Damping vs. Clamping to Mitigate the RHIC Triplet Oscillations

Technical Report · Sun Apr 01 04:00:00 EDT 2007

DOI:https://doi.org/10.2172/1061864· OSTI ID:1061864

Thieberger, P. ^[1]; Bonati, R. ^[1]; Montag, C. ^[1]; Trbojevic, D. ^[1]

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1. Brookhaven National Laboratory (BNL), Upton, NY (United States). Relativistic Heavy Ion Collider (RHIC)

In a recent article, C. Montag et.al. compare frequencies observed when studying beam position displacements, with frequencies of mechanical vibrations of the cryostat tank containing the dipoles D0 and the quadrupole lenses Q1, Q2 and Q3. They find agreement for several of the observed frequencies, and they conclude that quadrupole mechanical oscillations, if not mitigated, will affect horizontal beam position stability in ways that will limit future RHIC performance. Using finite element analysis they also compute expected eigenmode frequencies for the oscillatory motions of decoupled cold masses, and they find many lines, some in general agreement with measurements and beam observations. Here we prefer to concentrate exclusively on the main vibration modes, solely due to the flexibility of the supporting plastic posts. We use a simple model, similar to the one suggested by Montag, et.al. Understanding these modes and the associated spring constants is important in order to device solutions to this problem. We then use the obtained spring constants to specify stiffeners that will increase the resonant frequencies by factors of 2 or 3, and we estimate the associated heat losses. Finally we suggest several active damping arrangements that should be very effective in increasing the mechanical stability, incurring negligible heat loss penalties and that appear thus to be preferable to the static support solutions.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States). Relativistic Heavy Ion Collider (RHIC)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1061864
• Report Number(s): BNL--99423-2013-IR; C-A/AP/#273; KB0202011
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
relativistic heavy ion collider