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

Olsson, Teresia LU and Leemann, Simon LU (2013) PAC'13 (2013 Particle Accelerator Conference) In PAC 2013 Proceedings p.592-594
Abstract
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... (More)
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. (Less)
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author
organization
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type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
in
PAC 2013 Proceedings
pages
3 pages
publisher
IEEE--Institute of Electrical and Electronics Engineers Inc.
conference name
PAC'13 (2013 Particle Accelerator Conference)
ISBN
978-3-95450-138-0
language
English
LU publication?
yes
id
7254fb7e-e5f2-4935-be2f-8bfdf5dfc595 (old id 4248816)
alternative location
http://accelconf.web.cern.ch/AccelConf/PAC2013/papers/tupma02.pdf
date added to LUP
2014-01-14 22:51:09
date last changed
2016-04-16 09:47:26
@misc{7254fb7e-e5f2-4935-be2f-8bfdf5dfc595,
  abstract     = {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       = {Olsson, Teresia and Leemann, Simon},
  isbn         = {978-3-95450-138-0},
  language     = {eng},
  pages        = {592--594},
  publisher    = {ARRAY(0x9f70360)},
  series       = {PAC 2013 Proceedings},
  title        = {High-Chromaticity Optics for the MAX IV 3 GeV Storage Ring},
  year         = {2013},
}