Design and Development of a Superconducting Helical Undulator for a Polarized Positron Source

A small test model superconducting helical undulator for the production of 20 MeV photons has been constructed and tested. The undulator has a period of 14 mm, a bore of approximately 4 mm and produces a magnetic flux density on-axis of 0.8 T as required by the TESLA facility. Work is now underway to modify this design to meet the requirements of the ILC positron source and to manufacture a full scale prototype. This paper details the design, construction and measurements of the small test model and the modeling work necessary to extend that design for use in the ILC