Engineering design of the Z magnetically-insulated transmission lines and insulator stack

A 3.3 m diameter cylindrical insulator stack and a set of 3 m diameter conical magnetically-insulated transmission lines (MITLs) were built for the Z accelerator. The 1.7 m tall stack operates at /spl sim/20 MA and 2.5-3.5 MV, and was instrumented with 12 current and 24 voltage monitors. The stack was designed to provide vertical stability for the MITLs and to resist radial buckling. The 22 crosslinked polystyrene insulators, 18 grading rings, 3 anode rings, and 2 cathode rings of the stack were concentrically and azimuthally aligned within /spl plusmn/0.75 mm. 2-D and 3-D static finite element analyses (FEA) were used in designing the MITLs to limit gravity deflections to less than 0.25 mm 2-D FEA dynamic analyses were done to predict motion and to help design features to restrict damage. The tapered MITLs are supported by the stack electrode rings so that the gaps at small radius are adjustable from 0 to 22 mm. The MITL anodes were instrumented with 24 current monitors and have 48 additional diagnostic locations available. The MITLs were fabricated from 304L stainless steel except the outer anode sections, which were made from 6061-T6 aluminum alloy. Fabrication procedures were developed for the large and small diameter MITL cones, as well as for the stack electrode and grading rings. The power-flow surfaces were successfully machined to within /spl plusmn/0.25 mm of the specified contours. A large, multi-trolley MITL handling system was designed to allow for removal, cleaning and replacement of the MITLs for each shot, at a shot rate of 1.5 shots/day. Additional equipment allows for cleaning of the insulators.