Analysis of the secondary effect of a corrector magnet

A corrector magnet has a secondary effect of kicking the beam to a different direction from the designed direction. It has been difficult to analyze this effect due to its small signal-to-noise ratio. A new method of analyzing the secondary effect of a corrector magnet was developed. By this method the kick angle of a secondary direction is estimated by least squares and its significance is examined by t-test combined with the outlier detection. This method was applied to correctors in SPEAR storage ring. The correctors estimated to have significant secondary effects were found to be rotationally misaligned. (author)