Fabrication and Testing of 10-Pole Short-Period Nb3Sn Superconducting Undulator Magnets

Abstract

NbTi superconducting undulators (SCUs) are currently reliably operating at the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). These devices have significantly enhanced x-ray flux and brightness at the high energy spectrum. As NbTi SCU technology is close to its full potential, further performance enhancement requires using different superconducting materials. Nb3Sn is a promising candidate to achieve that goal. Recently the APS has started developing a Nb3Sn superconducting undulator compatible with the APS storage ring. The completed device is planned to be installed in the APS storage ring. To develop the Nb3Sn SCU technology, a series of short SCU models has been previously fabricated and successfully tested. In this study, the design has been further optimized to address previously unresolved problems. Several 10-pole, 4.5-period models were fabricated and tested. All of the fabricated models have reached the maximum operating current; however, one of the model, MM4, has failed right after reaching the maximum design current. The details of quench and training performances are presented.