1. Two styles of horn fastener insulation schemes Larry Bartoszek Bartoszek Engineering

2. Overview The fundamental difference between the two fastener styles we have been discussing for Horn 1 is whether the fastener is electrically touching one half of the outer conductor or not –The difference is not whether the fasteners are upstream or in the middle –The two styles can be applied at either location

3. Design already presented In the design I showed last week, the fasteners are not electrically touching either half of the outer conductor. They are at an indeterminate floating voltage. To make this style work, the fasteners must be completely surrounded by ceramic. The fasteners must be able to squeeze the connection mechanically, but not touch electrically.

5. The other style The alternative style of fastening and insulating is to thread the fastener into one half of the outer conductor with a tapped hole. The fastener then is electrically connected to that half of the outer conductor and must be isolated from the other half of the outer conductor.

7. Conclusion Either style of insulation can be used at either the middle or upstream ends. –MiniBooNE uses the second style at its upstream end Shortest path length to avoid voltage breakdown on ceramic in humid helium must be determined. Is there a downside to floating voltage on the fastener? I don’t know.