1. PH/DT2 Scientific Tea 29.4.2005 1 PH-DT2 Scientific Tea, 29 April 2005 : The CMS Tracker - Mechanical Aspects Antti Onnela, PH-DT2: 1. CMS Tracker and requirements for Mechanics 2. Structures of the Tracker Outer Barrel (TOB) Erkki Anttila, Helsinki Institute of Physics: 3. Example of TOB test setups: the Cosmic Rack

2. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela Introduction: CMS Tracker In the heart of the CMS experiment

3. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela Introduction: Tracker as part of CMS

4. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela Introduction: CMS Tracker Yes, but: Speed of light 40 million times per second

5. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela Introduction: CMS Tracker

6. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela Introduction: Tracker’s Eyes – Silicon Detector Module 512 (or 768) narrow “strips” side by side here on the silicon substrate 50 g ~2 W

7. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela Introduction: Tracker layout 15’000 x + control electr. + optical links + cables = 50 kW, 25 kA, 1.5 ton ! This simple layout means:

8. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela Introduction:Tracker layout 5.4 m 2,4 m End Caps – TEC (at the two ends, one shown only) Inner Barrel & Disks - TIB & TID - Outer Barrel - TOB - Pixel detector Beam pipe

9. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela Requirements for the Mechanics n Measurement of particle tracks with 50  m precision in a volume of 5.4 m in length and 2.4 m in diameter  High initial precision (strip positions known to ~ 0.3 mm)  Large, dimensionally very stable structures (0.000050 m vs. 5.4 m !) n Transparency to particles  Minimize material  Use transparent materials (low Z) n High magnetic field (4 Tesla)  Non-magnetic materials Favored material: Carbon-fiber / polymer composites

10. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela Requirements for the Mechanics n Remove heat load, keep silicon at -10 °C  High-performance cooling system  Reach all heat sources, protect silicon n Dimensional stability under changing temperature (+20 °C - -20°C) and change of humidity n 10+ years of operation, but very little possibilities for maintenance and repair (almost impossible to access; radio activation)  Satellite-level of reliability and high quality are a must n And this all with affordable costs…

11. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela Part 2: Mechanical Structures of the Tracker Outer Barrel (TOB) a PH/DT2 and Helsinki production

12. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela History: Wheel Prototype 1999 (MSGC barrel)

13. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela History: Rod Prototype 1999 (MSGC barrel)

14. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela Tracker Outer Barrel (TOB) Beams 700 kg total own mass + 300 kg supported (TIB + TID + Pixel) = total ~ 1000 kg

15. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela n 4128 R-  -detectors Strips aligned parallel to the beam-lineStrips aligned parallel to the beam-line n 1800 Stereo-detectors Similar sensors rotated by 100 mradSimilar sensors rotated by 100 mrad TOB Rod

16. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Rod 113 pieces / rod frame 760 rod frames in total (688 needed + 72 spares) = 85880 pieces in total !

17. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Rod Carbon-fiber profiles Pultrusion

18. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Rod Carbon-fiber profiles Water-jet cutting

19. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Rod Gluing and Thermal testing

20. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela Detector support inserts (e.g. 11, 12, 13, and 14) Define parallel planes on which the detectors are mountedDefine parallel planes on which the detectors are mounted Planarity requirement 0.05 mmPlanarity requirement 0.05 mm

21. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Rod measurements Geometrical precision of the module supports and positioning dowel pins measured to be better than 50  m over the whole rod area. 24 module supports / rod 12 dowel pins / rod

22. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela + cables + modules = a complete TOB Rod !

23. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Wheel: Gravitational loads Fully loaded, inclined TOB: Displacements < 0.5 mm expected. For rods – max. displacement ~ 0.1 mm

24. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Wheel: Dynamic loads n Dynamic loadings exited by cooling, ventilation, vibrations that are transmitted through the support structure, and seismic accelerations

25. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Thermal loads n Thermal: 15 kW thermal load, removed with cooling system15 kW thermal load, removed with cooling system Assembled at room temperature. Operates at - 10 ºC. Must be able to survive down to ~ - 30 ºC.Assembled at room temperature. Operates at - 10 ºC. Must be able to survive down to ~ - 30 ºC. n Due temperature change  T of 30 ºC  radial displacement ~ 0.1 mm  T of 30 ºC  radial displacement ~ 0.1 mm

26. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Humidity loads n Humidity: Assembled in room atmosphere. Operates in dry nitrogen atmosphere.Assembled in room atmosphere. Operates in dry nitrogen atmosphere. n Due humidity change drying of the structure  radial displacement ~ 0.3 mm, with carbon fibers in epoxy matrix (would be ~ 0.03 mm with cyanate ester matrix)drying of the structure  radial displacement ~ 0.3 mm, with carbon fibers in epoxy matrix (would be ~ 0.03 mm with cyanate ester matrix)

27. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Wheel Manufacture - Disks

28. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Wheel Manufacture - Disks

29. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Wheel Manufacture - Disks

30. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Wheel Manufacture - Cylinders

31. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Wheel Manufacture - Cylinders

32. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Wheel Manufacture - Cylinders

33. The CMS Tracker - Mechanical Aspects PH/DT2 Scientific Tea 29.4.2005, A. Onnela TOB Wheel Assembly Wheel assembly on-going. Visit to 186 after Erkki’s part and the tea…