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betatron

Paper Title Other Keywords Page
MOPAN004 Commissioning of the LNLS Elliptically Polarizing Undulator undulator, storage-ring, controls, multipole 149
 
  • P. F. Tavares
  • N. P. Abreu, J. F. Citadini, R. H.A. Farias, M. J. Ferreira, J. G.R. S. Franco, L. C. Jahnel, L. Liu, A. F.A. G. Moreira, X. R. Resende, G. Tosin
    LNLS, Campinas
  We present the results of the commissioning of the first Elliptically Polarizing Undulator to be installed at the 1.37 GeV electron storage ring of the Brazilian Synchrotron Light Source. The undulator is designed to provide UV and soft X-ray photons from 100 eV up to 1 keV with full polarization control. It uses the APPLE II design with 50 mm period and 22 mm gap and allows for both parallel and anti-parallel longitudinal motion of its magnet cassettes. We present the commissioning results including the measured orbit and tune perturbations as well as the non-linear effects of the undulator fields on the stored beam and the corresponding impact on the beam lifetime.  
 
MOPAN009 Transverse Feedback Development at SOLEIL feedback, impedance, damping, emittance 161
 
  • R. Nagaoka
  • L. Cassinari, J.-C. Denard, J.-M. Filhol, N. Hubert, M.-P. Level, P. Marchand, C. Mariette, F. Ribeiro, R. Sreedharan
    SOLEIL, Gif-sur-Yvette
  • K. Kobayashi, T. Nakamura
    JASRI/SPring-8, Hyogo-ken
  With reduced vertical chamber aperture adopted all around the machine, the transverse impedance for the SOLEIL ring is enhanced both in its resistive-wall and broadband content. The predicted instability threshold currents being significantly low as compared to the nominal current in multibunch and in several single bunch modes, a decision was taken to install a digital bunch by bunch feedback system, with an aim to make it operational since the beginning of the storage ring operation. The system implemented comprises components developed elsewhere, particularly the FPGA processor of SPring-8, chosen among different possible solutions. Using a BPM and a stripline in the diagonal mode, a single unit of the FPGA processor board has shown to successfully suppress resistive-wall and ion induced multibunch instabilities in either one or both transverse planes. On top of the system characteristics, the paper discusses details of the obtained performance, as well as future extensions to overcome the encountered limitations.  
 
MOPAN030 Analysis of Transverse Beam Oscillation at Photon Factory feedback, injection, damping, factory 221
 
  • W. X. Cheng
  • T. Obina
    KEK, Ibaraki
  FPGA based bunch by bunch feedback system to cure the transverse instabilities has been in operation stably since Oct. 2005. Specification and performance of the system will be introduced, transient measurement has been done to analyze the instability modes, which helps to understand the instability sources. Bunch by bunch beam oscillation, together with the digital turn-by-turn beam position measurement, injection oscillation damping is recorded and analyzed, transverse beam oscillation with and without the bunch by bunch feedback system will be shown in this paper. Precise tune measurement during this period will be presented. Turn by turn phase space monitor is also available with the data, from which the nonlinear beam dynamics can be revealed.  
 
MOPAN034 Development of a Pulsed Sextupole Magnet System for Beam Injection at the Photon Factory Storage Ring injection, emittance, sextupole, synchrotron 230
 
  • Y. Kobayashi
  • K. Harada, T. Honda, T. Miyajima, S. Nagahashi
    KEK, Ibaraki
  • N. Nakamura, H. Takaki
    ISSP/SRL, Chiba
  We proposed a single pulsed sextupole system for beam injection in electron storage rings. Now we are going to design a pulsed sextupole magnet and a ceramic chamber and install them at the Photon Factory storage ring next summer. The required specifications of the magnet and the vacuum chamber are estimated using a multi-particle tracking simulation. In this conference, we describe the design of the hardware for the system and the field measurement of the pulsed magnet.  
 
MOPAN074 Influence of Varying Tune Width on the Robustness of the LHC Tune PLL and its Application for Continuous Chromaticity Measurement resonance, controls, feedback, synchrotron 326
 
  • R. J. Steinhagen
  • A. Boccardi, M. Gasior, O. R. Jones, K. K. Kasinski
    CERN, Geneva
  Tune and chromaticity measurement is an integral part for safe and reliable LHC operation. Tight tolerances on the maximum transverse beam excursions allow oscillation amplitudes of less than 30 um. This leaves only a small margin for transverse beam and momentum excitations required for measuring tune and chromaticity. This contribution discusses a robust tune phase-locked-loop (PLL) operation in the presence of non-linearities and varying chromaticity. The loop design was tested at the SPS, using the LHC PLL prototype system. The system was also used to continuously measure tune width and chromaticity, using resonant transverse excitations of the tune side-slopes.  
 
TUODKI04 Accelerating Polarized Protons to 250 GeV resonance, polarization, proton, acceleration 745
 
  • M. Bai
  • L. Ahrens, I. G. Alekseev, J. G. Alessi, J. Beebe-Wang, M. Blaskiewicz, A. Bravar, J. M. Brennan, K. A. Brown, D. Bruno, G. Bunce, J. J. Butler, P. Cameron, R. Connolly, T. D'Ottavio, J. DeLong, K. A. Drees, W. Fischer, G. Ganetis, C. J. Gardner, J. Glenn, T. Hayes, H.-C. Hseuh, H. Huang, P. Ingrassia, J. S. Laster, R. C. Lee, A. U. Luccio, Y. Luo, W. W. MacKay, Y. Makdisi, G. J. Marr, A. Marusic, G. T. McIntyre, R. J. Michnoff, C. Montag, J. Morris, P. Oddo, B. Oerter, J. Piacentino, F. C. Pilat, V. Ptitsyn, T. Roser, T. Satogata, K. Smith, S. Tepikian, D. Trbojevic, N. Tsoupas, J. E. Tuozzolo, M. Wilinski, A. Zaltsman, A. Zelenski, K. Zeno, S. Y. Zhang
    BNL, Upton, Long Island, New York
  • D. Svirida
    ITEP, Moscow
  Funding: The work was performed under the US Department of Energy Contract No. DE-AC02-98CH1-886, and with support of RIKEN(Japan) and Renaissance Technologies Corp.(USA)

The Relativistic Heavy Ion Collider~(RHIC) as the first high energy polarized proton collider was designed to provide polarized proton collisions at a maximum beam energy of 250GeV. It has been providing collisions at a beam energy of 100GeV since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during the acceleration from injection to 100GeV with careful control of the betatron tunes and the vertical orbit distortions. However, the intrinsic spin resonances beyond 100GeV are about a factor of two stronger than those below 100GeV making it important to examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions. Polarized protons were accelerated to the record energy of 250GeV in RHIC with a polarization of 45\% measured at top energy in 2006. The polarization measurement as a function of beam energy also shows some polarization loss around 136GeV, the first strong intrinsic resonance above 100GeV. This paper presents the results and discusses the sensitivity of the polarization survival to orbit distortions.

