Lawrence Berkeley National Laboratory

An R&D effort is underway at Lawrence Berkeley National Laboratory (LBNL) to develop the technology of Nb 3Sn superconducting undulators (SCUs). Issues relating to the selection of the appropriate conductor are discussed. The design and fabrication of SCUs using Nb 3Sn is presented. Two prototype devices have been designed and fabricated at LBNL. The first device concentrated on basic fabrication issues and on magnet protection, a key concern due to extremely high copper current densities during a quench. Test on the first prototype demonstrated that such devices can be passively protected in a scalable manner. The second device incorporated design improvements as well as trim coils that are designed to serve as the basic element of a future active phase error correction approach. Preliminary tests on the second device are presented. The trim coils were successfully tested at a variety of field levels. Two quench runs were performed, both occurring at ∼70% of short-sample J c. Stability issues associated with flux-jumps and possible epoxy cracking are discussed. © 2005 IEEE.