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| MOPMF024 | Dipole Field Quality and Dynamic Aperture for FCC-hh | dipole, injection, alignment, optics | 137 |
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Funding: This Research and Innovation Action project submitted to call H2020-INFRADEV-1-2014-1 receives funding from the European Union's H2020 Framework Program under grant agreement No. 654305. The Nb3Sn dipole design for the hadron machine option of the Future Circular Colliders enters in an intense and long R&D phase. As a result, more realistic dipole field quality evaluations are available for beam dynamics studies. The paper discusses the impact of the main dipole field quality on the first and second order design of the hadron machine and on its dynamic aperture. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF024 | ||
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| MOPMF033 | Probing the Forced Dynamic Aperture in the LHC at Top Energy Using AC Dipoles | dipole, insertion, emittance, resonance | 165 |
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| Measurements of the dynamic aperture in colliders are a common method to ensure machine performance and offer an insight in the nonlinear content of the machine. Such direct measurements are very challenging for the LHC and High Luminosity LHC. Forced dynamic aperture has been demonstrated for the first time in the LHC at injection energy as a potential new observable to safely probe the nonlinear content of the machine. This paper presents the first measurements of forced dynamic aperture at top energy and discusses the proposed measurement schemes and challenges. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF033 | ||
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| MOPMF041 | Refining the HL-LHC Operational Settings with Inputs From Dynamic Aperture Simulations: A Progress Report | luminosity, octupole, operation, experiment | 188 |
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| Recent Dynamic Aperture (DA) simulations aimed at providing guidance for the latest updates of the operational scenario for the High Luminosity upgrade of the LHC. The impact of the increased chromaticity and octupole current has been assessed considering the latest updates of the optics. Additional means to improve the lifetime, such as tune optimization, have been identified and deployed. We also briefly discuss the impact of delivering high luminosity to the LHCb experiment. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF041 | ||
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| MOPMF057 | FCC-ee Dynamic Aperture Studies and Frequency Map Analysis | alignment, emittance, resonance, sextupole | 244 |
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| The FCC-ee Lepton Collider will provide e+e− collisions in the beam energy range of 45.6 GeV to 182.5 GeV. FCC-ee will be a precision measurement tool for Z, W, H and t physics with expected luminosities of 2.07× 1036 cm-2 s-1 at the Z-pole and 1.3 × 1034 cm-2 s-1 at the tt- threshold. In order to achieve the foreseen luminosities, a vertical β* of 1 mm to 2 mm is mandatory. Dynamic aperture and frequency map analysis for the 97.75 km machine with such a squeezed accelerator optics are studied. Furthermore, effects of machine misalignments on dynamic and momentum aperture are presented and estimations for the required tolerances are given | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF057 | ||
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| MOPMF069 | The High Energy LHC Beam-Beam Effects studies | octupole, beam-beam-effects, collider, experiment | 285 |
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Funding: This work is supported by the Swiss State Secretariat for Education, Research and Innovation SERI. We present in this paper the studies of beam-beam effects for the High Energy Large Hadron Collider. We will describe and review the different aspects of beam-beam interactions (i.e. orbit effects, Landau damping, compensation schemes and operational set-up). An operational scenario for the collider will also be given as a result of the study. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF069 | ||
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| MOPMF079 | The CEPC lattice design with combined dipole magnet | sextupole, dipole, collider, lattice | 315 |
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| For the lattice of CEPC collider ring, the combined magnet (dipole+sextupole) scheme has been developed to reduce the power consumption of the stand-alone sextu-poles. The power consumption of sextupoles has been decreased by 75% due to 50% reduction of strength. The dynamic aperture for the combined magnet scheme is as good as the original lattice. The magnet design for this kind of combined dipole has been done which provides a good support for this new idea. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF079 | ||
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| MOPMK006 | Experimental Interaction Region Optics for the High Energy LHC | optics, dipole, quadrupole, shielding | 360 |
