04 Hadron Accelerators

A04 Circular Accelerators

Paper Title Page
TUOCKI02 Summary of the RHIC Performance during the FY07 Heavy Ion Run 722
 
  • K. A. Drees, L. Ahrens, J. G. Alessi, M. Bai, D. S. Barton, J. Beebe-Wang, M. Blaskiewicz, J. M. Brennan, K. A. Brown, D. Bruno, J. J. Butler, R. Calaga, P. Cameron, R. Connolly, T. D'Ottavio, W. Fischer, W. Fu, G. Ganetis, J. W. Glenn, M. Harvey, T. Hayes, H.-C. Hseuh, H. Huang, J. Kewisch, R. C. Lee, V. Litvinenko, Y. Luo, W. W. MacKay, G. J. Marr, A. Marusic, R. J. Michnoff, C. Montag, J. Morris, B. Oerter, F. C. Pilat, V. Ptitsyn, T. Roser, J. Sandberg, T. Satogata, C. Schultheiss, F. Severino, K. Smith, S. Tepikian, D. Trbojevic, N. Tsoupas, J. E. Tuozzolo, A. Zaltsman, S. Y. Zhang
    BNL, Upton, Long Island, New York
  
  Funding: Work performed under Contract Number DE-AC02-98CH10886 under the auspices of the US Department of Energy.

After the last successful RHIC Au-Au run in 2004 (Run-4), RHIC experiments now require significantly enhanced luminosity to study very rare events in heavy ion collisions. RHIC has demonstrated its capability to operate routinely above its design average luminosity per store of 2x1026 cm-2 s-1. In Run-4 we already achieved 2.5 times the design luminosity in RHIC. This luminosity was achieved with only 40% of bunches filled, and with β* = 1 m. However, the goal is to reach 4 times the design luminosity, 8x1026 cm-2 s-1, by reducing the beta* value and increasing the number of bunches to the accelerator maximum of 111. In addition, the average time in store should be increased by a factor of 1.1 to about 60% of calendar time. We present an overview of the changes that increased the instantaneous luminosity and luminosity lifetime, raised the reliability, and improved the operational efficiency of RHIC Au-Au operations during Run-7.

 
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TUOCKI04 Experimental Demonstration of Beam-Beam Compensation by Tevatron Electron Lenses and Prospects for the LHC 728
 
  • V. D. Shiltsev, Y. Alexahin, V. Kamerdzhiev, G. F. Kuznetsov, X. Zhang
    Fermilab, Batavia, Illinois
  • K. Bishofberger
    LANL, Los Alamos, New Mexico
  
  We report the first experimental demonstration of compensation of beam-beam interaction effects with use of electron beams. Long-range and head-on interactions of high intensity proton and antiproton beams have been dominating sources of beam loss and lifetime limitations in the Tevatron in Collider Run II (2001-present). Electron lense acting on proton bunches has doubled their lifetime by compensating beam-beam interaction with antiprotons. We present results of the experiments, operational details and discuss possibilities of using electron lenses for beam-beam compensation in LHC.  
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TUZBKI01 Present and Future High-Energy Accelerators for Neutrino Experiments 731
 
  • I. Kourbanis
    Fermilab, Batavia, Illinois
  
  Application of high-energy proton accelerators for high-intensity neutrino beam production is a challenging task from standpoints of accelerator physics and operation. An overview of the machines presently used for neutrino experiments will be given as well as of the future projects, in particular of the Fermilab accelerator complex conversion after the Tevatron Run II completion.  
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TUODKI01 Status of J-PARC Main Ring Synchrotron 736
 
  • T. Koseki
    KEK, Ibaraki
  
  The J-PARC (Japan Proton Accelerator Research Complex) accelerator facility consists of a 400-MeV linac, a 3.0-GeV rapid cycling synchrotron (RCS), a 50-GeV slow cycling main ring synchrotron (MR). Beam commissioning of the linac has been started from this November and construction of the synchrotrons is now underway. The MR accelerates the 3-GeV beam from the RCS up to 30 - 50 GeV and provides the beam to the hadron beam facility via slow extraction and to the neutrino beam facility via fast extraction. In this paper, we present recent status of the accelerator construction and test operation results for some components of the MR. Beam commissioning scenario and related beam dynamics studies are also discussed.  
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TUODKI03 Multi-batch Slip Stacking in the Main Injector at Fermilab 742
 
  • K. Seiya, T. Berenc, B. Chase, J. E. Dey, P. W. Joireman, I. Kourbanis, J. Reid
    Fermilab, Batavia, Illinois
  
