Ideas and Plans on Tracker Module Mechanics Developments

1. Ideas and Plans on Tracker Module Mechanics Developments • Moduletypes • Modulemechanics common topicswithreferenceexamplesfrom the presentTracker • Planning Antti Onnela, CERN

2. Module types • The Phase II module mechanics depend strongly on the tracker layout and module types/functions. • Tracker’s trigger function (or not) is very decisive, upgrade tracker design hinges on it. • Several module types have been proposed: • “Vertically integrated 3D” • “2 Strip PT” • “Pixel + Strip PT” • “Stereo Strip” A. B. D. C. Antti Onnela, CERN

3. Modulemechanics, common topics • Buildthemlight! • Make sure theyareproperlycooled • Makethem to a reallyneededprecision • Buildmodulesrobustenough, for theirfulllife-cycle • A latepatchreinforcementadded to TOB modules to preventwirebonddamageduring transport • Limitnumber of modulevariants • Reduces design and prototyping work • Simplifies and reduces costs in production, logistics and spares • Particularly relevant for an end-cap design • Present studies assume use of barrel type rectangular modules, no wedge shapes  2 types of modules instead of ~ 10 types. Next slides Antti Onnela, CERN

4. Mass • Supportsaresignificant in the todaytracker • Modulesaresignificant in the presenttracker. • The upgradetrackerwillhave ~ sameamount of modulesagain. X/X0 Careful with this plot: It contains all TK supports, including the outermost parts (cylinders, end disks) which are much less harmful than those closer to the beam. Antti Onnela, CERN

5. Mass example from the present TK: TOB • Inner cylinder + disks ~75 kg • End-flange services 125 kg (two ends) • Cooling 66 • Cables 15 • Other electronics and connectors 44 • Total rods 626 kg • Modules 260 (31% of total TOB) • Cooling 66 • Electronics 206 • Mechanics 91 • Total: 826 kg Module frames: 8% of total TOB. Antti Onnela, CERN

6. Module mass The future does not seem easier than the past ! • Pixellated and 3D twin-detectors: • Spacers, interposers, heat spreaders particularly important. • We (CMS Tracker) need to gain know-how and experience with these ! • Room for plenty of further work: • Material choice • Geometry/dimension optimisation • Connections (mechanical, electrical) • Prototyping, testing Antti Onnela, CERN

7. Module cooling • Different variants of module cooling were applied in the present TK • So, we have now a wider experience than if everything would have been common... Antti Onnela, CERN

8. Module cooling: Present TK Support Antti Onnela, CERN

9. Module cooling • Uncertainities in calculation inputs (composites, glues, joints)  measurements are necessary, though not fully obvious either (e.g. inputting of power load, availability of correct materials/components) • For the present tracker calculations and tests done mostly in 2000-2002 Antti Onnela, CERN

10. Module cooling (TOB) • Coolant temperature: 5 - 6 ºC. • Module power loads: • FE-power ~ 0.45 W / APV • Silicon self-heating ~ 0.014W / module @ 5 fb-1,0.4W / module expected @ 500 fb-1 (10y LHC) • Silicon mean temp: 13 – 14 ºC • ΔT (silicon - coolant) = 7 – 9 ºC • Will grow to ~ 10 ºC due self-heating increase DS modules P = 3.6W SS6 modules P = 2.7 W SS4 modules P = 1.8 W Cooling segment #44TOB 1.3.1 (132 modules) off Plots by Christian Barth Antti Onnela, CERN

11. Modulecooling • Estimatedpowerload in a Pixel – Stripmodule: 5.6 W (TOB: 1.8 – 4.4 W) • Followingcalculations (A. Mussgiller, S. Kyre) and present TK experienceΔT (silicon – coolant) of 10 ºC seems reachable, but not automatic! • In present TK no active electronics placed directly on the silicon sensors. • In 3 of 4 proposed upgrade modules there are active read-out components on silicon. • Good quality dry cooling contact is sufficient • No need for thermal pastes. Avoid them, they are ‘dirty’ • But requires good planarity of the module and support contacts (no gaps, minimal stresses) • Even a small contact area is enough with these low powers, if the contact is good.  Room for plenty of furtherwork: • Choice of moduleframematerials (CFRP, TPG, PGS, …?) • In TOB aluheatspreaders. Couldwedowithoutthose? • Frame dimension and geometryoptimisation • Assemblyglues and methods, ensurethermalcontactswithin the module • Prototyping and testingareessential ! Antti Onnela, CERN

12. Module positioning • Like with the module cooling, in the present TK there is no common module positioning method • So, we have now a wider experience... Antti Onnela, CERN

13. Module positioning: TOB Antti Onnela, CERN

14. Module positioning: TEC TIB and TID? Like TEC? Antti Onnela, CERN

15. And the net result with TK precision? Already after first cosmic runs the residuals with Track Based Alignment are at ~50um rms, and improve within 2008 to ~30um. Much better than what the mechanics can (reasonably) do! Antti Onnela, CERN

16. Module positioning • Sufficient precision can be reached with the TEC method • Smaller and lighter than the TOB method • Maybe a sufficient precision can be reached even without positioning pins?! • Precisionscrew + hole / slot ? • Countersunkscrew + 2 holesor 1 hole and 1 slot ? • Usemoduleedge as guidereference ? • What is the material on the module side, areinsertsneeded? • Room for plenty of furtherwork: • Analyse the present TK results and set precisionrequirements for the upgrade TK. • This is veryimportant, impacts the mechanics design frommodulesup to complete TK, as well as whatneeds to bedone in terms of pre-alignment and measurements. • Design and prototyping of modulepositioningmaterials and methods • Aim for simplicity, reliability and lowmass. Antti Onnela, CERN

17. Planning • Upgrade TK installation in ~2021, not much time left anymore for R&D! • “R&D over” by Technical Proposal in 2014 ? • During 2012-2013 acquire as much as possible all needed ‘building blocks’ for making the final tracker design. • The more this is successful, the easier it is to use common, tested solutions throughout the TK. This part must be done better than in the present TK! • For mechanics the focal point now is on the modules, including their connections to cooling and other services. • In 2012: Continue calculations, consolidate our data base of materials and their use. Proceed to making test modules, support/cooling contacts. • CO2 cooling test equipment available (Pixel phase 1). Rods recently (this morning!) tested to hold >400 bar pressure and can be used as module test platforms with CO2. • 3D modelling on local and larger structures should advance as well, to make sure we have the needed concepts matching the proposed TK layouts. • We need to see that all essential topics are covered, who contributes where in 2012.  Discussions during this workshop, and after. Antti Onnela, CERN

18. Spares Antti Onnela, CERN

19. Module and layout variants From Stefano Mersi. More in his talk. Antti Onnela, CERN

20. Long barrel geometry Antti Onnela, CERN

21. End-cap: Minimise the module frames Nick Lumb / Lyon Antti Onnela, CERN

22. End-cap: Curved rod Nick Lumb / Lyon Antti Onnela, CERN

23. End-cap: Twin-disk Nick Lumb / Lyon Antti Onnela, CERN

24. Module frame mass • Is a closed frame needed, can the silicon sensors take the loads • And what are all the loads...? Antti Onnela, CERN