1. Hybrid Mechanical/Thermal Design ideas
Ray Thompson / Manchester FP420 meeting DESY 18/19 May 06

2. Issues
Heat removal to externally cooled interface - assume 0.4 w/ chip
Reduce scattering in chip area
Demountability of individual layers
Flexibility of thermal connection
Routeing of flex connections to controller chips
Internal alignment of the 10 ?? planes
External station alignment to beam pipe, wire alignment system

3. Materials choices
CTE
ppm/K
Thermal Conductivity
W/m.K
Density
Kg.m3
Rad
Length mm
Silicon
4.7
148
2.33 94
Al Nitride
4.4
3.26 84
Laser cuting
Machinable
AiN (Shapal)
5.2 90
2.95 93
Carbon - Carbon
1.5 6
parallel
perp
1.3/1.8
188
Easily machinable
Carbon – Carbon
‘Atlas sct’
700 parallel
20 perp
220
BeO 8
300
2.85
144
Toxic
Copper
16.7
385
8.96
14.4
5.5

4. Active Solder Active Solder Technology - Solder joining of ceramics
-Titanium/rare earth additives to conventional Sn/Ag 92/4 solder
additives react at oxide surfaces
Direct wetting of ceramics, metals
AiN , graphites , steel, aluminium
-S-Bond Sn/Ag 92/4
Solidus 221 C Liquidus 232 C Joining temp
Thermal Conductivity 48 W/m.k
See

5. X hybrid
Copper foil
Carbon –carbon Frame
Nominal
Readout kaptons
to control chip
3d silicon +
Readout chip
Carbon- carbon
Thined down to 0.5 mm

6. Y Hybrid
Y hybrid

8. Thermal connections Has to be demountable at the hybrid level
Has to be flexable/ moveable to take up CTE Mismatch
2 options - stress v mess
Mismatch in CTE
Copper foil – accept CTE mismatch , foil , W shape stress reduction
Direct sliding Thermal grease connections to Carbon Carbon
- Long term stability ?
- sharing between planes ?

9. Copper Thermal interface

10. Controller cards
At rear

11. Precision alignment washers
Used on Atlas Sct Modules
2mm Diam +1mm
Wirecut Al
+/- 5 micron
3mm Diam
Tolerance
3.000
3.010

12. Scattering material Previously 1mm ceramic 1.325% RL
gave rise to 0.47% loss
0.5 mm Carbon- Carbon % RL
Overall now % RL per plane
Crude scaling with RL would give
0.32 % loss /plane Not that Simple
X20 planes (4,6,10) gives 6.4% loss
Note conducting glue is 13 % of hybrid

13. Crude temperature drops
Cooling interface Deg below chip operating temp.

14. Next steps Agree acceptability of
Sort out routeing of kaptons to control cards
- May affect final positioning of cooling interface/ control cards
Machine carbon- carbon samples
Agree Chip glue – acceptable chip stresses
- (electrical) conducting or not
check - joining techniques
- measure real thermal gradients ( c-c anisotropy)
- mechanical stability – Thermal cycling
- alignment accuracy
Detailed thermal /stress Simulation

15. 10 80 5 10 30