1. 201 MHz Cavity Fabrication Update Derun Li Lawrence Berkeley National Lab MICE CM24 at RAL, UK June 1, 2009

2. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 2Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Four RF Cavities in each RFCC Module SC coupling Coil Cavity Couplers Vacuum Pump 201-MHz cavity Curved Be window

3. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 3Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Progress Summary (1/2) RFCC PDR and FDR completed during CM21 and CM22 201 MHz cavity detailed design and analysis were complete at CM23 Qualification of three cavity fab vendors completed late last year RFP for cavity fabrication released by LBNL in January 2009 Copper cavity material arrived at LBNL in January 2009 Cavity fabrication has been awarded to Applied Fusion in Feb. 2009 Cavity body fabrication started in April 2009 –A slight reduction in cavity diameter to raise the frequency has been specified and analyzed –Visited ACME Spinning re-spun two spare half shells to the new cavity profile and measured frequency shifts Developed cavity body fabrication procedures (based on lessons learned from the MuCool prototype) The first 5 cavities to be delivered by end of CY2009 with option to purchase 5 additional cavities

4. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 4Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Progress Summary (2/2) Other components: –Cavity tuner RF & structural analyses and CAD model are in progress –Structural analyses of cavity suspension system is complete –RF coupler based on design previously developed for MuCool cavity Ceramic RF windows (SNS window, off-shelf component) –Cavity cooling water feed-through concept has been developed –Beryllium windows Purchase order placed with Brush Wellman Company –Cavity and vacuum vessel interface with CC In progress

5. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 5Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Update on MICE RF Cavity Design 3-Dimensional RF cavity parameterized model to study frequency shifts from RF ports and curved Be windows and E peak Frequencies variation between cavities should be within  100 kHz Fabrication –Modification of the mold for prototype cavity Reduction in diameter to raise the MICE cavity frequency –Tune cavities close to design frequency by deformation of cavity body (if needed) –Fine tuners operate in the push-and-pull mode  230 kHz

6. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 6Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Cavity Design Parameters The cavity design parameters –Frequency: 201.25 MHz –β = 0.87 –Shunt impedance (VT 2 /P): ~ 22 M Ω /m –Quality factor (Q 0 ): ~ 53,500 –Be window diameter and thickness: 42-cm and 0.38-mm Nominal parameters for MICE and cooling channels in a neutrino factory –8 MV/m (~16 MV/m) peak accelerating field –Peak input RF power: 1 MW (~4.6 MW) per cavity –Average power dissipation per cavity: 1 kW (~8.4 kW) –Average power dissipation per Be window: 12 w (~100 w)

7. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 7Derun Li - Lawrence Berkeley National Lab – June 1, 2009 201 MHz Cavity Concept Spinning of half shells using thin copper sheets and e-beam welding to join the shells; extruding of four ports; each cavity has two pre-curved beryllium windows, but also accommodates different windows

8. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 8Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Visit to ACME Spinning in April 2009 (1/3) Machined the MuCool mold to the new profileMachined the MuCool mold to the new profile Re-spun the two half spare shells to new profileRe-spun the two half spare shells to new profile Measured frequency shifts before and after spinning Measured frequency shifts before and after spinning Expected frequency shift ~ 1 MHz Measurements: Shell #1: Shell #1: 197.275 MHz (before) 198.180 MHz (after)

9. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 9Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Visit to ACME Spinning in April 2009 (2/3) Spun and measured a new half shell (frequency: 198.415 MHz)Spun and measured a new half shell (frequency: 198.415 MHz) Developed a fabrication procedureDeveloped a fabrication procedure Pre-polishing copper sheetsPre-polishing copper sheets Inspecting the surfaceInspecting the surface Polishing visible scratches locally if necessary (before and after)Polishing visible scratches locally if necessary (before and after) Handling and shippingHandling and shipping Polished surface Local polishing to remove deeper scratches Surface inspection during the spinning

10. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 10Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Visit to ACME Spinning in April 2009 (3/3) Spinning of MICE cavity (April 22, 2009): Spinning of MICE cavity (April 22, 2009):

11. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 11Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Cavity Inspection at LBNL (1/2) 12 spun half shells arrived LBNL in May 2009 12 spun half shells arrived LBNL in May 2009 CMM scans to pair best matches of two half shells in diameters, 8 of them have been measured so farCMM scans to pair best matches of two half shells in diameters, 8 of them have been measured so far Polished cavity surface Center hole for handling & spinning Labeling each shell

12. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 12Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Cavity Inspection at LBNL (2/2) CMM scans to pair best matches of two half shells (diameters) CMM scans to pair best matches of two half shells (diameters) Over 1,500 points along the cavity perimeterOver 1,500 points along the cavity perimeter Find the best match of average radii, radius deviations and the location of the deviation anglesFind the best match of average radii, radius deviations and the location of the deviation angles Examples of two shellsExamples of two shells Shell 4B (blue) and 6B (yellow) Radius deviations are magnified by a factor of 55 here

13. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 13Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Fabrication Status at Applied Fusion (1/2) Fixtures used for the MuCool prototype shipped to Applied FusionFixtures used for the MuCool prototype shipped to Applied Fusion Two re-spun half shells arrived Applied Fusion in early May for fabrication test/practiceTwo re-spun half shells arrived Applied Fusion in early May for fabrication test/practice E-beam welding testsE-beam welding tests Stiffener ringsStiffener rings EquatorEquator Port extrudingPort extruding Water cooling pipesWater cooling pipes E-beam welding of the stiffener ring

14. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 14Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Fabrication Status at Applied Fusion (2/2) E-beam strength testing Port extruding and flange welding testing

15. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 15Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Current Plan at Applied Fusion June – September 2009:June – September 2009: ―Machine the shells and prep for EB ―EBW stiffener rings ―Equator welding ―Port extruding (4 in each cavity) ―Machine and weld port flanges ―Machine-finish and EBW of the nose rings ―Tig-weld water cooling pipes ―Vacuum check of the cavity and water cooling pipes Integration of cavities, coupling coils and other module components will take place at LBNL Integration of cavities, coupling coils and other module components will take place at LBNL

16. 201-MHz Cavity Fabrication Update, CM24, RAL, UK Page 16Derun Li - Lawrence Berkeley National Lab – June 1, 2009 Schedule Summary (Presented at CM23)