04 Hadron Accelerators
A04 Circular Accelerators
Paper Title Page
MOZGBF2 Status of the FAIR Project 63
  • P.J. Spiller, M. Bai, O. Boine-Frankenheim, A. Dolinskyy, F. Hagenbuck, C.M. Kleffner, K. Knie, S. Menke, C. Omet, A. Schuhmann, H. Simon, M. Winkler
    GSI, Darmstadt, Germany
  • J. Blaurock, M. Ossendorf
    FAIR, Darmstadt, Germany
  • I. Koop
    BINP SB RAS, Novosibirsk, Russia
  • D. Prasuhn, R. Tölle
    FZJ, Jülich, Germany
  The realization of the new Facility for Antiproton and Ion Research, FAIR at GSI, Germany, has advanced significantly. The civil construction process of the Northern part of the building complex, including the excavation of the SIS100 synchrotron tunnel has been launched end of 2017. On site of the GSI campus, major preparations and upgrade measures for the injector operation of the existing accelerator facilities are ongoing and will be completed mid of 2018. The shielding of the SIS18 accelerator tunnel has been enhanced for the booster operation at high repetition rates and high intensity Proton beams. Two new transformer stations were set-up and commissioned which will provide the required pulse and common power for FAIR. All major contracts for series production of SIS100 components have been signed and a large number of the superconducting SIS100 magnets has been produced and accepted. Major testing infrastructures for superconducting magnets of SIS100 and Super-FRS have been set-up at JINR, CERN and GSI. Also for all other FAIR accelerator systems, the procurement of the components is progressing well  
slides icon Slides MOZGBF2 [4.271 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOZGBF2  
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MOZGBF5 Analysis of Polarization Decay at RHIC Store 76
  • H. Huang, P. Adams, E.C. Aschenauer, A. Poblaguev, W.B. Schmidke
    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.
There are polarization losses in RHIC store due to various sources, such as emittance growth and higher order spin resonances. The beam polarization was measured several times over a store by the p-carbon polarimeters situated in both rings. These provide information on the polarization decay over time and also polarization profile development over time. A polarized jet was also used to monitor the polarization continuously through store, though with limited statistical accuracy. These polarization measurements and emittance measurements from the IPM are analyzed and the polarization loss from different sources are reviewed.
slides icon Slides MOZGBF5 [4.530 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOZGBF5  
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TUPAF004 Status of the MedAustron Beam Commissioning with Protons and Carbon Ions 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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TUPAF005 Status of AC-Dipole Project at RHIC Injectors for Polarized Helions 669
  • K. Hock, H. Huang, F. Méot, P. Oddo, N. Tsoupas, J.E. Tuozzolo, K. Zeno
    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.
Polarized helions will be used in the eRHIC collider to collide with polarized electrons. To allow efficient transport of polarized helions in the Booster, to rigidities sufficiently high (B rho=10.8 T.m, |G gamma|=10.5) for minimizing the optical perturbations from the two partial helical dipoles in the AGS, an upgrade for overcoming depolarizing intrinsic resonances is needed. An AC-dipole is being designed to induce spin flips through intrinsic resonances. Booster AC-dipole operation will be established with protons while the polarized helion source is being completed. This paper reports the status of the project (which is now well advanced after two years of theoretical and design studies) and provides an overview of proof of principle experiments to take place after successful installation of the AC-dipole, during RHIC Run 19 with polarized proton beams.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF005  
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TUPAF006 Operation of RHIC Injectors with Isobaric Ruthenium and Zirconium Ions 672
  • H. Huang, E.N. Beebe, I. Blacker, J.J. Butler, C. Carlson, P.S. Dyer, W. Fischer, C.J. Gardner, D.M. Gassner, D. Goldberg, T. Hayes, S. Ikeda, J.P. Jamilkowski, T. Kanesue, N.A. Kling, C. Liu, D. Maffei, G.J. Marr, B. Martin, J. Morris, C. Naylor, M. Okamura, D. Raparia, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, P. Thieberger, K. Zeno, I.Y. Zhang
    BNL, Upton, Long Island, New York, USA
  • H. Haba
    RIKEN Nishina Center, Wako, Japan
  • T. Karino
    Utsunomiya University, Utsunomiya, Japan