  The Main Injector (MI) is going to use slip stacking scheme for the NuMI neutrino experiment for effectively increasing proton intensity to the NuMI target by about a factor two in a MI cycle. The MI is going to accept 11 pluses at injection energy from the Booster and accelerate them to 120 GeV. By using Slip stacking, two of them are merged into one and sent to Anti-proton production and 9 of them, one single and four doubled density pulses, are going to be sent to the Numi beam line. We have been doing low intensity beam studies with 11 pulses injection and accelerated them with the total intensity of 3·1012 ppp to 120GeV. We discuss beam loss and technical issues on multi-batch slip stacking.  
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TUODKI05 Overcoming Depolarizing Resonances in the AGS with Two Helical Partial Snakes 748
 
  • H. Huang, L. Ahrens, M. Bai, K. A. Brown, C. J. Gardner, J. W. 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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TUODKI06 Observation of Proton Reflection on Bent Silicon Crystals at the CERN SPS 751
 
  • W. Scandale
    CERN, Geneva
  
  Funding: INTAS-CERN, contract number 05-96-7525 and CARE, contract number RII3-CT-2003-506395.

We report observations, performed by the H8-RD22 Collaboration*, of the so-called volume reflection effect with 400 GeV/c protons interacting with bent Silicon crystals in the H8 beam line at the CERN SPS. The volume reflection is closely related with particle channeling. This phenomenon occurs at the tangency point of a particle trajectory with the bent crystalline planes and consists in the reversal of the transverse component of the particle momentum. The measurements were collected with a high spatial resolution detector mainly based on Silicon strips. The proton beam was deviated in the direction opposite to that of channeling by ~12μrad, which is ~1.3 times the critical angle, with an efficiency larger than 97% in a range of the proton-to-crystal incident angle as large as the bending angle of crystallographic planes. This evidence opens new perspectives for manipulation of high-energy beams, e.g., for collimation and extraction in the new-generation of hadron colliders or as a method for high-energy experiments in the region near to the circulating beam.

* H8-RD22 collaboration: CERN, FNAL, INFN (Ferrara, Legnaro, Perugia, Roma, Milano, Trieste), IHEP, PNPI, JINR

 
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TUPAN014 Status of the FAIR SIS100/300 Synchrotron Design 1419
 
  • P. J. Spiller, U. B. Blell, H. Eickhoff, E. Fischer, E. Floch, P. Hulsmann, J. E. Kaugerts, M. Kauschke, H. Klingbeil, H. G. Koenig, A. Kraemer, D. Kramer, U. Laier, G. Moritz, C. Omet, N. Pyka, H. Ramakers, H. Reich-sprenger, M. Schwickert, J. Stadlmann
    GSI, Darmstadt
  • A. D. Kovalenko
    JINR, Dubna, Moscow Region
  
  The project status of the main accelerators, the SIS100 and SIS300 synchrotrons of the FAIR project will be presented. In order to accommodate more preferable technical solutions, the structure of the magnet lattice had to be modified in both machines. After these changes, more appropriate technical solutions for the main magnets and quench protection systems could be adapted. The general machine layout and design, e.g. of the demanding extraction schemes, has been detailed and open design issues were solved. The developments and design of all major technical systems are in progress and prototyping has started or is in preparation.  
TUPAN027 A New Complementary-Scan Technique for Precise Measurements of Resonance Parameters in Antiproton-Proton Annihilations 1448
 
  • G. Stancari
    INFN-Ferrara, Ferrara
  
  A new technique for precision measurements of resonance widths in antiproton-proton annihilations is presented. It is based on the analysis of excitation curves obtained by scanning the resonance twice, at constant orbit and at constant magnetic bend field, in an antiproton storage ring. The technique relies on precise revolution-frequency and orbit-length measurements, while making the results almost independent of the machine's phase-slip factor. The uncertainty is dominated by event statistics. The technique was recently applied by Fermilab Experiment E835 at the Antiproton Accumulator to obtain the most precise measurements to date of the total and partial widths of the psi(2S) charmonium meson. Future applications may include the PANDA experiment at the FAIR facility in Darmstadt.

