Determination of Linear and Non Linear Components in Rhic Interaction Regions from Difference Orbit Measurements

A novel technique is presented to precisely measure the multipole components at each triplet inside the RHIC Interaction Regions (IRs). The technique is based on measurements of the strength of the overall kick that the orbit naturally experiences at a particular triplet due to the presence of linear and nonlinear errors. To measure the kick strength at the triplet, the action and phase before and after the triplet are measured. Action and phases before and after the triplet can be easily related to the strength of the overall kick at the triplet. Action and phase measurements are done on an orbit obtained from the subtraction of an orbit produced by turning on a dipole corrector and the baseline orbit (difference orbit). Application of this technique to difference orbits obtained during the proton RHIC 2001 run is shown to be very precise method to extract quadrupole components and there is experimental evidence that the technique could be equally precise to extract nonlinear multipole components.