Feasibility and Features of a Staggered Undulator Constructed With HTS YBCO Bulks

A staggered undulator with high-temperature superconducting bulks might be a solution to achieve an undulator with an extremely short period for a synchrotron light source. YBCO bulk was thus selected to investigate the feasibility. This bulk (diameter 32 mm, thickness 2.5 mm) was used to build a staggered-magnet array structure and a mock-up staggered undulator of period 5 mm and fixed gap 4 mm was designed for this test. The potential generation of a sinusoidal field was tested in a 3-T magnetization system with field-cooling magnetization (FCM). The practicability of a HTS undulator is discussed in regard to the possibility of correction of the local field, repetition of field trapping and long-term stability. In addition, a field simulation concept was developed for designing the staggered undulator with YBCO bulks.