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Title: Single-particle dynamics in a nonlinear accelerator lattice: attaining a large tune spread with octupoles in IOTA

Abstract

Fermilab is constructing the Integrable Optics Test Accelerator (IOTA) as the centerpiece of the Accelerator R&D Program towards high-intensity circular machines. One of the factors limiting the beam intensity in present circular accelerators is collective instabilities, which can be suppressed by a spread of betatron frequencies (tunes) through the Landau damping mechanism or by an external damper, if the instability is slow enough. The spread is usually created by octupole magnets, which introduce the tune dependence on the amplitude and, in some cases, by a chromatic spread (tune dependence on particle's momentum). The introduction of octupoles usually lead to a resonant behavior and a reduction of the dynamic aperture. One of the goals of the IOTA research program is to achieve a high betatron tune spread, while retaining a large dynamic aperture using conventional octupole magnets in a special but realistic accelerator configuration. In this report, we present results of computer simulations of an electron beam in the IOTA by particle tracking and the Frequency Map Analysis. The results show that the ring's octupole magnets can be configured to provide a betatron tune shift of 0.08 (for particles at large amplitudes) with the dynamical aperture of over 20 beam sigmamore » for a 150-MeV electron beam. The influence of the synchrotron motion, lattice errors, and magnet imperfections is insignificant for the parameters and levels of tolerances set by the design of the ring. Here, the described octupole insert could be beneficial for suppression of space-charge induced instabilities in high intensity machines.« less

Authors:
 [1];  [2];  [2]
  1. Univ. of Chicago, Chicago, IL (United States)
  2. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1331786
Report Number(s):
FERMILAB-PUB-16-137-AD-APC; arXiv:1604.08565
Journal ID: ISSN 1748-0221; 1452854
Grant/Contract Number:  
AC02-07CH11359
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Instrumentation
Additional Journal Information:
Journal Volume: 12; Journal Issue: 04; Journal ID: ISSN 1748-0221
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; Accelerator modelling and simulations (multi-particle dynamics; single-particle dynamics); Beam dynamics; Beam Optics

Citation Formats

Antipov, S. A., Nagaitsev, S., and Valishev, A.. Single-particle dynamics in a nonlinear accelerator lattice: attaining a large tune spread with octupoles in IOTA. United States: N. p., 2017. Web. doi:10.1088/1748-0221/12/04/P04008.
Antipov, S. A., Nagaitsev, S., & Valishev, A.. Single-particle dynamics in a nonlinear accelerator lattice: attaining a large tune spread with octupoles in IOTA. United States. doi:10.1088/1748-0221/12/04/P04008.
Antipov, S. A., Nagaitsev, S., and Valishev, A.. Mon . "Single-particle dynamics in a nonlinear accelerator lattice: attaining a large tune spread with octupoles in IOTA". United States. doi:10.1088/1748-0221/12/04/P04008. https://www.osti.gov/servlets/purl/1331786.
@article{osti_1331786,
title = {Single-particle dynamics in a nonlinear accelerator lattice: attaining a large tune spread with octupoles in IOTA},
author = {Antipov, S. A. and Nagaitsev, S. and Valishev, A.},
abstractNote = {Fermilab is constructing the Integrable Optics Test Accelerator (IOTA) as the centerpiece of the Accelerator R&D Program towards high-intensity circular machines. One of the factors limiting the beam intensity in present circular accelerators is collective instabilities, which can be suppressed by a spread of betatron frequencies (tunes) through the Landau damping mechanism or by an external damper, if the instability is slow enough. The spread is usually created by octupole magnets, which introduce the tune dependence on the amplitude and, in some cases, by a chromatic spread (tune dependence on particle's momentum). The introduction of octupoles usually lead to a resonant behavior and a reduction of the dynamic aperture. One of the goals of the IOTA research program is to achieve a high betatron tune spread, while retaining a large dynamic aperture using conventional octupole magnets in a special but realistic accelerator configuration. In this report, we present results of computer simulations of an electron beam in the IOTA by particle tracking and the Frequency Map Analysis. The results show that the ring's octupole magnets can be configured to provide a betatron tune shift of 0.08 (for particles at large amplitudes) with the dynamical aperture of over 20 beam sigma for a 150-MeV electron beam. The influence of the synchrotron motion, lattice errors, and magnet imperfections is insignificant for the parameters and levels of tolerances set by the design of the ring. Here, the described octupole insert could be beneficial for suppression of space-charge induced instabilities in high intensity machines.},
doi = {10.1088/1748-0221/12/04/P04008},
journal = {Journal of Instrumentation},
number = 04,
volume = 12,
place = {United States},
year = {2017},
month = {4}
}

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