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extraction

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MOAP02 Recent Beam Commissioning Results from the Spallation Neutron Source linac, target, proton, emittance 6
 
  • S. Henderson
    ORNL, Oak Ridge, Tennessee
  The Spallation Neutron Source accelerator complex consists of a 2.5 MeV H- front-end injector system, a 186 MeV normal-conducting linear accelerator, a 1 GeV superconducting linear accelerator, an accumulator ring and associated beam transport lines. The beam commissioning campaign of the SNS accelerator complex, initiated in 2002, has been performed in seven discrete runs as each successive portion of the accelerator complex has been installed. The final beam commissioning run, in which beam was transported to the liquid mercury target was recently completed. In the course of beam commissioning, most beam performance parameters and beam intensity goals have been achieved at low duty factor. The beam performance and beam dynamics measurements of the linac and ring will be presented.  
 
MOCP01 Beam intensity upgrade at Fermilab proton, booster, target, antiproton 34
 
  • A. Marchionni
    Fermilab, Batavia, Illinois
 
TUAX01 Accumulation of High Intensity Beam and First Observations of Instabilities in the SNS Accumulator Ring* impedance, kicker, lattice, electron 59
 
  • V. V. Danilov, A. V. Aleksandrov, S. Assadi, W. Blokland, S. M. Cousineau, C. Deibele, S. Henderson, J. A. Holmes, M. A. Plum, A. P. Shishlo
    ORNL, Oak Ridge, Tennessee
  The Spallation Neutron Source accumulator ring, designed to accumulate up to 1.5·1014 protons per pulse, was commissioned in January of 2006. During the run, over 1.·1014 protons were accumulated in the ring in the natural chromaticity state without any sign of instabilities. The first beam instabilities were observed for a high intensity coasting beam with zero chromaticity. Preliminary analysis of data indicates instabilities related to extraction kicker impedances, and electron-proton instability. Here we review the background theory and design philosophy of the ring, as it relates to instabilities, and compare the pre-commissioning predictions with the experimental measurements.  
 
TUBX01 Impedance and radiation generated by a ceramic chamber with RF shields and TiN coating impedance, space-charge, electromagnetic-fields, synchrotron 125
 
  • Y. H. Chin, S. Lee, K. Takata, T. Toyama
    KEK, Ibaraki
  • Y. Shobuda
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • H. Tsutsui
    SHI, Tokyo
  In the RCS (Rapid Cycle Synchrotron) ring of J-PARC, we use ceramic chambers with the interior TiN coating and exterior Cu RF shields in the magnet sections. A new theory has been developed for calculation of impedance in this unusual configuration. When it was applied to a prototype RCS ceramic chamber, the calculation results got good agreement with the measurement results. We also considered the dipole radiation from gaps between Cu shields of the ceramic chamber in the bending magnets. The effects turn out to be rather small thanks to the special configuration of the ceramic chambers. We measured the radiation from a ceramic break with and without RF shields and capacitors in the KEK, PS and found that the RF shields with capacitors considerably suppress the radiation from the ceramic break. We summarize all these studies in this paper.  
 
TUBX03 Coupling impedance of the J-PARC kicker magnets kicker, impedance, coupling, synchrotron 140
 
  • T. Toyama, Y. Hashimoto, E. Nakamura, Y. Shirakabe
    KEK, Ibaraki
  • J. Kamiya, Y. Shobuda
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  The single- and twin-wire measurements both for the longitudinal ( ZL ) and transverse impedances ( ZT ) will be discussed for the J-PARC kicker magnets: a lumped circuit kicker and several types of traveling wave kickers. The question if a position shifted single-wire can measure ZT is discussed. The measurement results are compared with the equivalent circuit analysis. The relation between the imaginary part of the impedance and causality will also be discussed.  
 
WEAY02 Electron cooling of 8 GeV antiprotons at Fermilab’s Recycler: Results and operational implications electron, antiproton, emittance, beam-losses 182
 
  • L. R. Prost, D. R. Broemmelsiek, A. V. Burov, K. Carlson, C. Gattuso, M. Hu, T. K. Kroc, J. R. Leibfritz, S. Nagaitsev, S. M. Pruss, G. W. Saewert, C. W. Schmidt, A. V. Shemyakin, M. Sutherland, V. Tupikov, A. Warner
    Fermilab, Batavia, Illinois
  Electron cooling of 8 GeV antiprotons at Fermilab’s Recycler storage ring is now routinely used in the collider operation. It requires a 0.1-0.5 A, 4.3 MeV DC electron beam that reduces the longitudinal phase-space of the circulating antiproton beam. This paper first describes the characteristics of the electron beam that was achieved to successfully cool antiprotons as well as its necessary stability. Then, results from various cooling force measurements along with comparison to a simple non-magnetized model will be presented. Finally, operational aspects of the implementation of electron cooling at the Recycler will be discussed, such as regulation of the cooling rate and the influence of the electron beam on the antiprotons lifetime.  
 
