The exiting leads of both the flux loops and the electric heater strips pass through a silicone rubber sheet at the 2 ¾ inch CF flanges of the “Horse Collar”, which forms the gas tight seal at the cryostat boundary. In addition the heater leads have a solder joint close to the 2 3/4 inch CF flange. There is a concern that the rubber and solder joint not heat up to excessive temperatures. Bake out should be the worst case. The silicone rubber is good to + 425 º F and the solder joint to + 374 º F and the temperature limit of the flux loop terminal blocks-D subminiature connector is being pursued.

 

What maximum temperature do you expect to attain at the “Horse Collar” during bake out?  During the design review process it was thought the Port 12  to vacuum vessel interface would rise to 350 º C with a temperature gradient formed to a much lower temperature at the “Horse Collar”.  Hopefully the set point for the controllers of the outermost heater stripes can be set to a low enough to limit the temperature of the port nozzle and the exiting lead wires.

 

Please give me your comments especially analysis results if any.