| Paper |
Title |
Other Keywords |
Page |
| MOPLS001 |
Large Scale Beam-beam Simulations for the CERN LHC using Distributed Computing
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LHC, CERN, simulation, beam-beam-effects |
526 |
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- W. Herr, E. McIntosh, F. Schmidt
CERN, Geneva
- D. Kaltchev
TRIUMF, Vancouver
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We report on a large scale simulation of beam-beam effects for the CERN Large Hadron Collider (LHC). The stability of particles which experience head-on and long-range beam-beam effects was investigated for different optical configurations and machine imperfections. To cover the interesting parameter space required computing resources not available at CERN. The necessary resources were available in the LHC@home project, based on the BOINC platform. At present, this project makes more than 40000 hosts available for distributed computing. We shall discuss our experience using this system during a simulation campaign of more than six months and describe the tools and procedures necessary to ensure consistent results. The results from this extended study are presented and future plans are discussed.
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| MOPLS016 |
LHC IR Upgrade: A Dipole First Option with Local Chromaticity Correction
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LHC, sextupole, dipole, luminosity |
571 |
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- R. de Maria, O.S. Brüning
CERN, Geneva
- P. Raimondi
INFN/LNF, Frascati (Roma)
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In the framework of the LHC Luminosity Upgrade, we develop a new layout of the interaction region (IR) with betastar equal to 25cm in which the combination-separation dipoles come first with respect to the triplet assembly (dipole first) in opposition of the nominal layout (quadrupole first). The new layout presents several advantages (separate channel for multipole errors, straightforward crossing angle scheme, early separation of the beam). The payoff is a large beta function in the triplet, which enhances the chromaticity and other non-linear effects. We investigate options for local chromaticity correction and their effects on long-term stability.
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| MOPLS139 |
Choosing a Baseline Configuration for the ILC Damping Rings
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damping, lattice, wiggler, kicker |
885 |
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- A. Wolski
Liverpool University, Science Faculty, Liverpool
- J. Gao
IHEP Beijing, Beijing
- S. Guiducci
INFN/LNF, Frascati (Roma)
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The damping rings for the International Linear Collider must be capable of accepting large beams from the electron and positron sources, and producing highly damped beams meeting demanding stability specifications, at the machine repetition rate of 5 Hz. Between March and November 2005, a program of studies was undertaken by an international collaboration of 50 researchers to compare a number of configuration options, including ring circumferences between 3 and 17 km. Here, we outline the studies and discuss the principal considerations in the choices of the baseline and alternative damping ring configurations.
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| MOPLS142 |
Optimization of CESR-c Superferric Wiggler for the International Linear Collider Damping Rings
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wiggler, damping, lattice, TESLA |
894 |
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- J.T. Urban, G. Dugan, M.A. Palmer
Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
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We present the results of an optimization of the Cornell Electron Storage Ring (CESR) superferric wiggler for the International Linear Collider (ILC) damping ring. The superferric CESR wiggler has been shown to have excellent beam dynamics properties in the ILC damping ring. We reduced the physical size, and hence cost, of the CESR wiggler with minimal degradation of ILC damping ring beam dynamics. We will provide a description of the optimized superferric wiggler and show the performance of this wiggler in the ILC baseline damping ring.
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| WEPCH074 |
Progress with Non-linear Beam Dynamic Studies of the Diamond Storage Ring
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lattice, sextupole, injection, DIAMOND |
2089 |
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- R. Bartolini, I.P.S. Martin, B. Singh
Diamond, Oxfordshire
- J.K. Jones
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
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The conflicting requirements of high-brightness photon beams combined with adequate beam lifetime and high injection efficiency mean careful control of the non-linear lattice is crucial to achieving optimum performance. As part of the optimisation of the Diamond storage ring, studies have been made of both the Touschek lifetime and storage ring injection process, with the help of on-momentum and off-momentum frequency maps. The effect of chromaticity on Touschek lifetime has also been investigated and several new sextupole settings were identified achieving good Touschek lifetime and injection efficiency.
