Keyword: synchrotron
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MOPMF013 eRHIC EIC: Plans for Rapid Acceleration of Polarized Electron Bunch at Cornell Synchrotron polarization, electron, resonance, acceleration 108
 
  • F. Méot, E.C. Aschenauer, H. Huang, C. Montag, V. Ptitsyn, V.H. Ranjbar, E. Wang, Z. Zhao
    BNL, Upton, Long Island, New York, USA
  • I.V. Bazarov, D. L. Rubin
    Cornell University, Ithaca, New York, USA
  • L. Cultrera, G.H. Hoffstaetter, K.W. Smolenski, R.M. Talman
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • D. Gaskell, O. Glamazdin, J.M. Grames
    JLab, Newport News, Virginia, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
An option as an injector into the polarized-electron storage ring of eRHIC EIC is a rapid-cycling synchrotron (RCS). Cornell's 10 GeV RCS injector to CESR presents a good opportunity for dedicated polarized bunch rapid-acceleration experiments, it can also serve as a test bed for source and polarimetry developments in the frame of the EIC R&D, as polarized bunch experiments require disposing of a polarized electron source, and of dedicated polarimetry in the linac region and in the RCS proper. This is as well an opportunity for a pluri-disciplinary collaboration between Laboratories. This paper is an introduction to the topic, and to on-going activities towards that EIC R&D project.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF013  
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MOPMK010 Study Progress of the Coupling Resonance of the Crab Crossing Scheme in Electron-Ion Collider luminosity, electron, simulation, cavity 368
 
  • Y. Hao
    FRIB, East Lansing, USA
  • Y. Luo, V. Ptitsyn
    BNL, Upton, Long Island, New York, USA
  • J. Qiang
    LBNL, Berkeley, California, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Crab crossing scheme is essential collision scheme to achieve high luminosity for the future electron-ion collider (EIC). The bunch length effect of the ion beam cannot be ignored even when cooling is present compared with the wavelength of the crab cavity, therefore, the nonlinear dependence of the crabbing kick may present a challenge to the beam dynamics of the ion beam, hence an impact to the luminosity lifetime. In this paper, we present the result of numerical beam dynamics studies of the crab crossing scheme. The result indicates that there is a special coupling resonance in the nonlinear relation of the crab crossing scheme of the EIC, which dominates the luminosity degradation. And we will discuss the possible remedies for such resonance.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMK010  
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MOPML021 Shorter Treatment Time by Intensity Modulation with a Betatron Core Extraction betatron, extraction, proton, radiation 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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MOPML025 Slow Extraction Optimization at the MedAustron Ion Therapy Center: Implementation of Front End Acceleration and RF Knock Out extraction, proton, acceleration, kicker 453
 
  • A. De Franco, L. Adler, F. Farinon, N. Gambino, G. Guidoboni, G. Kowarik, M. Kronberger, C. Kurfürst, S. Myalski, S. Nowak, M.T.F. Pivi, C. Schmitzer, I. Strašík, P. Urschütz, A. Wastl
    EBG MedAustron, Wr. Neustadt, Austria
  • L.C. Penescu
    Abstract Landscapes, Montpellier, France
 
  Funding: This project has received funding from the European Union's Horizon 2020 research and Innovation programme under the Marie Skłodowska-Curie grant agreement No 675265.
MedAustron is a synchrotron-based ion therapy center allowing tumour treatment with protons and other light ion species, in particular C6+. Commissioning of all fixed lines, two horizontal and one vertical, has been completed for protons and in parallel to the commissioning of a gantry and C6+, a facility upgrade study is progressing. The upgrade study encompasses the optimization of the slow extraction mechanism by employing the RF empty bucket channeling and RF Knock Out techniques. The former is a front end acceleration technique that suppress spill ripples, fundamental to safely operate the machine at the highest intensities. The latter is an alternative extraction technique which opens up interesting possibilities for fast beam energy and intensity modulations. In this work, we quantify spill smoothening effect achieved with the first and report the results of a feasibility study of the second using a Schottky monitor as a transverse kicker.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML025  
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MOPML027 Status of Carbon Commissioning of the MedAustron Therapy Accelerator MMI, linac, ion-source, rfq 457
 
  • C. Schmitzer, L. Adler, A. De Franco, F. Farinon, N. Gambino, G. Guidoboni, M. Kronberger, C. Kurfürst, S. Myalski, S. Nowak, M.T.F. Pivi, I. Strašík, A. Wastl
    EBG MedAustron, Wr. Neustadt, Austria
  • L.C. Penescu
    Abstract Landscapes, Montpellier, France
 
  The MedAustron therapy accelerator is intended to treat cancer patients with proton and carbon beams of 62-252 MeV and 120-400 MeV respectively. The accelerator features three Supernanogan ECR ion sources, a 400 keV/u RFQ and a 7 MeV/u interdigital H-mode Linac. A middle energy beam transfer line also serves as injector into a 77m synchrotron from which the beam may be transferred to 4 different irradiation rooms, 3 of which are dedicated to medical treatment. The therapy accelerator is in clinical operation since end 2016 and is currently solely configured for the use of protons. The next clinical objective is to enable treatments using C6+ ions which triggered the carbon commissioning of the accelerator in 2017. This paper will discuss the latest results from carbon commissioning in the different sections of the accelerator, achieved efficiencies and outlook on future carbon activities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML027  
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MOPML050 A Massive Open Online Course on Particle Accelerators target, survey, radiation, neutron 512
 
  • N. Delerue, A. Faus-Golfe
    LAL, Orsay, France
  • M.E. Biagini
    INFN/LNF, Frascati (Roma), Italy
  • E. Bründermann, A.-S. Müller
    KIT, Eggenstein-Leopoldshafen, Germany
  • P. Burrows
    JAI, Oxford, United Kingdom
  • G. Burt
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • A. Cianchi
    Università di Roma II Tor Vergata, Roma, Italy
  • C. Darve, R.A. Yogi
    ESS, Lund, Sweden
  • V.V. Dmitriyeva, S.M. Polozov
    MEPhI, Moscow, Russia
  • J. Kvissberg
    Lund University, Lund, Sweden
  • P. Lebrun
    JUAS, Archamps, France
  • E. Métral, H. Schmickler, J. Toes
    CERN, Geneva, Switzerland
  • S.P. Møller
    ISA, Aarhus, Denmark
  • L. Rinolfi
    ESI, Archamps, France
  • A. Simonsson
    Stockholm University, Stockholm, Sweden
  • V.G. Vaccaro
    Naples University Federico II and INFN, Napoli, Italy
 
  Funding: European Union H2020 - ARIES Project
The TIARA (Test Infrastructure and Accelerator Research Area) project funded by the European Union 7th framework programme made a survey of provision of education and training in accelerator science in Europe highlighted the need for more training opportunities targeting undergraduate-level students. This need is now being addressed by the European Union H2020 project ARIES (Accelerator Research and Innovation for European Science and Society) via the preparation of a Massive Online Open Course (MOOC) on particle accelerator science and engineering. We present here the current status of this project, the main elements of the syllabus, how it will be delivered, and the schedule for providing the course.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML050  
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MOPML068 Training the Next Generation of Accelerator Experts network, FEL, laser, electron 564
 
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: Work supported by the European Union under grant agreements no 215080, 289191, 289485, 675265 and 721559.
Close collaboration between academia, research centres and industry has turned out to be crucial for the advancement of accelerator science and technology. It is also ideal for providing an efficient training of the next generation of particle accelerator experts and for linking the global accelerator community. Five international research and training networks (DITANET, oPAC, LA3NET, OMA and AVA) have been initiated and coordinated by the University of Liverpool/Cockcroft Institute since 2007. These networks have provided training to almost 100 Fellows from all over the world and organised dozens of international schools, topical workshops and international conferences for the accelerator community. The research activities of the networks have led to hundreds of journal publications and conference proceedings. This contribution presents the best practice in establishing such international collaborative projects, how to establish successful links between sectors and countries, and highlights the main research results that resulted from the research programs.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML068  
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TUXGBD1 Potential and Issues for Future Accelerators and Ultimate Colliders emittance, controls, photon, laser 578
 
  • S.J. Brooks
    BNL, Upton, Long Island, New York, USA
 
  Particle colliders have been remarkably successful tools in particle and nuclear physics. What are the future trends and limitations of accelerators as they currently exist, and are there possible alternative approaches? What would the ultimate collider look like? This talk examines some challenges and possible solutions. Accelerating a single particle rather than a thermal distribution may allow exploration of more controlled interactions without background. Also, cost drivers are possibly the most important limiting factor for large accelerators in the foreseeable future so emerging technologies to reduce cost are highlighted.  
slides icon Slides TUXGBD1 [2.590 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBD1  
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TUXGBF3 Reduction of the Kicker Impedance Maintaining the Performance of Present Kicker Magnet at RCS in J-PARC kicker, impedance, simulation, extraction 616
 
  • Y. Shobuda, Y. Irie, T. Takayanagi, T. Togashi, K. Yamamoto, M. Yamamoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
 
  The present kicker at RCS in J-PARC is designed to make a waveform by superposing the forward and backward currents from the power source to extract beams, so that one terminal of the kicker is shorted and the other one is open. On the other hand, the kicker impedance is the dominant source of the beam instability at the RCS. This report proposes a scheme to reduce the kicker impedance, maintaining the beneficial of the superposition of currents with the present kicker magnet.  
slides icon Slides TUXGBF3 [9.951 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBF3  
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TUPAF004 Status of the MedAustron Beam Commissioning with Protons and Carbon Ions MMI, proton, extraction, dipole 665
 
  • C. Kurfürst, L. Adler, A. De Franco, F. Farinon, N. Gambino, G. Guidoboni, G. Kowarik, M. Kronberger, S. Myalski, S. Nowak, M.T.F. Pivi, C. Schmitzer, I. Strašík, P. Urschütz, A. Wastl
    EBG MedAustron, Wr. Neustadt, Austria
  • L.C. Penescu
    Abstract Landscapes, Montpellier, France
 
  MedAustron is a synchrotron-based Particle Therapy Accelerator located in Wiener Neustadt, Austria, which is delivering beams for medical treatment since end of 2016. The accelerator provides clinical proton beams in the energy range 62-252 MeV and is designed to provide carbon ions in the range 120-400 MeV/n to three ion therapy irradiation rooms IRs, including a room with a proton Gantry. Proton beams of up to 800 MeV will be provided to a fourth room dedicated to research. Presently, proton beams are delivered to the fixed horizontal beam lines of three rooms. Beam commissioning of the vertical beam line of the second IR is being completed and the beam line is in preparation for clinical treatment. Commissioning of the accelerator with carbon ions is advancing and first clinical beams have been sent to the IRs, while the preparation for the Gantry beam line is ongoing. A slow extraction 3rd order resonance method is used to extract particles from the synchrotron between 0.1-10 seconds to favor control of the delivered dose during clinical treatments. The main characteristics of the accelerator and results obtained during the latest commissioning activities are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF004  
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TUPAF010 Empty Sweeping Bucket for Slow Extraction extraction, resonance, acceleration, hadrontherapy 676
 
  • L. Falbo, E. Bressi, C. Priano
    CNAO Foundation, Milan, Italy
 
  The extraction process from a synchrotron is one of the most important aspects of an accelerator devoted to clinical purposes, like the hadrontherapy in which hadron beams are used to treat tumors. Indeed the quality of the dose delivered to the patient, in terms of dose uniformity and precision in the beam characteristics, is defined by the way in which the beam is extracted. The quality of the extracted beam (the so called spill) is strongly affected by the stability of the power supplies of the synchrotron magnets whose field stability creates a ripple in the intensity of the extracted beam itself. When it is not possible to improve the power supply stability, it is needed to apply some additional techniques in order to cure the spill ripple. At CNAO, the italian hadrontherapy facility, it has been thought to improve the Empty Bucket Channelling technique by using an energy-moving bucket instead of a stationary bucket. The paper shows the implementation, the advantages and the efficacy of this RF gymnastic, named 'Empty Sweeping Bucket'.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF010  
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TUPAF011 Btrain Calibration with RF-Master Method dipole, cavity, injection, pick-up 679
 
