Computation of the main and fringe fields for the electrostatic quadrupoles of the muon $g - 2$ storage ring

Journal Article · Mon Dec 02 00:00:00 EST 2019 · International Journal of Modern Physics A

DOI:https://doi.org/10.1142/S0217751X19420417· OSTI ID:1561533

Valetov, Eremey  ^[1]; Berz, Martin ^[1]; Makino, Kyoko ^[1]

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1. Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy

This team developed a highly accurate and fully Maxwellian conformal mapping method for calculation of main fields of electrostatic particle optical elements. A remarkable advantage of this method is the possibility of rapid recalculations with geometric asymmetries and mispowered plates. We used this conformal mapping method to calculate the multipole terms of the high voltage quadrupoles in the storage ring of the Muon g-2 Experiment (FNAL-E-0989). Next, we demonstrate that an effect where the observed tunes correspond to a voltage that is about 4% higher compared to the voltage to which the Muon g-2 quadrupoles are set is explained by the conceptual and quantitative differences between the beam optics quadrupole voltage and the quadrupole voltage at the plates. Completing the methodological framework for field computations, we present a method for extracting multipole strength falloffs of a particle optical element from a set of Fourier mode falloffs. We calculated the quadrupole strength falloff and its effective field boundary (EFB) for the Muon g-2 quadrupole, which has explained the experimentally measured tunes, while simple estimates based on a linear model exhibited discrepancies up to 2%.

• Research Organization: Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Michigan State Univ., East Lansing, MI (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: AC02-07CH11359; FG02-08ER41546; SC0018636
• OSTI ID: 1561533
• Alternate ID(s): OSTI ID: 1661669
• Report Number(s): FERMILAB-PUB-19-092-PPD; oai:inspirehep.net:1753565
• Journal Information: International Journal of Modern Physics A, Vol. 34, Issue 36; ISSN 0217-751X
• Publisher: World Scientific
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
Muon g−2
anomalous magnetic dipole moment
storage rings
electrostatic quadrupoles
main field
multipole expansion
fringe field
effective field boundary
tunes
plate misalignments
mispowered plates
voltages
differential algebra
conformal mapping methods
43 PARTICLE ACCELERATORS