Tune Modulation Due to Gradient Ripple and the Dynamic Aperture

Technical Report · Fri Oct 01 00:00:00 EDT 1993

DOI:https://doi.org/10.2172/1119378· OSTI ID:1119378

Parzen, G. ^[1]

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1. Brookhaven National Lab. (BNL), Upton, NY (United States)

A tracking study was done of the effects of a tune modulation, due to a gradient ripple in the quadrupoles, on the dynamic aperture in RHIC lattices. Using tracking runs of about 1 x 10⁶ turns, the dynamic aperture was found to decrease roughly linearly with the amplitude of the tune modulation, and may be represented by A = A₀ (1 - 42 Δv) where A₀ is the dynamic aperture for Δv = 0, and v is the tune modulation amplitude. Two RHIC lattices were studied. One with 6 insertions having β* = 6m, and one with 6 insertions having β* = 2m. Roughly the same result, Eq. (1), was found for both lattices. The dependence of the dynamic aperture on the frequency of the gradient ripple was also studied. No appreciable dependence on the ripple frequency was found for the range covered in the ripple frequency and in the tune modulation amplitude.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-98CH1088
• OSTI ID: 1119378
• Report Number(s): BNL-102036-2013-IR
• Country of Publication: United States
• Language: English

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