exemplified by a typical spill and the differences from an ideal or Poisson spill. An appropriate spill characterization aims to provide a suitable abstraction for communication about the spill quality requirements between accelerator operations and users.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK007  
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THYGBD4 Landau Damping by Electron Lenses electron, proton, octupole, collider 2921
 
  • A.V. Burov, Y.I. Alexahin, V.D. Shiltsev, A. Valishev
    Fermilab, Batavia, Illinois, USA
 
  Modern and future particle accelerators employ increasingly higher intensity and brighter beams of charged particles and become operationally limited by coherent beam instabilities. Usual methods to control the instabilities, such as octupole magnets, beam feedback dampers and use of chromatic effects, become less effective and insufficient. We show that, in contrast, Lorentz forces of a low-energy, magnetically stabilized electron beam, or "electron lens", easily introduces transverse nonlinear focusing sufficient for Landau damping of transverse beam instabilities in accelerators. It is also important to note that, unlike other nonlinear elements, the electron lens provides the frequency spread mainly at the beam core, thus allowing much higher frequency spread without lifetime degradation. For the parameters of the Future Circular Collider, a single conventional electron lens a few meters long would provide stabilization superior to tens of thousands of superconducting octupole magnets.  
slides icon Slides THYGBD4 [4.506 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBD4  
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THYGBF1 High Power Beam Operation of the J-PARC RCS and MR operation, extraction, emittance, quadrupole 2938
 
  • Y. Sato
    KEK, Ibaraki, Japan
 
  This invited talk presents the most recent status of improving J-PARC main ring (MR) beam operation together with the rapid cycling synchrotron (RCS) effort. The RCS has optimized the beam performance for the MR injection as well as the muon and neutron targets, where each requires different emittance and beam halo size. The MR has two extraction modes; fast extraction (FX) for the long baseline neutrino oscillation experiment, T2K, and slow extraction (SX) for experiments in the hadron experimental facility. At present, achieved beam intensities are 2.4·1014 protons per pulse (ppp) with cycle time 2.48 s (470 kW) in the FX mode and 5.1013 ppp with cycle time 5.52 s (44 kW) in the SX mode. For the FX operation, recent improvements are settings of new betatron tune, corrections of resonances near the betatron tune, and adopting 2nd harmonic rf voltage to reduce space charge effect. Beam instabilities have been suppressed with controlling chromaticity correction and transverse feedback systems. For the SX mode, a dynamic bump scheme for reducing extracted beam loss is successfully adopted. A high extraction efficiency of 99.5 % is achieved at the 44 kW beam operation.  
slides icon Slides THYGBF1 [6.669 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBF1  
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THPAF010 Reduction of Coherent Betatron Oscillations Using RF Electric Fields in the Fermilab Muon g-2 Experiment dipole, quadrupole, experiment, simulation 2961
 
  • O. Kim, S. Hacıömeroğlu, Y.I. Kim, Y.K. Semertzidis
    CAPP/IBS, Daejeon, Republic of Korea
  • Y.F. Orlov
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  The Fermilab Muon g-2 experiment aims to measure the muon anomalous magnetic moment with a 140 parts-per-billion precision to investigate the greater than 3 standard deviation difference between the Standard Model prediction and the previous measurement by the BNL Muon g-2 experiment. The coherent betatron oscillation (CBO) beam effects must be corrected for in the decay-positron time spectra fits used in high precision muon storage ring based anomalous magnetic moment measurements. This MC simulation study indicates that the application of radio frequency (RF) electric fields to the muon storage ring beam can reduce the CBO amplitude by up to a factor of 10, as well to increase the symmetry of the beam phase space. This is achieved by correcting the mismatched oscillation phases between the high and low momentum muon populations by modulating the muon beam betatron oscillation frequencies with off-resonance RF fields.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF010  
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THPAF020 Measurement of Transverse Impedance of Specific Components in CESR Using BPM Measurements of Pinged Bunches impedance, undulator, cavity, experiment 2990
 
  • M.P. Ehrlichman, J.P. Shanks, S. Wang
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  A beam-based technique is applied to determine the quadrupole impedance of large-impedance components of the CESR storage ring. Two bunches separated by ~1/3 of the ring circumference are charged to 0.85 and 0.3 mA. Each bunch is given a single kick, either horizontal or vertical. Turn-by-turn, bunch-by-bunch position information is recorded for ~16 k turns. BPM-by-BPM phase is calculated using the All-phase FFT method of spectral analysis. The difference in the BPM-to-BPM phase advance between the two bunches is a measurement of the local transverse impedance. The impedances of the small-aperture in-vacuum undulators, collimators, scrapers, RF cavities, electrostatic separators, and bulk impedance of the remaining ring are determined in this manner.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF020  
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THPAF045 Performance Optimisation of Turn-by-Turn Beam Position Monitor Data Harmonic Analysis optics, lattice, software, electron 3064
 