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| WEPCH077 |
Particle Tracking in a Sextupole Field using the Euler Method Approximation
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sextupole, lattice, ELETTRA, LEFT |
2098 |
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| WEPCH085 |
Algorithms for Chromatic Sextupole Optimization and Dynamic Aperture Increase
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sextupole, lattice, storage-ring, betatron |
2116 |
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- E. Levichev, P.A. Piminov
BINP SB RAS, Novosibirsk
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Strong chromatic sextupoles compensating natural chromaticity of a storage ring may reduce dynamic aperture drastically. In the case of several sextupole families, one can find a lot of ways to correct chromaticity, which provides different sizes of the dynamic aperture. Finding a solution that gives the largest dynamic aperture is an important task for the storage ring design and operation. The paper discusses several approaches to sextupole arrangement optimization in order to obtain a large dynamic aperture.
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| WEPCH093 |
Parameter Scans and Accuracy Estimates of the Dynamic Aperture of the CERN LHC
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LHC, simulation, CERN, dipole |
2131 |
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- M. Giovannozzi, E. McIntosh
CERN, Geneva
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Techniques to make use of large distributed computing facilities allow for denser parameter scans of the dynamical aperture, i.e., the domain in phase space where bounded single-particle motion prevails. Moreover, one can also increase the number of 'seeds' each of which represents a possible realisation of multipolar components around the machine. In this paper the dependence of the dynamical aperture on the step size of the grid of initial conditions and on the number of seeds is studied. Estimates on the accuracy of the dynamic aperture are derived and the definition of an improved protocol for numerical simulations is presented.
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| WEPCH102 |
Studies of the Nonlinear Dynamics Effects of APPLE-II Type EPUs at the ALS
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polarization, multipole, lattice, simulation |
2152 |
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- C. Steier, S. Marks, S. Prestemon, D. Robin, D. Schlueter, W. Wan, W. Wittmer
LBNL, Berkeley, California
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Elliptically Polarizing Undulators (EPUs) have become more and more popular at synchrotron radiation sources, providing full polarization control of the photon beam. The fields of the most commonly used APPLE-II type EPUs have a very fast, intrinsic field roll-off, creating significant non-linearities of the beam motion with in some cases large impact on the dynamic (momentum) aperture. In general, the nonlinear effects get stronger with longer periods and higher undulator magnetic fields. One of the planned future beamlines at the ALS (MERLIN) will use a quasiperiodic EPU with 9 cm period and maximum B fields of about 1.3 T. We will present simulation studies for the proposed shimming schemes for this future device to reduce the nonlinear effects to acceptable values, as well as experimental studies for the existing 5 cm period EPUs already installed in the ALS.
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| WEPLS112 |
Study of 2-in-1 Large-aperture Nb3Sn IR Quadrupoles for the LHC Luminosity Upgrade
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quadrupole, LHC, magnet-design, luminosity |
2643 |
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- A.V. Zlobin, V. Kashikhin
Fermilab, Batavia, Illinois
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After LHC operates for several years at nominal parameters, it will be necessary to upgrade it to higher luminosity. Replacement of the low-beta insertions with higher performance design based on advanced superconducting magnets is one of the most straightforward steps in this direction. An interesting option for a new IR design is a double bore inner triplet with separation dipoles placed in front of the focusing quadrupoles. This approach reduces the number of parasitic collisions by more than a factor of three with respect to the quadrupoles-first option and allows independent field error correction for each beam. Several designs of the 2-in-1 Nb3Sn quadrupole magnets suitable for the LHC IR upgrade have been studied, including magnets with "cold" and "warm" iron yokes based on symmetric or asymmetric coils. This paper describes the design concepts of 2-in-1 large-aperture IR quadrupoles and compares their major performance parameters, including aperture, field gradient, field quality, electromagnetic stresses in the coils, and discuss some technological aspects of magnet fabrication.
