Paper |
Title |
Other Keywords |
Page |
MOAP02 |
Recent Beam Commissioning Results from the Spallation Neutron Source
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linac, target, proton, emittance |
6 |
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- S. Henderson
ORNL, Oak Ridge, Tennessee
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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.
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MOCP01 |
Beam intensity upgrade at Fermilab
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proton, booster, target, antiproton |
34 |
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- A. Marchionni
Fermilab, Batavia, Illinois
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TUAX01 |
Accumulation of High Intensity Beam and First Observations of Instabilities in the SNS Accumulator Ring*
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impedance, kicker, lattice, electron |
59 |
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- 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
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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.
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TUBX01 |
Impedance and radiation generated by a ceramic chamber with RF shields and TiN coating
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impedance, space-charge, electromagnetic-fields, synchrotron |
125 |
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- 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
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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.
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TUBX03 |
Coupling impedance of the J-PARC kicker magnets
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kicker, impedance, coupling, synchrotron |
140 |
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WEAY02 |
Electron cooling of 8 GeV antiprotons at Fermilabs Recycler: Results and operational implications
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electron, antiproton, emittance, beam-losses |
182 |
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- 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
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Electron cooling of 8 GeV antiprotons at Fermilabs 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.
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WEAZ01 |
Overview of beam loss mechanisms in injection and extraction
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injection, beam-losses, linac, emittance |
172 |
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WEAZ03 |
DESIGN AND TESTS OF A LOW-LOSS MULTI-TURN EJECTION FOR THE CERN PS
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septum, kicker, beam-losses, emittance |
192 |
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- M. Giovannozzi
CERN, Geneva
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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.
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WEAZ06 |
Transfer line damage during high intensity proton beam extraction from the SPS in 2004
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power-supply, simulation, vacuum, septum |
228 |
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- B. Goddard, V. Kain, V. Mertens, J. A. Uythoven, J. Wenninger
CERN, Geneva
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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.
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THAZ03 |
Safe LHC Beam Commissioning
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injection, dumping, collimation, beam-losses |
306 |
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- J. A. Uythoven, R. Schmidt
CERN, Geneva
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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.
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THAZ06 |
Commissioning scenarios for the J-PARC accelerator complex
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linac, injection, closed-orbit, acceleration |
329 |
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- T. Koseki
KEK, Ibaraki
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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.
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THBY01 |
Acceleration of Intense Beams of Highly-Charged Ions using Direct Plasma Injection Scheme
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ion, rfq, target, plasma |
341 |
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- 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
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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.
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FRAP03 |
Summary of Working Group C+G (Part I)
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beam-losses, target, collimation, injection |
365 |
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- 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
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