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Funding: Work supported by the Horizon 2020 project EuroCirCol, grant 654305 and by the Science and Technology Facilities Council The High Energy LHC (HE-LHC) is one option for a next generation hadron collider explored in the FCC-hh program. The core concept of the HE-LHC is to install FCC-hh technology magnets in the LHC tunnel. The higher beam rigidity and the increased radiation debris, however, impose severe challenges on the design of the triplet for the low beta insertions. In order to achieve 25 cm β* optics and survive a lifetime integrated luminosity of 10 ab-1 a new longer triplet was designed that provides sufficient shielding and enough beam stay clear. This triplet has been designed using complimentary radiation studies to optimise the shielding that will also be presented. The optics for the rest of the interaction region had to be adjusted in order to host this more rigid beam and longer triplet whilst leaving enough room for crab cavities. Moreover, the effects non-linear errors in this triplet have on the dynamic aperture will be outlined. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMK006 | ||
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| MOPML002 | Status of the JLEIC Ion Collider Ring Design | collider, solenoid, detector, survey | 394 |
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Funding: Authored by JSA, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the US DOE Contract DE-AC02-76SF00515. We present an update on the lattice design and beam dynamics study of the ion collider ring of JLEIC (Jefferson Lab Electron Ion Collider). The collider ring consists of two 261.7 degree arcs connected by two straight sections crossing each other. One of the straights houses an interaction region (IR) and is shaped to make a 50 mrad crossing angle with the electron beam at the interaction point (IP) to meet physics requirements. The forward acceptance requirements downstream of the IP in the ion direction lead to an asymmetric IR lattice design. The detector solenoid effects and the multipole fields of the IR magnets further complicate this picture. In this paper, compensation of the detector solenoid effects is considered together with orbit correction and multipole effects. We also study local compensation of the magnet multipoles using dedicated multipole correctors. And an optimization of the betatron tunes is also presented. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML002 | ||
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| MOPML008 | JLEIC Electron Ring Dynamic Aperture with Non-linear Field Errors | electron, emittance, lattice, sextupole | 404 |
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Funding: Authored by Jefferson Science Associates, LLC under US DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported by the US DOE Contract DE-AC02-76SF00515. We present results of dynamic aperture study for the updated electron ring lattice of the Jefferson Lab Electron-Ion Collider (JLEIC). The lattice design features low emittance arcs with local compensation of sextupole non-linear effects, and low emittance non-linear chromaticity correction sections. Dynamic aperture tracking simulations are performed to evaluate the effects of non-linear field errors, the sensitivity to betatron tune, and the impact of momentum error. Dynamic aperture is also evaluated with the measured PEP-II field errors. Preliminary tolerances to the non-linear field errors in the Final Focus quadrupoles are estimated. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML008 | ||
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| TUPAL064 | Extended-Domain Tune-Scans for the HL-LHC Dynamic Aperture in Presence of Beam-Beam Effects | resonance, lattice, octupole, beam-beam-effects | 1163 |
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| We report simulations of the HL-LHC dynamic aperture (DA) at collision energy in the presence of beam-beam effects (weak-strong approximation) aiming to determine its dependence on the working point in tune space. Both linear domains working points are explored, spanning over (0.028 – 0.33) in horizontal tune, and two-dimensional ones which focus on more promising sub-regions near the diagonal. The range of parameters, such as bunch intensity and emittance, are chosen to correspond to the more important HL-LHC scenarios. A comparison with the LHC as built is also made. Direct benefit from these studies is the possible identification of working points alternative to the nominal one (in terms of dynamic aperture). They also help to understand the dependence of DA on particular resonance lines present in the vicinity of the footprint. In this work, the necessary resources were provided by the LHC@home project, based on the BOINC-SixTrack platform for distributed Computing. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL064 | ||
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| WEPAL047 | Online Optimisation of the MAX IV 3 GeV Ring Dynamic Aperture | sextupole, octupole, optics, storage-ring | 2281 |
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| In order to improve the resilience of the MAX IV 3 GeV ring's beam to a horizontal dipole kick while at the design tunes (42.20, 16.28) the optimisation algorithm RCDS (Robust Conjugate Direction Search) was deployed. The algorithm was able to increase the horizontal acceptance by finding new settings for the sextupole and octupole magnets, whilst leaving the vertical acceptance virtually unchanged. Additionally, the optimisation increased the momentum acceptance of the lattice, increasing beam lifetime. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL047 | ||
