Design Notes

Mechanical design

• Cavity is split in two which could create problems in terms of alignment of the two halves
• Simulations may be required in order to comprehensively specify tolerances on all dimensions
• Surface roughness of the cavity and waveguides should be specified as well as the brazing surfaces

Brazing

• Imperfections were seen on the brazing surfaces. This should be less of a problem for later iterations where measurements may not be performed before brazing. Marble polishing was applied to the accessible surfaces. Stress relief was recommended.
• The outside of the cavity was coated with nickel - coating the inside would have resulted in a higher quality factor which was not observed

Feedthrough design

• A bead at the end of the feedthrough antennas will reduce the effects of the separation between the antennas and waveguide walls. Further work in simulation is required to optimise the coupler matching in this case.

Vacuum tighness

• The feedthroughs were fitted by hand with metal seals for vacuum tightness. The assembly was then vacuum tested and passed with a leakage of 2.4x10^-8 mbar⋅l/s.