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The FY18 RHIC physics program calls for Ru-Ru and Zr-Zr collisions at 100GeV using isobaric Ruthenium and Zirconium ions, each having 96 nucleons. In the injector chain, these two ions have to come from tandem and EBIS source, respectively. To reduce systematic errors in the detector, the luminosity between the two species combinations is matched as closely as possible, and the species are switched frequently. Several bunch merges are needed in the Booster and AGS to reach the desired bunch intensity for RHIC. The setup and performance of Booster and AGS with these ions are reviewed.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF006  
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TUPAF010 Empty Sweeping Bucket for Slow Extraction 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 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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TUPAF022 Studies of a New Optics With Intermediate Transition Energy as Alternative for High Intensity LHC Beams in the CERN SPS 713
  • M. Carlà, H. Bartosik, M.S. Beck, K.S.B. Li, M. Schenk
    CERN, Geneva, Switzerland
  • M. Schenk
    EPFL, Lausanne, Switzerland
  The LHC injector upgrade project calls for a twofold increase in intensity of the SPS proton beam. In this paper, we present studies with a new SPS optics called Q22, which has a transition energy in between the one of the operationally used Q20 and Q26 optics. This new optics provides a compromise between the stability of Q20, due to the low transition energy, and the reduced requirements in terms of RF voltage and power in Q26. A non-linear effective model of Q22 has been extrapolated from beam based measurements and used to complement the SPS non-linear optics model. Furthermore the studies of the TMCI threshold performed so far are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF022  
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TUPAF025 Multi-turn Study in FLUKA for the Design of CERN-PS Internal Beam Dumps 724
  • J.A. Briz Monago, M. Calviani, F. Cerutti, J.J. Esala, S.S. Gilardoni, F.-X. Nuiry, G. Romagnoli, G. Sterbini, V. Vlachoudis
    CERN, Geneva, Switzerland
  The CERN Proton-Synchrotron (PS) accelerator is currently equipped with two internal beam dumps in operation since the 1970's. An upgrade is required to be able to withstand the beams that will be produced after the end of the LIU (LHC Injector Upgrade) project. For the design of the new dumps, the interaction and transport of beam and all secondary particles generated has been simulated using FLUKA. The working principle of the internal beam dump in the PS ring is very peculiar with respect to the other dumps in the CERN accelerator complex. A moving dump intercepts the circulating beam during few milliseconds like a fast scraper. The moving dump shaving the beam, the multi-turn transport of beam particles in the PS accelerator and a time-dependent energy deposition in the dump were modeled. The methodology and the results obtained in our studies for the dump core and downstream equipment will be reported in this contribution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF025  
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TUPAF030 Electron Cloud Build Up for LHC Sawtooth Vacuum Chamber 744
SUSPF052   use link to see paper's listing under its alternate paper code  
  • 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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TUPAF036 Studies of the Injection and Cooling Efficiency in LEIR Using the Longitudinal Schottky Spectrum 765
  • S. Hirlaender, R. Alemany-Fernández, H. Bartosik, N. Biancacci, V. Kain
    CERN, Geneva, Switzerland
  The CERN Low Energy Ion Ring (LEIR) has two main operational beams with their associated cycles, the so-called EARLY and the NOMINAL beam. The EARLY beam consists of a single injected pulse from the LINAC3 accelerator, whereas seven consecutive injections are accumulated, and electron cooled for the NOMINAL beam. In both cases, the longitudinal Schottky monitor allows assessing the longitudinal particle distribution during the cooling process on the injection plateau. A method has been established to analyze the Schottky signal, reconstruct the initial particle momentum distribution and derive relevant parameters such as the cooling time, energy off-set of injected and stacked beam or the momentum distribution of the lost beam. The variations of the obtained parameters and the impact on the LEIR performance will be addressed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF036  
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TUPAF045 Studies for Future Fixed-Target Experiments at the LHC in the Framework of the CERN Physics Beyond Colliders Study 798
