Paper | Title | Page |
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WEYPLS1 | Building the Impedance Model of a Real Machine | 2249 |
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A reliable impedance model of a particle accelerator can be built by combining the beam coupling impedances of all the components. This is a necessary step to be able to evaluate the machine performance limitations, identify the main contributors in case an impedance reduction is required, and study the interaction with other mechanisms such as optics nonlinearities, transverse damper, noise, space charge, electron cloud, beam-beam (in a collider). The main phases to create a realistic impedance model, and verify it experimentally, will be reviewed, highlighting the main challenges. Some examples will be presented revealing the levels of precision of machine impedance models that have been achieved. | ||
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Slides WEYPLS1 [5.648 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEYPLS1 | |
About • | paper received ※ 10 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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WEPMP041 | Damping Bunch Oscillations Due to Off-Axis Injection | 2422 |
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Funding: This work was supported by the European Commission under the HORIZON 2020 project ARIES, grant agreement no. 730871. In the FCC-ee pre-injector complex, a slightly modified SPS can serve as pre-booster. The baseline design foresees injecting the low-emittance electron and positron bunches off-axis into the SPS, and deploying strong wigglers to greatly enhance the radiation damping at the injection energy. We here compare the damping of large injection oscillations by means of radiation damping with the effect of other possible damping mechanisms such as a fast bunch-by-bunch feedback system and/or head-tail damping via nonzero chromaticity. As a by-product, we investigate the transverse beam stability. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP041 | |
About • | paper received ※ 10 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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WEPTS044 | Instability Latency in the LHC | 3204 |
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The Large Hadron Collider (LHC) has experienced multiple instabilities that occur between minutes and hours after the last modification of the machine settings. The existence of instabilities with high latency has been reproduced also in simulations. Dedicated experiments, injecting a controlled noise into the beam, have now been performed to discover the dependence of this latency on key parameters. The results seem compatible with a mechanism linked to a steady and slow modification of the transverse beam distribution leading to a loss of Landau damping. | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS044 | |
About • | paper received ※ 30 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | |
Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |