Accelerator Technologies for Present and Future Accelerator Facilities, Advanced Sources for Accelerators

The DOE requires advanced undulator radiation sources for current and future light sources. An undulator is a magnetic device for installation on a storage ring. As the stored electron beam travels along the undulator axis, the beam sees a magnetic field that oscillates in space, causing the electrons to wiggle from side to side. This wiggling produces intense photon beams that travel out to the beamlines of the storage ring and are employed in experiments. Superconducting undulators are of particular interest, and Nb3Sn wire is attractive as a superconductor because it has a higher critical current and higher critical temperature than traditional NbTi. However, Nb3Sn wire must be wound in an unreacted state and then reacted at a higher temperature to form the superconducting wire, because it becomes very brittle after firing. The insulation that is put on the wire before winding must withstand the high temperatures of heat treatment without disintegration. This project will develop technology to insulate Nb3Sn wire for use in superconducting undulators. To be useful, the insulation must be suitable for application to hundreds of continuous meters of wire, without significant flaws and at a thickness comparable to that used on NbTi (~15 ¿m). Phase I involves the development of a coating system for the insulation. In Phase II, a system will be built to insulate at least 500 m lengths of Nb3Sn. Commercial Applications and other Benefits as described by the awardee: The technology should be of interest to national and international laboratories and institutions working with or interested in superconducting undulators and free-electron lasers, as well as superconducting magnets in general. Of immediate interest are light source users that need short period, 12-15 millimeter undulators to achieve x-ray beams of higher energy than possible with conventional permanent magnet undulators.