Kyoto IAE, Kyoto
UVSOR, Okazaki
A new type of undulator which consists of high-temperature superconductor bulk magnets in the staggered array configuration inside a solenoid is being developed, aimed at short period, high undulator field and controllability by the solenoid current.[1] In order to develop a numerical model, the field calculations were performed and comparisons were made with prototype measurements at the liquid nitrogen temperature. The field in the bulk magnet was modeled by loop currents of which amounts were determined by the critical current density which follow Bean model.[2] In the unsaturated condition, which is decided by the critical current density and the dimension of the bulk magnets, the field distributions and the dependence on the solenoid field were reproduced well. We then estimated the unsaturated performance at the liquid helium temperature, where increment of the critical current density is known [3] and significant improvement of the undulator performance is expected accordingly. In the conference, the experimental results, the detail of modeling and numerical results will be shown and also the performance estimation will be discussed.
[1] T. Kii, et al. FEL 2006, THPPH035 (2006),
R. Kinjo, et al., FEL 2008, THAAU03 (2008)
[2] C.P. Bean, Phys. Rev. Lett. 8, 250 (1962)
[3] M. Morita, et al. NIPPON STEEL TECHNICAL REPORT No. 93 (2006)