 
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TUODKI05 Overcoming Depolarizing Resonances in the AGS with Two Helical Partial Snakes resonance, polarization, extraction, injection 748
 
  • H. Huang
  • L. Ahrens, M. Bai, K. A. Brown, C. J. Gardner, J. Glenn, F. Lin, A. U. Luccio, W. W. MacKay, T. Roser, S. Tepikian, N. Tsoupas, K. Yip, K. Zeno
    BNL, Upton, Long Island, New York
  Funding: Work performed under contract No. DE-AC02-98CH1-886 with the auspices of the DoE of United States, and support of RIKEN(Japan).

Dual partial snake scheme has provided polarized proton beams with 1.5*1011 intensity and 65% polarization for RHIC spin program. To overcome the residual polarization loss due to horizontal resonances in the AGS, a new string of quadrupoles have been added. The horizontal tune can now be set in the spin tune gap generated by the two partial snakes, such that horizontal resonances are avoided. This paper presents the accelerator setup and preliminary results.

 
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TUOCC02 Progress in Tune, Coupling, and Chromaticity Measurement and Feedback during RHIC Run 7 feedback, coupling, controls, injection 886
 
  • P. Cameron
  • J. Cupolo, W. C. Dawson, C. Degen, A. Della Penna, L. T. Hoff, Y. Luo, A. Marusic, R. Schroeder, C. Schultheiss, S. Tepikian
    BNL, Upton, Long Island, New York
  • M. Gasior
    CERN, Geneva
  Funding: US DOE

Tune feedback was first implemented in RHIC in 2002 as a specialist activity. The transition to full operational status was impeded by dynamic range problems, as well as by overall loop instabilities driven by large coupling. The dynamic range problem was solved by the CERN development of the Direct Diode Detection Analog Front End. Continuous measurement of all projections of the betatron Eigenmodes made possible the world's first implementation of coupling feedback during beam acceleration, resolving the problem of overall loop instabilites. Simultaneous tune and coupling feedbacks were utilized as specialist activities for ramp development during the 2006 RHIC run. At the beginning of the 2007 RHIC run there remained two obstacles to making these feedbacks fully operational in RHIC - chromaticity measurement and control, and the presence of strong harmonics of the power line frequency in the betatron spectrum. We report here on progress in tune, coupling, and chromaticity measurement and feedback, and discuss the relevance of our results to the LHC commissioning effort. The results of investigations of power line harmonics in RHIC are presented elsewhere in these proceedings.

 
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TUODC02 Development of 3D Beam-Beam Simulation for the Tevatron simulation, impedance, collider, dipole 905
 
  • E. G. Stern
  • J. F. Amundson, P. Spentzouris, A. Valishev
    Fermilab, Batavia, Illinois
  • J. Qiang, R. D. Ryne
    LBNL, Berkeley, California
  We present status of development of a 3D Beam-Beam simulation code. The essential features of the code are 3D particle-in-cell Poisson solver, multi-bunch beam transport and interaction, chromaticity and machine impedance. The simulations match synchro-betatron oscillations measured at the VEPP-2M collider. The impedance model is compared to analytic expressions for instability growth.  
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TUPAN042 Synchroton Radiation Interferometer Calibration Check by Use of a Size Control Bump in KEKB coupling, sextupole, simulation, luminosity 1478
 
  • N. Iida
  • J. W. Flanagan, Y. Funakoshi, K. Oide
    KEK, Ibaraki
  KEKB B-Factory is one of the second generation lepton colliders. The energies of the two beams are 3.5 GeV for positron and 8 GeV for electron. Synchrotron Radiation Monitors(SRMs) are installed in the both rings and usually used for measuring beam sizes on real times. On the other hand, we use useful vertical bumps to control beam sizes of the beams. In this paper a method for calibrating the SRM by using the vertical bumps is described.  
 
TUPAN047 Beam-beam Effects in Crab Crossing and Crab Waist Schemes sextupole, resonance, emittance, electromagnetic-fields 1493
 
  • K. Ohmi
  • M. E. Biagini, P. Raimondi, M. Zobov
    INFN/LNF, Frascati (Roma)
  • Y. Funakoshi
    KEK, Ibaraki
  To boost up the luminosity performance in B factories, crab crossing and crab waist schemes are proposed. The crab crossing scheme compensates crossing angle, while the crab waist scheme compensates nonlinear tems induced by crossing angle with sextupole magnets. We discuss which nonlinear terms in the beam-beam map are enhanced by the crossing angle and which terms are compensated by the crab waist sextupole.  
 
TUPAN048 Beam-beam Effects With an External Noise in LHC emittance, simulation, feedback, luminosity 1496
 
  • K. Ohmi
  • R. Calaga
    BNL, Upton, Long Island, New York
  • W. Hofle, R. Tomas, F. Zimmermann
    CERN, Geneva
  Proton beam do not have any damping mechanism for an incoherent betatron motion. A noise, which kicks beam particles in the transverse plane, gives a coherent betatron amplitude. Nonlinear force due to the beam-beam interactions causes a decoherence for the betatron motion with keeping an amplitude of each beam particle, with the result that an emittance growth arises. We focus fast transverse turn by turn noises caused by a bunch by bunch feedback system and a cavity phase zitter in crab collision.  
 
TUPAN049 Low Emittance Lattices and Final Focus Design for the SuperB Project sextupole, lattice, emittance, dynamic-aperture 1499
 
  • Y. Ohnishi
  • M. E. Biagini, P. Raimondi
    INFN/LNF, Frascati (Roma)
  • Y. Cai, J. Seeman, M. K. Sullivan, U. Wienands
    SLAC, Menlo Park, California
  • A. Wolski
    Liverpool University, Science Faculty, Liverpool
  For the SuperB project* very low emittances (horizontal < 1 nm) and small beta functions at the Interaction Points are required to achieve the design luminosity of 1036/cm2/s. Low emittance lattice have been designed, using the PEP-II magnets, for the two rings of 4 and 7 GeV, which will have the same emittances and damping times. A new Final Focus section has also been designed to get the strong focusing at the Interaction Point, at the same time providing local correction of the high chromaticity and exploiting the large crossing angle and crabbed waist concepts. Lattice features and chromaticity correction schemes will be discussed. Dynamic apertures, with damping wigglers similar to the ILC ones, will also be presented.