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| THPAF028 | Multi-Objectives Genetic Algorithms (MOGA) Optimization of PETRA IV Scenarios | lattice, injection, sextupole, SRF | 3015 |
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| This paper reports the application of Multi-Objective Genetic Algorithms (MOGA) to optimize the linear and nonlinear beam dynamics of the different PETRA IV scenarios to transform PETRA III storage ring in a diffracted limited one. As it is well known, the dynamic aperture and momentum acceptance of these kinds of lattices are dramatically reduced due to the increase of the sextupoles strengths to compensate its strong focusing. The reduction of the dynamic aperture jeopardizes the current off-axis injection system and lower beam lifetimes increase the beam instabilities and the radiation safety concerns of the storage ring. MOGA searches the best settings of quadrupoles and sextupoles in a multi-dimensional parameter space taking into account the dynamic properties and the natural emittance as objectives at the level of ten picometers. The lattices studied are the so-called 'Twist lattice' based in a phase space exchange lattice, a solution based in the ESRF-Hybrid Multi-bend Achromat (HMA) design and finally the 'double 'I' lattice combining a non-interleaved sextupoles cell with an ESRF-HMA cell. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF028 | ||
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| THPAF030 | PETRA III Storage Ring Performance Improvement Based on Multi-Objective Genetic Algorithms (MOGA) | injection, storage-ring, operation, multipole | 3018 |
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| The performance of the 3th generation light sources relies on the beam lifetime and the injection efficiency, both related with the beam dynamic properties of the storage ring as momentum acceptance and dynamic aperture, respectively. High values of beam lifetime and injection efficiency are desirable to reduce the storage ring instabilities during injection, the radiation losses and the energy consumption of the facility. This paper reports the first application of Multi-Objective Genetic Algorithms (MOGA) to optimize the linear and non-linear beam dynamics of PETRA III storage ring. Genetic algorithms are a heuristic search that mimics the process of natural evolution to optimize problems with a high level of complexity, as in the case of PETRA III storage ring composed by hundreds of magnets. This computational method uses hundreds of CPUs. MOGA is used to maximize the dynamic aperture and the momentum acceptance finding new combinations of quadrupole and sextupole settings in a multi-dimensional parameter space maintaining the solutions in the level of ten picometers. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF030 | ||
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| THPAF086 | Beam Dynamics Simulations for Operating a Robinson Wiggler at the MLS | wiggler, optics, operation, storage-ring | 3189 |
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| A Robinson wiggler is planned to be installed in the storage ring of the Metrology Light Source (the MLS). The Robison wiggler (RW) is a device consisting of a chain of combined-function magnets (CFMs), intended to manipulate the damping partition numbers and thus adjust the longitudinal emittance. The objective is to lengthen the bunch in order to improve the Touschek lifetime. However, the nonlinear perturbation of the beam dynamics due to the Robinson wiggler could limit the achievable improvement. Therefore, a symplectic method of modeling the wiggler has been established to study these nonlinear effects. Optimized solutions have been developed for both the ramping procedure and the future daily operation of the wiggler and are presented in this paper. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF086 | ||
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| THPAK004 | Accurate and Efficient Tracking in Electromagnetic Quadrupoles | quadrupole, multipole, HOM, optics | 3207 |
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| Accelerator physics needs advanced modeling and simulation techniques, in particular for beam stability studies. A deeper understanding of the effects of magnetic fields nonlinearities will greatly help in the improvement of future colliders design and performance. This paper presents a study of quadrupole tracking using realistic field maps and measured or simulated longitudinal harmonics. The main goal is to describe the effect of the longitudinal dependence of high order non-homogeneity of the field in the case of the HL-LHC inner triplet. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK004 | ||
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| THPAK133 | Magnetic Field Tolerances of Dipole and Quadrupole Magnets for XiPAF Synchrotron | dipole, quadrupole, multipole, synchrotron | 3551 |
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| The magnets are being constructed for Xi'an Proton Application Facility (XiPAF) synchrotron. A study is started to obtain the specifications and tolerances of the magnets to avoid beam lost by the excessive magnetic field errors. The study includes the effect of field and alignment errors of the magnets on the closed orbit and beam optics. Also a preliminary study of effect due to multipole components in dipole and quadrupole magnets on dynamic aperture has been done. The tolerances of dipole and quadrupole magnets on field errors, including multipole components, and alignment errors are described in this paper. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK133 | ||
