| Paper | Title | Page |
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| MOPRB005 | Study of Higher-Order Achromat Lattice as an Alternative Option for the SOLEIL Storage Ring Upgrade | 586 |
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| A ring composed of 20 symmetrical 7BA cells in which of a pair of chromaticity correcting sextupoles placed around horizontal dispersion bumps à la ESRF-EBS was developed as a baseline lattice for the SOLEIL storage ring upgrade (presented at IPAC2018). The strict phase relation between the two dispersion bumps provides an efficient way of optimizing the (on-momentum) nonlinear optics with a limited number of sextupoles. As an alternative, a scheme known as Higher-Order Achromat (HOA) develops a MBA (Multi-Bend Achromat) lattice where chromaticity correcting sextupoles are distributed in each M unit cell with a strict phase relation cell-wise such as to cancel basic geometric and chromatic resonance driving terms. The beam dynamics in a 20-fold 7BA HOA ring is compared with those of the baseline lattice, with focus on off-momentum properties such as Touschek lifetime, which are important for medium energy rings like SOLEIL. The robustness against errors, the reduction of the ring symmetry by introducing 4 longer straight sections, as well as a horizontal dispersion bump to cope with longitudinal on-axis injection scheme are also presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB005 | |
| About • | paper received ※ 22 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| MOPGW039 | Investigation of Longitudinal Beam Dynamics With Harmonic Cavities by Using the Code Mbtrack | 178 |
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In diffraction-limited light sources, the study of collective effects is essential. With harmonic cavities (HCs), the ’flat potential condition’ can be achieved, lengthening the bunch by a factor of ~5. However, the effective rf voltage seen by the beam becomes sensitive to both positions and distributions of all bunches, as the beam-induced voltage of both HCs and fundamental cavities (FCs) contribute. In addition, when there are empty buckets, the transient beam loading induces considerable variations of the rf voltage impacting the beam performance*. Here the use of analytical approaches is difficult. Then we introduced the new functions to treat the high-Q resonators driven by either or both of the beams and external generators to the code mbtrack**. Using these features, various operating conditions with arbitrary fill patterns can be studied; coupled bunch instability induced by HOMs of the cavity, Robinson instabilities and general beam dynamics with HCs. The growth rates of the instabilities described above are compared with analytical results. The ring performance with HCs in several fill patterns shall be also reported.
* N.Yamamoto, et al., PRAB, 21, 012001 (2018). **G. Skripka, et al., NIM A806, 221 (2016). |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW039 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| MOPGW097 | SOLEIL Storage Ring Upgrade Performance in Presence of Lattice Imperfections | 350 |
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| The design for the upgrade of the SOLEIL third generation light source is progressing. At the present stage, different lattices are evaluated as possible candidates for the storage ring upgrade and an important factor for the comparison of their performances is the robustness against lattice imperfections. The strategy for this study consists in defining a set of misalignments of the lattice elements and field errors of the magnets that are expected to be attained after the commissioning, applying them to the lattice models and correcting them using response matrix based techniques. A dedicated algorithm was developed in Accelerator Toolbox in order to accomplish this procedure and compare the different lattices. In this paper the results of this study at the current state are presented, including the considered lattice imperfections, the correction method applied and the final performance of the lattices. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW097 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019 | |
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| WEPTS011 | Intra-Beam Scattering Effect in the SOLEIL Storage Ring Upgrade | 3106 |
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| As the work on the design of the upgrade of SOLEIL storage ring advances, the study of the impact of Intra-Beam Scattering (IBS) on the equilibrium emittance is also progressing, showing a significant contribution of this effect. Different measures can be taken to mitigate the emittance dilution, like operating the machine with full transverse coupling and using harmonic cavities to increase bunch length. The calculation of the IBS effect needs then to take into account the different beam dynamics and its effect on the particle distribution. In this paper the current state of the ongoing study is presented, reporting on the results obtained for the different options considered, and comparing the results of different codes and their implicit assumptions. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS011 | |
| About • | paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019 | |
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