* P. Raimondi, "New Developments for SuperB Factories", Invited talk, this Conference

 
 
TUPAN085 LHC Impedance Reduction by Nonlinear Collimation impedance, collimation, insertion, damping 1571
 
  • J. Resta-Lopez
  • A. Faus-Golfe
    IFIC, Valencia
  • F. Zimmermann
    CERN, Geneva
  A nonlinear collimation system can allow larger aperture for the mechanical jaws, and it thereby can help to reduce the collimator impedance, which presently limits the LHC beam intensity. Assuming the nominal LHC beam at 7 TeV, we show how a nonlinear betatronic collimation insertion would reduce considerably the LHC coherent tune shift for the most critical coupled-bunch mode as compared with the conventional baseline linear collimation system of Phase-I. In either case, the tune shifts of the most unstable modes are compared with the stability diagrams for Landau damping.  
 
TUPAS033 Field Fluctuation and Beam Screen Vibration Measurements in the LHC Magnets dipole, quadrupole, emittance, resonance 1724
 
  • V. D. Shiltsev
  • T. Kroyer, R. de Maria
    CERN, Geneva
  We present experimental methods and results of magnetic field fluctuation and beam screen vibration measurements in the LHC magnets. These noises can lead to an emittance grwoth in proton beams if they have spectral components at the betatron lines. A preliminary estimates of the effects are given.  
 
TUPAS068 A Transverse Beam Instability in the PEP-II HER Induced by Discharges in the Vacuum System vacuum, monitoring, coupling, background 1811
 
  • U. Wienands
  • W. S. Colocho, S. DeBarger, F.-J. Decker, S. Ecklund, A. S. Fisher, J. D. Fox, A. Kulikov, A. Novokhatski, M. Stanek, M. K. Sullivan, W. Wittmer, D. Wright, G. Yocky
    SLAC, Menlo Park, California
  Funding: Work supported by US Dept. of Energy

During Run 5, PEP-II has been plagued by beam instabilities causing beam aborts due to radiation in the BaBar detector or due to fast beam loss triggering the dI/dt interlock. The latest of such instabilities occurred in the High Energy Ring (HER), severely curtailing the maximum beam current achievable during physics running. Techniques used in tracking down this instability included fast monitoring of background radiation, temperatures and vacuum pressure. In this way, the origin of the instability was localized and inspection of the vacuum system revealed several damaged bellows shields. Replacing these units significantly reduced the incident rate but did not eliminate it fully. After the end of the run, a number of damaged rf seals were found, possibly having caused the remaining incidents of instability. In this paper we will outline the steps taken to diagnose and remedy the issue and also compare the different signatures of vacuum-induced instabilities we have seen in both rings of PEP-II during the run.

 
 
TUPAS085 RHIC Spin Flipper dipole, proton, resonance, simulation 1847
 
  • M. Bai
  • A. U. Luccio, Y. Makdisi, P. H. Pile, T. Roser
    BNL, Upton, Long Island, New York
  Funding: The work was performed under the auspices of the US Department of Energy.

Full spin flip in the presence of full Siberian snake has been achieved by using an rf dipole or solenoid as spin flipper at IUCF and COSY. This technique requires one to change the snake configuration to move the spin tune away from half integer. However, this is not practical for an operational high energy polarized proton collider like RHIC where beam lifetime is sensitive to small betatron tune change. An new technique of achieving full spin flip with the spin tune staying at half integer is proposed. This paper presents the design of RHIC spin flipper along with simulation results.

 
 
TUPAS086 Snake Depolarizing Resonance Study in RHIC resonance, polarization, proton, quadrupole 1850
 
  • M. Bai
  • P. Cameron, H. Huang, A. U. Luccio, V. Ptitsyn, T. Roser, S. Tepikian
    BNL, Upton, Long Island, New York
  Funding: US Department of Energy, RIKEN(Japan), Renaissance Technologies Corp.(USA)

Snake depolarizing resonances due to the imperfect cancellation of the accumulated perturbations on the spin precession between snakes were observed at the Relativistic Heavy Ion Collider~(RHIC). During the RHIC 2005 and 2006 polarized proton runs, we mapped out the spectrum of odd order snake resonance at Qy=7/10. Here, Qy is the beam vertical betatron tune. We also studied the beam polarization after crossing the 7/10th resonance as a function of resonance crossing rate. This paper reports the measured resonance spectrum as well as the results of resonance crossing.

The work was performed under the US Department of Energy Contract No. DE-AC02-98CH1-886, and with support of RIKEN(Japan) and RenaissanceTechnologies C orp.(USA)

 
 
WEOCAB01 Design of the Beam Delivery System for the International Linear Collider collimation, linac, extraction, diagnostics 1985
 
