END FIELD TERMINATION FOR BULK HTSC STAGGERED ARRAY UNDULATOR

Aiming at realizing a short period undulator with strong magnetic field, we have proposed a Bulk HTSC (High Temperature SuperConductor) Staggered Array Undulator which consists of Bulk HTSC magnets with a staggered array configuration [1]. The experiment with the prototype undulator at 77 K shows this configuration can be applicable to real device [2, 3]. We also estimated the magnetic performance of real devices by calculations with a loop current model based on Bean model of type II superconductor [4]. In these experiments, the magnetic field in the ends of the prototype were larger than the field in the center area. End field termination is required for practical use. To suppress the larger magnetic field for end field termination, we performed the calculations and the prototype experiments with the large end gap method. We concluded that the method is effective for Bulk HTSC Staggered Array Undulator.