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| THPLS021 |
Dynamic Aperture Studies for PETRA III
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sextupole, PETRA, undulator, wiggler |
3320 |
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- Y.J. Li, K. Balewski, W. Decking
DESY, Hamburg
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PETRA III is a low-emittance storage ring dedicated to synchrotron radiation. For efficient injection in the top-up mode, the dynamic aperture has to be larger than 30 mm-mrad in the horizontal plane. This paper presents the choice of tunes and the optimization of the sextupole configuration. Tracking simulations have been performed, including the non-linear effects of 20 four-meters-long damping wigglers and a representative set of undulators. Misalignment and multipole errors are considered as well, leading to specifications for the magnet design and alignment procedure.
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| THPLS035 |
Next Generation Light Source Storage Ring at SPring-8
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emittance, storage-ring, sextupole, coupling |
3362 |
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- K. Tsumaki, N. Kumagai
JASRI/SPring-8, Hyogo-ken
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A linac-based XFEL and an ERL are widely accepted as next-generation light sources. But they still have many technologically difficult problems to overcome. In contrast, electron beams in a storage ring are very stable. Thus, we examined the possibility of the storage ring as a next-generation light source. We designed a storage ring with an energy of 6 GeV and a circumference of 1436 m. The ring consists of 24 ten-bend achromat cells and has a natural emittance of 83 pm·rad. The circumference is equal to that of SPring-8 storage ring and the cell length is two times, which enables us to replace the existing storage ring with this new one in the SPring-8 tunnel and use the photon beam-lines without constructing new ones. Particle tracking simulation showed that the horizontal dynamic aperture at the center of a straight section is -3.7 mm and +3.4 mm and that it can be increased to -6.6 mm and +10.0 mm by changing the sextupole strength for chromaticity correction while keeping zero chromaticity. In this paper, we describe the design and the dynamic aperture of the extremely low emittance storage ring at SPring-8.
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| THPLS048 |
Beam-optics Analysis and Periodicity Restoration in the Storage Ring of the Pohang Light Source
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storage-ring, quadrupole, optics, focusing |
3395 |
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- S.H. Shin, M. Yoon
POSTECH, Pohang, Kyungbuk
- E.-S. Kim
PAL, Pohang, Kyungbuk
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The PLS is a third-generation synchrotron radiation source, which provides intense light from ultraviolet to soft x-rays. Similar to other light sources, the PLS is characterized by a small emittance in order to achieve a very high spectral brightness and stably circulating electron beam. To guarantee these characteristics, a thorough understanding of the linear optics has to be carried out, and many storage rings employ LOCO (Linear Optics from Closed Orbits) to analyse the linear optics. This paper will describe the LOCO implementation at PLS and the results.
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| THPLS054 |
Closed Orbit Correction and Beam Dynamics Issues at ALBA
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lattice, quadrupole, multipole, vacuum |
3404 |
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- M. Muñoz, D. Einfeld, T.F. Günzel
ALBA, Bellaterra
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ALBA is a 3 GeV light source being built in Spain. The light source should be operational in 2010.The lattice for the storage ring is now finalized. The basic cells is an extended DBA-like structure with finite dispersion in the straight sections, providing low emittance (under 5nmrad) , small beam cross sections at the source points (less than 150 micro-m horizontal and 10micro-m vertical), and a large number of straight sections (4 times 8m, 12 times 4.2m and 8 times 2.6m). In this paper we review the properties of the lattice with special emphasis in the closed orbit correction system and the lifetime limits.
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| THPLS063 |
Nonlinear Beam Dynamics of TPS
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lattice, sextupole, resonance, injection |
3430 |
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- H.-P. Chang, P.J. Chou, C.-C. Kuo, G.-H. Luo, H.-J. Tsai, M.-H. Wang
NSRRC, Hsinchu
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A design study of 3.0 GeV high performance low emittance storage ring Taiwan Photon Source has been conducted recently The natural emittance of the storage ring can be as low as 1.7 nm-rad in our design and its lattice structure is a 24-cell double bend achromat type with circumference of 518.4 m, which will be located in the existing NSRRC site in Hsinchu. The strong focusing requires strong aberration correction with nonlinear sextupole magnets. The distribution of the sextupoles and number of families are studied to ensure a good dynamic aperture. The nonlinear effects in both betatron and synchrotron motions are investigated. Nonlinear beam dynamics effects in the presence of magnetic field imperfections as well as the insertion devices are simulated. The physical aperture limitations are included in the study too, and the Touschek lifetime is calculated. The tracking data are analyzed using frequency map analysis method and corresponding beam dynamics behavior can be revealed more precisely.
