1. Ideas and Plans on Tracker Module Mechanics Developments
Module types
Module mechanics common topics with reference examples from the present Tracker
Planning
FNAL CMS Upgrade Workshop, Nov 2011
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. C. D.
FNAL CMS Upgrade Workshop, Nov 2011
Antti Onnela, CERN

3. Module mechanics, common topics
Next slides
Build them light!
Make sure they are properly cooled
Make them to a really needed precision
Build modules robust enough, for their full life-cycle
A late patch reinforcement added to TOB modules to prevent wire bond damage during transport
Limit number of module variants
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.
FNAL CMS Upgrade Workshop, Nov 2011
Antti Onnela, CERN

4. Mass Supports are significant in the today tracker
Modules are significant in the present tracker.
The upgrade tracker will have ~ same amount of modules again.
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.
FNAL CMS Upgrade Workshop, Nov 2011
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)
Electronics 206
Mechanics 91
Total: 826 kg
Module frames:
8% of total TOB.
FNAL CMS Upgrade Workshop, Nov 2011
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
FNAL CMS Upgrade Workshop, Nov 2011
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...
FNAL CMS Upgrade Workshop, Nov 2011
Antti Onnela, CERN

8. Module cooling: Present TK
Support
FNAL CMS Upgrade Workshop, Nov 2011
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
FNAL CMS Upgrade Workshop, Nov 2011
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 / 5 fb-1, 0.4W / module 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 #44 TOB (132 modules) off
Plots by Christian Barth
FNAL CMS Upgrade Workshop, Nov 2011
Antti Onnela, CERN

11. Module cooling
Estimated power load in a Pixel – Strip module: 5.6 W (TOB: 1.8 – 4.4 W)
Following calculations (A. Mussgiller, S. Kyre) and present TK experience ΔT (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 further work:
Choice of module frame materials (CFRP, TPG, PGS, …?)
In TOB alu heat spreaders. Could we do without those?
Frame dimension and geometry optimisation
Assembly glues and methods, ensure thermal contacts within the module
Prototyping and testing are essential !
FNAL CMS Upgrade Workshop, Nov 2011
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...
FNAL CMS Upgrade Workshop, Nov 2011
Antti Onnela, CERN

13. Module positioning: TOB
FNAL CMS Upgrade Workshop, Nov 2011
Antti Onnela, CERN

14. Module positioning: TEC
TIB and TID? Like TEC?
FNAL CMS Upgrade Workshop, Nov 2011
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!
FNAL CMS Upgrade Workshop, Nov 2011
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?!
Precision screw + hole / slot ?
Counter sunk screw + 2 holes or 1 hole and 1 slot ?
Use module edge as guide reference ?
What is the material on the module side, are inserts needed?
Room for plenty of further work:
Analyse the present TK results and set precision requirements for the upgrade TK.
This is very important, impacts the mechanics design from modules up to complete TK, as well as what needs to be done in terms of pre-alignment and measurements.
Design and prototyping of module positioning materials and methods
Aim for simplicity, reliability and low mass.
FNAL CMS Upgrade Workshop, Nov 2011
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 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  Discussions during this workshop, and after.
FNAL CMS Upgrade Workshop, Nov 2011
Antti Onnela, CERN

18. Spares
FNAL CMS Upgrade Workshop, Nov 2011
Antti Onnela, CERN

19. Module and layout variants
From Stefano Mersi. More in his talk.
FNAL CMS Upgrade Workshop, Nov 2011
Antti Onnela, CERN

20. Long barrel geometry FNAL CMS Upgrade Workshop, Nov 2011
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21. End-cap: Minimise the module frames
Nick Lumb / Lyon
FNAL CMS Upgrade Workshop, Nov 2011
Antti Onnela, CERN

22. End-cap: Curved rod Nick Lumb / Lyon
FNAL CMS Upgrade Workshop, Nov 2011
Antti Onnela, CERN

23. End-cap: Twin-disk Nick Lumb / Lyon
FNAL CMS Upgrade Workshop, Nov 2011
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...?
FNAL CMS Upgrade Workshop, Nov 2011
Antti Onnela, CERN