Beam-based measurement of the non-linearity of the RHIC Low-beta quadrupole magnetic field

by J.P. Koutchouck (SL Division)

Thursday 8 Nov 2001, 14:15 → 15:15 Europe/Zurich

30-7- (CERN)

In both RHIC and LHC, the low-beta quadrupole magnetic field is foreseen to require correction up to the dodecapole order. The best strategy to set the multipole correctors is to use beam diagnostics. The method tested at RHIC relies on the measurement of the feed-down of higher-order perturbations to the closed orbit and betatron tune orders. I will summarize in an informal talk the principle of the method, the experimental results obtained a few weeks ago (amongst which the measurement of a dodecapole field) and their estimated accuracy. The technical measurement issues which can be relevant to LHC will be analysed.