A Prestressed-Core Hollow-Strap-Coil Test Magnet for the Omnitron

Design, fabrication, and preliminary testing of a test prototype gradient magnet for the Omnitron incorporating several novel design features is reported. The laminated magnet core achieves structural integrity with prestressed tension rods which hold the 0.014-in.-thick M-19 steel laminations with an average interlamination pressure of 200 psi. Some advantages of such a system are: elimination of strong backs for support of individual laminations, a higher steel packing factor than for glued laminations, and easy disassembly of the magnet to make changes during test and development. Simplicity in coil design is achieved using a continuous 9/32- by 3-in. hollow-strap** aluminum conductor wound in a single layer. The high section modulus of the strap eliminates the need for coil clamps at the ends of the magnet. Furthermore, this coil design avoids multiple cooling connections between "pancakes" and saddle-shaped coil ends, because notches can be machined into the coils after they are wound.