Minutes RF structure meeting 28.11.2008

F.Gerigk, S. Ramberger, G. De Michele, F. Grespan

DTL

• 3D simulation (HFSS) of the Prototype (without post-couplers, without tuners) (action FrancescoGrespan). see SPL/DriftTubeLinac/PrototypeSimulations
  • 1 % slope for nominal geometry.
  • Having aluminum end half drift tubes reduces Q by only 250 (It is expected that with RF gaskets the nominal Q should be reached).
• Comparison of bead-pull measurements on post-coupler modes, and 3D simulations (HFSS) for the DTL prototype with post-couplers shows very good agreement. (action FrancescoGrespan, GiovanniDeMichele). see SPL/DriftTubeLinac/PrototypeMeasurements, SPL/DriftTubeLinac/PrototypeSimulations
• Frequency measurements around the confluence point: Discontinuities appear where a post-coupler mode crosses the TM₀₁₀ mode.(action FrancescoGrespan, GiovanniDeMichele). see SPL/DriftTubeLinac/PrototypeMeasurements
• F.Gerigk suggests to find the proper length for each post coupler, using the Slater perturbation theorem, before starting the tilt sensitivity measurements.
• J.-M. Giguet got a special sliding calliper from the metrology lab to measure gap lengths inside the tank (SuitbertRamberger). Up to three gaps can be measured through the beam tube.
• High-power tests should be started as soon as possible - Mid January 2009 appears feasible (FrankGerigk, SuitbertRamberger).
  • start without having the water cooled post couplers ready
  • monitor with 2 pick-ups if there is a possible field tilt
  • go back to cold measurements
  • at a later moment introduce water cooled post couplers
  • re-do high-power test.
• Bead-pulls to measure tilt sensitivity for various post coupler settings need to be done after high-power tests.
• See SPL/DriftTubeLinac/PrototypeProduction for a task list on how to continue (SuitbertRamberger)