Empty-bucket techniques for spill-quality improvement at the CERN Super Proton Synchrotron

Synchrotrons can provide long spills of particles by employing resonant extraction where the circulating beam is slowly ejected over thousands to millions of turns by exploiting the amplitude growth caused by a transverse resonance. In the CERN Super Proton Synchrotron (SPS), this method is used to...

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Bibliographic Details
Published in:	Physical review. Accelerators and beams Vol. 27; no. 7; p. 074001
Main Authors:	Arrutia Sota, Pablo A., Fraser, Matthew A., Hagmann, Gregoire, Kain, Verena, Papotti, Giulia, Spierer, Arthur, Velotti, Francesco M., Burrows, Philip N., Piandani, Roberto
Format:	Journal Article
Language:	English
Published:	American Physical Society 01-07-2024
Online Access:	Get full text
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Summary:	Synchrotrons can provide long spills of particles by employing resonant extraction where the circulating beam is slowly ejected over thousands to millions of turns by exploiting the amplitude growth caused by a transverse resonance. In the CERN Super Proton Synchrotron (SPS), this method is used to satisfy the experimental requests of the North Area. However, the extracted particle flux is modulated by power-converter ripple, an issue shared across all sychrotrons that perform resonant extraction. In order to suppress such modulations, empty-bucket techniques can be employed, which take advantage of chromaticity to quickly accelerate particles into resonant motion by using a longitudinal rf system. This paper explores empty-bucket techniques via theory, simulation, and measurement, providing a systematic characterization with general applicability to any machine. Additionally, the operational implementation in the SPS is detailed, where the impact on the beam profile and extracted intensity is addressed. Published by the American Physical Society 2024
ISSN:	2469-9888 2469-9888
DOI:	10.1103/PhysRevAccelBeams.27.074001