  • L. Falbo, E. Bressi, M. Pezzetta, C. Priano
    CNAO Foundation, Milan, Italy
 
  CNAO is the only Italian hadrontherapy facility able to treat tumors with beams of protons and carbon ions. It is based on a synchrotron with a 77 m ring equipped with 16 normal conducting dipoles characterized by a long delay in the field stabilization. B-Train system is a fundamental device of the whole machine; it is used in feedback to the dipole power supply in order to regulate the magnetic field reducing the natural stabilization times that would cause long treatments. B-Train system allows to obtain the magnetic field starting from measurements of magnetic field changes: it works as an integrator and then it needs a system to reset the counts compensating the electronic and numerical drift of the system itself. An innovative method has been implemented at CNAO to reset Btrain counts exploiting beam measurements after the RF cavity trapping. This procedure has the advantage to avoid external and additional element like NMR probes. The paper shows the use of B-train system at CNAO and its calibration with this method, called "RF-master method".  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF011  
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TUPAF026 Higher-Harmonic RF System for Landau Damping in the CERN PS damping, flattop, dipole, cavity 728
 
  • H. Damerau, A. Lasheen, E.N. Shaposhnikova
    CERN, Geneva, Switzerland
 
  Longitudinal coupled-bunch instabilities after transition crossing and at the flat-top limit the intensity of LHC-type beams in the CERN Proton Synchrotron (PS). A dedicated coupled-bunch feedback for dipole oscillation modes, using a Finemet cavity as wide-band longitudinal kicker, suppresses the instabilities up to an intensity of about 2·1011 particles per bunch at extraction. However, dipole and quadrupole coupled-bunch oscillations are observed beyond this intensity. At the flat-top they were damped with a 40 MHz RF cavity operated as a higher-harmonic RF system to increase Landau damping, in addition to the principal RF system at 10 MHz. The existing 40 MHz RF system, designed for RF manipulations at fixed frequency, does not cover the frequency range required during acceleration. It is therefore proposed to install a tunable RF system with a 5% relative frequency swing. This paper summarizes the observations of instability damping at the flat-top and presents preliminary parameters for the higher-harmonic RF system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF026  
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TUPAF030 Electron Cloud Build Up for LHC Sawtooth Vacuum Chamber electron, vacuum, photon, simulation 744
 
  • G. Guillermo Cantón, F. Zimmermann
    CERN, Geneva, Switzerland
  • G.H.I. Maury Cuna, E. D. Ocampo
    Universidad de Guanajuato, División de Ciencias e Ingenierías, León, Mexico
 
  At high proton-beam energies, beam-induced synchrotron radiation is an important source of heating, of beam-related vacuum pressure increase, and of primary photoelectrons, which can give rise to an electron cloud. For the arcs of LHC a sawtooth pattern had been imprinted on the horizontally outward side  of the vacuum chamber in order to locally absorb synchrotron radiation photons without dispersing them all around the chamber. Using the combination of the codes Synrad3D and PyCLOUD we examine the effect of realistic absorption distributions with and without sawtooth on the build up of electron clouds.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF030  
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TUPAF073 Simulation of Integrable Synchrotron with Space-charge and Chromatic Tune-shifts lattice, space-charge, simulation, optics 894
 
  • J.S. Eldred, A. Valishev
    Fermilab, Batavia, Illinois, USA
 
  We present a nonlinear rapid-cycling synchrotron designed as a high-intensity replacement of the Fermilab Booster. The design incorporates integrable optics, an innovation in particle accelerator design that enables strong nonlinear focusing without generating parametric resonances. We use the Synergia space-charge tracking code to demonstrate the stability of a beam in this lattice with a space-charge tune-shift up to 0.4 and a rms momentum spread up to 0.4\%. We demonstrate the benefit of increased lattice periodicity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF073  
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TUPAF081 Measurements and Simulations of the Spill Quality of Slowly Extracted Beams from the SIS-18 Synchrotron sextupole, extraction, resonance, experiment 924
 
  • S. Sorge, P. Forck, R. Singh
    GSI, Darmstadt, Germany
 
  In this contribution, results of recent measurements of the spill structure of slowly extracted beams out of the GSI heavy ion synchrotron SIS-18 are presented and compared to results of simulations. Aim of the study is the determination of spill structures at several kHz which arise from ripples in the fields of the accelerator magnets due to imperfections of the magnets' power supplies. The goal of the study is to understand how the ripple is transferred from the magnets to the spill and to find possible ways for spill smoothing. For this purpose a comprehensive simulation model for slow extraction is in preparation which will be validated with beam-based measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF081  
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TUPAF085 Status of Link Existing Facility Project for FAIR linac, shielding, operation, radiation 934
 
  • J. Stadlmann, C. Omet, A. Schuhmann, P.J. Spiller
    GSI, Darmstadt, Germany
 
  The project "Link existing Facility", or GaF (GSI Anbindung an FAIR), is an important subproject of the overall FAIR facility. In order to serve as injector for SIS100, the main accelerator of FAIR, the existing GSI synchrotron SIS18 is undergoing an upgrade program leading to about 100 times higher beam intensities. Especially the foreseen operation with 4 GeV Protons with up to 5·1012 protons per second increases the radiation protection requirements to such an extent that the existing radiation protection measures are no longer sufficient. The project consists of 78 individual measures. The four most substantial activities are the construction of a table-like structure to carry additional shielding. The creation of an opening and a first part of transfer tunnel for the beamlines towards the future FAIR campus. The preparation for the building, beam dump and connection of the FAIR proton injector. The incorporation of state-of-the-art radiation- and fire-protection measures into the present facilities including the a new technical building to house technical infrastructure. We report on the project status which is foreseen to finish mid-2018.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF085  
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TUPAL027 Design of Multi-MW Rapid Cycling Synchrotron for Accelerator Driven Transmutation System lattice, extraction, acceleration, proton 1057
 
  • Y. Fuwa
    Kyoto ICR, Uji, Kyoto, Japan
  • N. Amemiya
    Kyoto University, Kyoto, Japan
  • Y. Ishi, Y. Kuriyama, T. Uesugi
    Kyoto University, Research Reactor Institute, Osaka, Japan
 
  For the practical application of Accelerator Driven System (ADS) that reduces the harmfulness of radioactive waste by transmutation, we are studying the development of a compact accelerator using a synchrotron as an accelerator capable of supplying a stable proton beam to a nuclear reactor. In this plan, we aim to realize down-sizing and high reliability by adopting an alternating high temperature superconducting magnet and a high repetition synchrotron applying resonant beam extraction. In this presentation we report the basic design of the optical system and beam acceleration sequence of this synchrotron.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL027  
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TUPAL028 New Feature of the Oscillating Synchrotron Motion Derived from the Hamiltonian Composed of Three Motions betatron, 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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TUPAL029 Harmonictron acceleration, cavity, proton, operation 1063
 
  • Y. Mori
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • H. Arima, N. Ikeda, Y. Yonemura
    Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka, Japan
  • Y. Waga
    Kyushu University, Hakozaki, Japan
 
  The possibility of high intensity hadron/lepton accelerator based on a vertical scaling FFAG with harmonic number jump acceleration, named "Harmonictron", has been proposed. The presentation gives a design example of the Harmonictron for accelerating protons from 50 MeV to 500 MeV for generation intense secondary particles such as muon, neutron etc.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL029  
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TUPAL036 Slow Extraction Techniques at the Marburg Ion-Beam Therapy Centre extraction, simulation, controls, resonance 1084
 
  • C. Krantz, T. Fischer, Th. Haberer, B. Kroeck, U. Scheeler, A. Weber, M. Witt
    MIT, Marburg, Germany
  • R. Cee, F. Faber, E. Feldmeier, M. Galonska, Th. Haberer, A. Peters, S. Scheloske, C. Schömers
    HIT, Heidelberg, Germany
  • F. Faber
    Technische Universität Darmstadt (TU Darmstadt, RMR), Darmstadt, Germany
 
  The Marburg Ion-Beam Therapy Centre offers hadron therapy using proton and carbon beams. The accelerator is based on a 65-m ion synchrotron by Danfysik/Siemens Healthcare. Beam extraction from the synchrotron is driven by a transverse RF knock-out (KO) system featuring Dynamic Intensity Control (DIC) of the spill. DIC allows modulation of the extraction rate by factors up to 30 on millisecond time scales. A fast response of the system to the variable intensity set-point can be obtained by careful adjustment of the RF-KO spectrum relative to the machine tune. Tracking simulations of the extraction phase have been conducted to refine that behaviour. Presently, we investigate how fast machine tune shifts, induced by an air-core quadrupole lens, can be used as a way to further improve the spill quality.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL036  
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TUPAL054 Experimental Measurements of Resonances near to the ISIS Working Point resonance, experiment, controls, space-charge 1132
 
  • P.T. Griffin-Hicks, B. Jones, B.G. Pine, C.M. Warsop, M. Wright
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  ISIS is the pulsed spallation neutron source located at the Rutherford Appleton Laboratory in the UK. Operation is based on a 50 Hz, 800 MeV proton synchrotron, accelerating up to 3·1013 protons per pulse (ppp), which provides beam to two target stations. ISIS is beam loss limited, so to achieve greater beam intensity and optimal operation, losses must be reduced. Some beam loss may be attributed to resonance lines found in betatron tune space. These could be driven by higher order magnet field components, errors or misalignment. This paper describes work measuring losses against tune space around the ISIS working point. Experiments have been carried out to measure beam loss against tune in the ISIS synchrotron. The experiments were done at low intensity to minimise space charge and intensity effects. Resonance lines that cause beam loss can be clearly identified and provide new information about the machine. The experimental process has been automated in order to decrease experiment duration and to reduce systematic human error. MAD-X models that compare the beam envelope at different points in tune space to the beam pipe aperture are used to distinguish between losses caused by increased envelope size and losses induced by driven resonances.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL054  
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TUPAL055 Progress with Carbon Stripping Foils at ISIS operation, vacuum, injection, proton 1136
 
  • B. Jones, H.V. Cavanagh
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  The ISIS Facility at the Rutherford Appleton Laboratory produces intense neutron and muon beams for condensed matter research. The facility's 50Hz rapid cycling synchrotron accelerates protons from 70 to 800MeV to deliver a mean beam power of 0.2MW to two target stations. Since 2016, ISIS has routinely used commercially produced carbon based foils for beam stripping during charge-exchange injection. Recent experience and developments to increase useful foil lifetime are presented including in-house high temperature annealing of foils prior to use. The installation and performance of a new foil imaging system are described and, finally, the procedure to change the stripping foil is described. Issues with the current arrangements and options for redesign are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL055  
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TUPAL069 Experimental Demonstration of Ion Beam Cooling with Pulsed Electron Beam electron, experiment, simulation, data-analysis 1174
 
