Eight-Tesla Synchrotron Dipoles -- Design Alternatives

Superconducting accelerator bending magnets in the 4 to 5 tesla field range have been, or are being, developed for the LBL ESCAR, FNAL Doubler, and BNL ISABELLE projects and can be considered as state-of-the-art. We are now engaged in a program to develop accelerator dipoles with significantly enhanced performance, into the 8-tesla range. Analytical design studies, based on idealized configurations, have been done to trace the dependence of stresses within the coil and overall magnet size on the magnet aperture, coil current density, central magnetic field, structural ring stress, and magnetic induction in the iron flux-return yoke. Our development program includes: 1. Development, and measurement at 4.2°K, of coil structures consistent with the requirements of the analytical design studies. 2. Superfluid helium II at 1.8° K and at atmospheric pressure. Large magnets as well as conductors will be tested. 3. Development and evaluation of aluminum stabilization and various A-15 superconductors. 4. Tests of various model dipoles with instrumentation to measure mechanical motion.