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| THPLS068 |
Design of Taiwan Future Synchrotron Light Source
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emittance, coupling, lattice, synchrotron |
3445 |
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- C.-C. Kuo, H.-P. Chang, C.-T. Chen, P.J. Chou, H.J. Jhao, G.-H. Luo, H.-J. Tsai, M.-H. Wang
NSRRC, Hsinchu
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We report updated design works for a new 3-3.3 GeV synchrotron light source with a high performance and low emittance storage ring, called Taiwan Photon Source (TPS). With its natural horizontal emittance less than 2 nm-rad and low emittance coupling, TPS will be able to provide an extremely bright photon beam to the demanding users, especially the x-ray community. The lattice type of the TPS is a 24-cell DBA structure and the circumference is 518.4 m. We present the lattice design, the accelerator physics issues and its performances.
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| THPLS085 |
Nonlinear Dynamics in the SPEAR 3 Double-waist Chicane
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optics, injection, insertion, SLAC |
3475 |
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- J.A. Safranek, X. Huang, A. Terebilo
SLAC, Menlo Park, California
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A quadrupole triplet has been included in the center of a 7.6 m long chicane in SPEAR 3 to create a novel and technically challenging 'double waist' optics with betay=1.6m at the center of each of two future small-gap insertion devices. The new optics also reduces betay to 2.5m in the four adjacent 4.8m straight sections. In this paper, we discuss key issues associated with design of the machine optics, insertion device compatibility issues, optimization of dynamic aperture and initial measurements of machine performance in the new configuration.
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| THPLS087 |
A Control Theory Approach for Dynamic Aperture
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sextupole, lattice, controls, synchrotron |
3478 |
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- J. Bengtsson
BNL, Upton, Long Island, New York
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The dynamic aperture problem dates back to the design of the first synchrotrons. Over time, both analytical and numerical methods have been pursued. In the former case mainly by applying techniques developed for celestial mechanics to rather simplified equations of motion. Over the last decade, analysis of the Poincare map has become the method of choice. In particular, application of symplectic integrators, truncated power series algebra, and Lie series techniques has led to a complete set of tools for self-consistent numerical simulations and analytic treatment of realistic models. Nevertheless, a control theory for the general nonlinear case remains elusive. We summarize how to apply this framework to the design of modern synchrotron light sources. Moreover, we also outline how a control theory can be formulated based on the Lie generators for the nonlinear terms.
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| THPLS090 |
Consideration of the Double Bend Achromatic Lattice for NSLS-II
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lattice, wiggler, emittance, insertion |
3487 |
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| THPLS091 |
Control of Dynamic Aperture with Insertion Devices
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lattice, optics, quadrupole, sextupole |
3490 |
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- T.V. Shaftan, J. Bengtsson, S.L. Kramer
BNL, Upton, Long Island, New York
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It is well known that insertion devices (IDs) perturb the linear optics in the vertical plane. In particular, that the effect can be corrected locally by a symmetric arrangement of four quadrupoles on each side of the IDs. We show how to control an arbitrary set of IDs in this configuration with the response matrix for the beta-beat and perturbation of the phase advance and SVD, i.e., to maintain the dynamic aperture. We also evaluate the residual impact on the dynamic aperture from the nonlinear terms and outline how to control these. As an example, we discuss an impact of some ID models on the NSLS-2 dynamic aperture. Results for a single ID and a set of 20 IDs with random field strengths are presented.
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