1. Status of RFCC-Module Development Derun Li Center for Beam Physics Lawrence Berkeley National Laboratory MICE Collaboration Meeting at INFN-LNF, Frascati, ITALY June 26 ~ 29, 2005

2. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 2 The RFCC-Module in MICE Coupling Coils Eight 201 MHz cavities Power couplers

3. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 3 Overview Status and development  Progress on the 201 MHz Prototype Cavity (MUCOOL/MICE)  Current level of completion  RF couplers  Curved Be windows  Other accessories  High power test at MTA, FNAL (development)  Coupling coil magnet (M. Green)  Forces and quench protections Integration to AFC module (W. Lau/S. Virostek)

4. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 4 Status of the cavity  In collaboration with J-Lab, U. of Mississippi, Oxford University  Cavity fabrication: e-beam welding, EP and cleaning  Power couplers: assembly and high power tests at SNS  Vacuum assembly, …, shipping  Curved Be windows  In MTA, FNAL  Preparation for accepting the cavity  Cleaning room purchased and will allow us for in situ assembly of  Couplers  Window replacement  Inspection of cavity  Low power measurement: frequency and coupling  High power test at MTA, FNAL  Plan being developed

5. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 5 Cavity: Current Level of Completion E-beam welding Ports Water cooling lines Couplers assembled first time (mid-April-2005) First low power measurement frequency ~ 199.5 MHz coupling ~ 5 (max) Q ~ 5000

6. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 6 Cavity Progress (Apr-2005) Ready for mechanical cleaning and EP Couplers ready for conditioning

7. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 7 Cavity Progress: EP (June-05) U-Shape Electrode After 1 st EP run (Early June 2005)

8. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 8 Cavity Status EP setup works, but the first EF was not satisfactory –~ 13 lbs of copper removed –40.6 in 3 removed (0.32 lb/in 3 ) –Cavity interior surface area: ~ 4700 in 2 –Average thickness removed: 8.6 mils (219 microns) –Amounts to 3.4% to 5.0% of the initial thickness –Green crystals developed due to the saturated solution –Un-even surface and hard to clean away Mechanical cleaning again (over last weekend) 2 nd EP under way –New solution –New chiller to cool the electrode –More cautiously Expect the cavity at MTA next month (July 2005)

9. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 9 Cavity Development in UK Recent development in UK (K. Long, Graham Gosling) –Cavity fabrication of the RFCC-module 1 st meeting in June 15, 2005 –Exchange ideas and information for cavity fabrication and future development –More meetings in the future (?) Tuner and mounting ideas

10. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 10 RF Power Two couplers Load Two Couplers (ready!) ─ Critical coupling ─ Ceramic windows are integrated in the couplers ─ Design and built at LBNL ─ Conditioning started using 805 MHz RF power at the SNS ─ Good vacuum ~ low 10 -8 T ─ Achieved 600 kW in TW mode (matched load) ─ Achieved 10 kW average power (~ 9 kW average for nominal NF parameters) ─ Achieved 2.4 MW peak power in SW mode (at variable short positions) ─ Ceramic windows work fine during two weeks of the RF conditioning RF Couplers

11. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 11 Curved Be Windows Succeeded in two curved Be windows so far for the 201-MHz cavity The windows are 0.38 mm thick, 420 mm diameter RF heating ~100 watts per window with ∆T~ 55 degrees for nominal Study-II parameters Window is formed by applying a die at elevated temperature Copper frame is brazed to Be window Be windows will be Ti-N coated shortly Asymmetry RF heating 420 mm Curved-in window experiences 40% more RF heating than the one that curved-out - Small changes respect to overall RF power dissipation on the cavity - FEA (in collaboration with Oxford group) indicates the window should still work

12. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 12 Support Stand/Manual Tuner Manual tuner consists of thick aluminum plates connected by adjustable struts Tuner allows cavity frequency adjustment while providing support for interior vacuum load Parts for tuner fabricated in U. of Miss. Shop, and now at J-Lab Support stand attaches to one tuner plate and allows cavity to be placed adjacent to MTA magnet Support design and construction have completed, now at J-Lab MTA (Lab G) Magnet

13. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 13 The Cavity & its accessories Need careful planning and coordination!

14. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 14 High Power Test at MTA Plans under way –Coordination among LBNL, J-Lab, ANL and FNAL –Diagnostics (identified in last MICE meeting in Berkeley) –Preliminary plan so far >In situ assembly of couplers, vacuum pump and gauges >Power splitter (Tee) at 6” coaxial transmission lines >Transitions to 4” coaxial lines with elbows to the couplers >Ti-N coated flat copper windows >In situ baking (choices: hot N 2 or water) > Low power RF measurement of frequency and Q >Coupling balance and adjustment >Calibration of RF probes >Conditioning without magnetic field first –Suggestions are very welcome

15. MICE Collaboration Mgt, Frascati, Italy June 26-29, 2005 Status of the RFCC-Module Derun Li Center for Beam Physics LBNL Page 15 Summary Cavity fabrication is nearly complete with unexpected delays –EP + pressured water rinsing –Packing and shipping to MTA, FNAL Two couplers have been high power processed and ready for final assembly at MTA Significant progress on curved Be window High power test plans being developed Recent development of RFCC-module in UK –MICE tuner ideas can be tested at RM and low power –Integration of RF coupler to MICE RFCC-module –Future cavity fabrication