  • A. Seryi
  • I. V. Agapov, G. A. Blair, S. T. Boogert, J. Carter
    Royal Holloway, University of London, Surrey
  • M. Alabau, P. Bambade, J. Brossard, O. Dadoun
    LAL, Orsay
  • J. A. Amann, R. Arnold, F. Asiri, K. L.F. Bane, P. Bellomo, E. Doyle, A. F. Fasso, L. Keller, J. Kim, K. Ko, Z. Li, T. W. Markiewicz, T. V.M. Maruyama, K. C. Moffeit, S. Molloy, Y. Nosochkov, N. Phinney, T. O. Raubenheimer, S. Seletskiy, S. Smith, C. M. Spencer, P. Tenenbaum, D. R. Walz, G. R. White, M. Woodley, M. Woods, L. Xiao
    SLAC, Menlo Park, California
  • M. Anerella, A. K. Jain, A. Marone, B. Parker
    BNL, Upton, Long Island, New York
  • D. A.-K. Angal-Kalinin, C. D. Beard, J.-L. Fernandez-Hernando, P. Goudket, F. Jackson, J. K. Jones, A. Kalinin, P. A. McIntosh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • R. Appleby
    UMAN, Manchester
  • J. L. Baldy, D. Schulte
    CERN, Geneva
  • L. Bellantoni, A. I. Drozhdin, V. S. Kashikhin, V. Kuchler, T. Lackowski, N. V. Mokhov, N. Nakao, T. Peterson, M. C. Ross, S. I. Striganov, J. C. Tompkins, M. Wendt, X. Yang
    Fermilab, Batavia, Illinois
  • K. Buesser
    DESY, Hamburg
  • P. Burrows, G. B. Christian, C. I. Clarke, A. F. Hartin
    OXFORDphysics, Oxford, Oxon
  • G. Burt, A. C. Dexter
    Cockcroft Institute, Warrington, Cheshire
  • J. Carwardine, C. W. Saunders
    ANL, Argonne, Illinois
  • B. Constance, H. Dabiri Khah, C. Perry, C. Swinson
    JAI, Oxford
  • O. Delferriere, O. Napoly, J. Payet, D. Uriot
    CEA, Gif-sur-Yvette
  • C. J. Densham, R. J.S. Greenhalgh
    STFC/RAL, Chilton, Didcot, Oxon
  • A. Enomoto, S. Kuroda, T. Okugi, T. Sanami, Y. Suetsugu, T. Tauchi
    KEK, Ibaraki
  • A. Ferrari
    UU/ISV, Uppsala
  • J. Gronberg
    LLNL, Livermore, California
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto
  • W. Lohmann
    DESY Zeuthen, Zeuthen
  • L. Ma
    STFC/DL, Daresbury, Warrington, Cheshire
  • T. M. Mattison
    UBC, Vancouver, B. C.
  • T. S. Sanuki
    University of Tokyo, Tokyo
  • V. I. Telnov
    BINP SB RAS, Novosibirsk
  • E. T. Torrence
    University of Oregon, Eugene, Oregon
  • D. Warner
    Colorado University at Boulder, Boulder, Colorado
  • N. K. Watson
    Birmingham University, Birmingham
  • H. Y. Yamamoto
    Tohoku University, Sendai
  The beam delivery system for the linear collider focuses beams to nanometer sizes at the interaction point, collimates the beam halo to provide acceptable background in the detector and has a provision for state-of-the art beam instrumentation in order to reach the physics goals. The beam delivery system of the International Linear Collider has undergone several configuration changes recently. This paper describes the design details and status of the baseline configuration considered for the reference design.  
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THPMN073 Collimation Optimisation in the Beam Delivery System of the International Linear Collider collimation, lattice, luminosity, quadrupole 2871
 
  • F. Jackson
  • R. J. Barlow, A. M. Toader
    UMAN, Manchester
  • A. Latina, D. Schulte
    CERN, Geneva
  The collimation systems of the International Linear Collider (ILC) Beam Delivery System (BDS) must perform efficient removal of halo particles which lie outside the acceptable ranges of energy and spatial spread. An optimisation strategy based on earlier work is applied to the latest version of the BDS lattice. The resulting improvement in collimation performance is studied by halo tracking simulations, and the luminosity performance of the optimised lattice is also examined.  
 
THPMS018 High Average Current Betatrons for Industrial and Security Applications acceleration, focusing, electron, injection 3035
 
  • S. Boucher
  • R. B. Agustsson, P. Frigola, A. Y. Murokh, M. Ruelas
    RadiaBeam, Los Angeles, California
  • F. H. O'Shea, J. B. Rosenzweig, G. Travish
    UCLA, Los Angeles, California
  Funding: DOE Grant DE-FG02-04ER84051

The fixed-field alternating-gradient (FFAG) betatron has emerged as a viable alternative to RF linacs as a source of high-energy radiation for industrial and security applications. For industrial applications, high average currents at modest relativistic electron beam energies, typically in the 5 to 10 MeV range, are desired for medical product sterilization, food irradiation and materials processing. For security applications, high power x-rays in the 3 to 20 MeV range are needed for rapid screening of cargo containers and vehicles. In a FFAG betatron, high-power output is possible due to high duty factor and fast acceleration cycle: electrons are injected and accelerated in a quasi-CW mode while being confined and focused in the fixed-field alternating-gradient lattice. The beam is accelerated via magnetic induction from a betatron core made with modern low-loss magnetic materials. Here we present the design and status of a prototype FFAG betatron, called the Radiatron, as well as future prospects for these machines.

 
 
THPMS056 Emittance Preservation in the International Linear Collider Ring to Main Linac Transfer Line emittance, coupling, simulation, survey 3118
 
  • P. Tenenbaum
  • K. Kubo
    KEK, Ibaraki
  • A. Latina
    CERN, Geneva
  • J. C. Smith
    CLASSE, Ithaca
  Funding: Work supported by the US Department of Energy, contract DE-AC02-76SF00515.

The very small vertical beam emittance in the International Linear Collider (ILC) can be degraded by dispersion, xy coupling, transverse wakefields, and time-varying transverse fields introduced by elements with misalignments, strength errors, xy rotation errors, or yz rotation errors in the Ring to Main Linac (RTML) transfer line. We present a plan for emittance preservation in this beamline which uses local, quasi-local, and global correction schemes. Results of simulations of the emittance preservation algorithm are also presented and discussed.

 
 
THPMS092 Superconducting Non-Scaling FFAG Gantry for Carbon/Proton Cancer Therapy proton, hadron, dipole, ion 3199
 
  • D. Trbojevic
  • R. C. Gupta, B. Parker
    BNL, Upton, Long Island, New York
  • E. Keil
    CERN, Geneva
  • A. Sessler
    LBNL, Berkeley, California
  Funding: * Supported by the U. S. Department of Energy under Contract No. DE-AC02-98CH10886. ** Work supported by the U. S. Department of Energy under Contract No. DE-AC02-05CH11231

We report on improvements in the non-scaling Fixed Field Alternating Gradient (FFAG) gantry design. As we previously reported*, a major challenge of the carbon/proton cancer therapy facilities is isocentric gantry design. The weight of the isocentric gantry transport elements in the latest Heidelberg carbon/proton facility is 135 tons**. In this report we detail improvements to the previous non-scaling gantry design. We estimate that this non-scaling FFAG gantry would be almost hundred times lighter than traditional heavy ion gantries. Very strong focusing with small dispersion permits passage of different energies of carbon beams through the gantry's fixed magnetic field.*

 
 
THPMS093 Muon Acceleration with the Racetrack FFAG acceleration, extraction, injection, lattice 3202
 
  • D. Trbojevic
  Funding: Supported by the U. S. Department of Energy under Contract No. DE-AC02-98CH10886.

