120 Beam-based Correction and Optimization for Accelerators
beating (amplitude) is as high as 40% in the horizontal plane and 18% for the
vertical plane. The quadrupole gradient results of the constrained fitting were
applied to the machine for optics correction. Orbit response matrix data were
taken and fitted again. The beta beating after correction, as obtained from
the second data set, was found to be reduced to below 3.5% and 2% for the
two planes, respectively (see Figure 4.7). The correction did not completely
eliminate the linear optics errors, probably because magnet hysteresis in the
quadrupoles with large changes (up to 3% in
∆K
K ) caused deviations from the
expected gradient correction. A second round of correction was applied and
the beta beating was brought down to below 1% in both planes.
beating (amplitude) is as high as 40% in the horizontal plane and 18% for the
vertical plane. The quadrupole gradient results of the constrained fitting were
applied to the machine for optics correction. Orbit response matrix data were
taken and fitted again. The beta beating after correction, as obtained from
the second data set, was found to be reduced to below 3.5% and 2% for the
two planes, respectively (see Figure 4.7). The correction did not completely
eliminate the linear optics errors, probably because magnet hysteresis in the
quadrupoles with large changes (up to 3% in
∆K
K ) caused deviations from the
expected gradient correction. A second round of correction was applied and
the beta beating was brought down to below 1% in both planes.