1. 56 MHz SRF Cavity Cryostat support system and Shielding C. Pai 1-19-2011

2. Configuration of 56 MHz Cryostat

3. Total Weight estimate of 56 RF cavity cryostat Niobium + Titanium Vessel: 760 lb Tuner Linkage: 100 lb Space Frame: 400 lb Heat Shield: 150 lb Inner Magnetic Shield: 200 lb Outer Magnetic Shield: 250 lb Mis. : 240 lb Total Inside cryostat: 2100 lb Vacuum Chamber: 1500 lb Tuner, 2 nd stage 200 lb Thermal transition+ 500 lb Piping and Mis. 200 lb Total in Cryomodule: 4500 lb

4. Space Frame and Nitronic Rod (Cavity not shown)

5. Load Path in the 56 MHz Cryostat

6. Cryostat support Isolator Actuator

7. Nitronic Rod Stretch and spring Load

8. Radial Nitronic rod configuration 1. Length of Rod: Warm: 22.158” Cold shrink: a. Due to Helium tank shrink: +.0085” too long ( 22.1498”) b. Due to Rod shrink: -.0339” Net shrink of rod: +.0085-.0339= -.0254” (D) 2. Force induced in the rod with out spring: F=K*D=962 lb

9. Parts No. AM281413 Quantity: 2 in parallel Material: Stainless steel Load at 3/4 deflection: =540 lb x2=1080 lb K of spring =42,477 lb/in (2 in Parallel) Stiffness of Rod: 37,909 lb/in (K) Combined stiffness of system: K=20,031 lb/in Force induced in the rod: F= 500.7 lb Add two Disk Springs for Radial support

10. Axial Nitronic Rod Configuration 1. Length of Rod: Warm: 26.5875” Cold shrink: a. Due to Helium tank shrink: -.0054” ( 26.5929”) b. Due Rod shrink: -.03988” Net shrink of rod: -.0054-.03988= -.04528” (D) 2 Force induced in the rod without spring: F=K*D= 1,430 lb

11. Torsion spring for Nitronic Rod (No Friction Loss for Tuning operation) Material: Ti-6Al-4V Yield strength: 128,000 psi K=840/.02=42,000 lb/in Stiffness of Rod: 31,593 lb/in (K) Combined stiffness of System: K=18,117 lb/in Force induced in the rod: F=K*D= 815 lb (@ 3/5 load) S=70,123 psi

12. 56 MHz SRF Cavity Nitronic Rod Support System Stiffness Analysis C. Pai 1-19-2011

13. SRF cavity Support, Space Frame with Nitronic Rods Space Frame Axial Nitronic Rods Radial Nitronic Rods

14. Model, Helium vessel support by Nitronic rods, with disk spring Loading in Nitronic Rods Case 1. Cold Shrink force Case 2. Tuning Force Case 3. Combined Shrink + tuning Springs are simulated by Combined elastic modulus E radial: 14.7E6 psi E axial: 16.1E6 psi

15. Loading in the Nitronic rods Loading in Nitronic Rods Case 1. Tuning Force, 300 lb Case 2. Shrink to 4.5 K Case 3. Combined Shrink + tuning force

16. Stress plot, loading: Under tuning force only Tuning Force F=300 lbf Stress in Nitronic rod Max. S: 1313 psi Yield Strength: 55,000 psi Annealed

17. Under tuning force only, deflection plot Max. deflection at Bracket:.00181” Ratio of stiffness: tuning plate to support system Ratio=.060/.00181=33.1

18. Under Tuning Force only, Animation

19. Temperature distribution in the support system 4.5 K 300K Unit: F

20. Thermal load only, Stress plot Stress in Nitronic rod Max S: 34,242 psi, Axial S: 15,638 psi, Radial Yield Strength: 55,000 psi Annealed

21. Thermal load only, Deflection plot Max. deflection: Far end: -.0799” Near End:.0194” Fixed bracket: about.001”

22. Thermal load only, Animation

23. Both Thermal and force load, Stress plot Stress in Nitronic rod Max S: 32,939 psi, Axial S: 14,890 psi, Radial Yield Strength: 55,000 psi Annealed

24. Both Thermal and force load, Deflection plot Max. deflection: Far end: -.0818” Near End:.0175” Fixed bracket: DY=.0033”

25. Animation, Both thermal and force load

26. Space Frame strength Calculation

27. Model and Loading Material: SS304 Yield strength: 30,000 psi Gusset

28. Deflection Max. ∆ Y=.040” Max. ∆ Y=.023”

29. Max stress, S=15,454 psi Von Mises Stress

30. Max stress, S=15,454 psi Yield strength: 30,000 psi Eqv Stress

31. Stress at end plate Typical bending stress, S=3867 psi

32. Heat shield, Inner and Outer Magnetic shields

33. Cross section view of 3 shields Thermal heat shield Supported by Vacuum chamber Inner magnetic shield Inside of Space Frame Outer magnetic shield Outside of spaced frame Space Frame

34. Thermal Heat Shield (aluminum,.080”) Cooling Tube ID: 0.5” (aluminum extrusion) Thickness for welding, t=.19” Supported by Vacuum chamber

35. Inner Magnetic shield, Supported at inside of space frame Amumetal,.062”, Room Temperature

36. Outer Magnetic Shield, Supported at outside of space frame Amumetal,.062”, room temperature

37. Magnetic shielding effect: (Attenuation) Properties of Amumetal: Mu=60,000, t=.0625” Inner Radius: 18.148 in, Outer Radius: 21.25 in Attenuation of outer shield = 88.8 Attenuation of inner shield=103.8 Total combined Attenuation: 2643. Effect: if stray magnetic field from DX magnet is 10 gauss, the penetrated field to RF cavity is about.00378 gauss. Magnetic shielding effect: (Attenuation)

38. Assembled Cryostat