Improvement on Short Period Planer Undulator

U.S. Department of Energy, Office of Basic Energy Sciences (BES) under Topic 11 ADVANCED SOURCES FOR ACCELERATOR FACILITIES Subtopic (b), Undulator Radiation Sources, is seeking superconducting undulators that can generate tunable (i.e. variable field) mono- chromatic x-ray beams in the 2-30 keV photon energy range from medium-energy (2-3 GeV) synchrotrons. These requirements demand that the undulators have short periods (around 1.5 cm) and high peak magnetic fields (around 1.6 tesla). For the windings of such undulators the solicitation also requests the use of new superconducting materials such as improved Nb3Sn superconductors and high temperature superconductor such as YBCO tape, and the development of appropriate coil manufacturing techniques. In Phase I, we propose to model, design and wind, using state-of-the-art internal-tin-with-distributed-barrier Nb3Sn wire, a short demonstration undulator in the form of a planar coil set, and to measure its electromagnetic properties in a variable temperature cryostat paying particular attention to temperatures above 4.2 K. Winding schemes will be evaluated best suited to Nb3Sn wire, but a single piece length is favored. Paying attention to the request for the development of coil manufacturing techniques, we plan to make extensive use of both electromagnetic and thermal FE modeling. Together, they will enable us to optimize the use of iron and copper in the undulator structure, (i) iron for maximizing the bore field for a given winding current density and (ii) copper as an essential component of the cryogenic thermal management system. Commercial applications and other benefits: The coil design/winding experience developed under this program will have wide ranging benefits. The high Jc, fine filament, Nb3Sn strand could be suitable for the windings of high field accelerator magnets and magnets for advanced fusion applications. The Nb3Sn strands have relatively high Tc (thermal margin), hence radiation tolerance, and its use in wigglers and undulators may lead to the development of more potent synchrotron light sources. As radiation sources, these machines find use in research, medicine, and industry. According to a U.S. EPA article, more than 97% of the 15,000 accelerators in use around the world have commercial applications, e.g. in diagnosing and treating cancer, locating oil and minerals in the earth, processing semiconductor chips for computers, determining the age of materials through radiocarbon dating and sterilizing medical equipment and food products