| Paper | Title | Page |
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| MOZGBF2 | Status of the FAIR Project | 63 |
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| The realization of the new Facility for Antiproton and Ion Research, FAIR at GSI, Germany, has advanced significantly. The civil construction process of the Northern part of the building complex, including the excavation of the SIS100 synchrotron tunnel has been launched end of 2017. On site of the GSI campus, major preparations and upgrade measures for the injector operation of the existing accelerator facilities are ongoing and will be completed mid of 2018. The shielding of the SIS18 accelerator tunnel has been enhanced for the booster operation at high repetition rates and high intensity Proton beams. Two new transformer stations were set-up and commissioned which will provide the required pulse and common power for FAIR. All major contracts for series production of SIS100 components have been signed and a large number of the superconducting SIS100 magnets has been produced and accepted. Major testing infrastructures for superconducting magnets of SIS100 and Super-FRS have been set-up at JINR, CERN and GSI. Also for all other FAIR accelerator systems, the procurement of the components is progressing well | ||
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Slides MOZGBF2 [4.266 MB] | |
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOZGBF2 | |
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| MOPMF029 | FCC-hh transverse impedance budget | 149 |
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| Contributions of different machine elements of the proposed Future Circular Collider (FCC-hh) impedance budget are calculated based on beam stability considerations. For each element (the beamscreen, the collimators, etc), effective impedances are calculated at the injection energy and at the collision energy for considered instabilities. The considered instabilities include the transverse coupled bunch instability (TCBI) and the transverse mode coupling instability (TMCI). Limitations to each total effective impedance are estimated and the critical points in the impedance budget are determined. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF029 | |
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| THPAF079 | Landau Damping and Tune-Spread Requirements for Transverse Beam Stability | 3168 |
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| Passive mitigation methods are effective cures for collective instabilities in ring accelerators. For decades, octupole magnets have been used as an established and well-understood passive mitigation method. Present and the future accelerator facilities, like FAIR or FCC, impose new challenges on the passive mitigation due to higher energies and smaller beam emittances. Lattice resonances usually restrict the tolerable tune-spreads which are essential for the passive mitigation methods. We study the stability of transverse bunch oscillations provided by octupole magnets and radio-frequency quadrupoles. The special focus of our study is on the interplay and role of decoherence, phase-mixing and Landau damping for the different mitigation schemes. Particle tracking simulations are performed and the tune spreads for the different mechanisms are compared with each other and also with analytical dispersion relations. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF079 | |
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| THPAF080 | SIS100 Beam Dynamics Challenges Related to the Magnet System | 3172 |
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| The SIS100 synchrotron is the central accelerator of the upcoming FAIR project at GSI, Darmstadt, Germany. The major challenges of the future operation are related to high-intensity, low beam loss operation for a wide range of ion species and charge states, for different operational cycles and extraction schemes. The magnet system consists of 108 dipole, 166 quadrupole and additional correction superconducting superferric magnets. The magnets are presently under production and testing, with detailed measurements of the magnetic field imperfections. This results in the construction of a complete database for the SIS100 magnet system. We analyse implications of the magnetic field imperfections for the single-particle stability, space charge induced tune-shifts and resonance crossing for the different SIS100 operation modi. Resonance compensation and magnet sorting schemes are discussed as possible measures. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF080 | |
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| THPAK008 | Space Charge and Microbunching Studies for the Injection Arc of MESA | 3221 |
| SUSPF083 | use link to see paper's listing under its alternate paper code | |
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For intense electron bunches traversing through bends, as for example the recirculation arcs of an ERL, space charge (SC) may result in beam phase space deterioration. SC modifies the electron transverse dynamics in dispersive regions along the beam line and causes emittance growth for mismatched beams or for specific phase advances. On the other hand, longitudinal space charge together with dispersion can lead to the microbunching instability. The present study focuses on the 180° low energy (5 MeV) injection arc lattice for the multi-turn Mainz Energy-recovering Superconducting Accelerator (MESA), which should deliver a CW beam at 105 MeV for physics experiments with an internal target. We will discuss matching conditions with space charge together with the estimated microbunching gain for the arc. The implication for the ERL operation will be outlined, using 3D envelope and tracking simulations.
Supported by the DFG through GRK 2128 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK008 | |
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| THPAK117 | Space Charge Limitations for Bunch Compression in Synchrotrons | 3518 |
| SUSPF082 | use link to see paper's listing under its alternate paper code | |
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| Bunch compression achieved via a fast bunch rotation in longitudinal phase space is a well-accepted scheme to generate short, intense ion bunches for various applications. During bunch compression, coherent beam instabilities and incoherent single particle resonances can occur because of increasing space charge, resulting in an important limitation for the bunch intensity. We present an analysis of the relevant space charge driven beam instability and resonance phenomena during bunch compression. A coupled longitudinal-transverse envelope approach is compared with Particle-In-Cell (PIC) simulations. Two distinct cases of crossing are discussed and applied to the GSI SIS18 heavy-ion synchrotron. It is shown that during bunch compression, the 90° condition of phase advance is associated with a fourth order single particle resonance and the 120° condition with the recently discovered dispersion-induced instability. The agreement between the envelope and PIC results indicates that the stop band is defined by the 120° dispersion instability, which should be avoided during bunch compression. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK117 | |
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