Muon acceleration for muon collider or neutrino factory is still in the stage where further improvements are likely as a result of further study. This report presents a design of the racetrack non-scaling Fixed Field Alternating Gradient (NS-FFAG) accelerator to allow fast muon acceleration in small number of turns. The racetrack design is made of four arcs: two arcs at opposite sides have a smaller radius and are made of closely packed combined function magnets, while two additional arcs with a very large radius are used for muon extraction, injection, and RF accelerating cavities. The ends of the large radii arcs are geometrically matched at the connections to the arcs with smaller radii. The dispersion and both horizontal and vertical amplitude functions are matched at the central energy.

 
 
THPMS094 Acceleration of Electrons with the Racetrack Non-Scaling FFAG for e-RHIC linac, acceleration, electron, lattice 3205
 
  • D. Trbojevic
  • I. Ben-Zvi, J. S. Berg, M. Blaskiewicz, V. Litvinenko, W. W. MacKay, V. Ptitsyn, T. Roser, A. G. Ruggiero
    BNL, Upton, Long Island, New York
  Funding: Supported by the U. S. Department of Energy under Contract No. DE-AC02-98CH10886

Acceleration of electrons up to 10 GeV for a future electron-ion collider eRHIC (Relativistic Heavy Ion Collider) could be performed with the energy recovery linac with multiple passes. An energy recovery scheme is required if a superconducting linac is used for acceleration. We report on an attempt to make a combination of a multi-pass linac with non-scaling Fixed Field Alternating Gradient (NS-FFAG) arcs. Two NS-FFAG arcs would allow electrons to pass through the same structure with different energies. The beam will be accelerated by the superconducting linac at the top of the sine function, and returned to the front of the linac by the non-scaling FFAG. This process is repeated until the total energy of 10 GeV is reached. After collisions the beam is brought back by the NS-FFAG and decelerated before being dumped.

 
 
THPAN007 Parallel Beam-Beam Simulation Incorporating Multiple Bunches and Multiple Interaction Regions simulation, collider, beam-beam-effects, interaction-region 3235
 
  • F. W. Jones
  • W. Herr
    CERN, Geneva
  • T. Pieloni
    EPFL, Lausanne
  The simulation code COMBI has been developed to enable the study of beam-beam effects in the full collision scenario of the LHC, with multiple bunches interacting at multiple head-on and long-range collision points. The code is structured in a general way, allowing any number of bunches and interaction points (IP's) and procedural options for collisions, beam transport, and output of statistics and coherent mode data. The scale of this problem escalates into the parallel computing arena, and herein we will describe the construction of an MPI-based version of COMBI able to utilize arbitrary numbers of processors to support efficient calculation of multi-bunch multi-IP interactions and transport. After an overview of the basic methods and numerical components of the code, the computational framework will be described in detail and the parallel efficiency and scalability of the code will be evaluated.  
 
THPAN009 Orbit Properties of Non-Scaling FFAG Accelerators Using Constant-Gradient Magnets lattice, quadrupole, synchrotron, vacuum 3241
 
  • M. K. Craddock
  • S. R. Koscielniak
    TRIUMF, Vancouver
  Very high momentum compaction can be obtained in non-scaling FFAG accelerators using constant-gradient magnets with their field strengths decreasing outwards - sufficiently high that the magnet apertures (and vacuum chamber) need be little wider than in a strong-focusing synchrotron. Such machines are of great potential interest for applications in the 0.1 - 50 GeV energy range requiring higher intensities or pulse repetition rates than synchrotrons can provide. Analytic formulae have been developed for the basic orbit properties, particularly their momentum dependence, in various lattices, and give accurate enough results to provide a useful tool for choosing the magnet parameters. In this paper the dependences of orbit offset and circumference on momentum are explored for doublet lattices, and numerical results from the formulae are compared with those from lattice codes.  
 
THPAN011 Non Linear Space Charge Effects on Transverse Beam Stability simulation, space-charge, impedance, damping 3247
 
  • J. J. Espinosa
  • J. F. Cardona
    UNAL, Bogota D. C
  Funding: This work is funded by DINAIN, Division Nacional de Investigacion, Universidad Nacional de Colombia, Bogota - Colombia.

Simbad code is used to study the combined effect of external non linearities and space charge non linearities on the beam stability using a simple FODO lattice. Gaussian and parabolic particle distribution are used for these simulations and results are compared with Mohl and Metral theoretical results.

 
 
THPAN037 Beam-Beam Effects Observed at KEKB luminosity, simulation, feedback, emittance 3309
 
  • Y. Funakoshi
  • K. Ohmi, K. Oide, M. Tawada
    KEK, Ibaraki
  KEKB is an e+ e- collider with a world-highest luminosity of 1.7 x 1034 /cm2/s. It has a half-crossing angle of 11 mrad. We are installing crab cavities for the purpose of eliminating effects of crossing angle in the begining of 2007. Another feature of KEKB is that its operating points are very close to the half interger in the horizontal direction. This report summarizes beam-beam effects observed at KEKB.  
 
THPAN043 Comparison of Trajectory Between Modeling and Experiment for J-PARC Linac linac, quadrupole, simulation, beam-transport 3324
 
  • T. Ohkawa
  • H. Ao, A. Ueno
    JAEA/LINAC, Ibaraki-ken
  • K. Hasegawa
    JAEA, Ibaraki-ken
  • M. Ikegami
    KEK, Ibaraki
  • H. Sako
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  In the beam commissioning of J-PARC (Japan Proton Accelerator Research Complex) linac, three simulations codes are used to model the accelerator. We have compared with the experimental results obtained in the beam commissioning to date, where a basic agreement has been confirmed between the modeling and the actual beam behavior.  
 
THPAN102 Tevatron Optics Measurements using an AC Dipole dipole, optics, synchrotron, kicker 3465
 
  • R. Miyamoto
  • A. Jansson, M. J. Syphers
    Fermilab, Batavia, Illinois
  • S. E. Kopp
    The University of Texas at Austin, Austin, Texas
  The AC dipole is a device that can be used to study beam optics of hadron synchrotrons. It can produce sustained large amplitude oscillations with virtually no emittance growth. A vertical AC dipole for the Tevatron was recently implemented and a maximum oscillation amplitude of 2 (4) σ beam size at 980 (150) GeV was achieved. If such large oscillations are combined with the Tevatron's BPM system (20 micron resolution), not only linear but even nonlinear optics can be measured not depending on machine models. This paper discusses how to make model independent measurements of ring-wide beta functions using the AC dipole and shows test results and comparisons to other methods. The emittance preserving nature of the AC dipole allows multiple measurements on the same beam. By repeating measurements with a small change to the optics every time, the accuracy of measurements using the AC dipole can be determined. Results of such tests are also presented.  
 