On behalf of the Fermilab E835 Collaboration

 
TUPAN028 A Low Beta Section for Polarization Studies of Antiprotons by Spin Filtering 1451
 
  • M. Statera, P. Lenisa, G. Stancari
    INFN-Ferrara, Ferrara
  • A. Garishvili, B. Lorentz, S. A. Martin, F. Rathmann
    FZJ, Julich
  
  In the framework of the FAIR* project, the PAX collaboration has suggested new experiments using polarized antiprotons**. The central physics issue is now to study the polarization build-up by spin filtering of antiprotons via multiple passages through an internal polarized gas target. The goals for spin-filtering experiments with protons at COSY are to test our understanding of the spin-filtering processes and to commission the setup for the AD experiments with antiprotons at the AD (CERN). Spin-filtering experiments with antiprotons at the AD will allow us to determine the total spin-dependent transversal and longitudinal cross sections. The low-beta section at COSY is composed of two superconducting quadrupole magnets on each side of the target, while at the AD, we will use three quadrupoles on each side. Accelerator technical problems and details for COSY and AD to carry out the planned spin-filtering studies together with the technical problems and details of the superconducting quadrupoles with their respective cryogenics will be discussed in this talk. The status of the construction of the quadrupoles will be reported as well.

* Conceptual Design Report for an International Facility for Antiprotonand Ion Research, www.gsi.de/GSI-future/cdr.** PAX Technical Proposal, www.fz-juelich.de/ikp/pax.

 
TUPAN061 Updated Simulation for the Nuclear Scattering Loss Estimation at the RCS Injection Area 1526
 
  • P. K. Saha, H. Hotchi, Y. Irie, F. Noda
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • S. Machida
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
  
  We have updated the simulation for the realistic beam loss estimation at the RCS (Rapid Cycling Synchrotron) injection area of J-PARC(Japan Proton Accelerator Research Complex). At the injection area, beam loss caused by the nuclear scattering together with the multiple coulomb scattering at the charge-exchange foil is the dominant one and is an important issue for designing mainly the foil thickness and other beam elements like, the falling time of bump magnets after the injection is finished and so on. The simulation tool GEANT for the scattering effect and the real injection process have been employed together in order to estimate the beam loss turn by turn including identification of loss points too.  
TUPAN092 Schedule evolution during the life-time of the LHC project 1592
 
  • K. Foraz, E. Barbero-Soto, H. Gaillard, C. Hauviller, S. Weisz
    CERN, Geneva
  
  The Large Hadron Collider Project was approved by the CERN Council in December 1994. The CERN management opted from the beginning of the project for a very aggressive installation planning based on a just-in-time sequencing of all activities. This paper aims to draw how different factors (technical development, procurement, logistics and organization) have impacted on the schedule evolution through the lifetime of the project. It describes the cause effect analysis of the major rescheduling that occurred during the installation of the LHC and presents some general conclusions potentially applicable in other similar projects.  
TUPAN093 Simulation of the CERN PS Booster Performance with 160 MeV H- Injection from Linac4 1595
 
  • F. Gerigk, M. Aiba, C. Carli, M. Martini
    CERN, Geneva
  • S. M. Cousineau
    ORNL, Oak Ridge, Tennessee
  
  The ultimate luminosity (2.3 x 1034 cm-2 s-1) in the LHC can only be reached or even exceeded if a major upgrade of the CERN proton injector complex takes place. The first identified bottleneck towards higher brightness beams is the 50 MeV proton injection of Linac2 into the PS booster (PSB). Doubling the intensity in the PSB can be achieved with a new linac (Linac4) which increases the injection energy to 160 MeV. Linac4 will provide H- ions and charge-exchange injection will be used in the PSB instead of using the present multi-turn proton injection scheme. The code ACCSIM is used to study the H- injection process and to determine if the requested intensities can be reached within the specified emittance budgets. The results are then compared with ORBIT simulations. In the longitudinal plane we use ESME to study various capture schemes.  
TUPAN101 Tracking Studies with Variable Magnetic Field to Characterize Quadrupole Failures in LHC 1616
 
  • A. Gomez Alonso, R. Schmidt
    CERN, Geneva
  
  During LHC operation, energies up to 360 MJ will be stored in each proton beam and more than 10 GJ in the superconducting magnets. With these energies, a magnet failure can lead to important equipment damage if the beam is not extracted in time. The machine protection systems should detect such failures and trigger the beam extraction system. In order to characterize the beam response after magnet failures, tracking simulations have been performed with MAD-X. The magnetic field was set to change with time according to realistic current changes in the electrical circuits with the magnets after a powering failure. The effect on the beam of powering failures in the normal conducting quadrupoles has been studied. For fast failures (beam lost in less than 100 ms) the nonlinear effects are negligible. For slower failures, higher order resonances may lead to beam losses of up to ~8% of the beam.  
TUPAS031 Analysis of Optics Designs for the LHC IR Upgrade 1718
 