  • L. Malina, J.M. Coello de Portugal, J. Dilly, P.K. Skowroński, R. Tomás, M.S. Toplis
    CERN, Geneva, Switzerland
  • J.M. Coello de Portugal
    UPC, Barcelona, Spain
 
  Nowadays, turn-by-turn beam position monitor data is increasingly utilized in many accelerators, as it allows for fast and simultaneous measurement of various optics parameters. The accurate harmonic analysis of turn-by-turn data costs beam time when needed online. Generally, the electronic noise is avoided by cleaning of the data based on singular value decomposition. In this paper, we exploit the cleaning procedure to compress the data for the harmonic analysis. This way the harmonic analysis is sped up by an order of magnitude. The impact on measurement accuracy is discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF045  
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THPAF046 Optics Measurements in Storage Rings Based on Simultaneous 3-Dimensional Beam Excitation optics, dipole, synchrotron, storage-ring 3068
 
  • L. Malina, J.M. Coello de Portugal
    CERN, Geneva, Switzerland
  • J.M. Coello de Portugal
    UPC, Barcelona, Spain
 
  Optics measurements in storage rings usually employ excitation in both transverse directions. This needs to be repeated at several different beam energies and is time-consuming. In this paper, we develop a new optics measurement technique, which excites the beam in all three spatial dimensions simultaneously. It allows measuring the linear optics and chromatic properties at the same time, leading to speed up of the optics measurements. The measurement method has been successfully demonstrated in the LHC using AC-dipoles and RF frequency modulation. Analysis methods have been derived for the 3-dimensional beam excitation case. We quantify the resolution of the measured optical quantities. The first results suggest that the added complexity does not deteriorate the resolution of the linear optics measurement. In the future, this method can serve as an operational tool to check the optics or even to correct it.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF046  
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THPAF067 Effects of Synchrotron Motion on Nonlinear Integrable Optics synchrotron, optics, coupling, lattice 3131
 
  • S.D. Webb, N.M. Cook
    RadiaSoft LLC, Boulder, Colorado, USA
  • J.S. Eldred
    Fermilab, Batavia, Illinois, USA
 
  Funding: This work was supported in part by the Department of Energy, Office of Science, Office of High Energy Physics under contract number DE-SC0011340.
An integrable Rapid-Cycling Synchrotron (iRCS) has been proposed as a replacement for the Fermilab Booster to achieve multi-MW beam power for the Fermilab high-energy neutrino program.* The successful application of nonlinear integrable optics to proton synchrotrons requires careful examination of single-particle longitudinal effects, especially synchrotron motion. For example, synchrobetatron coupling may excite transverse resonances in the ring. We will use the Synergia code to simulate the effects of this synchrobetatron coupling on the iRCS design with nonlinear inserts. Our goal will be to identify new invariants in the presence of this coupling. Assuming the synchrotron tune is sufficiently small, we have identified one or more adiabatic invariants of the motion. These invariants suggest that integrable optics with synchrobetatron coupling retains integrability when averaged over a synchrotron period.
* J. Eldred and A. Valishev, "Design Considerations for Proposed Fermilab Integrable RCS," arXiv 1703.00952 (2017).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF067  
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THPAF074 Landau Damping Studies for the FCC: Octupole Magnets, Electron Lens and Beam-Beam Effects octupole, damping, flattop, feedback 3150
 
  • C. Tambasco, J. Barranco García, T. Pieloni, L. Rivkin
    EPFL, Lausanne, Switzerland
  • S. Arsenyev, X. Buffat, D. Schulte
    CERN, Geneva, Switzerland
 
  Funding: This work is supported by the Swiss State Secretariat for Education, Research and Innovation SERI.
Stability studies for the FCC-hh operational cycle are explored using Landau octupoles and electron lenses alone and in the presence of long-range as well as head-on beam-beam effects. Pros and cons of the various methods are compared and an optimum operational scenario to guarantee the maximum stability is proposed.
 
