| Paper | Title | Page |
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| WEPLM04 | Precision Cavity Higher-Order Mode Tuning Scheme for Stabilizing the Stored Beam in the Advanced Photon Source Upgrade | 670 |
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Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 The Advanced Photon Source Upgrade will suffer longitudinal multi-bunch instability because of the presence of several monopole higher-order mode (HOMs) of the 12 352-MHz rf cavities. Even with a feedback system, it would be good to mitigate any driving terms with conventional means such as tuning HOM frequencies with temperature. However the latter is problematic because there will be 90 or so HOMs that are potentially harmful. A scheme is developed, utilizing the measured spectrum of HOMs, to find the best temperature setting for each cavity. We present measurements of 30 or so HOMs, and a thermal model of HOM frequencies using cavity wall power and cooling water temperature as inputs to maintain the optimum tuning condition with sufficient accuracy. The newly acquired Dimtel iGp12 processor box is central to the HOM frequency measurements. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM04 | |
| About • | paper received ※ 29 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| WEPLM11 | Closed Loop Modeling of the APS-U Orbit Feedback System | 683 |
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Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-ACO2-O6CH11357. Orbit stabilization to 10% of the expected small beam sizes for Advanced Photon Source Upgrade (APS-U) requires pushing the state of the art in fast orbit feedback (FOFB) control, both in the spatial domain and in dynamical performance. We are building a Matlab/Simulink fast orbit feedback system model to guide decisions about APS-U fast orbit feedback system implementation and to provide a test bench for optimal-control methodologies and orbit correction algorithms applicable to the APS-U. A transfer function model was built from open-loop frequency-response and step-response measurements of the present APS and subsequently validated against closed-loop measurements. A corresponding model for APS-U fast orbit feedback was generated by substituting measured responses of APS-U prototype corrector magnets and power supplies into this same model. Stabilizing PID gains are designed using model, and simulated dynamic performance of the new controller is validated through experiments. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM11 | |
| About • | paper received ※ 27 August 2019 paper accepted ※ 19 November 2019 issue date ※ 08 October 2019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |