1. Shuichi Noguchi 、 KEK 6-th ILC School, November 20111 Superconducting Cavity  Design ( RF, Mechanical, Thermal )  Material  Fabrication Techniques  Surface Treatment  Surface Inspection  Vertical Measurement  Cavity Behavior  Diagnostics Part-1

2. Shuichi Noguchi 、 KEK 6-th ILC School, November 20112 SRF Cavity Peculiarities  Surface Condition is essential, but is usually irregular and contaminated.  No Theory except BCS Surface Resistance.  RF Magnetic Field Limit ?  Many Steps in Production & Clean Works to realize Ideal Surface

3. Shuichi Noguchi 、 KEK 6-th ILC School, November 20113 SRF Cavity Peculiarities PropertyRealityConsequence SuperconductingNeed Helium Thin Wall for better Cooling Nb, Type II Need Magnetic ShieldEven Hext << Hc 1 Multi Layer Structure MaterialNot Uniform, Not IdealGrain Boundary Large Grain ? Contaminated SurfaceIrregularity, Contamination Lattice Orientation Field Enhancement, H & E RF SuperconductivityNot Lossless but Very Low LossResidual Surface Resistance0.3 nΩ/ mgauss Maximum Field Limit Smooth Shape, Less Holes High Impedance 、 HOM Need HOM Dumper StructureMaterial is ExpensiveThin WallMechanical Stability, Coating ProductionDeep Drawing + Machining + EBW Defect Quench Surface Treatment Chemical Treatment + Ultra pure Water Rinsing ContaminationQuench, Field Emission AssemblyClass 10 Clean Room Scatter of Performance PeripheralThermal Insulation in Vacuum Many Critical Components Ceramic Break Others Vacuum Seal

4. Shuichi Noguchi 、 KEK 6-th ILC School, November 20114 Superconducting Cavity Accelerator Users Cryostat Refrigerator High Power RF Low Level RF Input Coupler HOM Coupler Tuner Forming, EBW Surface Treatment Particle Physics Material Science Medical Application Design

5. Shuichi Noguchi 、 KEK 6-th ILC School, November 20115 Design Process Design ParametersInputConstraints Frequency, StructureAccelerating, Deflecting,.... Mode Particle β gap Length Ring / Linac Iris Aperture Operating GradientAccelerator Scale, CW / PulseBeam Power (Coupler) Cooling Power Material Operating TemperatureFrequency, Structure, GradientCooling Power Cavity Unit LengthBeam Current, GradientBeam Power (Coupler) Accelerator ScaleHOM damping Module LengthAccelerator Scale If Pbeam>>Pcavity  Normal

6. Shuichi Noguchi 、 KEK 6-th ILC School, November 20116  > 0.4  < 0.4 Particlee, ProtonProton, Ion Frequency Ring 0.3~0.5 GHz Linac 0.7~3 GHz Linac 50~300 MHz Beam Current Ring >1 A Linac > 100 mA > 1mA< 1mA Accelerating Elliptical Spoke, Spoke, Half Wave, Quarter Wave DeflectingCrab Cavities FocusingRFQ Structure Examples

7. Shuichi Noguchi 、 KEK 6-th ILC School, November 20117 Accelerating Gap g E E z Space Distribution g

8. Shuichi Noguchi 、 KEK 6-th ILC School, November 20118 Accelerating Gap g g ~  Small  enough g Lower Frequency  -Mode 0-Mode

9. Shuichi Noguchi 、 KEK 6-th ILC School, November 20119 Eacc Acceleration by RF Cavity Frequency Shape Beam RF Resonator, Strong E field on axis Z   - Mode

10. Shuichi Noguchi 、 KEK 6-th ILC School, November 201110 Cavity RF Parameters

11. Shuichi Noguchi 、 KEK 6-th ILC School, November 201111 General RF Design PreferenceCompromise Power EfficiencyHigher R sh R sh of HOM Aperture Acceleration Efficiency Enough Acceleration GapFrequency Cavity Size Multi-Gap/Cell Beam QualityEnough ApertureR sh

12. Shuichi Noguchi 、 KEK 6-th ILC School, November 201112 Q-E Curves （ Performance ） Q0Q0 Quench ? Global Heating Q Switch Field Emission Ideal (Constant Q = Constant R s, T) Quench Multipacting Q Slope H Q-Dieses Eacc

