1. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 1 Status of Vertex at NIKHEF VELO Mechanics  RF/vacuum foil  Rectangular bellow  RF measurements  Cabling Summary & Outlook

2. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 2 VELO Overview

3. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 3 Secondary vacuum box

4. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 4 Material data Material:AlMg3 Young's modulus:70.000 MPa Poisons ratio:0.33 Shear Modulus:27.3 GPa Yield Strength:80-180 MPa Ultimate Strength:180-260 MPa Electrical conductivity:1.9x10 7 ohm -1 m -1 (almost 50% of pure Al) Weldable!

5. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 5 Full size foil Vacuum tight foil from 300 µm AlMg3 Buckling in the center toblerones is solved Ribs (2.5mm high) are added at the forward-end to increase the stiffness.

6. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 6 FEM analysis ACP 5080, AlMg4.5Mn (Alimex)

7. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 7 FEM analysis: input Input model for the FEM calculations

8. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 8 FEM analysis: results CONCLUSION: The max stress (91 MPa) is 33% below the Yield Strength (130 MPa), so still elastic and safe. A max displacement of 0.3 mm is no problem.

9. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 9 RF foil and Silicons- reinforcements

10. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 10 Bellow

11. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 11 Rectangular Bellow Sagging problemsVacuum leaks in corners Parallel effort in edge-welding

12. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 12 RF pick-up (1) Foil thickness: 30  m Al; Power level in the 50 ohm coaxial line: 10 Watts at 40MHz. The Si detector was 5 mm from the foil outside conductor of the coax. In this condition there was no influence on the noise background.

13. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 13 RF pick-up (2) Cut a hole in the foil and put the silicon strip just 5 mm in front of this hole. The power level in this coax line was still 10 watt at 40MHz. The result was that we do not see influence on the working of the silicon in combination with the electronics of the test setup at NIKHEF in febr. 2002. The fieldlevels from this radiator are much higher then we can obtain with the beam through the RF foil.

14. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 14 RF shielding Frans Kroes has produced a note on Attenuation of an EM field by AlMg4 screen of 0.2 mm Conclusion: Assuming a conductivity of 0.33 of pure Al: At 1 mm distance to the rf screen: 1.415 x 10 -3 V/m

15. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 15 Conductivity  Pure Al = 37 x 10 6 Ohm -1 m -1 Measured (accuracy 10%) conductivity of 1 m long 1 cm wide strips of AlMg3:  undeformed = 17 x 10 6 Ohm -1 m -1  deformed = 11 x 10 6 Ohm -1 m -1 45% for undeformed 30% for deformed material

16. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 16 Cabling Cables inside vacuum: Heat production Signal shielding Kapton with 3 Cu layers: = 25 micron kapton outside layer --- 17 micron Cu (foil) = 75 micron kapton --- 17 micron lines (100 micron width) = 75 micron kapton ---17 micron Cu (foil) = 25 micron kapton outside layer

17. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 17 Outgassing (2) Poly-amide-imide coating:1.5 m 2 Kapton cables:20 m 2

18. EDR - Mech. 2; December 16/17, 2002 Hans de Vries - 18 Summary and outlook Bellow –Still under development RF measurements –300 µm Al gives sufficient rf shielding –Side flaps not needed Outgassing –poly-amide-imide –Kapton cables with 3 Cu layers