THPAN104 Coupled Optics Reconstruction from TBT Data using MAD-X optics, lattice, quadrupole, injection 3471
 
  • Y. Alexahin
  • E. Gianfelice-Wendt
    Fermilab, Batavia, Illinois
  • V. V. Kapin
    MEPhI, Moscow
  • F. Schmidt
    CERN, Geneva
  Funding: Work supported by the Universities Research Assoc., Inc., under contract DE-AC02-76CH03000 with the U. S. Dept. of Energy

Turn-by-turn BPM data provide immediate information on the coupledoptics functions at BPM locations. In the case of small deviations from the known (design) uncoupled optics some cognizance of the sources of perturbation, BPM calibration errors and tilts can also be inferred without detailed lattice modelling. In practical situations, however, fitting the lattice model with the help of some optics code would lead to more reliable results. We present an algorithm for coupled optics reconstruction from TBT data on the basis of MAD-X and give examples of its application for the Fermilab Tevatron and Booster accelerators.

 
 
THPAS011 Investigation of Residual Vertical Intrinsic Resonances with Dual Partial Siberian Snakes in the AGS resonance, polarization, acceleration, emittance 3534
 
  • F. Lin
  • L. Ahrens, M. Bai, K. A. Brown, E. D. Courant, J. Glenn, H. Huang, A. U. Luccio, W. W. MacKay, T. Roser, N. Tsoupas
    BNL, Upton, Long Island, New York
  • S.-Y. Lee
    IUCF, Bloomington, Indiana
  Funding: The work was performed under the US Department of Energy Contract No. DE-AC02-98CH1-886, No. DE-FG02-92ER40747, NSF PHY-0552389, and with support of RIKEN(Japan) and Renaissance Technologies Corp.(USA)

Two partial helical dipole snakes were found to be able to overcome all imperfection and intrinsic spin resonances provided that the vertical betatron tunes were maintained in the spin tune gap near the integer 9. Recent vertical betatron tune scan showed that the two weak resonances at the beginning of the acceleration cycle may be the cause of polarization loss. This result has been confirmed by the vertical polarization profile measurement, and spin tracking simulations. Possible cure of the remaining beam polarization is discussed.

 
 
THPAS055 Long Time Electron Cloud Instability Simulation Using QuickPIC With Pipelining Algorithm simulation, electron, plasma, acceleration 3615
 
  • B. Feng
  • V. K. Decyk, C. Huang, W. B. Mori
    UCLA, Los Angeles, California
  • T. C. Katsouleas, P. Muggli
    USC, Los Angeles, California
  Funding: This work was supported by the Department of Energy contract DE-FG02-92-ER40745

We proposed a novel algorithm, which uses pipelining to reduce the simulation time for beam-electron cloud interaction. In the pipelining algorithm the processors are divided into subgroups, and during the simulation different groups will be on consecutive time steps. The pipelining algorithm is applied to the fully parallelized Particle-In-Cell (PIC) code QuickPIC to overcome the limit of the number of processors that can be used at each time step. With the new algorithm, the accuracy of the simulation is preserved; and the speed of the simulation is improved by a factor proportional to the number of processors available. The long term beam evolution results for the CERN-LHC and the FNAL main injector are presented using the QuickPIC with pipelining algorithm.

 
 
THPAS070 Validation of PEP-II Resonantly Excited Turn-by-Turn BPM Data optics, coupling, lattice, storage-ring 3645
 
  • Y. T. Yan
  • Y. Cai, W. S. Colocho, F.-J. Decker
    SLAC, Menlo Park, California
  Funding: Work supported by US DOE un contract No. DE-AC02-76SF00515

For optics measurement and modeling of the PEP-II electron (HER) and position (LER) storage rings, we have been doing well with MIA* which requires analyzing turn-by-turn Beam Position Monitor (BPM) data that are resonantly excited at the horizontal, vertical, and longitudinal tunes respectively. However, in anticipating that certain BPM buttons or even pins in the PEP-II IR region will be missing for the next run starting in January 2007, we have been developing a data validation process, hoping to reduce the effect due to the reduced BPM data accuracy on PEP-II optics measurement and modeling. Besides the routine process for ranking BPM noise level through data correlation among BPMs, allowing BPMs to have linear gains and linear cross couplings, we can also check BPM data symplecticity by comparing the invariant ratios. We may also work out nonlinear BPM data correction if needed. Results on PEP-II measurement will be presented.

* Y. T. Yan, et. al. EPAC06 Proceedings, WEPCH062, (2006)

 
 
THPAS081 Particle-in-Cell Simulations of Halo Particle Production in Intense Charged Particle Beams Propagating Through a Quadrupole Focusing Field with Varying Lattice Amplitude lattice, simulation, focusing, emittance 3669
 
  • M. Dorf
  • R. C. Davidson, E. Startsev
    PPPL, Princeton, New Jersey
  Funding: Research supported by the U. S. Department of Energy.

The transverse compression and dynamics of intense charged particle beams, propagating through a periodic quadrupole lattice, play an important role in many accelerator physics applications. Typically, the compression can be achieved by means of increasing the focusing strength of the lattice along the beam propagation direction. However, beam propagation through the lattice transition region inevitably leads to a certain level of beam mismatch and halo formation. In this paper we present a detailed analysis of these phenomena using particle-in-cell (PIC) numerical simulations performed with the WARP code. A new definition of beam halo is proposed in this work that provides the opportunity to carry out a quantitative analysis of halo production by a beam mismatch.

 
 
FRPMN032 On Skew Nonlinear Resonance in the SPring-8 Storage Ring resonance, coupling, sextupole, storage-ring 4003
 
  • M. Takao
  • M. Masaki, J. Schimizu, K. Soutome, S. Takano
    JASRI/SPring-8, Hyogo-ken
  Recently we accomplish the matrix formulation for the canonical perturbation theory of the linear betatron coupling resonance. By merging the perturbation theory with the matrix formalism, we manifest the symplectic structure of the former theory, and conversely derive the analytical representation for the latter. The formulation for the coupled betatron motion implies that the linear coupling causes the excitation of skew resonances by nonlinear fields with mid-plane symmetry. This effect is visible in the vicinity of the linear coupling resonance, which is observed in the SPring-8 storage ring, for example, as the blow-up of the vertical beam size on the third order skew coupling resonance. For the purpose of studying the impacts of the skew nonlinear resonance on the beam dynamics, we investigate the characteristic behavior of the resonance expected by the matrix formulation.  
 