13. Shuichi Noguchi 、 KEK 6-th ILC School, November 201113 RFQ INFN-Legnaro Difficulty High Power Coupler End Flange Contact Frequency Tuning

14. Shuichi Noguchi 、 KEK 6-th ILC School, November 201114 Quarter Wave ( /4) & Split Ring ANL Coaxial Resonator Mechanical Vibration, High Power Coupler

15. Shuichi Noguchi 、 KEK 6-th ILC School, November 201115 Half Beam

16. Shuichi Noguchi 、 KEK 6-th ILC School, November 201116 Half to Spoke By Squeezing the Height

17. Shuichi Noguchi 、 KEK 6-th ILC School, November 201117 Multicell Spoke

18. Shuichi Noguchi 、 KEK 6-th ILC School, November 201118 Two Axis Coupled Cavity Acceleration Beam Coupler Drive Beam

19. Shuichi Noguchi 、 KEK 6-th ILC School, November 201119 Smaller R iris R / Q ; Larger E sp / E acc ; Smaller H sp / E acc ; Smaller Cell Coupling ; Smaller Cleaning ; More Difficult Alignment ; Tight RF Design,  = 1

20. Shuichi Noguchi 、 KEK 6-th ILC School, November 201120 The mechanical design of a cavity follows its RF design: Lorentz Force Detuning Mechanical Resonances Mechanical Design Cavities Lorentz Force Detuning E and H at E acc = 25 MV/m in TESLA inner-cup 50 MV/m 92 kA/m Mechanical Design

21. Shuichi Noguchi 、 KEK 6-th ILC School, November 201121 Surface deformation without and with stiffening ring (courtesy of I. Bonin, FERMI) Mechanical Design Cavities 10 -4 m 3∙10 -5 m No stiffening ring Wall thickness 3mm Stiffening ring at r=54mm Wall thickness 3mm k L = -1 Hz/(MV/m) 2 Essential for the operation of a pulsed accelerator Δf = k L (E acc ) 2 Lorentz Force Deformation - df

22. Shuichi Noguchi 、 KEK 6-th ILC School, November 201122 Lorentz ( Maxwell ) Detuning Ｋ ｊａ ｃｋｅｔ Ｋ tuner Ｋ cavity FZFZ FZFZ ＦｚＦｚ ＦｒＦｒ 42 N 135 N E acc = 35MV/m TTF Saclay-ISTF Slide JackBlade AHz / (MeV/m) 2 0.37(TESLA) BN / (MeV/m) 2 0.034 df / dlHz /μm300 KSKS N /μm207222 K jacket N /μm509540 K tuner N /μm3029050 Stationary Δf (31.5 MV/m)Hz880510800  f (Compensation) Hz510140460 Necessary Tuning Strokeμm1.70.51.5

23. Shuichi Noguchi 、 KEK 6-th ILC School, November 201123 Deformation is the Sum of all the Mechanical Modes

24. Shuichi Noguchi 、 KEK 6-th ILC School, November 201124 Two Dominant Mechanical Modes Single –Cell ~ + ~2500Hz~200Hz Need Stiff Cavity Need Stiff Jacket-Tuner System 2-nd order modeFundamental mode F(H 2 ) F(E 2 )

25. Shuichi Noguchi 、 KEK 6-th ILC School, November 201125 1/9  mode 204Hz 2/9  mode 376Hz 3/9  mode 548Hz FixFree Longitudinal Modes 9000N by Tuner

26. Shuichi Noguchi 、 KEK 6-th ILC School, November 201126 Transverse Modes 1/9  56Hz 2/9  141Hz 3/9  251Hz

27. Shuichi Noguchi 、 KEK 6-th ILC School, November 201127 Material  High Purity Niobium is almost an unique Choice at the moment. RRR~300 Pb ( Plating ) was used for some Application. Nb 3 Sn (Vapor Deposition + Heat Treatment) NbTiN (Sputtering) High T c Materials are still very difficult.

