2S Module Workshop, 30 Jan 2012
Module positioning and cooling contacts
2S Module Workshop, 30 Jan 2012 Antti Onnela, CERN
The objectives
Module positioning
Module cooling contacts
ΔT: 5-7 ºC
• Module positioning: – Sufficiently precise initial geometry (< 1mm overall) to ensure module overlaps.– High stability (<< 0.1 mm) to minimize calibration needs during operation.
• Cooling contacts between module and cooling pipe:– Silicon T max: -20 ºC, or preferably -25 ºC.– ΔT (silicon sensor – coolant) must be ≤ 10 ºC
• To avoid need for very cold coolant.Though, we face a major problem here as the current pipe insulation is designed for -25 ºC and tested to -20 ºC . But, the coolant would need to be -30ºC or lower !
– The available ΔT of 10 ºC splits roughly into• ΔT (within module) < 7 ºC• ΔT (module cooling contact – module support piece – pipe wall) < 2 ºC. • ΔT (pipe wall – fluid) < 1 ºC, which seems achievable with 2-phase CO2.
• Develop and qualify tracker-wide common solutions, keeping in mind different module types (2S, PS, Stereo, Vertical 3D) + Barrel and End-cap geometries.
The objectives
2S Module Workshop, 30 Jan 2012 Antti Onnela, CERN
Module positioning
• In the present TK there is no common module positioning method– So, we have now a wider experience...
2S Module Workshop, 30 Jan 2012 Antti Onnela, CERN
Module positioning: TIB
2S Module Workshop, 30 Jan 2012 Antti Onnela, CERN
Inputs from A. Basti / INFN Pisa
Precision insert
Slot insert
Inserts with clearance
Module positioning: TEC
2S Module Workshop, 30 Jan 2012 Antti Onnela, CERN
Inputs from M. Wlochal / Aachen
And the net result with TK precision?
2S Module Workshop, 30 Jan 2012 Antti Onnela, CERN
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!
Module positioning
• Sufficient precision can be reached with the TIB & TEC methods– 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 ?– Are inserts needed on the module?
• Captive screws (permanently with module) could be excellent to have.– Not fully obvious, due small dimensions
Tasks for 2012-2013:– Analyse the present TK results and set precision requirements for the upgrade
TK.• 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.– Produce test assemblies and measure their mechanical quality (precision,
strength, ...).• Need sample materials/components for these tests !2S Module Workshop, 30 Jan 2012 Antti Onnela, CERN
Module cooling contacts
• Different variants of module cooling contacts were applied in the present TK– So, we have now a wider experience...
2S Module Workshop, 30 Jan 2012 Antti Onnela, CERN
Module cooling
• Uncertainties 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
2S Module Workshop, 30 Jan 2012 Antti Onnela, CERN
• 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
Module cooling currently (TOB)
2S Module Workshop, 30 Jan 2012 Antti Onnela, CERN
Plots by Christian Barth
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
Module cooling contacts• Estimated power load in a 2S module: ~3.5 W (TOB: 1.8 – 4.4 W)• Following calculations (A. Mussgiller) and present TK experience
ΔT (silicon – coolant) of 10 ºC seems reachable, but is not automatic!– 10 ºC easily ‘lost’ already within the module.
• Good quality dry cooling contact can be 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.
Tasks for 2012-2013:– Study the support/cooling contacts in the modules
• Is aluminium the choice? Any other candidates?– Study the module support/cooling blocks.
• Is aluminium the choice? Any other candidates?• Geometry and dimensions. Connection to cooling pipe.
– Qualification of assembly glues and methods, for all mechanical/thermal contacts– Produce test assemblies and measure their thermo-mechanical performance.
• Need sample materials/components for these tests !2S Module Workshop, 30 Jan 2012 Antti Onnela, CERN