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Title: Modeling of Dipole and Quadrupole Fringe-Field Effects for the Advanced Photon Source Upgrade Lattice

Abstract

The proposed upgrade of the Advanced Photon Source (APS) to a multibend-achromat lattice requires shorter and much stronger quadrupole magnets than are present in the existing ring. This results in longitudinal gradient profiles that differ significantly from a hard-edge model. Additionally, the lattice assumes the use of five-segment longitudinal gradient dipoles. Under these circumstances, the effects of fringe fields and detailed field distributions are of interest. We evaluated the effect of soft-edge fringe fields on the linear optics and chromaticity, finding that compensation for these effects is readily accomplished. In addition, we evaluated the reliability of standard methods of simulating hardedge nonlinear fringe effects in quadrupoles.

Authors:
;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1379943
DOE Contract Number:
AC02-06CH11357
Resource Type:
Conference
Resource Relation:
Conference: 2016 North American Particle Accelerator Conference, 10/09/16 - 10/14/16, Chicago, IL, US
Country of Publication:
United States
Language:
English

Citation Formats

Borland, M., and Lindberg, R. Modeling of Dipole and Quadrupole Fringe-Field Effects for the Advanced Photon Source Upgrade Lattice. United States: N. p., 2017. Web. doi:10.18429.
Borland, M., & Lindberg, R. Modeling of Dipole and Quadrupole Fringe-Field Effects for the Advanced Photon Source Upgrade Lattice. United States. doi:10.18429.
Borland, M., and Lindberg, R. Thu . "Modeling of Dipole and Quadrupole Fringe-Field Effects for the Advanced Photon Source Upgrade Lattice". United States. doi:10.18429. https://www.osti.gov/servlets/purl/1379943.
@article{osti_1379943,
title = {Modeling of Dipole and Quadrupole Fringe-Field Effects for the Advanced Photon Source Upgrade Lattice},
author = {Borland, M. and Lindberg, R.},
abstractNote = {The proposed upgrade of the Advanced Photon Source (APS) to a multibend-achromat lattice requires shorter and much stronger quadrupole magnets than are present in the existing ring. This results in longitudinal gradient profiles that differ significantly from a hard-edge model. Additionally, the lattice assumes the use of five-segment longitudinal gradient dipoles. Under these circumstances, the effects of fringe fields and detailed field distributions are of interest. We evaluated the effect of soft-edge fringe fields on the linear optics and chromaticity, finding that compensation for these effects is readily accomplished. In addition, we evaluated the reliability of standard methods of simulating hardedge nonlinear fringe effects in quadrupoles.},
doi = {10.18429},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 2017},
month = {Thu Jun 01 00:00:00 EDT 2017}
}

Conference:
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  • A 67-pm hybrid-seven-bend achromat (H7BA) lattice is proposed for a futureAdvanced Photon Source (APS)multibend- achromat (MBA) upgrade. This lattice requires use of a swap-out (on-axis) injection scheme. Alternate lattice design work has also been performed to achieve better beam dynamics performance than the nominal APS MBA lattice, in order to allow beam accumulation. One of such alternate H7BA lattice designs, which still targets a very low emittance of 76 pm, is discussed in this paper. With these lattices, existing APS injector complex can be employed without the requirement of a very high charge operation. Studies show that an emittance belowmore » 76 pm can be achieved with the employment of reverse bends in an alternate lattice. We discuss the predicted performance and requirements for these lattices and compare them to the nominal lattice.« less
  • The Advanced Photon Source (APS) is pursuing an upgrade to the storage ring to a hybrid seven-bend-achromat design [1]. The nominal design provides a natural emittance of 67 pm [2]. By adding reverse dipole fields to several quadrupoles [3, 4] we can reduce the natural emittance to 41 pm while simultaneously providing more optimal beta functions in the insertion devices and increasing the dispersion function at the chromaticity sextupole magnets. The improved emittance results from a combination of increased energy loss per turn and a change in the damping partition. At the same time, the nonlinear dynamics performance is verymore » similar, thanks in part to increased dispersion in the sextupoles. This paper describes the properties, optimization, and performance of the new lattice.« less
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