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THPAK007 Beam Extraction from TR24 Cyclotron at IPHC extraction, cyclotron, closed-orbit, emittance 3218
 
  • N.Yu. Kazarinov, I.A. Ivanenko
    JINR, Dubna, Moscow Region, Russia
  • F.R. Osswald
    IPHC, Strasbourg Cedex 2, France
 
  The CYRCé cyclotron is used at IPHC (Institut Pluridisciplinaire Hubert Curien) for the production of radio-isotopes for diagnostics, medical treatments and fundamental research in radiobiology. The TR24 cyclotron manufactured and commercialized by ACSI delivers a 16-25 MeV proton beam with intensity from few nA up to 500 microA. The TR24 is a separated-sector isochronous cyclotron with normal-conducting magnet and stripper foil. It is a challenge to fit the high intensity proton beam used for target irradiation to radiobiology and analytical applications due to requirements on beam quality and energy resolution. Field distribution in the region of the extraction performed with OPERA 3D as well as beam dynamics related with stripping are analysed. 3D calculation model and hypothesis about geometry and beam are described. Our goal is to evaluate the extraction efficiency and the beam characteristics in the focusing plane outside the cyclotron which will serve as inputs for the design of future beam lines and enable beam matching conditions. Therefore, different issues are discussed: energy dispersion, transverse dynamics and orbit separation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK007  
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THPAK034 Practical Betatron Tune Behavior During Acceleration in Scaling FFAG Rings at KURNS booster, acceleration, proton, extraction 3287
 
  • Y. Ishi, Y. Fuwa, Y. Kuriyama, Y. Mori, H. Okita, T. Uesugi
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • J.-B. Lagrange
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
 
  In scaling FFAG* accelerators, ideally, betatron tunes are fixed for each closed orbit concerned with the certain beam energy. Therefore, they should not vary during the acceleration. However, it is not the case since practical implementations of the magnetic field can not provide perfect scaling conditions. There are two types of radial scaling FFAG ring at Kyoto University Research Reactor Institute: one has no return yokes so called 'yoke free type' adopted by MAIN RING which has a large tune variations causing non negligible beam losses; the other has return yokes and filed clamps adopted by BOOSTER RING which has smaller tune variations compared with MAIN RING. We report the tune measurements and calculations based on 3-d magnetic field calculations about these two types of ring and discuss the scaling conditions in FFAG accelerators.
FFAG* : FFAG stands for fixed filed alternating gradient. It describes one the focusing scheme in the circular accelerator.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK034  
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THPAK036 Accurate Modeling of Fringe Field Effects on Nonlinear Integrable Optics in IOTA optics, quadrupole, octupole, lattice 3294
 
  • C.E. Mitchell, R.D. Ryne
    LBNL, Berkeley, California, USA
  • F.H. O'Shea
    RadiaBeam, Santa Monica, California, USA
 
  Funding: This work is supported by the U.S. Department of Energy, Office of High Energy Physics.
The Integrable Optics Test Accelerator (IOTA) is a novel storage ring under commissioning at Fermi National Accelerator Laboratory designed to investigate the dynamics of beams with large transverse tune spread in the presence of strongly nonlinear integrable optics. Uncontrolled nonlinear effects resulting from magnetic fringe fields can affect the integrability of particle motion, and long-term numerical tracking requires an accurate representation of these effects. Surface fitting algorithms provide a robust and reliable method for extracting this information from 3-dimensional magnetic field data provided on a grid. These algorithms are applied to investigate the unique nonlinear magnetic insert of the IOTA ring, and consequences of the fringe fields to the long-term dynamics of the beam are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK036  
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THPAK118 Beam Dynamics Studies for a Strong-Focusing Cyclotron cavity, dipole, focusing, cyclotron 3522
 
  • J. Gerity, S. Assadi, P.M. McIntyre, A. Sattarov
    Texas A&M University, College Station, USA
 
  Results are presented from end-to-end simulation of a 100 MeV strong focusing cyclotron (SFC). The develop-ment of the high-current SFC is motivated by applica-tions for production of medical isotopes and for a proton driver for subcritical fission. It uses a novel superconducting cavity to provide suffi-cient energy gain to fully separate all turns. An arc-contour F-D doublet, trim dipole winding, and sextupole are located along each turn within the aperture of each sector dipole to control the betatron and synchrotron motion and to stabilize non-linear dynamics with high-current operation. The phase space evolution of a proton bunch in the SFC was simulated using both the code OPAL and an ad hoc Runge-Kutta tracker. Iterative optimization of the dipole, quadrupole, and sextupole fields was used to provide precise isochronicity, favorable betatron phase advance, and cancellation of dispersion in each cell.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK118  
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THPAK126 Revised Optics Design for the JLEIC Ion Booster booster, lattice, sextupole, injection 3537
 
