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201 MHz Cavity Fabrication Update. Derun Li Lawrence Berkeley National Lab. MICE CM24 at RAL, UK June 1, 2009. SC coupling Coil. Curved Be window. Cavity Couplers. Vacuum Pump. 201-MHz cavity. Four RF Cavities in each RFCC Module. RFCC PDR and FDR completed during CM21 and CM22 - PowerPoint PPT Presentation
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201 MHz Cavity Fabrication Update
Derun LiLawrence Berkeley National Lab
MICE CM24 at RAL, UK
June 1, 2009
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 Pump201-MHz cavity201-MHz cavity
Curved Be window
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
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
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 Epeak
•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
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 (VT2/P): ~ 22 MΩ/m– Quality factor (Q0): ~ 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)
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
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 profile Re-spun the two half spare shells to new profile • Measured frequency shifts before and after Measured frequency shifts before and after spinningspinning
Expected frequency shift ~ 1 MHzExpected frequency shift ~ 1 MHzMeasurements:Measurements: Shell #1:Shell #1:
197.275 MHz (before)197.275 MHz (before)198.180 MHz (after)198.180 MHz (after)
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: Spun and measured a new half shell (frequency: 198.415 MHz)198.415 MHz)
•Developed a fabrication procedureDeveloped a fabrication procedure• Pre-polishing copper sheetsPre-polishing copper sheets
• Inspecting the surface Inspecting the surface
• Polishing visible scratches locally if necessary (before and Polishing visible scratches locally if necessary (before and after)after)
• Handling and shippingHandling and shippingPolished surfacePolished surface
Local polishing to remove Local polishing to remove deeper scratches deeper scratches
Surface inspection during Surface inspection during the spinningthe spinning
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):
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 200912 spun half shells arrived LBNL in May 2009•CMM scans to pair best matches of two half shells in CMM scans to pair best matches of two half shells in
diameters, 8 of them have been measured so fardiameters, 8 of them have been measured so far
Polished cavity Polished cavity surfacesurface
Center hole for Center hole for handling & spinninghandling & spinning
Labeling eachLabeling eachshell shell
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 CMM scans to pair best matches of two half shells
(diameters) (diameters) • Over 1,500 points along the cavity perimeter Over 1,500 points along the cavity perimeter • Find the best match of average radii, radius Find the best match of average radii, radius
deviations and the location of the deviation angles 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
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 Fixtures used for the MuCool prototype shipped to Applied FusionApplied Fusion
•Two re-spun half shells arrived Applied Fusion in early Two re-spun half shells arrived Applied Fusion in early May for fabrication test/practiceMay for fabrication test/practice
• E-beam welding testsE-beam welding tests• Stiffener ringsStiffener rings• Equator Equator
• Port extruding Port extruding • Water cooling pipes Water cooling pipes
E-beam welding of E-beam welding of the stiffener ringthe stiffener ring
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 testingE-beam strength testing
Port extruding and flange Port extruding and flange welding testingwelding testing
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 flangesMachine and weld port flanges
― Machine-finish and EBW of the nose ringsMachine-finish and EBW of the nose rings
― Machine-finish and EBW of the nose ringsMachine-finish and EBW of the nose rings
― Tig-weld water cooling pipes Tig-weld water cooling pipes
― Vacuum check of the cavity and water cooling pipesVacuum check of the cavity and water cooling pipes
Integration of cavities, coupling coils and other module Integration of cavities, coupling coils and other module components will take place at LBNLcomponents will take place at LBNL
201-MHz Cavity Fabrication Update, CM24, RAL, UK
Page 16Derun Li - Lawrence Berkeley National Lab – June 1, 2009
Schedule Summary (Presented at CM23)