High-Chromaticity Optics for the MAX IV 3 GeV Storage Ring

Summary, in English

The ultralow emittance lattice of the MAX IV 3 GeV storage ring has a large negative natural chromaticity. This has to be corrected to positive values to prevent head-tail instabilities. On the other hand, high linear chromaticity can lead to a large tune footprint which limits Touschek lifetime. Therefore, the linear chromaticity is corrected to +1.0 in both planes with sextupoles while octupoles are used to further reduce the tune footprint. Studies indicate this design leads to threshold currents for resistive wall and transverse mode coupling instabilities beyond what is expected during regular user operation. However, since these are only preliminary studies based on approximations, the possibility of instability issues during commissioning needs to be considered. An inexpensive, short term solution is to operate the storage ring at a higher chromaticity. This paper describes the development of a high-chromaticity optics for the MAX IV 3 GeV storage ring. It focuses on reduction of chromatic and amplitude-dependent tune shifts to maximize dynamic aperture and Touschek lifetime. A comparison between the performance of the new high-chromaticity optics and the design optics is also presented.

• Author: Teresia Olsson; Simon Leemann
• Department/s: MAX IV Laboratory
• Publishing year: 2013
• Language: English
• Pages: 592-594
• Publication/Series: PAC 2013 Proceedings
• Full text: - 236 kB; Download statistics
• Links: http://accelconf.web.cern.ch/AccelConf/PAC2013/papers/tupma02.pdf
• Document type: Conference paper
• Publisher: IEEE - Institute of Electrical and Electronics Engineers Inc.
• Topic: Physical Sciences; Natural Sciences
• Conference name: PAC'13 (2013 Particle Accelerator Conference)
• Conference date: 2013-09-29
• Conference place: Pasadena CA, United States
• Status: Published
• ISBN/ISSN/Other: ISBN: 978-3-95450-138-0