  • S. Redaelli, M. Ferro-Luzzi
    CERN, Geneva, Switzerland
  • C. Hadjidakis
    IN2P3-CNRS, Orsay, France
  A study on prospects for Physics Beyond Colliders at CERN was launched in September 2016 to assess the capabilities of the existing accelerators complex. Among several other working groups, this initiative triggered the creation of a working group with the scope of studying a few specific proposals to perform fixed-target physics experiments at the Large Hadron Collider (LHC). This includes for example physics experiments with solid or gaseous internal targets, polarized gas targets, and experiments using bent-crystals for halo splitting from beam core for internal targets. The focus of the working group's activities is on the technical feasibility and on implications to the LHC ring. In this paper, the current status of the studies is presented and future plans are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF045  
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TUPAF047 Systematic Studies of Transverse Emittance Measurements Along the CERN PS Booster Cycle 806
  • A. Santamaría García, S.C.P. Albright, H. Bartosik, J.A. Briz Monago, G.P. Di Giovanni, V. Forte, B. Mikulec, F. Roncarolo, V. Vlachoudis
    CERN, Geneva, Switzerland
  The CERN Proton Synchrotron Booster (PSB) will need to deliver 2 times the current brightness to the Large Hadron Collider (LHC) after the LHC Injectors Upgrade (LIU) to meet the High-Luminosity-LHC beam requirements. Beam intensity and transverse emittance are the key parameters to increase brightness, the latter being more difficult to manipulate. It is, therefore, crucial to monitor not only the emittance evolution between the different injectors but also along each acceleration cycle. To this end, detailed emittance measurements were carried out for the four rings of the PSB at various times in the cycle with different beam types. A thorough analysis of systematic error sources was conducted including multiple Coulomb scattering happening during profile measurements with wire scanners, where experimental and analytical treatments of the emittance blow-up were compared to FLUKA simulations. In order to properly account for the dispersive contribution, the full momentum spread profile was considered using a deconvolution method. We conclude with an assessment of this first comprehensive emittance evolution measurement along the PSB cycle.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF047  
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TUPAF049 Analysis of Loss Signatures of Unidentified Falling Objects in the LHC 814
  • L. K. Grob, M. Dziadosz, E.B. Holzer, A. Lechner, B. Lindstrom, R. Schmidt, D. Wollmann, C. Zamantzas
    CERN, Geneva, Switzerland
  Particulates in the LHC beam pipes can interact with the proton beams and cause significant beam losses. The "UFOs" (unidentified falling objects) hypothesis describes a particle falling into the beam, creating particle showers, being ionized and repelled. Though the signals of the beam loss monitors support this, many aspects remain unknown. Neither the source of the dust nor the release mechanism from the beam pipe are understood. The same holds for the forces involved in the interaction and the observed UFO rate reduction over the years. These open questions are approached from different angles. Firstly, a new data analysis tool was established featuring advanced raw data selection and statistical analysis. Results of this analysis will be presented. Secondly, dust samples were extracted from LHC components and analyzed to gain insight into the size distribution and material composition of the contamination. The performed observations and analysis lead to a better modelling of the UFO events and helped to understand the physics involved. The validated UFO models will be crucial in view of the high luminosity upgrade of the LHC (HL-LHC) and the Future Circular Collider (FCC).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF049  
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TUPAF057 The SPS Tests of the HL-LHC Crab Cavities 846
  • R. Calaga, O. Capatina, G. Vandoni
    CERN, Geneva, Switzerland
  Funding: Research supported by the HL-LHC project
Two superconducting crab cavities in the framework of the High Luminosity (HL-LHC) LHC were built to test for the first time with proton beams in the Super Proton Synchrotron (SPS) at CERN. These tests will address the operation of the crab cavities in a high current and high intensity proton machine through the full energy cycle with a primary focus on cavity transparency, performance and stability, failures modes and long term effects on proton beams. An overview of the SPS cryomodule development towards the SPS tests along with the first test results are presented.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF057  