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| THPAK145 | Methods to Increase the Dynamic Aperture of the FCC-hh Lattice | lattice, luminosity, quadrupole, interaction-region | 3593 |
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| The Future Circular Collider (FCC) design study aims to develop the designs of possible circular colliders in the post LHC era. In particular the FCC-hh will aim to produce proton-proton collisions at a center of mass energy of 100 TeV. Initial tracking studies for the FCC-hh lattice at collision energy including field errors on the final focus triplet showed a very low dynamic aperture, most likely affected by the large beta functions and integrated length of the quadrupoles. Using non-linear correctors, the dynamic aperture was increased to acceptable levels; however, the difficulty to have an accurate magnetic model of the magnets required for this correction motivates the development of alternative methods. This work explores the possibility to increase the dynamic aperture by optimizing the phase advance between the main interaction regions. The description of this method along with its impact on the dynamic aperture will be given on this paper. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK145 | ||
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| THPAK152 | Study of GF Symplectic Tracking Method and Compensation for the EPU104 at the HLS-II | undulator, electron, synchrotron, synchrotron-radiation | 3603 |
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| An elliptically polarized undulator (EPU) was applied to obtain high-brightness coherent synchrotron radiation at the upgraded Hefei Light Source, HLS-II. However, the EPU has serious dynamic effects on the beam performances including close orbit, emittance and dynamic aperture etc. when installed at the storage ring. In order to understand the effects, a Taylor expanded generating method was adopted to generate a fast and symplectic map for particle tracking. As for the compensation of the EPU, striplines were equipped above and below the vacuum chamber to reduce the nonlinear effects. With the symplectic tracking routine and the surface fitting method, different parameters such as dynamic aperture and the driving terms, could be set as the objective function to accomplish the optimization of the EPU. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK152 | ||
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| THPMF008 | Conceptual Design of an Accumulator Ring for the Diamond II Upgrade | emittance, injection, storage-ring, lattice | 4046 |
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| Diamond Light Source is in the process of reviewing several lattice options for a potential storage ring upgrade. As part of these studies, it has become clear that a substantial reduction in emittance can be achieved by adopting an on-axis injection scheme, thereby relaxing the constraints on the dynamic aperture. In order to achieve the necessary injected bunch properties for this to be viable, a new accumulator ring would be needed. In this paper we review the requirements placed on the accumulator ring design, describe the lattice development process and analyse the performance of the initial, conceptual design. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF008 | ||
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| THPMF051 | Research of a Locally-round Beam in HEPS Storage Ring Using Solenoids | solenoid, storage-ring, emittance, undulator | 4175 |
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| "Round beam", that is, a beam with equivalent transverse emittance, is expected for a significant fraction of the beamline users in light sources. We investigate the possibility of reaching round beam in a storage ring, by means of a local exchange of the apparent horizontal and vertical emittance, performed with solenoids in a dedicated insertion line in the storage ring. In this paper, we show that a locally-round beam can be achieved by using solenoid in High Energy Photon Source (HEPS) storage ring, particularly to one of the design having natural emittance of 34.2 pm·rad. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF051 | ||
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| THPML117 | Study of the Impact of Linear Coupling on Off-Axis Injection | coupling, resonance, injection, quadrupole | 4943 |
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| The next generation of storage ring light sources will likely operate with high linear coupling, which could potentially prevent the use of off-axis injection as large horizontal oscillation of the injected beam is coupled to the vertical plane. We did experiments on the SPEAR3 storage ring to study how linear coupling impact the dynamic aperture and the off-axis injection efficiency. The results show that the dynamic aperture is significantly reduced and injection efficiency can drop to zero when operated on the coupling resonance. However, with large nonlinear detuning, the dynamic aperture and high injection efficiency can survive with the stored beam at full coupling because the injected beam is shifted away from the coupling resonance. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML117 | ||
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