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Other Keywords |
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| MOPLT055 |
RF Excitation of Linear and Curved Sections of the CRFQ Project
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quadrupole, rfq, simulation, proton |
677 |
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- D. Davino
Universita' degli Studi del Sannio, Benevento
- L. Campajola, V.G. Vaccaro
Naples University Federico II, Mathematical, Physical and Natural Sciences Faculty, Napoli
- M.R. Masullo
INFN-Napoli, Napoli
- A. Ruggiero
BNL, Upton, Long Island, New York
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The Circular Radiofrequency Quadrupole is basically a Linear Radio-Frequency Quadrupole completely bent on a circle. A 30-keV prototype is being presently designed and manufactured for testing of the fundamental principles within the scope of a collaboration between BNL and Italian research centers. The storage ring is made of a proton source, a Linear RfQ section 70 cm long, for injection and matching, and eight Curved sections also each about 70 cm long. The proton beam is provided by a modified RF source with electrostatic acceleration at the emittance, intensity and energy required by the beam dynamics.The design of the initial linear prototype is based on a 4-rods geometry having a beam gap diameter of 10mm, and circular 10mm diameters rods. The sector is placed in a 150mm diameter pipe, making it as a very compact structure. The dimensions of the device are adjusted to resonate at 202.56 MHz. A RF power source will be soon available to test the device. The paper describes the compact RF cells arrangement in the design of the two sections.
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| TUPKF010 |
Cryogenic Considerations for CW Operation of TESLA-type Superconducting Cavity Modules for the BESSY FEL
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linac, simulation, cryogenics, extraction |
976 |
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- J. Knobloch, W. Anders, X. Yu
BESSY GmbH, Berlin
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The proposed BESSY FEL uses a CW superconducting driver linac to provide acceleration up to 2.3 GeV. Its design is based on well-established TESLA technology, originally intended for heat loads of order 1 W/m at 2.0 K. CW operation increases this load to levels of order 15 W/m at 1.8 K for a total heat load of 3 kW at 2.3 GeV (given conservative assumptions for the attainable Q-factor). Presented here is an analysis of the cryogenic layout, including two-phase-flow simulations of the 1.8-K helium which help identify the changes needed for reliable CW operation. A modified ‘‘CW'' module and helium distribution scheme is proposed.
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| TUPLT006 |
Simple Analytic Formulae for the Properties of Nonscaling FFAG Lattices
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quadrupole, lattice, injection, betatron |
1138 |
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- S.R. Koscielniak
TRIUMF, Vancouver
- M.K. Craddock
UBC & TRIUMF, Vancouver, British Columbia
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A hallmark of the "non-scaling" FFAG lattices recently proposed for neutrino factories and muon colliders is that a wide range of momentum is compacted into a narrow radial band; dL/L is of order 10(-3) for dp/p of order unity. This property is associated with the use of F0D0 or FDF triplet lattices in which the F magnet provides a reverse bend. In this paper simple analytic formulae for key lattice properties, such as orbit displacement and path length as a function of momentum, are derived from thin-element models. These confirm the parabolic dependence of path-length on momentum observed with standard orbit codes, reveal the factors which should be adjusted to minimize its variation, and form a useful starting point for the thick-element design (for which analytic formulae are also presented). A key result is that optimized doublet, F0D0 and triplet cells of equal length and phase advance have equal path-length performance. Finally, in the context of a 10-20 GeV/c muon ring, the thin-element formulae are compared against lattice optical properties computed for thick-element systems; the discrepancies are small overall, and most discernible for the triplet lattices.