WEAZ01 Overview of beam loss mechanisms in injection and extraction injection, beam-losses, linac, emittance 172
 
  • M. Tomizawa
    KEK, Ibaraki
 
WEAZ03 DESIGN AND TESTS OF A LOW-LOSS MULTI-TURN EJECTION FOR THE CERN PS septum, kicker, beam-losses, emittance 192
 
  • M. Giovannozzi
    CERN, Geneva
  Following the positive results of the three-year measurement campaign at the CERN Proton Synchrotron, the study of a possible implementation of the proposed multi-turn extraction based on beam splitting with stable islands in the transverse phase space was undertaken. A substantial reduction of beam losses, with respect to the present extraction scheme, should be achieved with the proposed technique when delivering the high-intensity proton beams required for the planned CERN Neutrino to Gran Sasso Project. Major modifications to the ring layout are foreseen, such as a new design of the extraction bumps including also the installation of three additional kickers to create a closed-bump over the five turns used to extract the split beam. The ring aperture was reviewed and improvements are proposed to reduce possible beam losses between beam splitting and extraction. The goal consists of implementing the proposed changes by beginning of 2008 and to commission the novel extraction during the 2008 PS physics run.  
 
WEAZ06 Transfer line damage during high intensity proton beam extraction from the SPS in 2004 power-supply, simulation, vacuum, septum 228
 
  • B. Goddard, V. Kain, V. Mertens, J. A. Uythoven, J. Wenninger
    CERN, Geneva
  During extraction of a high intensity beam from the SPS in 2004 an incident occurred in which the vacuum chamber of a transfer line quadrupole magnet was badly damaged. The beam was a 450 GeV full LHC injection batch of 3.4·1013 p+ in 288 bunches, and was extracted with the wrong trajectory. The incident causes have been identified, with details reconstructed from the logged data and the damage to the vacuum chamber. The remedial measures which were taken are explained, and further recommendations made concerning the interlocking system performance and tests, as well as the operational procedures which must be adopted when commissioning with high intensities. The specific issues of how the incident happened, why the existing protection system was not sufficient and what can/has been done about it are addressed.  
 
THAZ03 Safe LHC Beam Commissioning injection, dumping, collimation, beam-losses 306
 
  • J. A. Uythoven, R. Schmidt
    CERN, Geneva
  Due to the large amount of energy stored in magnets and beams, safe operation of the LHC is essential. The commissioning of the LHC machine protection system will be an integral part of the general LHC commissioning program. A brief overview of the LHC Machine Protection System will be given, identifying the main components: the Beam Interlock System, the Beam Dumping System, the Collimation System, the Beam Loss Monitoring system and the Quench Protection System. An outline is given of the commissioning strategy of these systems during the different commissioning phases of the LHC: without beam, injection and the different phases with stored beam depending on beam intensity and beam energy.  
 
THAZ06 Commissioning scenarios for the J-PARC accelerator complex linac, injection, closed-orbit, acceleration 329
 
  • T. Koseki
    KEK, Ibaraki
  The J-PARC accelerator complex consists of a 400-MeV linac, a 3.0-GeV rapid-cycling synchrotron (RCS), a 50-GeV main ring (MR) and associated beam transport lines to experimental facilities, which use the 3- and 50-GeV proton beams. It is now under construction in the Tokai campus of JAEA as a joint project between JAEA and KEK. The beam commissioning of each accelerator is scheduled to start for linac in December 2006, RCS in September 2007 and MR in May 2008. The commissioning strategy for the accelerator complex will be presented.  
 
THBY01 Acceleration of Intense Beams of Highly-Charged Ions using Direct Plasma Injection Scheme ion, rfq, target, plasma 341
 
  • A. Kondrashev
    ITEP, Moscow
  • R. A. Jameson, M. Okamura
    RIKEN, Saitama
  • T. Kanesue
    Kyushu University, Fukuoka
  • H. Kashiwagi
    JAEA/ARTC, Gunma-ken
  • K. Sakakibara
    RLNR, Tokyo
  • J. Tamura
    TIT, Yokohama
  Laser Ion Source (LIS) is the most intense source of highly-charged ions capable to provide beams with current 10 / 100 mA and pulse durations 1 / 10 μs. Such parameters well meet requirements of single turn injection into synchrotron rings and FFAG. Few years ago Direct Plasma Injection Scheme (DPIS) was proposed to extract and accelerate intense ion beams from laser induced plasma. By this approach extraction of ions happens almost inside first acceleration cell of RFQ, eliminating severe space charge problems in LEBT and LEBT itself. About 35 mA of 12C4+ ions and 17 mA of 12C6+ ions were accelerated by RFQ up to 100 keV/u using DPIS. Amplitude of total current of carbon ions is equal to 60 mA. The latest results on 27Al and 56Fe ions acceleration using DPIS are presented. The results obtained show that DPIS is, probably, the best choice as a high current injector of highly-charged ions for FFAG.  
 
FRAP03 Summary of Working Group C+G (Part I) beam-losses, target, collimation, injection 365
 
  • N. V. Mokhov
    Fermilab, Batavia, Illinois
  • K. Hasegawa
    JAEA, Ibaraki-ken
  • S. Henderson
    ORNL, Oak Ridge, Tennessee
  • R. Schmidt
    CERN, Geneva
  • M. Tomizawa
    KEK, Ibaraki
  • K. Wittenburg
    DESY, Hamburg