1. Integration of Cavities and Coupling Coil Modules Steve Virostek Lawrence Berkeley National Laboratory MICE Collaboration Meeting March 28 – April 1, 2004

2. Cavity/Coil Integration Steve Virostek - LBNLPage 2 Summary of Integration Issues Coupling coil geometry RF module vacuum system RF coupler configuration Cavity mounting scheme Cavity port connections Vacuum vessel flange joints Module assembly scheme LN2 operation design issues

3. Cavity/Coil Integration Steve Virostek - LBNLPage 3 MICE RF Module Layout

4. Cavity/Coil Integration Steve Virostek - LBNLPage 4 Coupling Coil Geometry Latest revision of coil design (per Mike Green) is wider than the previous version New design does not infringe on vacuum vessel interior space Flange welds to the coil cryostat have been replaced by a single mid-point weld in the vessel A more compact RF coupler design is required to accommodate the wider coil

5. Cavity/Coil Integration Steve Virostek - LBNLPage 5 RF Module Vacuum System Cavity pairs are pumped by a single cryo-pump through a vacuum manifold Annular opening around cavity pump-outs provides pumping for vacuum vessel Common vacuum on both sides of cavities prevents differential pressure across Be windows Low conductance path prevents cavity vacuum from being affected by vessel gas loads

6. Cavity/Coil Integration Steve Virostek - LBNLPage 6 RF Coupler Configuration As before, all couplers are to be oriented normal to the vacuum shell All couplers and cavities are identical Normal orientation facilitates cavity alignment and installation Bellows eliminates tolerance issues Coupler body is based on a standard 4- 1 / 16 ” transmission line Current layout shows an SNS style RF window (will be used for prototype)

7. Cavity/Coil Integration Steve Virostek - LBNLPage 7 Cavity Mounting Scheme No interconnection between adjacent cavities Cavities are mounted to vacuum vessel walls through tuner mechanisms Cavities are installed individually into vacuum vessel Cavity center lines do not shift during tuning Cavities are symmetric to coupling coil RF coupler connections to cavity can be rigid

8. Cavity/Coil Integration Steve Virostek - LBNLPage 8 Cavity Port Connections All ports are on the cavity equator Local cavity shape is spherical to facilitate port construction Ports will be formed using a “pulling” technique Flange clamp is applied after cavity is installed in vacuum shell Vacuum sealing is not required Good RF contact will be achieved by using a canted spring RF seal

9. Cavity/Coil Integration Steve Virostek - LBNLPage 9 Vacuum Vessel Flange Joints Sealing flange slides away from mating flanges to provide a clear gap between vacuum vessels Flexible connection and oversized bolt holes allows for small misalignments between vessel flanges in all 6 DOF Flexible connection design will cover vessel mfg tolerance range while having adequate strength to satisfy PV code Magnet forces carried separately from joints

10. Cavity/Coil Integration Steve Virostek - LBNLPage 10 Module Assembly Scheme Curved beryllium windows are installed on cavities Tuner mechanisms are applied to cavities Coupling coil can is assembled to two vacuum vessel halves; vessel joint is welded from inside Assembled cavities are inserted into vacuum vessel from the ends, one at a time Tuner mechanisms are connected to vessel wall RF couplers are installed and flange clamps are applied Vacuum, cooling and electrical connections are made

11. Cavity/Coil Integration Steve Virostek - LBNLPage 11 LN2 Operation Issues Frequency shift caused by cavity thermal contraction Solution: Change RF source frequency to be resonated with cavities Apply force to permanently deform cavity & lower frequency Thermal losses to vacuum vessel through cavity connections Solution: No direct vacuum connection to cavities, coupler bodies are long with thin walls, low thermal conductivity isolator materials used for tuner-to-vessel connections Mechanical stresses at connections between cavity and vessel (tuner mounts, RF couplers, vacuum, etc.) due to thermal contraction of cavity Solution: No direct vacuum connection to cavities, bellows in RF couplers, non-redundant cavity mounting scheme