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| WEPLT025 |
LHC Reference Database : Towards a Mechanical, Optical and Electrical Layout Database
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vacuum, collider, instrumentation, injection |
1882 |
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- P. Le Roux, S. Chemli, A. Jimeno Yepes, B. Maire, H. Prin, A. Vergara-Fernández, M. Zerlauth
CERN, Geneva
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The LHC project has entered a phase of integration and installation of thousands of diverse components. The Hardware Commissioning work has also started. Collecting and distributing reliable and coherent information on the equipments and their layout becomes a crucial requirement in the lifecycle of the project. Existing database tools had to evolve to a more generic model to cover not only optical layout, but also the mechanical and the electrical aspects. This paper explains the requirements, the implementation and the benefits of this new database model.
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| WEPLT077 |
DESIGN OF A FULL-CUSTOM ACCURATE I-Q MODULATOR
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simulation, impedance, coupling, insertion |
2029 |
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- M. Luong, M. Desmons
CEA/DSM/DAPNIA, Gif-sur-Yvette
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The I-Q modulator is a key component in a digital Low Level RF (LLRF) system for amplitude and phase feedbacks. Its residual errors in offset or gain have a strong impact on the dynamic and accuracy of the feedback loops. For some frequencies, commercial I-Q modulators are available on the market. But even in that case, these components are usually designed for broadband communication purposes, and their performances in term of residual errors may not fit the strict requirements on the final amplitude and phase loop stability. Since LLRF systems for accelerators are typically narrow-banded, i.e. limited to few MHz, it is possible to achieve a high directivity and a very accurate coupling for hybrids, and an excellent matching for all subcomponents in a fully custom design. This approach guarantees the lowest residual errors for an I-Q modulator. The principle for the design and the process for the optimization are presented in this paper.
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| WEPLT092 |
Equilibrium Longitudinal Distribution for Localized Regularized Inductive Wake
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synchrotron, damping, radiation, vacuum |
2065 |
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- S. Petracca, T. Demma
U. Sannio, Benevento
- K. Hirata
GUAS, Kanagawa
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In a recent paper [*] we have shown that a localized wake assumption and the Gaussian approximation for the longitudinal beam distribution function can be used to understand the nature of the stationary solutions for the inductive wake, by comparison between the resulting map and the Haissinski equation, which rules the (less realistic) case of a uniformly distributed wake. In particular we showed the non-existence of solutions of Haissinski's equation when the inductive wake strength exceeds a certain threshold [**] to correspond to the onset of chaos in the map evolving the moments of the beam distribution from turn to turn. In this paper we use the same formalism to confirm that as noted in [**] for Haissinski's equation, a steady state solution for the longitudinal phase space distribution function always exists if a physically regularized inductive wake, which satisfies an obvious causality condition, is used.
* S. Petracca and Th. Demma, Proc. of the 2003 PAC, IEEE Press, New York, 2003, ISBN 0-7803-7739-9, p.2996.** Y. Shobuda and K. Hirata, Part. Accel. vol. 62, 165 (1999).
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| THOALH01 |
Bunch Length Measurements at the SLS Linac using Electro-optical Techniques
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laser, linac, radiation, electron |
253 |
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- A. Winter, M. Tonutti
RWTH, Aachen
- S. Casalbuoni, P. Schmüser, S. Simrock, B. Steffen
DESY, Hamburg
- T. Korhonen, T. Schilcher, V. Schlott, H. Sigg, D. Suetterlin
PSI, Villigen
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The temporal profile of the electron bunches in the SLS Linac will be determined by means of electro-optical techniques. A mode locked Ti:Sa Laser with 15 fs pulse width is used for coincidence measurements between the laser pulse and the coherent transition radiation (CTR) generated by short electron bunches. Synchronization accuracy of 100 fs rms between the 3 GHz Linac RF and the 81 MHz repetition rate of the laser was achieved, which is important for the optimum time resolution of the applied electro-optical sampling technique. Likewise, a mode locked Nd:YAG laser with 400 ps long pulses will be used for electro-optical autocorrelation measurements between the CTR and the laser pulses. This alternative technique promises single shot capability and requires much relaxed synchronization stability between laser and electron beam.
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Video of talk
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Transparencies
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