FRPMN035 Crabbing Angle Measurement by Streak Camera at KEKB luminosity, optics, synchrotron, synchrotron-radiation 4018
 
  • H. Ikeda
  • J. W. Flanagan, H. Fukuma, S. Hiramatsu, T. Mitsuhashi
    KEK, Ibaraki
  Crab cavities will be installed in the KEKB rings in order to increase luminosity. We measure the crabbing angle using a streak camera and show the results in this paper.  
 
FRPMN038 Simulation of Synchro-betatron Sideband Instability caused by Electron Clouds at KEKB simulation, electron, emittance, feedback 4033
 
  • J. W. Flanagan
  • E. Benedetto
    CERN, Geneva
  • J. Hyunchang
    POSTECH, Pohang, Kyungbuk
  • K. Ohmi
    KEK, Ibaraki
  Electron cloud causes a fast head-tail instability above a threshold density. Experiments at KEKB showed synchro-betatron sideband, which indicates the head-tail instability. The sideband appears near νy+kνs, where 1<k<2, that differs from ordinary instability seen near νy-νs. We investigate the origin of the sideband using a computer simulation.  
 
FRPMN039 Measurement of Quadrupolar Tune Shifts After the Reconstruction of the Photon Factory Storage Ring quadrupole, storage-ring, factory, photon 4039
 
  • S. Sakanaka
  • T. Mitsuhashi, T. Obina
    KEK, Ibaraki
  The tune shift of transverse quadrupolar oscillations is a measure of a quadrupolar component of wakefields in the storage ring*. By measuring both dipolar and quadrupolar tune shifts, one can estimate the dipolar and the quadrupolar components of wakefields (exactly, kick factors) independently. We carried out such measurements before and after the upgrade of the Photon Factory storage ring. The results showed the change in the tune shifts which were caused by the replacement of many (about two-thirds of the ring) vacuum chambers.

* S. Sakanaka, T. Mitsuhashi, and T. Obina, Phys. Rev. ST Accel. Beams 8, 042801 (2005).

 
 
FRPMN046 Effects of Magnetic Field Tracking Errors on Beam Dynamics at J-PARC RCS resonance, space-charge, simulation, quadrupole 4078
 
  • H. Hotchi
  • S. Machida
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
  • F. Noda
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  The 3-GeV Rapid-Cycling Synchrotron (RCS) of J-PARC aims at providing a 1-MW proton beam at a repetition rate of 25 Hz for an injection energy of 400 MeV. In this paper, we discuss influences of field tracking errors between dipoles and quadrupoles and between different families of quadrupoles on beam dynamics in combination with effects of the space charge and intrinsic nonlinear fields for the J-PARC RCS.  
 
FRPMN073 The FPGA-based Continuous FFT Tune Measurement System for the LHC and its Test at the CERN SPS target, controls, pick-up, extraction 4204
 
  • A. Boccardi
  • M. Gasior, O. R. Jones, K. K. Kasinski, R. J. Steinhagen
    CERN, Geneva
  A base band tune (BBQ) measurement system has been developed at CERN. This system is based on a high-sensitivity direct-diode detection technique followed by a high resolution FFT algorithm implemented in an FPGA. The system allows acquisition of continuous real-time spectra with 32-bit resolution, while a digital frequency synthesiser (DFS) can provide an acquisition synchronised chirp excitation. All the implemented algorithms support dynamic reconfiguration of processing and excitation parameters. Results from both laboratory measurements and tests performed with beam at the CERN SPS are presented.  
 
FRPMN076 Nominal LHC Beam Instability Observations in the CERN Proton Synchrotron electron, extraction, feedback, proton 4222
 
  • R. R. Steerenberg
  • G. Arduini, E. Benedetto, A. Blas, W. Hofle, E. Metral, M. Morvillo, C. Rossi, G. Rumolo
    CERN, Geneva
  The nominal LHC beam has been produced successfully in the CERN Proton Synchrotron since 2003. However, after having restarted the CERN PS in spring 2006, the LHC beam was set-up and observed to be unstable on the 26 GeV/c extraction flat top. An intensive measurement campaign was made to understand the instability and to trace its source. This paper presents the observations, possible explanations and the necessary measures to be taken in order to avoid this instability in the future.  
 
FRPMS005 The Tevatron AC Dipole System dipole, impedance, emittance, synchrotron 3868
 
  • R. Miyamoto
  • A. Jansson, M. J. Syphers
    Fermilab, Batavia, Illinois
  • S. E. Kopp
    The University of Texas at Austin, Austin, Texas
  The AC dipole is an oscillating dipole magnet which can induce large amplitude oscillations without causing emittance growth. This makes it a good tool to measure optics of a hadron synchrotron. The vertical AC dipole for the Tevatron is powered by an inexpensive high-power audio amplifier since its operating frequency is approximately 20 kHz. The low impedance magnet is incorporated into a parallel resonant system to form an 8 Ω equivalent circuit to maximize the power output of the amplifier. The magnet used is a vertical pinger previously installed in the Tevatron making the cost relatively inexpensive. Recently, the initial system was upgraded with a more powerful amplifier and oscillation amplitudes up to 2-σ beam size were achieved at 980 GeV. The paper discusses details of the resonant circuit. It also shows test results of the system both on the bench and with the beam.  
 
FRPMS007 Status of the FNAL Digital Tune Monitor proton, antiproton, pick-up, collider 3877
 
  • J.-P. Carneiro
  • V. Kamerdzhiev, A. Semenov, R. C. Webber
    Fermilab, Batavia, Illinois
  We have implemented a real-time method for betatron tune measurements from each bunch at Tevatron based on 16bit 100MHz ADC. To increase the betatron signal level from pick-up we have used a modified version Direct Diode Detection method combined with fast FPGA algorithm and 14 bit DAC for suppression of low frequency beam motion and noise background before final amplifying stage. A descritpion of this devise will be presented in the paper together with first results.  
 
FRPMS013 Chromaticity Tracking Using a Phase Modulation Technique synchrotron, pick-up, controls, emittance 3910
 
  • C.-Y. Tan
  Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy.