  • Y. Zhang, A. Hutton, K. Jordan, T. Powers, R.A. Rimmer, M. F. Spata, H. Wang, S. Wang, H. Zhang
    JLab, Newport News, Virginia, USA
  • J. Li, X.M. Ma, L.J. Mao, M.T. Tang, J.C. Yang, X.D. Yang, H. Zhao, H.W. Zhao
    IMP/CAS, Lanzhou, People's Republic of China
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Cooling ion beams at high energy is presently considered for several ion colliders, in order to achieve high luminosities by enabling a significant reduction of emittance of hadron beams. Electron beam at cooling channel in a few to tens MeV can be accelerated by a RF/SRF linac, and thus using bunched electrons to cool bunched ions. To study such cooling process, the DC electron gun of EC35 cooler at the storage ring CSRm, IMP was modified by pulsing the grid voltage. A 0.07-3.5 micro-second pulse length with a repetition frequency of less than 250 kHz and synchronized with the ion revolution frequency was obtained. The first experimental demonstration of cooling of a coasting and bunched ion beam by a pulsed electron beam was carried out. Data analysis indicates the bunch length shrinkage and the momentum spread reduction of bunched 12C+6 ion beam as evidence of cooling. A longitudinal grouping effect of the coasting ion beam by the electron pulses has also been observed*. In this paper, we will present experimental results and comparison to the simulation modelling, particularly on the bunched electron cooling data after carefully analyzing the beam diagnostic signals.
* L.J. Mao et al., Experimental Demonstration of Electron Cooling with Bunched Electron Beam, TUP15, Proceedings of COOL2017, Bonn, Germany
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL069  
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TUZGBF3 Betatron Core Slow Extraction at CNAO betatron, extraction, 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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TUPMF071 Status of Impedance Modeling for the PETRA IV impedance, wakefield, lattice, status 1423
 
  • Y.-C. Chae, R. Wanzenberg
    DESY, Hamburg, Germany
 
  The diffraction limited synchrotron light source envisioned for the PETRA IV project will require strong focusing to produce the small emittances in both planes. The large natural chromaticity together with small dispersion will require very strong sextupoles. In order to cope with high gradient magnets the radius of vacuum chamber tends to be in the range of 10 mm, which is very small compared to the current 40-mm wide elliptic chamber. The impedance element in the PETRA III was scaled down to fit into the smaller aperture so that the short range wakepotential can be computed numerically. For instance the beam position monitor (BPM) was reduced to 60% in dimension so that it can be used in PETRA IV. Even if the actual design of hardware does not exist yet, we assume that generic feature of PETRA III model is still valid. In this paper we report the up-to-date information on impedance model of PETRA IV together with the preliminary impedance budget based on the analytical formula. We also report the specific studies carried out to understand the kickfactor scaling with the chamber aperture whose radius is in the range of 8-12 mm.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF071  
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TUPMF074 Control of Collective Effects by Active Harmonic Cavity in an MBA-based Light Source with Application to the PETRA Upgrade cavity, impedance, emittance, lattice 1433
 
  • Y.-C. Chae, J. Keil
    DESY, Hamburg, Germany
 
  Based on the reference lattice for PETRA IV* we investigated collective effects with non-zero current. Out of many possibilities we firstly computed the intrabeam-scattering (IBS) effects on the emittance as well as lifetime as a function of current. The result indicated that PETRA IV would benefit from the reduced peak current when the harmonic cavity lengthens the bunch. The operating point of harmonic cavity was explored by tracking simulations as well as analytic formula. In order to compute the energy spread and bunch length we had used the known impedance function of the APS**. In this way more realistic estimation of IBS effects was expected. However, because of the complex nature of PETRA IV lattice, which includes achromatic cells for undulators, arc cells of octants and straight sectors for damping wigglers, we simplify the longitudinal dynamics by assuming the ring made of 92 multi-bend-achromat (MBA) cells. The optics is approximated as a linear-chromatic transfer map enabling fast tracking and the ring impedance is concatenated into the one location. The detailed collective effects with and without harmonic cavities are presented in the paper.
* J. Keil, "A PETRA IV Lattice Based on Hybrid Seven Bend Achromats", these proceedings.
** Y.-C. Chae and Y. Wang, "Impedance Database II for the Advanced Photon Source Storage Ring", Proc. PAC2007.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF074  
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TUPMF083 Influence of Intrabeam Scattering on the Emittance of PETRA III emittance, scattering, damping, wiggler 1463
 
  • J. Keil, G. Kube, G.K. Sahoo, R. Wanzenberg
    DESY, Hamburg, Germany
 
  PETRA~III is a 6 GeV hard X-ray synchrotron radiation source at DESY in Hamburg (Germany) and is in user operation since~2010. The natural emittance of PETRA III is extremely low with 1.3 nm*rad and the coupling is typically less than 1%. PETRA III is operated with a beam current of 100 mA using two different filling modes: a continuous mode with 960 bunches and a timing mode with 40 bunches. It has been observed that the horizontal emittance depends on the filling pattern and is in timing mode slightly larger compared to the emittance in the continuous mode. Despite the high energy of 6 GeV intrabeam scattering contributes for a slight emittance growth due to the small natural emittance and coupling of the machine. The increase of the emittance as a function of the single bunch current has been measured by using different filling patterns at a fixed beam current of 100 mA. The measurements of the emittance and the lifetime as a function of the single bunch current will be compared with theoretical expectations of the emittance growth due to intrabeam scattering and the Touschek lifetime.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF083  
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TUPML078 Fast Quadrupole Beam Based Alignment Using AC Corrector Excitations quadrupole, alignment, closed-orbit, optics 1727
 
  • Z. Martí, G. Benedetti, U. Iriso
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
 
  A novel method to perform Beam Based Alignment has been tested at ALBA using the 10kHz fast acquisition BPMs together with an AC excitation of the corrector magnets allowing to speed up the beam based alignment process. The former approach relies on software synchronization and tango device servers to execute a series of DC corrector magnets and quadrupoles settings designed to avoid the quadrupole hysteresis effects. The approach that we present here is simpler, gives the same level of accuracy and precision and speeds up the measurement by a factor 10. The total measurement time has changed from 5 hours to 10 minutes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML078  
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WEXGBE1 Review of Top-up Injection Schemes for Electron Storage Rings injection, kicker, septum, storage-ring 1745
 
  • M. Aiba
    PSI, Villigen PSI, Switzerland
 
  Top-up operation, which nowadays is standard for lepton colliders and synchrotron light sources, has been developed over last decades. The accelerator performances have been drastically improved through top-up operation. However, future electron storage rings are designed, aiming at further high performance, to operate with strong nonlinear magnetic fields that may restrict their dynamic aperture. Consequently, the conventional off-axis injection and accumulation may become impossible. New injection schemes have been proposed and under development to overcome the difficulties and limitations expected in these machines. This paper reviews top-up injection schemes, including novel ideas recently proposed.  
slides icon Slides WEXGBE1 [3.589 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEXGBE1  
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WEPAF006 Fast Photodetector Bunch Duration Monitor for the Advanced Photon Source Particle Accumulator Ring detector, laser, linac, photon 1819
 
  • J.C. Dooling, J.R. Calvey, K.C. Harkay, B.X. Yang, C. Yao
    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.
A fast photodetector is used to monitor the bunch duration in the Advanced Photon Source (APS) Particle Accumulator Ring (PAR). The Bunch Duration Monitor (BDM) diagnostic provides an accurate measure of the PAR bunch length. PAR BDM data show good agreement with streak camera measurements. The BDM is based on the metal-semiconductor-metal (MSM) photodetector Hamamatsu G4176-03 MSM with specified rise and fall times of 30 ps. The BDM has sufficient frequency response to resolve the PAR bunch near extraction where, under low-charge conditions, minimum rms pulse durations of 200-300 ps are observed. Beam from the PAR is injected into the Booster; for efficient capture, injected rms bunch duration from the PAR must be less than 600 ps. The MSM detector exhibits a ringing response to fast input signals. To overcome this, the BDM output is de-convolved with the impulse response function of the detector-amplifier circuit. Turn-by-turn bunch duration data is presented versus charge and time in the PAR cycle. Charge calibration is used to determine fit parameters for bunch duration measurements in peak-detection mode. Observations relevant to APS Upgrade high-charge studies are presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF006  
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WEPAF013 Database for the Management of NSLS-II Active Interlock System database, interface, MMI, storage-ring 1841
 
  • J. Choi, R.P. Fliller, K. Ha, Y. Tian
    BNL, Upton, Long Island, New York, USA
 
  Funding: DOE Contract No. DE-SC0012704
NSLS-II is operating the active interlock (AI) system to protect the machine components from the synchrotron radiation from the accidentally mis-steered electron beam. For the systematic management, a relational database is dedicated to the AI system and working as the data provider as well as the archiver. The paper shows how the database is structured and used for the AI system.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF013  
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WEPAF044 Automatic Tuning of PETRA, its Injector Complex, and Prospects of Autonomous Operation of PETRA IV controls, operation, optics, software 1912
 
  • I.V. Agapov, H. Ehrlichmann, J. Keil, G.K. Sahoo, R. Wanzenberg
    DESY, Hamburg, Germany
  • Y.-C. Chae
    ANL, Argonne, Illinois, USA
 
  We present the progress in tuning automation of the PETRA injection complex. The OCELOT optimizer has been ported to the PETRA control system and proof-of-principle tests of transmission efficiency optimization done. We further argue that the next steps in tuning and automation are impossible without rethinking the architecture of the high level contol system. A possible approach to the new system is then sketched.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF044  
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WEPAF083 Distributed Optical Fiber Radiation Sensing at CERN radiation, distributed, operation, extraction 2039
 
  • G. Li Vecchi, M. Brugger, S. Danzeca, D. Di Francesca, R. Ferraro, Y. Kadi, O. Stein
    CERN, Geneva, Switzerland
  • S. Girard
    Univ-Lyon Laboratoire H. Curien, UMR CNRS 5516, Saint Etienne, France
 
  The CERN's accelerator tunnels are associated with very complex mixed field radiation environments. Radiation degrades electronic components and directly affects their lifetimes causing failures that contribute to the machine downtime periods. In our contribution, we will report on the development and first employment of a Distributed Optical Fiber Radiation Sensor (DOFRS) at CERN. The most interesting feature of DOFRS technology is to provide an online and spatially distributed map of the dose levels in large machines with spatial resolution of the order of one meter. This fiber based dose sensor will provide valuable information in addition to the currently installed active and passive dosimeters. After demonstrating the working principle of DOFRS*, the first operational prototype was installed in the Proton Synchrotron Booster during last 2016/17 end-of-the-year technical stop. The DOFRS has been acquiring data successfully since the beginning of 2017 operations. The performances that were achieved by the first prototype will be discussed in the final contribution. The DOFRS measurements will also be bench-marked to the results provided by other punctual dosimeters.
*I. Toccafondo et al., 'Distributed Optical Fiber Radiation Sensing in a Mixed-Field Radiation Environment at CERN,' J. Lightw. Technol. 35, 3303, 3310, 2017.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF083  
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WEPAG005 Synchrotron Radiation Beam Diagnostics for the Integrable Optics Test Accelerator controls, electron, optics, proton 2073
 
  • N. Kuklev, Y.K. Kim
    University of Chicago, Chicago, Illinois, USA
  • A.L. Romanov
    Fermilab, Batavia, Illinois, USA
 
  Funding: Work supported by the U.S. National Science Foundation under Award PHY-1535639. Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy.
The Integrable Optics Test Accelerator (IOTA) is a research electron and proton storage ring currently being commissioned at Fermilab's Accelerator Science and Technology (FAST) facility. An extensive beam physics research program is planned, including tests of novel techniques for improving beam intensity, stability, and emittance. A key part of IOTA beam diagnostics suite are synchrotron light beam monitors, mounted onto each dipole. In this paper, we present the hardware and software design of this system. Mechanical layout and actuator control electronics are described. High throughput image acquisition and analysis architecture is outlined, and its preliminary performance is explored. Integration of the system within accelerator control network and possible user applications, such as camera auto-focusing, are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAG005  
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WEPAK003 Effect of Model Errors on the Closed Orbit Correction at the SIS18 Synchrotron of GSI quadrupole, closed-orbit, controls, focusing 2080
 
  • S.H. Mirza, P. Forck, H. Klingbeil, R. Singh
    GSI, Darmstadt, Germany
  • H. Klingbeil
    TEMF, TU Darmstadt, Darmstadt, Germany
 
