1 Outer Tracker Mechanics, indico: May 2014, A.Onnela 21 May 2014 Thermally conductive carbon-fibre composite material for module and mechanics prototyping Phase 2 Outer Tracker Mechanics meeting, 21 May 2014 Thermally conductive carbon-fibre composite material for module and mechanics prototyping

2 The need Outer Tracker Mechanics, indico: May 2014, A.Onnela Thermally conductive carbon-fibre composites needed for 2S and PS modules Module support surfaces in the TIB TEC Dees in the PS module areas

3 Carbon-fibre composites in the 2S modules Outer Tracker Mechanics, indico: May 2014, A.Onnela 0.5 mm thick carbon-fibre composite support / heat-spreaders under the hybrids 0.5 mm thick hybrid fold-over supports thermally less important Note: All carbon-composite thicknesses are preliminary. Significant changes possible following further design work and prototyping.

4 Carbon-fibre composites in the PS modules Outer Tracker Mechanics, indico: May 2014, A.Onnela 0.2 mm thick module base-plate 0.2 mm thick support / heat-spreaders under all hybrids 0.2 mm thick hybrid fold-over supports thermally less important. Attention: These on the sensor spacers model Parylene coating, not C-fibre! Note: All carbon-composite thicknesses are preliminary. Significant changes possible following further design work and prototyping.

5 TIB flat module support plates Outer Tracker Mechanics, indico: May 2014, A.Onnela 0.5 mm thick carbon-fibre skins for module support and structural stiffness Foam core, in carbon foam? Note: All carbon-composite thicknesses are preliminary. Significant changes possible following further design work and prototyping.

6 TIB tilted module support rings Outer Tracker Mechanics, indico: May 2014, A.Onnela Module support / cooling contacts need to be studied. Aluminium / carbon-fibre composite? Carbon-fibre / polymer composite? Aluminium?

7 TEC module support Dees TEC Dee skins in carbon-fibre composite Skins with high thermal conductivity in the inner rings with PS modules. Outer Tracker Mechanics, indico: May 2014, A.Onnela Dee structure with 0.5 mm carbon-fibre skins Note: All carbon-composite thicknesses are preliminary. Significant changes possible following further design work and prototyping.

8 Requirements Key requirements for the needed thermally conductive carbon-fibre composites High thermal conductivity –Fibres with very high thermal conductivity: > 600 W/mK Standard modulus fibres 20 – 200 W/mK, copper 400 W/mK, aluminium 210 W/mK. Transverse thermal conductivity dominated by the resin (conductivity ~ 0.1 – 0.2 W/mK). Can be accepted if the composite pieces are thin and if the fibres can be oriented along the dominating heat path. Thermal stability –CTE close to that of silicon: 2.6 ppm/K Stiffness –Fibres with high tensile modulus: > 600 GPa Standard modulus fibres 230 – 350 GPa, steel 210 GPa, aluminium 70 GPa. –High fibre content in the composite: > 60% in mass. –Unidirectional, long fibres rather than weaves and chopped fibers. Radiation resistance –HL-LHC dose in CMS Tracker: ~1 20 cm, after 3000 fb -1 Possibility to obtain thin laminates, down to 0.2 mm total thickness –Requires high-quality thin prepregs, in 0.05 – 0.07 mm thickness. Suitable processing properties –Low temperature curing: max 130 C Many resin systems require 170 – 180 C, leading to higher residual stresses. –High-precision components with flatness of ~50 µm over 100 mm. Outer Tracker Mechanics, indico: May 2014, A.Onnela

9 Past experience? Apart from the higher radiation levels and aim for thinner laminates the requirements for the thermally conductive composite materials are identical with the current Tracker. Composite material used for the module frames of the current Tracker were: Fibre: Mitsubishi type K13D2U; Resin: YLA Cyanate Ester CE3 (RS3); Unidirectional pre-preg with 125 um nominal thickness; Four layer lay-up [0 o /90 o /90 o /0 o ] for 0.5 mm total thickness. –Used in the TIB and TID modules. Five layer lay-up [0 o /90 o /0 o /90 o /0 o ] for 0.63 mm total thickness. –Used in the TOB and TEC modules. Successful production of the module frames, and of the modules in the required quality. The old specification documents available in Upgrade/mechanics/SitePages/Home.aspx - Documents - Existing Tracker's Design Parameters, Specifications and other Documents Outer Tracker Mechanics, indico: May 2014, A.Onnela

10 Mitsubishi K13D2U Mitsubishi high-performance fibers (represents the state-of-the-art available today) Outer Tracker Mechanics, indico: May 2014, A.Onnela

11 Reuse the same composite material again? Good experience from the current Tracker. Reuse? –Yes, the first 2S module prototype hybrids use exactly the same material K13D2U/CE3, cut from spare laminate pieces produced in December –But no, the same composite material cannot be procured anymore, as the resin system YLA Cyanate Ester CE3 (RS3) is not produced anymore. The company YLA does not exist anymore, bought by TenCate in What choice to be made? –Fibres: The Mitsubishi K13D2U still a good choice. –Resin system: Three alternative producers: TenCate: Known, radiation tested products. Produces thin prepregs. Renegade: New company, no radiation tested products. Hexcel: Known, radiation tested products. Thin prepregs not in base-line production.  TenCate preferred. Cyanate ester resin system EX Proven radiation resistance, low temperature 127C cure. Outer Tracker Mechanics, indico: May 2014, A.Onnela

12 TenCate EX-1515 Further info: Upgrade/mechanics/SitePages/Home.aspx - Documents - Materials composites/def_prod/prepregs_list/default. aspx Outer Tracker Mechanics, indico: May 2014, A.Onnela

13 Purchasing prepreg material for prototyping Main objectives: Allow testing the manufacture of thin laminates in 0.2 – 0.5 mm thickness. –The 0.2 mm thickness is very challenging, not sure we will succeed. –What is the exact, thinnest laminate thicknesses we should use in the modules and in the structures matching manufacturability, flatness requirements, thermal performance? What is the cost? Provide laminates to be used for the 2S and PS module prototyping, as well as for the development of the TIB and TEC support/cooling structures. –What are the exact dimensions to be used in each part? Optimisation on manufacture, thermal performance, and total mass. Outer Tracker Mechanics, indico: May 2014, A.Onnela

14 Purchasing prepreg material for prototyping A shared purchase order being placed right now. K13D2U / EX-1515 prepreg from TenCate –67% Carbon fibre and 33% Cyanate Ester resin (mass percentage) –In rolls of 6” width –Delivery in 3 different prepreg thicknesses to enable studying different laminate thicknesses and layouts: Fiber Areal Weight FAW of 45, 80, and 120 g/m 2, corresponding to about 45, 80, 120 µm of cured ply thickness. For CMS Tracker Phase 2 Upgrade project, ALICE ITS development, and Linear Collider Detector development. Client users within CMS Tracker: Known: CERN and DESY. Still some ‘spare’ material possible to share. Others interested? Lyon? Outer Tracker Mechanics, indico: May 2014, A.Onnela