Quadrupole Strength Analysis

The data for the graph below can be found in the ATF2/Bpm shift log from yesterday. several calibrations at the same quadrupole strength were used to determine the deviation of repeat measurements in both position scale and IQ rotation. There was not enough time to take repeat measurements so this is used as the error on each experimental point (marked with a 'x') on the plots. The solid line and square points are predictions from a model based on linear optics. There is a change in the calibration over large changes in quad strength but it appears to not be fully compatible with the model. Further investigation is needed. The two points at the centre of the plots were the first and last points taken. The difference between them is larger than two errors indicating possible drift during the experiment. There is further evidence for this on the plot of IQ rotation angles, whose change with quad strength is negligible. The deviation in IQ rotation during the experiment was larger than what would be expected for repeat measurements. The blue line marks the mean value.