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TUPAF081 Measurements and Simulations of the Spill Quality of Slowly Extracted Beams from the SIS-18 Synchrotron 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 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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TUPAK005 Upgrade Plan of J-PARC MR - Toward 1.3 MW Beam Power 966
  • T. Koseki
    KEK, Ibaraki, Japan
  The Main Ring Synchrotron (MR), a 30-GeV slow cycling proton synchrotron, delivers intense proton beam to a long-baseline neutrino oscillation experiment, T2K, by fast extraction and to an experimental facility, which is called hadron hall by slow extraction. The achieved beam intensities for routine operations are 470 kW ( 2.4 x 1014 ppp) for the fast extraction and 44 kW ( 5.1 x 1013 ppp) for the slow extraction. In order to increase the beam intensity, a plan to replace the magnet power supplies are now in progress for operation with a higher repetition rate. After the replacement, the cycle time will be shortened about a half and increase beam intensities two times larger for the fast extraction. In addition, a further upgrade plan for the fast extraction is mainly reinforcement of rf power supplies. The goal of the upgrade plan is reaching 1.3 MW beam power for the neutrino experiment.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK005  
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TUPAL027 Design of Multi-MW Rapid Cycling Synchrotron for Accelerator Driven Transmutation System 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 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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TUPAL064 Extended-Domain Tune-Scans for the HL-LHC Dynamic Aperture in Presence of Beam-Beam Effects 1163
  • D. Kaltchev
    TRIUMF, Vancouver, Canada
  • N. Karastathis, Y. Papaphilippou, D. Pellegrini
    CERN, Geneva, Switzerland
  We report simulations of the HL-LHC dynamic aperture (DA) at collision energy in the presence of beam-beam effects (weak-strong approximation) aiming to determine its dependence on the working point in tune space. Both linear domains working points are explored, spanning over (0.028 – 0.33) in horizontal tune, and two-dimensional ones which focus on more promising sub-regions near the diagonal. The range of parameters, such as bunch intensity and emittance, are chosen to correspond to the more important HL-LHC scenarios. A comparison with the LHC as built is also made. Direct benefit from these studies is the possible identification of working points alternative to the nominal one (in terms of dynamic aperture). They also help to understand the dependence of DA on particular resonance lines present in the vicinity of the footprint. In this work, the necessary resources were provided by the LHC@home project, based on the BOINC-SixTrack platform for distributed Computing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL064  
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THYGBF1 High Power Beam Operation of the J-PARC RCS and MR 2938
  • Y. Sato
    KEK, Ibaraki, Japan
  This invited talk presents the most recent status of improving J-PARC main ring (MR) beam operation together with the rapid cycling synchrotron (RCS) effort. The RCS has optimized the beam performance for the MR injection as well as the muon and neutron targets, where each requires different emittance and beam halo size. The MR has two extraction modes; fast extraction (FX) for the long baseline neutrino oscillation experiment, T2K, and slow extraction (SX) for experiments in the hadron experimental facility. At present, achieved beam intensities are 2.4·1014 protons per pulse (ppp) with cycle time 2.48 s (470 kW) in the FX mode and 5.1013 ppp with cycle time 5.52 s (44 kW) in the SX mode. For the FX operation, recent improvements are settings of new betatron tune, corrections of resonances near the betatron tune, and adopting 2nd harmonic rf voltage to reduce space charge effect. Beam instabilities have been suppressed with controlling chromaticity correction and transverse feedback systems. For the SX mode, a dynamic bump scheme for reducing extracted beam loss is successfully adopted. A high extraction efficiency of 99.5 % is achieved at the 44 kW beam operation.  
slides icon Slides THYGBF1 [6.669 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBF1  
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