Status of 201 MHz Prototype and RFCC Module

1. Status of 201 MHz Prototype and RFCC Module Derun Li, S. Virostek, M. Zisman Center for Beam Physics Lawrence Berkeley National Laboratory In collaboration with R. Rimmer, L. Phillips, G. Wu (J-Lab) M. Green, W. Lau and S. Yang (Oxford Univ.) MICE Collaboration Meeting at Osaka University August 1-3, 2004

2. Outline • Updates of MICE RFCC Module • Status 201 MHz Prototype Cavity • MICE RF Power Source Development (Paul Drumm) • Summary Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

3. Updates of RFCC Module • Integration and support of the module • 201 MHz cavity prototype (MUCOOL) • Coupling coils updates ( inputs from M. Green) • Design • Cooling • Stress • Interface between absorber and RFCC modules Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

4. MICE Cooling Channel Layout Coupling coils LH absorber Eight 201 MHz cavities Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

5. 201 MHz Cavity Update • Propose to use NASA e-beam welder • Due to lower priority and busy schedule for using e-beam welder at J-Lab • Proposed to use NASA e-beam welder ~ 3 months ago • Convenient location (~ 20 minutes driving) • Better equipped and bigger vacuum chamber • Competent technical capability • Two to three months of delay for paper work between J-Lab and NASA • Ready to proceed now (finally) • Work at NASA • Nose piece welding • Port annealing + extruding • Cosmetic welding on the equator joints • … Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

6. Last MICE mgt: Ready for Equator Welding (March, 04) HISTORY! Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

7. The Cavity Status Now Pilot holes for extruding Beam iris (Be window) Cavity has been cleaned at J-Lab and ready for nose welding and ports annealing next week (August 2nd 2004) at NASA Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

8. 201 MHz Cavity (cont’d) • Development of water cooling line layout • Ports and flanges • RF loop coupler • Cavity support structure • Cavity tuner • RF windows (4” ceramic) • Curved Be windows (ordered) • MICE specifics • Tuners • Integration • joints and flanges • Possible LN2 operation Layout of water cooling lines Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

9. 201 MHz Test Plan at MTA (preliminary) • Test plans (not necessarily in sequence) (assume a clean and vacuum tight cavity, and available RF test stand) • Start with Cu windows (flat or curved) • May condition RF windows (ceramic) in advance • Low power measurements • Tuners for MICE RF cavities • Cavity conditioning • Curved Be windows with Ti-N coating • External magnetic fields? • LN2 operation? Comments and suggestions are welcome! Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

10. Progress on Coupling Coil • The design for coupling coil (dimensions) has not changed since the last MICE Collaboration Meeting at CERN (March 2004) • The coupling coil can be cooled by a single small cooler of either type (pulse tube cooler ~1 W or a GM cooler ~1.5 W), provided a liquid interface is used to connect the cooler cold head to the magnet • The stress and deflections for the coil and its case has been calculated using FEA. The peak stress in the coil and the case is reasonable at 240 MeV/c Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

11. y z The New Coupling Magnet • The new coil is longer and thinner • The coil length is limited by the feeds to the 201 MHz RF cavity • The coil design has better quench properties • The coupling magnet stored energy is about 8 MJ Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

12. Coupling Coil Structure Displacement and Stress Results for 200 MeV/c Case * * Data from S. Yang of Oxford University Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

13. Coupling Coil Structure Displacement and Stress Results for 240 MeV/c Case Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

14. Interface between AFC & RFCC • Bellows with flanges would be welded to both sides of RF Modules • Bellows and oversized holes in flanges can accommodate misalignments between vessels in all 6 DOF • Magnetic forces can be handled by both supports and interconnecting studs Sealing only bolts (24 each) RFCC Sealing/force transmission/opening studs (12 each) – closed position Details of the interface Open position AFC Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

15. Module Support Concept Assembled Modules Module Configuration Status of 201 MHz Prototype Cavity and RFCC Module Derun Li

16. Summary • Excellent progress on RFCC Modules since last MICE Collaboration Meeting at CERN • Integration and support • The 201 MHz cavity (MUCOOL) construction goes reasonably well regardless of the delay at NASA • Significant progress on curved window design and fabrication • Placed purchase order of 3 curved Be windows at Brush-Wellman company • Excellent progress on coupling coils • RF power sources (P. Drumm) Status of 201 MHz Prototype Cavity and RFCC Module Derun Li