Development of super module structures at Glasgow

Calum I. Torrie

20th April 2007

Development of super module structures at Glasgow

• For the sLHC Si tracker upgrade, the Glasgow group will contribute to the development of the supermodule mechanical and thermal design and prototyping of the structures.

• Design studies will be made using FEA analysis of different designs based on different support materials (eg carbon fibre and SiC cernamic) [this uses info from QMW thermal material project] to evaluate the thermal and mechanical behaviour of the prototypes.

• The thermal studies will look at the heat flow from the modules to the cooling fluid with the aim of optimizing the sensor temperature.

• The mechanical properties of the resulting design based on the optimization of the thermal properties can be studied, again using FEA, to evaluate the stablility, mass and strength of the structure.

Development of super module structures at Glasgow

• We also want to build prototypes to investigate the engineering feasibility of the best designs for a given material.

• In the first instance we want to look at a SiC ceramic. This material has been developed for lightweight mirror and space applications.

– A structure can be fabricated as a carbon ‘greenbody’ and is then made into a SiC ceramic by mixing with liquid Si.

– This has the potential to allow the construction of complex supermodules support structures to be fabricated with e.g. integrated cooling pipes, having the correct thermal and mechanical properties.

• We are therefore bidding for funds to purchase fabricate test structure based on this material. This study would be carried out in collaboration with ATC Edinburgh as they are investigating this material for future large telescopes.

• We are currently investigating UK companies that might be able to fabricate the test structures.

• The prototypes will be evaluated in the laboratory to benchmark the FEA studies using dummy modules to provide a realistic heat load.

Tests

• FEA– Using ANSYS Classic and ANSYS Workbench

• Material properties– Thermal and mechanical

• e.g. Thermal Conductivity & Breaking Stress– Measure Thermal Conductivity

» Temp range -50 oC to 300 oC

– Ordered Material• CSiC (Xycarb, Holland)• CeSiC (ECM, Germany)

– Proof samples• Stainless Steel & Aluminuim• Silicon

Samples

Vacuum chamber with 16 octal feed through service for thermocouple readout.

Copper cooling block with cooling service connections.

Two 4 input NI thermocouple data acquisition modules.

Computer controlled chiller using high performance coolant.

High performance woven matrix heating element.

PC interface with labview, DAQmx and chiller control Software.

16 PT 100 precision thermocouples

The Expt

Insert picture / info re: 2 samples

Liam

• Surface Characterisation• Flatness• Reflectivity• Surface profile

– Machined feature

• Surface details– SEM

Cryo

• Thermal Conductivity

• Heat capacity

• CTE– Maybe!

– Refer to talk from KT in Edinburgh!

C-SiC

• Currently investigating C-SiC– SiC ceramic– Manufacture “green bodies” from various

carbon fibre type materials– Infiltrate with Si by gas or liquid– Good combination of mechanical and

thermal properties– Being investigated for telescope and

spacecraft engineering

C-SiC properties

• Density: 2.65gcm-3

• Thermal conductivity: 180WmK-1

• ……

• Typical thickness > 1cm– Can it be made thinner?

Glasgow activities: Material properties

• Evaluate mechanical and thermal properties– Mechanical properties: UMT setup available– Thermal properties: setup measurement system for

thermal conductivity in lab – as used on TPG spines (H-G Moser et al)

– Sample designs developed

• Talking to manufacturers– Getting samples from Xycarb and ECM

• Also investigating bonding– Manufacture of complex structures

Glasgow Activities: FEA• Conceptual module

– Similar to concept presented at Genoa– Investigate thermal and mechanical behaviour of C-SiC– Solidworks (ANSYS)– Can a baseline module be agreed to allow common studies?– Module now in ANSYS (with help from Liverpool)

Plans

• Measure thermal and mechanical properties of samples

• Talk to manufacturers:– What can be made (thin layers and

complex structures?)– Variation of properties with processing

• Develop FEA analysis with C-SiC

Control chips 6x6mm2 P=1W

14 x ro chips 6x6mm2 P=0.5W/chip

Fan-ins, Al on glass1792 strips of Al 20m wide x 1mx10mm long

40mm

30mm 30mm

2x Si detector30mm x 90mm x 300m

Basic layout of module element

Top view

Bond wires:Ro chip -> fanin -> SiBond wires: 10mm x 25m diameter Al

Kapton substrate for hybrid

Conceptual module

90mm

Carbon/Si support structure10x10mm2

Kapton substrate for hybrid40mmx90mmx0.5mm

14 x ro chips 6x6mm2 P=0.5W/chip

2x Si detector30mm x 90mm x 300m

Cooling pipes 4mm diameterCarrying coolant at -40oC ->-20oC

Bond wires

5mm

Integrated Structures• Alternative to individual rigid modules on a rigid support:

“super-modules” (or “staves”) plus end-plates.• Minimize heat flow path lengths• Eliminate mechanical redundancy• Integrate support, cooling, electrical services

– Increased integration implies decreased material

• Assembly sites build, test, & deliver these units– Final assembly is simplified

• Include alternative powering schemes – reduce services• Create higher-value elements & assume greater risk

Thermal/Mechanical R&D Goals

• Develop long structures with low sag and low X0 percentages

• Understand & optimize temperature differentials & distortions

• Accommodate “moving” silicon temperature specifications and coolant properties

• Berkeley efforts are following the TMG program in the areas of– High TC materials– Thermal interface materials– Thermal resistance evaluations– Small and large prototypes– Thermal and mechanical simulations