  • T. Sen, J. A. Johnstone
    Fermilab, Batavia, Illinois
  
  We consider the different options proposed for the LHC IR upgrade. The two main categories: quadrupoles first (as in the baseline design) and dipoles first have complementary strengths. We analyse the potential of the proposed designs by calculating important performance parameters including luminosity reach, beam-beam resonances and chromaticity contributions. The goal is to enable a decision on the design path based on objective criteria.  
TUPAS032 Prospects of Diagnostics with Optical Diffraction Radiation in Hadron Colliders 1721
 
  • T. Sen, V. E. Scarpine, R. Thurman-Keup
    Fermilab, Batavia, Illinois
  
  Optical diffraction radiation has been observed and recently used to measure the beam size of electrons at KEK. This non-invasive technique also holds promise for imaging beams close to the interaction point in hadron colliders. In this paper we consider the feasibility of this technique for the Tevatron and the LHC.  
TUPAS033 Field Fluctuation and Beam Screen Vibration Measurements in the LHC Magnets 1724
 
  • V. D. Shiltsev
    Fermilab, Batavia, Illinois
  • 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.  
TUPAS086 Snake Depolarizing Resonance Study in RHIC 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)

 
TUPAS096 Setup and Performance of the RHIC Injector Accelerators for the 2007 Run with Gold Ions 1862
 
  • C. J. Gardner, L. Ahrens, J. G. Alessi, J. Benjamin, M. Blaskiewicz, J. M. Brennan, K. A. Brown, C. Carlson, W. Fischer, J. W. Glenn, M. Harvey, T. Hayes, H. Huang, G. J. Marr, J. Morris, F. C. Pilat, T. Roser, F. Severino, K. Smith, D. Steski, P. Thieberger, N. Tsoupas, A. Zaltsman, K. Zeno
    BNL, Upton, Long Island, New York
  
  Funding: Work performed under the auspices of the US Department of Energy.

Gold ions for the 2007 run of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) are accelerated in the Tandem, Booster and AGS prior to injection into RHIC. The setup and performance of this chain of accelerators will be reviewed with a focus on improvements in the quality of beam delivered to RHIC. In particular, more uniform stripping foils between Booster and AGS, and a new bunch merging scheme in AGS promise to provide beam bunches with reduced longitudinal emittance for RHIC.

 
TUPAS103 RHIC Challenges for Low Energy Operations 1877
 
  • T. Satogata, L. Ahrens, M. Bai, J. M. Brennan, D. Bruno, J. J. Butler, K. A. Drees, A. V. Fedotov, W. Fischer, M. Harvey, T. Hayes, W. Jappe, R. C. Lee, W. W. MacKay, G. J. Marr, R. J. Michnoff, B. Oerter, E. Pozdeyev, T. Roser, F. Severino, K. Smith, S. Tepikian, N. Tsoupas
    BNL, Upton, Long Island, New York
  
  Funding: Work supported by U. S. DOE under contract No DE-AC02-98CH1-886

There is significant interest in RHIC heavy ion collisions at c.m. energies of 5-50 GeV/u, motivated by a search for the QCD phase transition critical point. The low end of this energy range is well below the nominal RHIC injection c.m. energy of 19.6 GeV/u. There are several challenges that face RHIC operations in this regime, including longitudinal acceptance, magnet field quality, lattice control, and luminosity monitoring. We report on the status of work to address these challenges and include results from beam tests of low-energy RHIC operations with protons and gold.

 
THXAB02 Current Status of the FAIR-project 2598
 
  • D. Kramer
    GSI, Darmstadt
  
  Funding: Work supported by BMBF, State of Hessen and EU FP6

In 2006, GSI, together with a large international science community, presented the FAIR Baseline Technical Report (FBTR) on an unprecedented accelerator Facility for Antiproton and Ion beams Research in Europe, located in Darmstadt (Germany). This facility is based on extensive discussions and a broad range of workshops and working group reports, organized by the international user communities over a period of several years enabling unique experimental possibilities in the fields of nuclear- and astrophysics, hadron-, plasma and atomic physics as well as on applied physics. Following an in-depth evaluation of the proposal by the German Wissenschaftsrat and its recommendation to realize the facility, the Federal Government gave conditional approval for construction of FAIR in 2003. Since then the project has gone through major steps of development and significant progress has been achieved with regard to the scientific-technical and political preparation of the project under the governance of an international committee structure. The current status of the project will be reviewed.

 
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