28. Shuichi Noguchi 、 KEK 6-th ILC School, November 201128 Niobium Sheet Fabrication

29. Shuichi Noguchi 、 KEK 6-th ILC School, November 201129 Niobium Insufficient recrystallization, formability and mechanical properties are effected Fully recrystallized material after appropriate heat treatment (after rolling operation) X. Singer, DESY

30. Shuichi Noguchi 、 KEK 6-th ILC School, November 201130 Large Grain directly from Ingot Lattice Orientation, Slippage at Boundary

31. Shuichi Noguchi 、 KEK 6-th ILC School, November 201131 Property of Nb 2~5kRoom Temperature Density8.57 Lattice StructureB.C.C Melting Temperature 2468 ℃ Conductivity ~ 2x10 9   ・ m Thermal Conductivity 20 ~ 50 W / m ・ k Yield Strength~ 600 MPa~ 40 MPa Tensile Strength~ 900 MPa~ 160 MPa Elongation~ 15%~ 40% Yang Module~ 100 GPa Vickers Hardness~ 500 MPa

32. Shuichi Noguchi 、 KEK 6-th ILC School, November 201132 Niobium Thermal Conductivity  Post-Purification Treatment (G.R.Myneni, Jlab) RRR ; Residual Resistance Ratio Wiedemann-Franz

33. Shuichi Noguchi 、 KEK 6-th ILC School, November 201133 Cooling Efficiency (SRF93’)Temperature Mapping System Quench LimitHeat Flux He-I / He-II 1.8K 4.2K (EPAC96’) 2.17K

34. Shuichi Noguchi 、 KEK 6-th ILC School, November 201134 Cavity Fabrication

35. Shuichi Noguchi 、 KEK 6-th ILC School, November 201135 Cavity (9 Zeller) Endhalbzell- Endrohr- Einheit kurz Endhalbzell- Endrohr- Einheit lang Flansch (Hauptkoppler- Stutzen) Flansch (Endflansch) HOM-Koppler kurze Seite Rippe Anbindung (end-kurz-lang) Endhalbzelle kurz Antennenflansch NW 12 HOM-Koppler DESY End-kurz-lang Formteil F Bordscheibe lange Seite Endhalbzelle lang Flansch (end-kurz-lang) HOM-Koppler lange Seite Flansch (Endflansch) Antennenstutzen lang Endrohr lang Antennenflansch NW 12 Formteil F lang HOM-Koppler DESY End-kurz-lang Hauptkoppler- stutzen Endrohr kurz Cavity (9 cell TESLA / TTF design) End group 1End group 2 Hantel Normalhalb- Zelle Normalhalb- Zelle Stützring Nb-Blech Normalhalelle Nb-Blech Normalhalbzelle Dumb-bell Overview over cavity fabrication

36. Shuichi Noguchi 、 KEK 6-th ILC School, November 201136 Fabrication of STF Baseline Cavities Center-cells (Tokyo Denkai ; RRR~300 Nb) End-groups HOM coupler Magnetic Shield

37. Shuichi Noguchi 、 KEK 6-th ILC School, November 201137 Half Cell Press Forming Iris Thinner Equator Thicker

38. Shuichi Noguchi 、 KEK 6-th ILC School, November 201138 Fabrication

39. Shuichi Noguchi 、 KEK 6-th ILC School, November 201139 Beam Pipe & HOM Coupler Wire cutting of Nb Brock Beam tube HOM Coupler

40. Shuichi Noguchi 、 KEK 6-th ILC School, November 201140 Deepdrawing & Port Forming

41. Shuichi Noguchi 、 KEK 6-th ILC School, November 201141 End Group Ti End Plate End cell & End group

42. Shuichi Noguchi 、 KEK 6-th ILC School, November 201142 Electron Beam Welding (Jlab) DumbbellsStiffening Rings

43. Shuichi Noguchi 、 KEK 6-th ILC School, November 201143 Dumbbells With Stiffener

44. Shuichi Noguchi 、 KEK 6-th ILC School, November 201144

45. Shuichi Noguchi 、 KEK 6-th ILC School, November 201145 Electron Beam Welding (Jlab)

46. Shuichi Noguchi 、 KEK 6-th ILC School, November 201146 STF Baseline Cavity

47. Shuichi Noguchi 、 KEK 6-th ILC School, November 201147 Other Fabrication Technique  Hydro forming (W.Singer,DESY)Spinning (V.Palmieri,INFN Legnaro)

48. Shuichi Noguchi 、 KEK 6-th ILC School, November 201148 Thin Niobium Films Sputtering