  Funding: Deutscher Akademischer Austauschdienst under contract No. 91605207
A fast closed orbit feedback system (bandwidth in the order of 1 kHz) is under development at the GSI SIS18 synchrotron for the orbit correction from injection to extraction including the acceleration ramp. The static process model, represented as the orbit response matrix (ORM), is subjected to the systematic optics changes during ramp e.g. beta function and phase advance variations at the locations of BPMs and steerers. In addition to these systematic variations, model mismatches may arise from dipole and quadrupole magnet errors, space charge dependent tune shift as well as BPM and steerer calibration errors. In this contribution, the effects of these model errors on the closed orbit correction are investigated which is necessary for the robust stability analysis of the feedback controller. For the robustness tests, the traditional SVD-based matrix pseudo-inversion is compared to a Fourier-based analysis. The results are achieved by detailed simulations in MADX.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK003  
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WEPAL004 The Algorithm Research of DBPM for HEPS radiation, synchrotron-radiation, collider, injection 2147
 
  • F. Liu, J.S. Cao, Y.Y. Du, S.J. Wei
    IHEP, People's Republic of China
 
  The High Energy Photon Source (HEPS) is a 6-GeV, low-emittance, 1300m scale new generation photon source to be built in China [1]. As a key component, digital beam positon monitor (DBPM) needs to make the beam slow acquisition's resolution up to 0.1um. Because of the high requirements and large expenses, we designed our own DBPM system. In this paper, I will present the algorithm of our BPM. The algorithm is based on Discrete Fourier Transform (DFT) method and tested in BEPCII with using our own designed hardware. The Turn-by-Turn's resolution tested in BEPCII is 0.62um (STD value, 65080 counts, 1.2432MHz), the fast acquisition's resolution is 0.32um (STD value, 65080 counts, 10kHz), the slow acquisition's resolution is 0.18um (STD value, 65080 counts, 10Hz).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL004  
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WEPAL027 Filling Pattern Measurements Using Dead-Time Corrected Single Photon Counting photon, storage-ring, radiation, data-analysis 2219
 
  • B. Kehrer, E. Blomley, M. Brosi, E. Bründermann, A.-S. Müller, M. Schuh, P. Schönfeldt, J.L. Steinmann
    KIT, Karlsruhe, Germany
 
  Time-correlated single photon counting (TCSPC) is a versatile tool for various accelerator diagnostics aspects. Amongst others it allows a precise determination of the filling pattern. At the visible light diagnostics port at the Karlsruhe Research Accelerator (KARA), the KIT storage ring, a Single-Photon Avalanche Diode (SPAD) in combination with a histogramming device (PicoHarp) is used. To compensate for possible dead-time effects, a correction scheme was developed and tested successfully. The compensation increases the dynamic range in which accurate measurements are possible and avoids distortion of the measured filling pattern. This contribution presents the experimental setup, as well as a series of benchmark measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL027  
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WEPAL028 Study of the Influence of the CSR Impedance on the Synchronous Phase Shift at KARA impedance, simulation, storage-ring, radiation 2223
 
  • P. Schönfeldt, E. Blomley, M. Brosi, E. Bründermann, J. Gethmann, B. Kehrer, A.-S. Müller, A.I. Papash, J.L. Steinmann
    KIT, Karlsruhe, Germany
 
  Funding: This work has been supported by the German Federal Ministry of Education and Research (Grant No. 05K16VKA) and the Helmholtz Association (Contract No. VH-NG-320).
Measurements of the bunch current dependent synchronous phase shift are a standard method to characterize the impedance of a storage ring. To study this shift, different experimental approaches can be used. In this contribution, we first derive the phase shift caused by the impedance describing the emission of coherent synchrotron radiation (CSR) based on numerical simulations of the longitudinal phase space. The predicted shift is compared to measurement results obtained by time-correlated single photon counting.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL028  
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WEPAL062 Bunch Length Measurements with a Streak Camera in Low Alpha Lattice Operation at the TPS lattice, operation, photon, emittance 2316
 
  • C.H. Chen, J.Y. Chen, M.-S. Chiu, P.J. Chou, K.T. Hsu, K.H. Hu, C.-C. Kuo, C.C. Liang, C.Y. Liao, Y.-C. Liu, G.-H. Luo, H.-J. Tsai, F.H. Tseng
    NSRRC, Hsinchu, Taiwan
 
  We developed and tested lattice with lower momentum compaction factor (low alpha) in TPS (Taiwan Photon Source) recently. Operating low alpha lattice can provide picosecond bunch length for time-resolved research and coherent IR/THz synchrotron light. The bunch length around 2.5 picosecond rms was measured by a streak camera* in low alpha mode while operating in the routine users mode** it was around 10 picosecond. This paper presents the related processes and measurements.
* L.Y. Liao et al., "Preliminary beam test of synchrotron radiation monitoring system at Taiwan Photon Source", IPAC'15.
** C.C. Kuo et al., "Commissioning of Taiwan Photon Source", IPAC'15.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL062  
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WEPMF018 Magnet Designs for the eRHIC Rapid Cycling Synchrotron dipole, quadrupole, sextupole, magnet-design 2404
 
  • H. Witte, I. Marneris, V.H. Ranjbar
    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.
Presently the electron-ion collider eRHIC is under design, which aims to provide a facility with a peak luminosity of 1034cm-2sec-1. Part of the eRHIC design is a rapid cycling synchrotron, which accelerates electrons from 1-18 GeV. In this paper we present conceptual designs of the required dipole, quadrupole and sextupole magnets. The magnets meet the specifications in terms of performance and field quality with an acceptable power dissipation. The power supply requirements are also discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF018  
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WEPML035 Superconducting Dipoles for SIS100 dipole, operation, controls, superconducting-magnet 2768
 
  • C. Roux, P. Aguar Bartolome, A. Bleile, E.S. Fischer, G. Golluccio, F. Kaether, J. Ketter, J.P. Meier, A. Mierau, C. Omet, P.J. Spiller, K. Sugita, P.B. Szwangruber, A. Warth, H.G. Weiss
    GSI, Darmstadt, Germany
 
  The international facility for antiproton and ion research (FAIR) is currently being developed in Darmstadt, Germany, for fundamental research in various fields of modern physics. Its main accelerator, the SIS100 heavy ion synchrotron, utilizes fast-cycling superconducting magnets operated at cryogenic temperatures. An intense measurement program of first of series (FoS) module revealed excellent behaviour with respect to, e.g., quench performance and AC losses. With an optimized fabrication technique, the geometrical accuracy was improved to be sufficient to provide a highly homogeneous field. Consequently, the series production of 110 dipoles was released. First significant results on the reproducibility and the variation of physical properties along the series production gained at the test facility of GSI are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML035  
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THPAF046 Optics Measurements in Storage Rings Based on Simultaneous 3-Dimensional Beam Excitation optics, dipole, betatron, 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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THPAF048 Destabilising Effect of the LHC Transverse Damper coupling, damping, impedance, feedback 3076
 
  • E. Métral, D. Amorim, S. A. Antipov, N. Biancacci, X. Buffat, K.S.B. Li
    CERN, Geneva, Switzerland
 
  Three questions motivated this study for the CERN Large Hadron Collider in terms of beam stability: (i) why a chromaticity close to zero seemed more critical than predicted during Run 1 (in 2011 and 2012) and during Run 2 (in 2015)?; (ii) why some past simulations with a chromaticity close to zero revealed a more critical situation with the transverse damper than without?; (iii) what should be the minimum operational chromaticity in the future in the LHC and High-Luminosity LHC? A new Vlasov solver (called GALACTIC) was developed to shed light on the destabilising mechanism of the transverse damper, which is a potential contributor to explain the LHC observation. Due to the features, which are discussed in this paper, the name 'ISR (for Imaginary tune Split and Repulsion) instability' is suggested for this new kind of single-bunch instability with zero chromaticity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF048  
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THPAF067 Effects of Synchrotron Motion on Nonlinear Integrable Optics optics, coupling, betatron, 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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THPAF069 Particle Tracking Simulation of Collective Modes - Parametric Landau Damping Off Coupling Resonance damping, coupling, simulation, resonance 3137
 
  • A. Macridin, J.F. Amundson, A.V. Burov, P. Spentzouris, E.G. Stern
    Fermilab, Batavia, Illinois, USA
 
  Employing Synergia simulations with the DMD method we investigate the Landau damping of space charge modes in bunched beams. The simulations reveal two instances of the parametric damping mechanism in bunched beams. The first example occurs in the proximity of coupling resonance and is due to the oscillation of particles' amplitudes in the transverse plane. This oscillation modulates the mode-particle coupling with particle dependent trapping frequency. The second example is due to the modulation of the mode-particle coupling in one transverse plane by the oscillatory motion in the other plane.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF069  
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THPAF089 Mode Coupling Theory in Collisions With a Large Crossing Angle coupling, dipole, collider, positron 3197
 
  • N. Kuroo
    UTTAC, Tsukuba, Ibaraki, Japan
  • K. Hirosawa, K. Ohmi, D. Zhou
    KEK, Ibaraki, Japan
  • K. Oide, F. Zimmermann
    CERN, Geneva, Switzerland
 
  We discuss a novel coherent beam-beam instability in collisions with a large crossing angle. The instability appears in the correlated head-tail motion of the two colliding beams. Cross wake force is introduced to represent the head-tail correlation between colliding beams. The cross wake force is localized at the collision point. Mode coupling theory based on the cross wake force is developed. Collision scheme with a large crossing angle is being very popular in design of electron positron collider. In SuperKEKB project, a collision with a large crossing angle is performed to boost the luminosity ~ 1036 cm-2s−1. Future circular collider, FCC is also designed with a large crossing angle. Strong-strong simulations have shown a strong coherent head-tail instability, which can limit the performance of proposed future colliders. The mode coupling theory using the cross wake force explains the instability. The instability may affect all colliders designs based on the crab waist scheme.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF089  
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THPAK016 Measurement and Analysis of Synchrotron Tune Variation with Beam Current in BEPCII cavity, positron, electron, impedance 3237
 
  • N. Wang, Z. Duan, G. Xu, H.S. Xu, C.H. Yu, Y. Zhang
    IHEP, Beijing, People's Republic of China
 
  Coherent synchrotron frequency shift is observed during machine studies in BEPCII (Beijing Electron Positron Collider Upgrade). The results show that the synchrotron frequency varies parabolically with the increase of the beam current. This phenomenon is supposed to be induced by the interaction of the beam with the fundamental mode of the accelerating cavity. In order to explain this phenomenon, a simple physical model is developed from the couple bunch instability theory. The analytical estimations based on the physical model show good agreement with the measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK016  
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THPAK029 Studies of the Micro-Bunching Instability in the Presence of a Damping Wiggler damping, wiggler, radiation, bunching 3273
 
  • M. Brosi, A. Bernhard, J. Gethmann, B. Kehrer, A.-S. Müller, A.I. Papash, P. Schreiber, P. Schönfeldt, J.L. Steinmann
    KIT, Karlsruhe, Germany
 
  Funding: Funded by BMBF (grant: 05K16VKA) & Helmholtz (contract: VH-NG-320). Supported by the Helmholtz International Research School for Teratronics & Karlsruhe School of Elementary and Astroparticle Physics.
At the KIT storage ring KARA (KArlsruhe Research Accelerator), the momentum compaction factor can be reduced leading to natural bunch lengths in the ps range. Due to the high degree of longitudinal compression the micro-bunching instability arises. During this longitudinal instability the bunches emit bursts of intense coherent synchrotron radiation in the THz frequency range caused by the complex longitudinal dynamics. The temporal pattern of the emitted bursts depends on given machine parameters, like momentum compaction factor, acceleration voltage, and damping time. In this paper the influence of the damping time is studied by utilizing the CLIC damping wiggler prototype installed in KARA as well as by simulations using the Vlasov-Fokker-Planck solver Inovesa.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK029  
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THPAK030 Studies of Longitudinal Dynamics in the Micro-Bunching Instability Using Machine Learning longitudinal-dynamics, bunching, simulation, vacuum 3277
 
