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| TUODKI01 |
Status of J-PARC Main Ring Synchrotron
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736 |
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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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| TUODKI02 |
Optics Considerations for the PS2
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739 |
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- M. Benedikt
- W. Bartmann, C. Carli, B. Goddard, S. Hancock, J. M. Jowett, Y. Papaphilippou
CERN, Geneva
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CERN envisages replacing the existing Proton Synchrotron (PS) with a larger synchrotron (PS2) capable of injecting at higher energy into the SPS. Since it should increase the performance not only of the LHC but also CNGS and other users of beams from CERN's hadron injector complex, the new accelerator must retain much of the flexibility of the present complex. A number of candidate optics, with and without transition crossing, have been evaluated systematically and compared.
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| TUODKI03 |
Multi-batch Slip Stacking in the Main Injector at Fermilab
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742 |
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- K. Seiya
- T. Berenc, B. Chase, J. E. Dey, P. W. Joireman, I. Kourbanis, J. Reid
Fermilab, Batavia, Illinois
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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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| TUODKI04 |
Accelerating Polarized Protons to 250 GeV
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745 |
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- 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
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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
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748 |
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- 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
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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
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751 |
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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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