| Paper | Title | Page |
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| MOPAB114 | Development of a Decoherence Kicker for the ALS Upgrade Project (ALS-U) | 414 |
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| The Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory is upgrading the existing storage-ring lattice to a nine-bend-achromat lattice with on-axis swap-out injection. The upgraded storage ring will provide a highly focused beam of about 10 um in both horizontal and vertical directions with a single bunch train energy of about 60 J at 2.0 GeV. Such a small and intense beam could cause damage to the transfer line vacuum chambers in case of extraction element failures or damage to the storage ring vacuum chamber in case of RF failures. To mitigate these potential damages, a fast kicker magnet (so-called decoherence kicker) will be installed in the ALS-U storage ring and activated to dilute the beam charge density either on a train to be swapped out a few 100s turns before extraction or on the whole beam after RF failures. In this paper, we will present both physics and engineering designs of this decoherence kicker. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB114 | |
| About • | paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 20 August 2021 | |
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| WEPAB081 | The Broad-Band Impedance Budget in the Storage Ring of the ALS-U Project | 2779 |
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| Design work is underway for the upgrade of the Advanced Light Source (ALS-U) to a diffraction-limited soft x-rays radiation source. Like other 4th-generation light source machines, the ALS-U multiple-bend achromat storage-ring (SR) is potentially sensitive to beam-coupling impedance effects. This paper presents the SR broad-band impedance budget in both the longitudinal and transverse planes. In our modeling we follow the commonly accepted approach of separating the resistive-wall and the geometric parts of the impedance, the former being described by analytical formulas and the latter obtained by numerical electromagnetic codes (primarily CST Studio software) assuming perfectly conducting materials. We discuss the main sources of impedance. Results of our analysis are the basis for the single bunch instability study and would feedback on the design of critical vacuum components. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB081 | |
| About • | paper received ※ 20 May 2021 paper accepted ※ 01 July 2021 issue date ※ 20 August 2021 | |
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| WEPAB341 | Injection and Extraction Kickers for the Advanced Light Source Upgrade Project (ALS-U) | 3487 |
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Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The Advanced Light Source upgrade project (ALS-U) at Lawrence Berkeley National Laboratory includes the construction of a new accumulator ring and the replacement of the existing storage ring. Both ferrite-loaded kickers and stripline kickers are used in the ALS-U design for injection, extraction, and decohering the beam before storage ring extraction. In the accumulator ring, the rise and fall time requirements are based on the single bunch revolution time of 608 ns which allows the use of ferrite-loaded kickers. The 10 ns spacing between bunch trains in the storage ring requires stripline kickers to meet the rise and fall time requirements. Both types of kickers are driven by solid-state inductive voltage adders using MOSFETs. Modeling and prototyping efforts have characterized the kicker impedance and beam-induced heating, and explored the effects of beam strike on electrodes. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB341 | |
| About • | paper received ※ 20 May 2021 paper accepted ※ 27 July 2021 issue date ※ 24 August 2021 | |
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