  • T. Boltz, M. Brosi, E. Bründermann, A.-S. Müller, P. Schönfeldt, M. Yan
    KIT, Karlsruhe, Germany
  • M. Schwarz
    CERN, Geneva, Switzerland
 
  The operation of synchrotron light sources with short electron bunches increases the emitted CSR power in the THz frequency range. However, the spatial compression leads to complex longitudinal dynamics, causing the formation of micro-structures in the longitudinal bunch profiles. The fast temporal variation and small scale of these micro-structures put challenging demands on their observation. At the KIT storage ring KARA (KArlsruhe Research Accelerator), diagnostics have been developed allowing direct observation of the dynamics by an electro-optical setup, and indirect observation by measuring the fluctuation of the emitted CSR. In this contribution, we present studies of the micro-structure dynamics on simulated data, obtained using the numerical Vlasov-Fokker-Planck solver Inovesa, and first applications on measured data. To deal with generated data sets in the order of terabytes in size, we apply the machine learning technique k-means to identify the dominant micro-structures in the longitudinal bunch profiles. Following this approach, new insights on the correlation of the CSR power fluctuation to the underlying longitudinal dynamics can be gained.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK030  
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THPAK031 Suppression of Longitudinal Coupled Bunch Instability by Harmonic Cavity in UVSOR Electron Storage Ring damping, storage-ring, HOM, cavity 3280
 
  • A. Mochihashi
    KIT, Eggenstein-Leopoldshafen, Germany
  • M. Fujimoto, K. Hayashi, M. Katoh
    UVSOR, Okazaki, Japan
  • J. H. Hasegawa, M. Hosaka, M. Hosaka, Y. Takashima, Y. Takashima
    Nagoya University, Nagoya, Japan
  • M. Hosaka, Y. Takashima
    Aichi Synchrotron Radiation Center, Aichi, Japan
  • M. Katoh
    Sokendai - Okazaki, Okazaki, Aichi, Japan
 
  In the UVSOR electron storage ring, which is dedicated for a VUV synchrotron radiation light source, a longitudinal coupled bunch instability (LCBI) is observed in multi-bunch operation. To suppress the LCBI, we routinely operate a third harmonic cavity (HCV) in a passive mode. By properly tuning HCV, the instability is almost completely suppressed. Because of the lower beam energy (750 MeV) and brilliant beam emittance (17.5 nm-rad), the Touschek effect becomes severe in the UVSOR. To guarantee enough beam lifetime, we also apply HCV for lengthening the bunch. The suppression of the instability and increasing the beam lifetime are crucial benefits by HCV for the UVSOR. However, not only the origin of the LCBI but also the Landau damping effect by HCV has not been understood systematically yet. We have noticed that one of the HOMs at HCV itself could cause the LCBI and observed the behavior of the instability, which strongly depends on the beam current. From the experiment we have discussed the cause of the instability with the HOM theory. We have also tried to observe synchrotron tune spread and discussed a competition between the Landau damping and the instability growth.
Present affiliation of the first auther : Karlsruhe Institute of Technology
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK031  
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THPAK032 Elaborated Modeling of Synchrotron Motion in Vlasov-Fokker-Planck Solvers simulation, electron, storage-ring, damping 3283
 
  • P. Schönfeldt, T. Boltz, A. Mochihashi, A.-S. Müller, J.L. Steinmann
    KIT, Karlsruhe, Germany
 
  Funding: Funded by the German Federal Ministry of Education and Research (Grant No. 05K16VKA) & Initiative and Networking Fund of the Helmholtz Association (contract number: VH-NG-320).
Solving the Vlasov-Fokker-Planck equation is a well-tested approach to simulate dynamics of electron bunches self-interacting with their own wake-field. Typical implementations model the dynamics of a charge density in a damped harmonic oscillator, with a small perturbation due to collective effects. This description imposes some limits to the applicability: Because after a certain simulation time coherent synchrotron motion will be damped down, effectively only the incoherent motion is described. Furthermore - even though computed - the tune spread is typically masked by the use of a charge density instead of individual particles. As a consequence, some effects are not reproduced. In this contribution, we present methods that allow to consider single-particle motion, coherent synchrotron oscillation, non-linearities of the accelerating voltage, higher orders of the momentum compaction factor, as well as modulations of the accelerating voltage. We also provide exemplary studies - based on the KIT storage ring KARA (KArlsruhe Research Accelerator) - to show the potential of the methods.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK032  
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THPAK044 Self-Consistent Modeling using a Lienard-Wiechert Particle-Mesh Method space-charge, simulation, radiation, emittance 3313
 
  • R.D. Ryne, C.E. Mitchell, J. Qiang
    LBNL, Berkeley, California, USA
  • B.E. Carlsten
    LANL, Los Alamos, New Mexico, USA
 
  In this paper we describe a parallel, large-scale simulation capability using a Lienard-Wiechert Particle-Mesh (LWPM) method. The approach is a natural extension of the convolution-based technique to solve the Poisson equation in space-charge codes. It provides a unified method to compute both Coulomb-like self-fields and radiative phenomena like coherent synchrotron radiation (CSR). The approach brings together several mathematical and computational capabilities including the use of integrated Green function (IGF) methods and adaptive quadrature methods. We will describe the theoretical model and our progress to date.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK044  
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THPAK056 Resonance Identification Studies at the CERN PS resonance, space-charge, sextupole, experiment 3350
 
  • F. Asvesta
    NTUA, Athens, Greece
  • H. Bartosik, A. Huschauer, Y. Papaphilippou, G. Sterbini
    CERN, Geneva, Switzerland
 
  In view of the LHC Injectors Upgrade (LIU) and the challenging high brightness target beam parameters, a broad range of possible working points for the Proton Synchrotron (PS) is being investigated. High order resonances have been identified, both structural resonances driven by space charge due to the lattice harmonics of the PS, and resonances excited by multipolar components in the machine. This paper provides a summary of the performed tune scan studies, covering both experimental and simulation results. Furthermore, non-linear analysis techniques have been used to characterize the resonances and their effect on the beam in presence of space charge.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK056  
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THPAK058 Planned Detection and Amplification of Infared Synchrotron Radiation for Electron-Beam Diagnostics and Manipulations radiation, laser, experiment, synchrotron-radiation 3358
 
  • M.B. Andorf, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • P. Piot
    Fermilab, Batavia, Illinois, USA
 
  Amplification of beam-induced radiation (e.g. synchrotron or undulator radiation) is a necessary component of optical stochastic cooling of hadrons or heavy ions. We discuss a proposal to measure and amplify synchrotron radiation from a bending magnet of the Advanced Photon Source. The measurements will be in the short-wavelength infrared region (SWIR) and amplification will be accomplished using a pumped Chromium:Zinc Selenide (Cr:ZnSe) crystal with maximum gain at λ≅ 2.2~μm.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK058  
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THPAK100 Design and Fabrication of a Combined Function Magnet Prototype for Siam Photon Source quadrupole, simulation, dipole, multipole 3466
 
  • P. Sunwong, B. Boonwanna, S. Chaichuay, P. Klysubun, A. Kwankasem, C.P. Preecha, V. Sooksrimuang
    SLRI, Nakhon Ratchasima, Thailand
 
  A prototype of combined function magnet has been developed for a new facility of Siam Photon Source (SPS). The magnet is a combined dipole and quadrupole with the required dipole field and quadrupole gradient of 0.6 T and 30 T/m, respectively. The high field gradient is attained from an offset quadrupole design pioneered by the European Synchrotron Radiation Facility (ESRF). The prototype magnet is fabricated and tested in-house. Magnetic field quality is characterized by the field homogeneity in the central field region and multipole components of the magnetic field. Calculated results show that the gradient deviation and the normalized multipole error are less than 0.01 within the good field region of ±8 mm. Preliminary measurements show a good agreement with the calculation, although further measurements are required to verify the results and the multipole error of magnetic field.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK100  
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THPAK107 Space-Charge Hamiltonian with a Space Coordinate as Independent Variable plasma, space-charge, TRIUMF, vacuum 3484
 
  • T. Planche, P. M. Jung, S.D. Rädel
    TRIUMF, Vancouver, Canada
 
  We present a version of the Low Lagrangian tailored to treat space-charge effects in particle accelerators: the Lagrangian is relativistic and uses a space coordinate as the independent variable. From this Lagrangian we obtain the corresponding Hamiltonian. From the Hamiltonian we obtain equations of motion for the 8 canonical variables, which can be plugged into a symplectic numerical integrator. We will finally discuss the possibility of numerically solving this problem using an explicit symplectic integrator.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK107  
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THPAK115 Numerical Multiparticle Tracking Studies on Coupled-Bunch Instabilities in the Presence of RF Phase Modulation wakefield, cavity, impedance, damping 3511
 
  • M. Sommer, B.D. Isbarn, S. Koetter, B. Riemann, T. Weis
    DELTA, Dortmund, Germany
 
  Funding: Work supported by the BMBF under contract no. 05K13PEB.
Since 2008, longitudinal coupled-bunch instabilities are suppressed at DELTA by a modulation of the phase of the accelerating RF field inside the cavity. To achieve a deeper understanding of the interaction of both effects, experimental studies have been made in 2016. These studies show a quadratic dependency of the coupled-bunch mode damping rates on the phase modulation amplitude. Recently, a numerical particle tracking code has been developed to confirm the experimental results. It is based on long range wake field effects produced inside an RF cavity acting on multi particle bunches of arbitrary charge, together with phase focusing by a phase modulated accelerating field. The numerical results confirm the quadratic dependency of damping rates on the phase shift obtained in experimental studies before.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK115  
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THPAK117 Space Charge Limitations for Bunch Compression in Synchrotrons space-charge, resonance, simulation, emittance 3518
 
  • Y.S. Yuan, O. Boine-Frankenheim
    TEMF, TU Darmstadt, Darmstadt, Germany
  • G. Franchetti, I. Hofmann
    GSI, Darmstadt, Germany
 
  Bunch compression achieved via a fast bunch rotation in longitudinal phase space is a well-accepted scheme to generate short, intense ion bunches for various applications. During bunch compression, coherent beam instabilities and incoherent single particle resonances can occur because of increasing space charge, resulting in an important limitation for the bunch intensity. We present an analysis of the relevant space charge driven beam instability and resonance phenomena during bunch compression. A coupled longitudinal-transverse envelope approach is compared with Particle-In-Cell (PIC) simulations. Two distinct cases of crossing are discussed and applied to the GSI SIS18 heavy-ion synchrotron. It is shown that during bunch compression, the 90° condition of phase advance is associated with a fourth order single particle resonance and the 120° condition with the recently discovered dispersion-induced instability. The agreement between the envelope and PIC results indicates that the stop band is defined by the 120° dispersion instability, which should be avoided during bunch compression.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK117  
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THPAK133 Magnetic Field Tolerances of Dipole and Quadrupole Magnets for XiPAF Synchrotron dipole, quadrupole, multipole, dynamic-aperture 3551
 
  • H.J. Zeng, X. Guan, P.F. Ma, X.W. Wang, H.J. Yao, S.X. Zheng
    TUB, Beijing, People's Republic of China
  • H. Ning
    NINT, Xi'an, People's Republic of China
 
  The magnets are being constructed for Xi'an Proton Application Facility (XiPAF) synchrotron. A study is started to obtain the specifications and tolerances of the magnets to avoid beam lost by the excessive magnetic field errors. The study includes the effect of field and alignment errors of the magnets on the closed orbit and beam optics. Also a preliminary study of effect due to multipole components in dipole and quadrupole magnets on dynamic aperture has been done. The tolerances of dipole and quadrupole magnets on field errors, including multipole components, and alignment errors are described in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK133  
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THPAK144 A Pseudospectral Method for Solving the Bloch Equations of the Polarization Density in e- Storage Rings polarization, storage-ring, electron, ion-effects 3589
 
