Tests of Fill Fibers and Epoxy Resins for the Fabrication of Impregnated Superconducting Solenoids

Abstract

While fabricating a 6 tesla superconducting solenoid for an EBIT experiment¹ at the Lawrence Livermore National Laboratory, a pair of test solenoids were wound and potted to test fill fibers and resins systems for impregnating tightly wound superconducting solenoids. Two types of fibers were used as layer to layer insulation and to fill spaces between 0.75 mm diameter formvar insulated wires. Two resin systems with different cure temperatures were tested. Ground plane insulation with and without sheets of mica was also tested. Two closely packed solenoids with an outside diameter of 150 mm were wound on an aluminum mandrel. Once the solenoids were wound and resin impregnated, they were quickly cooled to 77 K using liquid nitrogen. After the cold shock test, the coils were inspected and sectioned. The results of these tests are presented in this report.