January 26, 2018 - Wien magnet coil discussion

Attending = Jay, Jeff, Danny, Joe

The purpose of the meeting is to discuss the 200kV prototype Wien magnet (modifications to coil, magnet steel, vacuum can), and form a plan to include any modifications to fabricate remaining coils.

Conclusions:

• The primary fabrication difficulties were a) the time required to bend the square wire at the end, and b) meeting the final cross-section area spec.
• The prototype cross-sectional area exceeds design cross section so a groove was cut in magnet steel, however, this reduces magnetic field by about 8%, thus requires more current.
• We discussed changing the coil geometry to better accommodate the square coil, however the prototype (standard) geometry remains the best solution, in part because Jeff developed can re-use the fixturing pieces.
• Because the square cross section is 33% less resistive than round wire, Jeff will continue with #13 square wire.
• Jeff will wind next coil with two modifications, a) will do a dry wind (rather than wet epoxy on each turn) so that a single layer can be constructed and fixtured/press tighter into design cross section more easily and will then fix and tap a layer, b) will wind as many turns as possible within the allowed cross-section specification - the design is for 13 turns, but 10 turns is required. Based on previous coil Jeff made at least 11 turns, and this time will aim for 13, but if necessary will stop at 12, and 11 seems worst case but still acceptable.
• When MIT Wien arrives, will evaluate similarly to CEBAF standard Wien. If similar, will modify the vacuum can ears and provide to Jeff so he can test fit new coils.