| Paper |
Title |
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| WEOBM01 |
R&D Activities Aimed at Developing a Curved Fast Ramped Superconducting Dipole for FAIR SIS300
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1950 |
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- P. Fabbricatore, S. Farinon, R. Musenich
INFN Genova, Genova
- F. Alessandria, G. Bellomo, G. Volpini
INFN/LASA, Segrate (MI)
- U. Gambardella
INFN/LNF, Frascati (Roma)
- J. E. Kaugerts, G. Moritz
GSI, Darmstadt
- R. Marabotto
ASG, Genova
- M. Sorbi
Universita' degli Studi di Milano & INFN, Segrate
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One of the basic components of the FAIR facility, under development at GSI, is the synchrotron SIS300 (300 Tm rigidity). In order to reach the required high intensities of proton and heavy ion beams, the magnets of this synchrotron have to be pulsed from the injection magnetic field of 1.5 T up to 4.5 T maximum field at the rate of 1 T/s. These 7.8 m long, cos-teta shaped coils with a 100 mm bore have the particular characteristic to be curved (the sagitta is 114 mm). All these aspects demand for a challenging R&D, aimed at the development of a low loss conductor and of a suitable winding technology for curved coil. Further design issues are related to the optimization of the stress distribution involving materials able to hold 107 cycles and to the maximization of the heat transfer to coolant (supercritical helium at 4.7 K). At the present time, design activities are going on with the aim to design, construct and test a 3.8 m long prototype within 2009. In order to achieve this objective, several intermediate milestones are included in the R&D program. One of the most challenging is the industrial development of a method for winding a curved cos-teta dipole.
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Slides
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| WEOBM02 |
Lessons Learned from PEP-II LLRF and Longitudinal Feedback
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1953 |
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- J. D. Fox, T. Mastorides, C. H. Rivetta, D. Van Winkle
SLAC, Menlo Park, California
- D. Teytelman
Dimtel, San Jose
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The PEP-II B Factory is in the final phase of operation at 2X the design current and 4X the design luminosity. Since the original design the machine has added 8 1.2 MW Klystrons and 12 RF cavities, and the machine is operating with longitudinal instability growth rates roughly 5X in excess of the original estimates. Since commissioning there has been continual adaptation of the LLRF control strategies, configuration tools and new hardware in response to unanticipated technical challenges. This paper presents the LLRF and feedback system evolution from the original design estimates through to the 1.2·1034 final machine. We highlight issues of RF station stability, the interplay of LLRF configuration and low-mode (cavity fundamental driven) longitudinal instabilities, impacts of non-linearities and imperfections in the LLRF electronics, control of HOM driven beam instabilities and the development of configuration tools and measurement techniques to optimally configure the LLRF over the wide range of operating currents. We present valuable "lessons learned" which are of interest to designers of next generation impedance controlled LLRF systems.
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Slides
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| WEOBM03 |
Development of a High Resolution Camera and Observations of Superconducting Cavities
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1956 |
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- Y. Iwashita, Y. Tajima
Kyoto ICR, Uji, Kyoto
- H. Hayano
KEK, Ibaraki
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An inspection system of the interior surface of superconducting RF cavities is developed in order to study the relation between the achievable field gradient and the defects of the interior surface. The achieved resolution is about 7 microns/pixel. So far there are good correlations between locations identified by a thermometry measurements and positions of defects found by this system. The heights or depths can be also estimated by measuring wall gradients for some well-conditioned defects. The detailed system and the data obtained from the system will be described.
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Slides
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| WEOBM04 |
LHC: The World's Largest Vacuum Systems being Commissioned at CERN
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1959 |
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- J. M. Jimenez
CERN, Geneva
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When it switches on in the spring of 2008, the 26.7 km Large Hadron Collider (LHC) at CERN, will have the world's largest vacuum system operating over a wide range of pressures and employing an impressive array of vacuum technologies. This system is composed by 54 km of UHV vacuum for the circulating beams and 24 km of insulation vacuum around the cryogenic magnets operated mainly at 1.9 K. Over the 54 km of UHV beam vacuum, 48 km of this must be at cryogenic temperature (1.9 K). The remaining 6 km of beam vacuum containing the insertions is at ambient temperature and uses non-evaporable getter (NEG) coatings – a vacuum technology that was born and industrialized at CERN. The pumping is completed using 600 ion pumps to remove noble gases and 1000 gauges are used to monitor the pressures. The cryogenic insulation vacuum, while technically less demanding, is impressive by its size - 24 km in length, 900 mm in diameter for a total volume of 640 m3. Once cooled at 1.9 K, the cryogenic pumping allows reaching pressure in the 10-6 mbar range. This paper described the entire vacuum system and the challenges of the design, manufacturing, installation and commissioning phases.
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Slides
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