Design of Staggered Undulator at SRRC

(MO-3-30)

C. H. Chang, C. S. Hwang, F. Z. Hsiao, T. C. Fan, Ch. Wang  

SRRC, Taiwan

A superconducting solenoid along with staggered array scheme was designed to enhance the magnetic field. In the staggered array, the permanent magnet blocks placed between the high permeability holmium pole are arranged to enhance the alternating vertical magnetic field strength. According to the field calculation, a significantly high vertical magnetic field of 1.9 T and a longitudinal magnetic field of 2.0 T are achieved for the 10-mm period length undulator at 2 mm gap width. The measured vertical magnetic field was 1.6 T with a vanadium permendur pole on a 3-period mock-up. In addition, the field simulations of the end magnet structure were performed to minimize the electron beam trajectory and increase the effective magnetic length.