Support Structure Consuming Expensive Space
Used in early BNL conceptual design.
Mechanical designs of other common coil magnets are different; but this ugly feature did not disappear.
Internal support at midplane
Investigate alternate mechanical designs.
Do we need it for field quality purpose?
See 80% good field aperture in RHIC D0.
Average Field errors ~10-4 up to 80% of the coil radius