Active and passive compensation of APPLE II-introduced multipole errors through beam-based measurement

作者：Chung Ting Yi^*; Huang Szu Jung; Fu Huang Wen; Chang Ho Ping; Chang Cheng Hsiang; Hwang Ching Shiang

来源：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment , 2016, 826: 48-54.

DOI：10.1016/j.nima.2016.04.030

• APPLE II
• EPU
• Dynamic multipole
• Coupling
• Skew quadrupole

The effect of an APPLE II-type elliptically polarized undulator (EPU) on the beam dynamics were investigated using active and passive methods. To reduce the tune shift and improve the injection efficiency, dynamic multipole errors were compensated using L-shaped iron shims, which resulted in stable top-up operation for a minimum gap. The skew quadrupole error was compensated using a multipole corrector, which was located downstream of the EPU for minimizing betatron coupling, and it ensured the enhancement of the synchrotron radiation brightness. The investigation methods, a numerical simulation algorithm, a multipole error correction method, and the beam-based measurement results are discussed.

• 出版日期2016-8-1