Quantitative analysis of multipole errors induced by mechanical deformations of an undulator

To minimize unwanted beam dynamics effects in a storage ring, multipole errors in an undulator are normally reduced by sorting and shimming methods. Nonetheless, an investigation of the error source is worth pursuing and interesting. Our work focuses on multipole errors introduced by mechanical deformations of an APPLE-II type undulator, which undergoes complicated forces during operation. Our results give guidelines for mechanical specifications derived from quantitative analyses. (paper)