In the classical chromaticity measurement technique, chromaticity is measured by measuring the change in betatron tune as the the RF frequency is varied. This paper will describe a way of measuring chromaticity: we will phase modulate the RF with a known sine wave and then phase demodulate the betatron frequency . The result is a line in Fourier space which corresponds to the frequency of our sine wave modulation. The peak of this sine wave is proportional to chromaticity. For this technique to work, a tune tracker PLL system is required because it supplies the betatron carrier frequency. This method has been tested in both the SPS and Tevatron and we will show the results here.

 
 
FRPMS014 Chromaticity Measurement Using a Continuous Head-Tail Kicking Technique emittance, impedance, synchrotron, simulation 3916
 
  • C.-Y. Tan
  • V. H. Ranjbar
    Tech-X, Boulder, Colorado
  Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy.

In the classical head-tail chromaticity measurement technique, a single large kick is applied transversely to the beam. The resulting phase difference between the head and the tail is measured and the chromaticity extracted. In the continuous head-tail kicking technique, a very small transverse kick is applied to the beam and the asymptotic phase difference between the head and the tail is found to be a function of chromaticity. The advantage of this method is that since the tune tracker PLL already supplies the small transverse kicks, no extra modulation is required.

 
 
FRPMS015 Correction of Second Order Chromaticity at Tevatron sextupole, quadrupole, resonance, injection 3922
 
  • A. Valishev
  • G. Annala, V. A. Lebedev, R. S. Moore
    Fermilab, Batavia, Illinois
  Correction of the second order betatron tune chromaticity is essential for operation at the working point near half integer resonance which is proposed as one of the ways to improve performance of the Tevatron. In this report the new chromaticity correction scheme with split sextupole families is described. Details of implementation and commissioning at the present working point are discussed.  
 
FRPMS026 Strong-Strong Simulation of Long-Range Beam-Beam Effects at RHIC emittance, sextupole, resonance, simulation 3979
 
  • J. Qiang
  • W. Fischer
    BNL, Upton, Long Island, New York
  • T. Sen
    Fermilab, Batavia, Illinois
  Funding: This work was supported by the U. S. Department of Energy under Contract no. DE-AC02-05CH11231.

Long-range beam-beam interactions can cause significant degrade of beam quality and lifetime in high energy ring colliders. At RHIC, a series of experiments were carried out to study these effects. In this paper, we report on numerical simulation of the long-range beam-beam interactions at RHIC using a parallel strong-strong particle-in-cell code, BeamBeam3D. The simulation includes nonlinearities from both the beam-beam interactions and the arc sextupoles. We observed significant emittance growth for beam separation below 4 σs under nominal tunes. A scan study in tune space shows strong emittance growth around 7th order resonance. Including the tune modulation due to chromaticity and synchrotron motion shows larger emittance growth than the case without the tune modulation.

 
 
FRPMS044 A Tune Measurement System for Low Current and Energy Ramping Operation of a Booster Synchrotron booster, synchrotron, electron, storage-ring 4063
 
  • Y. K. Wu
  • J. Li, S. F. Mikhailov, V. Popov, P. Wang
    FEL/Duke University, Durham, North Carolina
  Funding: This work is supported by the US AFOSR MFEL grant #FA9550-04-01-0086 and by U. S. DOE grant DE-FG05-91ER40665.

The betatron tune measurement system is one of the most important diagnostics for any circular accelerator. During the commissioning of a booster synchrotron newly developed for top-off injection into the Duke storage ring, a versatile tune measurement system employing a photomultiplier tube (PMT) and a space filter has been developed to provide reliable measurements for low current operation at a few micro-amperes of beam-current. Using the turn-by-turn technique, this tune measurement system is being used as a live tune monitor during the booster energy ramping. This system has also be used to measure chromaticity and other important beam parameters. In this paper, we describe the tune measurement system in detail and report our most recent experimental results using this system.

 
 
FRPMS046 Optical-Fiber NOTCH Filter for Storage Ring Transverse Feedback System feedback, storage-ring, insertion, laser 4075
 
  • Y. Yin
  • X. Che
    Y. Y. Labs, Inc., Fremont, California
  • J. H. Wang, K. Zheng
    USTC/NSRL, Hefei, Anhui
  An optical-fiber two-tap FIR filter has been developed for storage ring transverse feedback system. The optical FIR filter has advantage of low loss which is not related to the size of the storage ring, and high-frequency response, compact in size. Measurements have been done with storage ring beam signal. The paper will present the principle and the experimental results.  
 
FRPMS109 Measurement and Correction of Third Resonance Driving Term in the RHIC resonance, dipole, sextupole, proton 4351
 
  • Y. Luo
  • M. Bai, J. Bengtsson, R. Calaga, W. Fischer, N. Malitsky, F. C. Pilat, T. Satogata
    BNL, Upton, Long Island, New York
  Funding: Work supported by U. S. DOE under contract No DE-AC02-98CH10886.

To further improve the polarized proton (pp) run collision luminosity in the Relativistic Heavy Ion Collider, correction of the horizontal two-third resonance is desirable to increase the available tune space. The third resonance driving term (RTD) is measured with the turn-by-turn (TBT) beam position monitor (BPM) data with AC dipole excitation. A first order RTD response matrix based on the optics model is used to on-line compensate the third resonance driving term h30000 while keeping other first order RTDs and first order chromaticities unchanged. The results of beam experiment and simulation correction are presented and discussed.

 
 
FRPMS110 Online Nonlinear Chromaticity Correction Using Off-Momentum Tune Response Matrix sextupole, optics, simulation, dipole 4357
 
  • Y. Luo
  • W. Fischer, N. Malitsky, S. Tepikian, D. Trbojevic
    BNL, Upton, Long Island, New York
  Funding: Work supported by U. S. DOE under contract No DE-AC02-98CH10886.

With 8 arc sextupole families in each RHIC ring, the nonlinear chromaticities can be corrected on-line by matching the off-momentum tunes onto the wanted off-momentum tunes with linear chromaticity only. The Newton method with singular value decomposition (SVD) technique is used for this multi-dimensional nonlinear optimization, where the off-momentum tune response matrix with respect to sextupole strength changes is adopted to simplify and fasten the on-line optimization process. The off-momentum tune response matrix can be calculated with the on-line accelerator optics model or directly measured with the real beam. This correction method will be verified and used in the coming RHIC run'07.