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| MO2I02 |
Fast Orbit Feedback for Diamond-II |
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- I. Kempf, M.G. Abbott, L. Bobb, G.B. Christian
DLS, Oxfordshire, United Kingdom
- S. Duncan
University of Oxford, Oxford, United Kingdom
- G. Rehm
HZB, Berlin, Germany
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Funding: Diamond Light Source and Engineering and Physical Sciences Research Council
The electron beam stability is critical for 4th generation light sources. As opposed to 10% of beam size up to 140 Hz at Diamond, advances in detector speed and resolution at Diamond-II increase the stability requirements to 3% up to 1 kHz. This paper presents a novel control methodology for the fast orbit feedback at Diamond-II, which will stabilise the beam using two arrays of 252 slow and 144 fast correctors and 252 beam position monitors at 100 kHz. In contrast to existing approaches that separate slow and fast feedback loops, our approach is based on a two-matrix factorisation called the generalised singular value decomposition (GSVD), which decouples the system into 144 two-input modes controlled by slow and fast magnets and 108 modes controlled by slow magnets only. The GSVD-based controller is implemented in the existing Diamond storage ring using a centralised communication architecture, such as planned for Diamond-II. We present results from the Diamond storage ring and simulation, which confirm that the proposed approach meets the target specification for Diamond-II.
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Slides MO2I02 [3.686 MB]
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| DOI • |
reference for this paper
※ doi:10.18429/JACoW-IBIC2023-MO2I02
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| About • |
Received ※ 06 September 2023 — Revised ※ 07 September 2023 — Accepted ※ 11 September 2023 — Issue date ※ 18 September 2023 |
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| MOP041 |
Modified Fast Orbit Feedback Controller for Disturbance Attenuation in Long Straights for Diamond-II |
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- S. Banerjee, M.G. Abbott, L. Bobb, I. Kempf
DLS, Harwell, United Kingdom
- I. Kempf
University of Oxford, Oxford, United Kingdom
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At Diamond Light Source, the fast orbit feedback (FOFB) uses one array of correctors and the controller is designed using the internal model control (IMC) structure. The Diamond-II upgrade will introduce an additional array of fast correctors and a new controller that is designed using the generalised modal decomposition, increasing the overall closed-loop bandwidth from 140 Hz to 1 kHz. Although simulation results have shown that the resulting beam displacement is within specification in all straights, they have also shown that the performance on long straights is limited, particularly in the vertical plane. In this paper, the controller is tuned in order to increase the FOFB performance in long straights by introducing a mode-by-mode regularisation parameter. The performance of the controller beyond 1 kHz is assessed using new disturbance data and a new measurement noise model, showing that the Diamond-II performance criteria are met, even in the presence of measurement noise.
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| DOI • |
reference for this paper
※ doi:10.18429/JACoW-IBIC2023-MOP041
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| About • |
Received ※ 07 September 2023 — Revised ※ 09 September 2023 — Accepted ※ 13 September 2023 — Issue date ※ 16 September 2023 |
| Cite • |
reference for this paper using
※ BibTeX,
※ LaTeX,
※ Text/Word,
※ RIS,
※ EndNote (xml)
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