  • K.A. Heinemann, O. Beznosov, J.A. Ellison
    UNM, Albuquerque, New Mexico, USA
  • D. Appelö
    University of Colorado at Boulder, Boulder, USA
  • D.P. Barber
    DESY, Hamburg, Germany
 
  Funding: Work supported by DOE under DE-SC0018008
We consider the numerical evolution of Bloch equations for the polarization density in high-energy electron storage rings. Equilibrium polarization is well characterized by the DK formulas for current rings, but deviations may be important at the high energies we have in mind. We believe the Bloch equations derived in* give a more accurate description at all energies. These form a system of three coupled linear partial differential equations for the three components of the polarization density. Following** we formulate the equations in action-angle variables and approximate the Fokker-Planck terms. We aim to integrate these equations numerically in order to approximate the equilibrium and compare with the DK formulas. The smoothness and simple geometry of the problem makes it amenable to pseudospectral discretization using Fourier modes in the angles and Chebyshev polynomials in the actions, leading to a large ODE system. We will explore time stepping algorithms for the needed long time integration. Here, we present results for simple models checking the accuracy of the numerical method but note that our ultimate goal is to simulate polarization in the FCC and CEPC rings.
* Ya.S.Derbenev, A.M.Kondratenko, Sov. Phys. Dokl., 19, p.438 (1975).
** D.P.Barber, K.Heinemann, H.Mais, G.Ripken,
A Fokker-Planck treatment of stochastic particle motion…,
DESY-91-146, 1991.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK144  
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THPAK148 Preliminary Study of a Nine-Bend Achromat Lattice for a Diffraction-Limited Storage Ring lattice, emittance, storage-ring, sextupole 3600
 
  • P.H. Yang, Z.H. Bai, L. Wang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  In recent years, multi-bend achromat (MBA) lattices have been widely used for the design of diffraction-limited storage rings (DLSRs) being developed around the world as the next-generation storage ring synchrotron sources. To better solve the problem of very serious non-linear dynamics in the DLSR lattice design, recently we proposed a new MBA lattice concept called the MBA lattice with interleaved dispersion bumps *, which was then applied to designing 7BA lattices for the Hefei Ad-vanced Light Source (HALS), with the result showing rather good nonlinear dynamics performance. In this paper, a 9BA lattice also following our MBA concept is preliminarily designed as a possible option for the HALS with a natural emittance of less than 30 pm·rad. Since generally the 9BA lattice can have a much lower emit-tance than the usually used 7BA lattice, the work in the paper will provide an inspiration for the existing third-generation synchrotron sources to upgrade to DLSRs with much lower emittances.
* Zhenghe Bai et al., MOPH13, Proc. SAP2017, Jishou, China, 2017.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK148  
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THPAK152 Study of GF Symplectic Tracking Method and Compensation for the EPU104 at the HLS-II undulator, dynamic-aperture, electron, synchrotron-radiation 3603
 
  • Z.H. Yang, Z.H. Bai, W. Li, G. Liu, L. Wang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  An elliptically polarized undulator (EPU) was applied to obtain high-brightness coherent synchrotron radiation at the upgraded Hefei Light Source, HLS-II. However, the EPU has serious dynamic effects on the beam performances including close orbit, emittance and dynamic aperture etc. when installed at the storage ring. In order to understand the effects, a Taylor expanded generating method was adopted to generate a fast and symplectic map for particle tracking. As for the compensation of the EPU, striplines were equipped above and below the vacuum chamber to reduce the nonlinear effects. With the symplectic tracking routine and the surface fitting method, different parameters such as dynamic aperture and the driving terms, could be set as the objective function to accomplish the optimization of the EPU.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK152  
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THPAL028 Commissioning of the Bunch-by-Bunch Feedback System in the MAX IV 1.5 GeV Ring feedback, cavity, storage-ring, kicker 3688
 
  • D. Olsson, Å. Andersson, F.J. Cullinan, P.F. Tavares
    MAX IV Laboratory, Lund University, Lund, Sweden
 
  The MAX IV 1.5 GeV ring is an electron storage ring for production of synchrotron light in the IR to soft X-ray spectral range. The ring will deliver light to its first users during 2018. Bunch-By-Bunch (BBB) feedback has been needed to suppress coupled-bunch mode instabilities (CBMIs), and the feedback has this far been provided in all three planes by a single stripline kicker. This is done by combining the horizontal and vertical baseband feedback signals with the longitudinal feedback signal that is upconverted to the 150 MHz - 250 MHz range. The combined signal is then fed to two stripline electrodes. The layout of the BBB feedback system in the MAX IV 1.5 GeV ring is presented in this paper. Results from instability studies are also discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL028  
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THPAL050 Beam Dynamics of the First Beams for the IFMIF-EVEDA RFQ Commissioning operation, controls, storage-ring, site 3754
 
  • C.S. Chen, W.S. Chan, Y.Y. Cheng, Y.-C. Chung, C.Y. Liu, Y.-H. Liu, Z.-D. Tsai
    NSRRC, Hsinchu, Taiwan
 
  Since December 31th 2014, the first synchrotron light from Taiwan Photon Source (TPS) was stored in the storage ring, the challenge to operate both Taiwan Light Source (TLS) and TPS smoothly and reliably became a significant issue for all members in NSRRC. On the one hand, the beam quality of former TLS must not been impaired due to the occupied resources by TPS, on the other hand, the most efforts were devoted to achieving steady operation of TPS. In order to operate both ring stably, some mutual backup structures were designed in the compressed air system and the chilled water system between TLS and TPS. The primary advantage of these mutual backup systems is minimizing the risk of beam-trip while any one of the utility system fails. Secondly, the mutual backup structures provide more flexible usage to accomplish energy conservation. From both risk-reduction and energy conservation points of view, the backup systems will do a great deal of good in the future.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL050  
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THPAL051 The Data Acquisition on Vibration Evaluation for Ice Water Pumps Systems in TPS data-acquisition, status, operation, controls 3757
 
  • Y.-H. Liu, C.-S. Chen, Y.-C. Chung, Z.-D. Tsai
    NSRRC, Hsinchu, Taiwan
 
  The vibration status is a critical problem for the utility system, especially for those continuously operate deionized and cooling water pumps used in synchrotron accelerator. The purpose of this paper is to evaluate the vibration level and spectrum condition for TPS water pump systems. In order to predictive maintenance before pump systems fail, the vibration monitoring system was constructed. After vibration test for several months, the alignment of some of the ice water pumps were found mismatched because of poor system positioning and operate continuously. Besides, the ice water pump were redundantly operated and switch over every Monday morning. The recorded data showed the system sometimes switch fail because of control status or system stability. Thus, the water pump systems were repaired and maintained base on vibration monitoring system. There is still some remain problems for ice water pump systems. The utility systems could prevent malfunction through regular vibration inspection and daily data acquisition.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL051  
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THPAL052 Finite Element Analysis on Beam-Induced Heat Load in in-Vacuum Undulators with a Small Magnet Gap undulator, simulation, vacuum, synchrotron-radiation 3760
 
  • J.-C. Chang, Y.-H. Liu
    NSRRC, Hsinchu, Taiwan
 
  In-vacuum undulators with a small gap and short period have been applied in synchrotron accelerators for hard X-rays users for years. However, beam-induced heat load resulted from synchrotron radiation or the image current will not only degrade the performance of undulator but damage the magnet foil. It is difficult to quantitatively study heat transfer phenomenon of the magnet foil through physical experiment. In this study, finite element analysis was applied to study the effect of beam-induced heat load on an in-vacuum undulator.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL052  
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THPAL056 Vibration Measurements in the TPS Vacuum System vacuum, radiation, storage-ring, synchrotron-radiation 3772
 
  • Y.C. Yang, C.K. Chan, C.-C. Chang, C.S. Chen, J. -Y. Chuang, Y.M. Hsiao, C.C. Liang, Y.Z. Lin
    NSRRC, Hsinchu, Taiwan
 
  The Taiwan Photon Source (TPS) is currently operated in top-up mode for users. In order to improve the stability of the synchrotron light source, vibrations related to the vacuum system have been investigated and improved by turning off pumping systems and reducing the flow rate in chamber cooling water circuits. In this paper, vibrations in different vacuum chambers with normal cooling water condition were investigated, their sources were recorded and clarified and properties of different materials for water tubes were also compared.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL056  
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THPAL107 Three Years of Operational Experience With the Solaris Vacuum System vacuum, storage-ring, electron, MMI 3888
 
  • A.M. Marendziak, M. Rozwadowski, T. Sobol, M.J. Stankiewicz, A.I. Wawrzyniak
    Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland
 
  Solaris, a 1.5 GeV third generation synchrotron light source, was commissioned in 2016 April and is currently operated in decay mode. Two beamlines PEEM/XAS and UARPES were installed and now are being commis-sioned. Three more PHELIX, XMCD and diagnostic beamlines have received funding and will be installed and commissioned in next few years. With total accumu-lated beam dose near to 690 A.h and three orders of mag-nitude reduction of outgassing the design goal of 500 mA beam current and electron energy of 1.5 GeV has been achieved. As the beam current was increased, a few vacu-um problems were encountered, including vacuum leaks in RF and arc sectors and unexpected pressure bursts near photon absorbers. Lessons learned and operational expe-rience will be presented and discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL107  
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THPMF005 Evaluating the Impact of Diamond-II Possible Lattices on Beamlines lattice, photon, radiation, emittance 4033
 
  • M. Apollonio, L. Alianelli, F. Bakkali Taheri, R. Bartolini, A.J. Dent
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini, J. Li
    JAI, Oxford, United Kingdom
 
  At Diamond Light Source we are considering an upgrade of the machine aimed at significantly reduced emittance (la factor 20), that follows a worldwide trend in similar synchrotron radiation sources. An important aspect in the design of the upgrade is the optimization of the photon beam properties, such as flux, brilliance, spot size, divergence or coherence of the new sources and how these are translated into requirements on the electron beam and on the machine design. We present a study based on a combination of accelerator physics tracking codes (AT, elegant) and of radiation codes (SPECTRA, SRW, SHADOW), with the aim at bridging the gap between machine and beamlines.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF005  
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THPMF006 Control of the Nonlinear Dynamics for Medium Energy Synchrotron Light Sources lattice, controls, storage-ring, optics 4037
 
  • J. Bengtsson, R. Bartolini, H. Ghasem, B. Singh
    DLS, Oxfordshire, United Kingdom
  • A. Streun
    PSI, Villigen PSI, Switzerland
 
  MAX-IV has introduced a paradigm shift in the design philosophy for the "Engineering-Science" in the quest for a diffraction limited Synchrotron Light Source. Similarly, SLS-2 has introduced a systematic method for controlling the Linear Optics beyond some 20 years of TME inspired paper designs; by introducing Reverse Bends to disentangle dispersion and focusing, which enables Longitudinal Gradient Bends to efficiently reduce the emittance. Similarly, we outline a systematic approach for how to control the Nonlinear Dynamics for these systems, by a method that was pioneered for the conceptual design of the Swiss Light Source in the mid-1990s; subsequently benchmarked and validated by the commissioning.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF006  
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THPMF013 The Stripline Kicker Prototype for the CLIC Damping Rings at ALBA: Installation, Commissioning and Beam Characterisation kicker, extraction, storage-ring, impedance 4062
 
  • M. Pont, N. Ayala, M. Carlà, T.F.G. Günzel, U. Iriso, Z. Martí, R. Monge, A. Olmos, F. Pérez, M. Quispe
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • M.J. Barnes, C. Belver-Aguilar, Y. Papaphilippou
    CERN, Geneva, Switzerland
 
  The extraction system for the CLIC Damping Rings has very tight specifications. Therefore a full characterisation of the behaviour of the stripline kicker under conditions as close as possible to the expected working conditions will be very valuable. To that end the CLIC stripline has been installed in the ALBA Synchrotron Light Source and has been characterised with beam. Prior to its installation, the effect of the stripline kicker on the machine impedance has been assessed. The installation has required the design of an absorber to screen the stripline from synchrotron radiation and additional BPMs have been installed for a better kick angle determination. The commissioning of the stripline with beam has been performed following closely beam parameters, pressure and temperature. The studies with beam include the determination of the longitudinal and transverse impedance of the kicker*, the field homogeneity when excited with a dc field and the field ripple when pulsed. This contribution reports on the first experience with the stripline kicker for the CLIC DR in the ALBA storage ring and presents the results of the initial beam characterisation.
* M. Carla et al., "Beam based impedance measurements of the CLIC stripline at ALBA", Proc. of IPAC'2017.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF013  
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THPMF020 A 4th Generation Light Source for South-East Europe lattice, emittance, SRF, storage-ring 4084
 
  • H. Ghasem, R. Bartolini
    DLS, Oxfordshire, United Kingdom
  • D. Einfeld
    ESRF, Grenoble, France
 
  In Europe, most of the Synchrotron Light Sources are located in the middle, west and northern regions while the south-east is still lacking any major project. Hence a new initiative has been set up to propose the construction of a 4th Generation Light Source in that region. Design requirements limit the beam energy between 2.5 GeV to 3 GeV, the circumference is limited to 350 m, the emittance should be smaller than 250 pm rad and at least 14 to 16 straights have to be available for the users. Several mag-net configurations have been investigated and the results revealed that the HMBA lattice can fully meets the requirements and is therefore proposed for the Light Source in the SEE-region of Europe. These studies show that for a 4th Generation Light Source with energies up to 3 GeV a circumferences of 350 m will be adequate.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF020  
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THPMF033 Design of the Beamline Elements in the BESSY VSR Cold String cavity, HOM, shielding, operation 4123
 
  • H.-W. Glock, F. Glöckner, J. Knobloch, E. Sharples, A.V. Tsakanian, A.V. Vélez
    HZB, Berlin, Germany
  • T. Flisgen
    Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Berlin, Germany
 
  Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of the Helmholtz Association
The four SRF cavities in the BESSY VSR module will be linked by bellows, which will be equipped with inner coaxial shielding pipes to prevent both parasitic fundamental mode losses and beam-induced heating. The central bellow will also act as a collimator for synchrotron radiation generated in the closest upstream dipole magnet. Additional bellows at the module's ends are needed to connect with the warm BESSY beam pipe. Outside the module the beam pipe cross section transitions will be located, which will be equipped with toroidal HOM absorbing elements. In the paper the recent design considerations and specifications for all those components will be described.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF033  
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THPMF035 Numerical Analysis of Excitation Property of Pulse Picking by Resonant Excitation at BESSY II betatron, 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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THPMF066 Performance of a Full Scale Superconducting Undulator with 20 mm Period Length at the KIT Synchrotron undulator, storage-ring, operation, electron 4223
 
  • S. Casalbuoni, S. Bauer, E. Blomley, N. Glamann, A.W. Grau, T. Holubek, E. Huttel, D. Saez de Jauregui
    KIT, Eggenstein-Leopoldshafen, Germany
  • C. Boffo, T.A. Gerhard, M. Turenne, W. Walter
    Bilfinger Noell GmbH, Wuerzburg, Germany
 
  Within the collaborative effort between KIT and Bilfinger Noell GmbH the development of a full scale superconducting undulator with 20 mm period length (SCU20) has been completed. This device addresses the reliability and reproducibility aspects of the manufacturing process, allowing for the status of a commercial product. The conduction cooled 1.5 m long coils were characterized in the KIT horizontal test facility CASPER II and later assembled in the final cryostat. The system was extensively tested in the final configuration before installation in the KIT storage ring KARA (Karlsruhe Research Accelerator) to be the source of the NANO beamline in December 2017. Here we present the performance of the device.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF066  
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THPMF067 Design and Tests of Switchable Period Length Superconducting Undulator Coils undulator, photon, insertion-device, insertion 4226
 
  • T. Holubek, S. Casalbuoni, S. Gerstl, N. Glamann, A.W. Grau, C.A.J. Meuter, D. Saez de Jauregui
    KIT, Eggenstein-Leopoldshafen, Germany
 
  Several photon beamlines in different synchrotron make use of undulators with switchable period length, which offer a larger tunability of the emitted photons energy. Superconducting technology allows switching the period length by changing the sign of the current in separately powered subset of windings. We present here the design and tests performed in liquid helium of switchable period length superconducting undulator coils performing period doubling from 17 mm to 34 mm.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF067  
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THPMF069 Perturbation to Stored Beam by Pulse Sextupole Magnet and Disturbance of the Sextupole Magnetic Field in Aichi Synchrotron Radiation Center radiation, synchrotron-radiation, injection, simulation 4232
 
  • A. Mochihashi
    KIT, Eggenstein-Leopoldshafen, Germany
  • M. Fujimoto, M. Katoh
    UVSOR, Okazaki, Japan
  • M. Hosaka, M. Hosaka, Y. Takashima, Y. Takashima, K. Y. Yamamura
    Nagoya University, Nagoya, Japan
  • M. Hosaka, H. Ohkuma, Y. Takashima
    Aichi Synchrotron Radiation Center, Aichi, Japan
  • M. Katoh
    Sokendai - Okazaki, Okazaki, Aichi, Japan
  • H. Ohkuma
    JASRI/SPring-8, Hyogo-ken, Japan
 
  In the Aichi synchrotron radiation center (Aichi-SR), a pulse sextupole magnet (PSM) has been installed as a pulse magnet for beam injection. This leads to the injection scheme without using a bump orbit and stable supply of the synchrotron radiation. In Aichi-SR we have performed usual injection scheme with 4 kicker magnets and making the bump. Because the circumference of the Aichi-SR is only 72 m, 3 beam lines are inside the bump. The Aichi-SR has performed top-up operation since its public open, so it is a crucial subject to eliminate the disturbance of the synchrotron radiation during the injection. We have installed the PSM in 2015 and developed the beam study continuously. At present, however, a perturbation to the stored beam by the PSM still has been observed and is not acceptable. We have performed beam diagnostic experiment and concluded that an additional dipole kick affects the beam. From the magnetic field measurement data, we have discussed the source of the additional kick; most likely is an eddy current on the Ti coating inside the ceramics duct of the PSM. The beam diagnostics experiment and the magnetic field measurement will be discussed in the presentation.
Present affiliation of the first auther : Karlsruhe Institute of Technology
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF069  
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THPMK052 Numerical Simulation of Phase-Shift Method for Fel Power Enhancement in PAL-XFEL undulator, electron, FEL, radiation 4402
 
  • C.-Y. Tsai, J. Wu, C. Yang, G. Zhou
    SLAC, Menlo Park, California, USA
  • H.-S. Kang
    PAL, Pohang, Kyungbuk, Republic of Korea
  • M. Yoon
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • G. Zhou
    IHEP, Beijing, People's Republic of China
 
  Funding: The work was supported by the US Department of Energy (DOE) under contract DE- AC02-76SF00515 and the US DOE Office of Science Early Career Research Program grant FWP-2013-SLAC-100164.
Recently the phase jump method for efficiency enhancement in free-electron laser (FEL) was proposed*. One of the unique features of PAL-XFEL with phase shifters may be taken for the experimental demonstration of this phase jump scheme. In this paper we numerically investigate the scheme using the three-dimensional numerical simulation code GENESIS**. The physical parameters are based on hard x-ray line of PAL-XFEL***. The preliminary simulation results indicate that this potential phase jump scheme can enhance at least one order of magnitude of FEL power performance. Combination of this scheme with undulator tapering is also discussed in this paper.
*A. Mak, F. Curbis, and S. Werin, PRAB 20, 060703 (2017)
**S. Rieche, NIMA 429(1):243-248 (1999)
***I. S. Ko et al., Appl. Sci. 2017, 7, 479 (2017)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK052  
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THPMK086 Low Intensity Electron Beam Measurement at SLRI Beam Test Facility electron, booster, target, detector 4502
 
  • K. Kittimanapun, N. Chanlek, A. Lakrathok, N. Laoiamnongwong
    SLRI, Nakhon Ratchasima, Thailand
 
  Funding: This work is supported by the National Science and Technology Development Agency (NSTDA) under contract FDA-C0-2558-855-TH.
The SLRI Beam Test Facility (SLRI-BTF), the latest extension of the existing accelerator complex, has recently been in operation at the Synchrotron Light Research Institute (SLRI). SLRI-BTF is capable of providing electron test beams with desired intensity and energy. By means of a wedge target downstream of the 40-MeV linac, the electron intensity of the test beam produced is variable between a few to millions of electrons per burst. The test beam energy is adjustable from 40 MeV to 1.2 GeV, depending on the acceleration time of the synchrotron booster. SLRI-BTF targets to service electron test beams to the development of the high-energy particle detectors and diagnostic instrumentations. In this paper, the measurement of the low intensity electron beam will be discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK086  
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THPMK092 SOLEIL Status Report operation, storage-ring, controls, undulator 4516
 
  • L.S. Nadolski, G. Abeillé, Y.-M. Abiven, P. Alexandre, F. Bouvet, F. Briquez, P. Brunelle, A. Buteau, N. Béchu, M.-E. Couprie, X. Delétoille, T. Didier, J.M. Dubuisson, C. Herbeaux, N. Hubert, C.A. Kitegi, M. Labat, J.-F. Lamarre, P. Lebasque, A. Lestrade, A. Loulergue, P. Marchand, O. Marcouillé, F. Marteau, A. Nadji, R. Nagaoka, P. Prigent, F. Ribeiro, K.T. Tavakoli, M.-A. Tordeux, M. Valléau
    SOLEIL, Gif-sur-Yvette, France
 
  SOLEIL is both a synchrotron light source and a research laboratory at the cutting edge of experimental techniques dedicated to matter analysis down to the atomic scale, as well as a service platform open to all scientific and industrial communities. This French 2.75 GeV third generation synchrotron light source provides today extremely stable photon beams to 29 beamlines (BLs) complementary to ESRF. We report facility performance, ongoing projects and recent major achievements. A significant work was performed in order to secure the operation of the two canted 5.5 mm in-vacuum cryogenic permanent magnet undulators (CPMUs). Major R&D areas will also be discussed, and progress towards a lattice baseline for making SOLEIL a diffraction limited storage ring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK092  
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THPMK099 Measurement of the Laser-Induced Energy Modulation Amplitude at the Short-Pulse Facility at DELTA laser, electron, radiation, experiment 4538
 
  • A. Meyer auf der Heide, B. Büsing, S. Khan, N.M. Lockmann, C. Mai, B. Riemann, B. Sawadski
    DELTA, Dortmund, Germany
 
  The short-pulse facility at the synchrotron light source DELTA operated by the TU Dortmund University employs coherent harmonic generation (CHG) to provide ultrashort pulses in the vacuum ultraviolet and terahertz regime. Here, a laser-electron interaction results in a modulation of the electron energy which is transformed into a density modulation by a magnetic chicane. Measurements of the energy modulation amplitude with different techniques including an RF phase modulation are presented. A combination of the results allow to estimate the energy spread of the electron beam.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK099  
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THPMK132 Generation of Terahertz Synchrotron Radiation Using Laser-Bunch Slicing at Hefei Light Source laser, undulator, radiation, electron 4626
 
  • W. Xu, S.W. Wang, S.C. Zhang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  Hefei Light Source is a second-generation low-energy synchrotron light source. The low energy machine is ca- pable of generating intense Terahertz radiation through co- herent synchrotron radiation. To realize this, one method is to shorten the bunch length to the same level of its radi- ation wavelength, e.g. by adopting low-α lattice. Another method is to modulate the electron bunch to produce mi- costructure at picosecond scale and intense Terahertz co- herent synchrotron radiation can be obtained due to the in- crease ofthebunchformfactor. This techniqueis calledthe laser bunch slicing method which introduces a laser beam into an undulator to interact with the electron bunches. In this paper we report our work on the simulation of the laser bunch slicing at Hefei Light Source.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK132  
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THPMK144 Lattices for a 4th-Generation Synchrotron Light Source lattice, emittance, SRF, radiation 4639
 
  • G. K. Shamuilov
    Uppsala University, Uppsala, Sweden
 
  Inspired by the ESRF upgrade (Extremely Brilliant Source, EBS), I present some modern lattices for a medium-sized 4th-generation synchrotron radiation source. They incorporate new elements, such as anti-bend magnets. The composed lattices are optimized using a simple double-objective algorithm. Its goal is to minimize the natural emittance and absolute chromaticities simultaneously. Then, the lattices are analyzed and compared to a version of the ESRF-EBS lattice scaled down in size. The design is performed to meet the needs of the user community of the Siberian Synchrotron and Terahertz Radiation Centre under the umbrella of the Budker Institute of Nuclear Physics.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK144  
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THPML066 Filling Pattern Measurement System Upgrade in SSRF* operation, storage-ring, SRF, injection 4791
 
  • N. Zhang, F.Z. Chen, Y.M. Zhou
    SSRF, Shanghai, People's Republic of China
 
  Funding: Work supported by National Natural Science Foundation of China (No.11575282 No.11375255 No.11305253)
Filling pattern affects various operation performance of a synchrotron light source. A new diagnostic beam charge monitor (BCM) with high bandwidth multi-channels digitizer was developed to perform bunch-by-bunch charge measurement and record filling pattern for SSRF storage ring. Signals picked up from button elec-trodes were sampled synchronously with RF frequency, and IQ (In-phase and Quadrature phase) sampling meth-od was employed for noise-filtering and phase independ-ence calibration. Layout and evaluation experiment of the system are presented in this paper.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML066  
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THPML070 Point Spread Function Study of Quasi-Monochromatic X-Ray Pinhole Camera at SSRF simulation, photon, SRF, experiment 4803
 
  • B. Gao, H.J. Chen
    SINAP, Shanghai, People's Republic of China
  • J. Chen, Y.B. Leng
    SSRF, Shanghai, People's Republic of China
 
  Since 2009 an X-ray pinhole camera that has been used to present the transverse beam size and emittance on diagnostic beam line of the storage ring at SSRF. The real beam size is a function of the image size of the CCD camera and point spread function (PSF) of the system. The performance of the measurement of the transverse electron beam size is given by the width of the PSF of X-ray pinhole camera. The contributions to the PSF width are the PSF of pinhole itself due to diffraction, and the PSF of the screen and camera. An X-ray monochromatic system has been established to measure the PSF accurately, and decrease the variation in the beam size between the theoretical values and the measured ones at SSRF. In this article, both calculated and measured PSF of quasi-monochromatic X-ray pinhole camera will be presented in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML070  
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THPML074 Image Reconstruction Technique Based on Coded Aperture Imaging for SuperKEKB X-ray Beam Size Monitor detector, optics, luminosity, electron 4819
 
  • E. Mulyani, J.W. Flanagan
    Sokendai, Ibaraki, Japan
  • J.W. Flanagan, H. Fukuma, H. Ikeda, M. Tobiyama
    KEK, Ibaraki, Japan
 
  The fast reconstruction techniques based on principles originally developed for coded aperture imaging have been investigated for SuperKEKB accelerator. The establishment of this technique will very important for measuring the beam sizes of all 2500 bunches in the SuperKEKB accelerator over thousands of turns, as needed for instability studies and luminosity tuning, due to the vast quantity of data that needs to be processed in a timely manner.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML074  
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THPML085 Intelligent Controls for the Electron Storage Ring DELTA controls, network, storage-ring, electron 4855
 
  • D. Schirmer
    DELTA, Dortmund, Germany
 
  In recent years, artificial intelligence has become one of the buzzwords in the field of controlling, monitoring and optimizing complex machines. Particle accelerators belong to this class of machines in particular. In accelerator controls one has to deal with a variety of time-varying parameters, nonlinear dynamics as well as a lot of small, compounding errors. Therefore, to cope with these tasks and to achieve higher performance, particle accelerators require new advanced strategies in controls and feedback systems. Machine learning through (deep) neural networks, genetic algorithms, swarm intelligence and adaptive controls are some of the proposed approaches. Increased computational capability and the availability of large data sets in combination with better theoretical understanding of new network architectures and training paradigms allow for promising approaches for novel developments. This report aims to discuss the state of the art techniques and presents ideas for possible applications of intelligent controls at the synchrotron radiation source DELTA.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML085  
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THPML089 Tuning of 3-tap Bandpass Filter During Acceleration for Longitudinal Beam Stabilization at FAIR emittance, feedback, controls, operation 4866
 
  • B.R. Reichardt, D. Domont-Yankulova
    Technische Universität Darmstadt (TU Darmstadt, RMR), Darmstadt, Germany
  • D. Domont-Yankulova, H. Klingbeil
    TEMF, TU Darmstadt, Darmstadt, Germany
  • H. Klingbeil, D.E.M. Lens
    GSI, Darmstadt, Germany
 
  During acceleration in the heavy-ion synchrotrons SIS18/SIS100 at GSI/FAIR longitudinal beam oscillations are expected to occur. To reduce longitudinal emittance blow-up, dedi- cated LLRF beam feedback systems are planned. To date, damping of longitudinal beam oscillations has been demon- strated in SIS18 machine experiments with a 3-tap filter controller (e.g. *), which is robust in regard to control pa- rameters and also to noise. On acceleration ramps the control parameters have to be adjusted to the varying synchrotron frequency. Previous results from beam experiments at GSI indicate that a proportional tuning rule for one parameter and an inversely proportional tuning rule for a second parameter is feasible, but the obtained damping rate may not be opti- mal for all synchrotron frequencies during the ramp. In this work, macro-particle simulations are performed to evaluate, whether it is sufficient to adjust the control parameters pro- portionally (inversely proportionally) to the change in the linear synchrotron frequency, or if it is necessary to take more pa- rameters, such as bunch-length and synchronous phase, into account to achieve stability and a considerable high damping rate for excited longitudinal dipole beam oscillations. This is done for single- and dual-harmonic acceleration ramps.
* H. Klingbeil et al., "A Digital Beam-Phase Control System for Heavy-Ion Synchrotrons", in IEEE Transactions on Nuclear Science, vol. 54, no. 6, pp. 2604-2610, Dec. 2007.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML089  
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THPML098 Design of Beam Profile Monitor Used at the Xi'an Proton Application Facility (XiPAF) detector, proton, radiation, experiment 4892
 
  • D. Wang, Z.M. Wang
    State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Shannxi, People's Republic of China
  • W. Chen
    NINT, Xi'an, People's Republic of China
  • P.F. Ma, Y.G. Yang
    TUB, Beijing, People's Republic of China
  • W. Wang
    Tsinghua University, Beijing, People's Republic of China
 
  A pixel ionization chamber for beam profile monitor (BPrM) is designed and manufactured by a new technology .The detector will be installed on the beam line just upstream of the target device of XiPAF. It has many advantages such as high resolution, high radiation hardness and it can work as a real-time monitor to show the distribution of the delivered relative dose. The physics design and construction of the detector are described in this paper, and its performances are tested offline.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML098  
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THPML121 Compensation of Transient Beam Loading in Ramping Synchrotrons Using a Fixed Frequency Processing Clock FPGA, cavity, feedback, LLRF 4957
 
  • F.J. Galindo Guarch, J.M.M.A. Moreno Arostegui
    Universitat Politécnica de Catalunya, Barcelona, Spain
  • P. Baudrenghien, F.J. Galindo Guarch
    CERN, Geneva, Switzerland
 
  Transient beam loading compensation schemes, such as One-Turn-FeedBack (OTFB), require beam synchronous processing (BSP). Swept clocks derived from the RF, and therefore harmonic to the revolution frequency, are widely used in CERN synchrotrons; this simplifies implementation with energy ramping, where the revolution frequency changes. It is however not optimal for state-of-the-art digital hardware that prefers fixed frequency clocks. An alternative to the swept clocking is the use of a deterministic protocol, for example, White Rabbit (WR): a fixed reference clock can be extracted from its data stream, while enabling digital distribution of the RF frequency among other data. New algorithms must be developed for BSP using this fixed clock and the digital data transmitted on the WR link. This is the strategy adopted for the SPS Low Level RF (LLRF) upgrade. The paper gives an overview of the technical, technological and historical motivations for such a paradigm evolution. It lists the problems of fixed clock BSP, and presents an innovative solution based on a real-time variable ratio re-sampler for implementing an OTFB with the new fixed clock scheme.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML121  
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THPML123 The ESR Barrier-Bucket LLRF System - Design and First Results LLRF, cavity, controls, experiment 4964
 
  • J. Harzheim, D. Domont-Yankulova, K. Groß, H. Klingbeil
    TEMF, TU Darmstadt, Darmstadt, Germany
  • M. Frey, H. Klingbeil, D.E.M. Lens
    GSI, Darmstadt, Germany
 
  At GSI, Darmstadt, Germany, a Barrier-Bucket (BB) RF System is currently under development for the Experimental Storage Ring (ESR). The system consists of two broadband RF cavities, each driven by a solid state amplifier, with the purpose to produce two voltage pulses per beam revolution. This will enable highly sophisticated longitudinal beam manipulations like longitudinal capture, compression and decompression or stacking of the beam. For the LLRF System, several requirements have to be fulfilled. Besides high standards concerning the pulsed gap signal quality (e.g. ringing <2.5%), the system has to provide the flexibility for adiabatic voltage ramp-up and adiabatic pulse shifting with high timing accuracy. A connection to the FAIR Central Control System (CCS) is necessary, as amplitude and phase ramp data will be provided by the CCS. In this contribution, the structure of the ESR BB LLRF system is presented together with experimental results from the first version of the system, which will be installed in the ESR in March 2018.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML123  
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THPML128 Production and Secondary Electron Yield Test of Amorphous Carbon Thin Film electron, vacuum, synchrotron-radiation, site 4980
 
  • Y.X. Zhang, X.Q. Ge, S.W. Wang, Y. Wang, W. Wei, B. Zhang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  Amorphous carbon (a-C) thin film applied to vacuum chambers of high-energy particle accelerators can decrease secondary electron yield(SEY)and suppress electron-cloud effectively. A dc magnetron sputtering apparatus to obtain a-C film has been designed. With the equipment, a-C thin film can be deposited on the inner face of stainless steel pipes ultimately which is uniform and high-quality. Meanwhile, it is found that a-C has a low SEY<1.2 measured by the secondary electron emission measurement set-up in the National Synchrotron Radiation Laboratory. The result indicates that a-C is an ideal material for modern accelerators.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML128  
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THPML130 Applications of a Distributed Beam Loss Monitor at the Australian Synchrotron storage-ring, target, detector, injection 4986
 
  • P.J. Giansiracusa, T.G. Lucas, R.P. Rassool, M. Volpi
    The University of Melbourne, Melbourne, Victoria, Australia
  • M.J. Boland
    CLS, Saskatoon, Saskatchewan, Canada
  • G. LeBlanc
    SLSA, Clayton, Australia
 
  A distributed beam loss monitoring system, based on Cherenkov silica fibres, has been installed at the Australian Synchrotron. The fibres are installed parallel to the beam pipe and cover the majority of the injection system and storage ring. Relativistic charged particles from beam loss events that have a velocity above the Cherenkov threshold produce photons in the fibres. These photons are then guided along the fibres to detectors outside of the accelerator tunnels. Originally the system was installed to determine its suitability for measuring losses at a future linear collider, such as the Compact Linear Collider, with single pass 150 ns bunch trains. This study builds on these results and attempts to use the system to measure loss locations with a circulating beam. We present the preliminary results and describe how the system could be improved.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML130  
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