  • E.W. Nissen, T. Satogata
    JLab, Newport News, Virginia, USA
 
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
We outline the recently redesigned booster for the pro-posed Jefferson Lab Electron Ion Collider (JLEIC). This booster will inject protons (or ions of equivalent rigidity) at 280 MeV and accelerate them to 8 GeV kinetic energy. To avoid transition crossing, the booster uses flexible momentum compaction (FMC) lattices to raise the transi-tion gamma above the reach of the machine. We also include several families of sextupoles to simultaneously control the chromaticities, and nonlinear dispersions that were excited by the FMC cells.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK126  
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THPMF035 Numerical Analysis of Excitation Property of Pulse Picking by Resonant Excitation at BESSY II synchrotron, kicker, emittance, radiation 4131
 
  • J.G. Hwang, M. Koopmans, R. Müller, M. Ries, A. Schälicke
    HZB, Berlin, Germany
 
  The pulse picking by resonant excitation (PPRE) method is applied at BESSY II to provide pseudo single bunch operation by separating the radiation from one horizontally enlarged bunch from the light of the multi-bunch filling. The bunch is enlarged by an excitation with an external signal close to the tune resonance. The variation of the beam size depends strongly on the frequency and amplitude of the excitation signal. In this paper we show the properties of the PPRE bunch studied by analytical modeling and numerical calculations using Elegant. The simulation results are compared with beam size measurements using a new interferometry beam size monitor at BESSY II.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF035  
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THPML072 Injection Comparison using Bunch-by-Bunch Beam Size Measurement System at SSRF injection, damping, SRF, storage-ring 4811
 
  • H.J. Chen, J. Chen, B. Gao, Y.B. Leng
    SINAP, Shanghai, People's Republic of China
 
  Injection transient process happens every 5-10 minutes in storage ring during normal top-up operating mode at SSRF, which is a proper window for machine status and injection performance evaluation. In the recent year, a bunch-by-bunch beam size measurement system has been implemented at SSRF, which has the capability to offer transverse bunch-by-bunch position and size information and is a powerful tool for injection study. In this paper, we summarize three injection study results from July 2017 to April 2018, including betatron oscillation amplitude, spectrum, horizontal tune and damping time comparison. The oscillation amplitude and temporal behavior of recent injection are all better than results before contributed to the injection optimization work during maintenance in 2018 winter. In addition, the principal component analysis method is also applied to further study the injection behavior in turn-by-turn or bunch-by-bunch direction to the refilled bucket.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML072  
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THPML084 Validating the COBEA Algorithm at the DELTA Storage Ring storage-ring, optics, closed-orbit, lattice 4851
 
  • B. Riemann, B.D. Isbarn, S. Khan, S. Koetter, T. Weis
    DELTA, Dortmund, Germany
 
  Closed-Orbit Bilinear-Exponential Analysis (COBEA) is an algorithm to decompose monitor-corrector response matrices into (scaled) beta optics values, phase advances, scaled dispersion and betatron tunes. No explicit magnetic lattice model is required for COBEA - only the sequence of monitors and correctors along the beam path (no lengths, no strengths approach). To obtain absolute beta values, the length of one drift space can be provided as optional input. In this work, the application of COBEA to the DELTA storage ring, operated by TU Dortmund University, is discussed, and its results for betatron tunes and scaled dispersion are compared with those of conventional, direct measurement methods. COBEA is also put in a historical perspective to other diagnostic algorithms. Improvements in the Python implementation of COBEA, which is available as free software, are presented. Due to COBEA being relatively modest regarding its requirements on input data respectively hardware, it should be applicable to the majority of existing storage rings.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML084  
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THPML111 Test of the Tune Measurement System Based on BBQ at HLS-II Storage Ring storage-ring, ion-source, experiment, controls 4926
 
  • L.T. Huang, F.L. Gao, P. Lu, B.G. Sun, H.Q. Wang, J.G. Wang, Q. Wang, F.F. Wu, Y.L. Yang, T.Y. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  Funding: Supported by the National Science Foundation of China (Grant No. 11705203, 11575181)
The HLS-II storage ring is a crucial part of Hefei Light Source. Tune is one of the most important parameters of the electron storage ring, of which the tune measurement system is an integral component. In this paper, the design of a new tune measurement system based on BBQ (base band tune), is presented. Some experiments are performed to test this system. The new system is compared with the original system and the TBT (turn-by-turn) method respectively. The obtained results illustrate higher accuracy and higher stability for the new system. A new approach of calculating the betatron oscillation amplitude is proposed, and the betatron oscillation amplitudes in the normal running stage for the HLS-II storage ring are estimated at 95 nm (horizontal) and 60 nm (vertical).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML111  
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