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Bridge Thermal ModelBridge Thermal Model

• Salient FeaturesSalient Features– High conductivity (700W/mK, 0.5mm thick) CC bridge material support High conductivity (700W/mK, 0.5mm thick) CC bridge material support

for 0.28mm thick hybrid(1W/mK)for 0.28mm thick hybrid(1W/mK)– 40 chips @ 0.25W/chip40 chips @ 0.25W/chip– Detector 0.28mm thick, 148W/mKDetector 0.28mm thick, 148W/mK– Allcomp carbon foam for bridge support (isotropic 45W/mK)Allcomp carbon foam for bridge support (isotropic 45W/mK)– Carbon Foam for tube support (45/45/45 W/mK)Carbon Foam for tube support (45/45/45 W/mK)

• Reduced density over POCO foam (0.2g/cc versus 0.5 g/cc)Reduced density over POCO foam (0.2g/cc versus 0.5 g/cc)– Sandwich foamSandwich foam

• Allcomp foam option, ~0.1g/cc @ 3W/mKAllcomp foam option, ~0.1g/cc @ 3W/mK

• Comparison with Hybrid on 10cm DetectorComparison with Hybrid on 10cm Detector– Thermal solution with both with inner tube wall at -28Thermal solution with both with inner tube wall at -28ºCºC

• Simulates -30Simulates -30ºC with 8000W/mºC with 8000W/m22KK

• No change made to material properties in 10cm detector No change made to material properties in 10cm detector with integrated hybrid with integrated hybrid

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10cm Detector-No Bridge10cm Detector-No Bridge

Old model parameters

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10cm Detector-No Bridge10cm Detector-No Bridge

• Material PropertiesMaterial Properties– See previous slide (#2)See previous slide (#2)

• 40 chips per detector, 80 40 chips per detector, 80 totaltotal– 0.25W/chip Q (Si)=0W0.25W/chip Q (Si)=0W– Tube inner surface -28Tube inner surface -28ºC, no ºC, no

convection coefficientconvection coefficient

• Interest in Interest in ΔΔT from chip T from chip and detector surface to and detector surface to tube surfacetube surface

• Peak chip temperaturePeak chip temperature– Middle hybrid region: -20.5ºCMiddle hybrid region: -20.5ºC

• Peak DetectorPeak Detector– Middle hybrid region: -21.5ºCMiddle hybrid region: -21.5ºC

– ΔΔT in region of max T in region of max gradient: 6.5ºCgradient: 6.5ºC

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10 CM Wide Stave-No Bridge10 CM Wide Stave-No Bridge

• SolutionSolution– Replaced honeycomb Replaced honeycomb

core with Allcomp carbon core with Allcomp carbon foam (<0.2g/cmfoam (<0.2g/cm33: : 45W/mK)45W/mK)

– Also, replaced POCO Also, replaced POCO foam tube support with foam tube support with same foamsame foam

• Peak Chip Temp: -Peak Chip Temp: -22.722.7ºCºC

• Peak Detector: -24ºCPeak Detector: -24ºC– ΔΔT (referenced to tube T (referenced to tube

wall)wall)

• 4ºC4ºC

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10 CM Wide Stave-No Bridge10 CM Wide Stave-No Bridge

• Solution: Simulate “outer” Solution: Simulate “outer” long strip detectorlong strip detector– One upper and power hybrid for One upper and power hybrid for

10cm detector10cm detector– 20 chips @ 0.25W/chip20 chips @ 0.25W/chip– Coolant tube inner surface: -28Coolant tube inner surface: -28ºCºC– Materials, see slide (#2)Materials, see slide (#2)

• DetectorDetector– Peak temp beneath hybrid: -Peak temp beneath hybrid: -

24.824.8ºCºC– ΔΔT in region of max gradient: T in region of max gradient:

3.2ºC3.2ºC

• Chip Peak Temp: -24.1ºCChip Peak Temp: -24.1ºC

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Thermal Bridge Model (1/2 of 10cm)Thermal Bridge Model (1/2 of 10cm)

Wire bonds, simulated as thin solid, reduced K to 97W/mK

Chips 0.38mm thick (148W/mK)

Al Cooling tube 0.21mm ID

Separation between facings 4.95mm

10cm

Foam bridge support

1mm air gap for bridge

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Bridge Thermal ModelBridge Thermal Model

Enclosed bridge model in an air box. Air participates only through pure conduction. Air fills all cavities not occupied by a solid

Air box

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Model ParametersModel Parameters

Cable and adjacent adhesive layers modeled as single layer 0.227mm and K=0.31W/mK

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Solution with -30Solution with -30ºC ºC Tube 8000 W/mTube 8000 W/m22K K 0.5W/chip Q (Si)=00.5W/chip Q (Si)=0

Slight asymmetry caused by variance in interior coolant wall temperature

Detector max=-21.4ºC

Chip peak=-16.5ºC

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Solution with -30Solution with -30ºC ºC Tube 8000 W/mTube 8000 W/m22K K 0.25W/chip Q (Si)=00.25W/chip Q (Si)=0

Slight asymmetry caused by variance in interior coolant wall temperature

Detector max=-25.8ºC

Chip peak=-23.3ºC

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Solution with -30Solution with -30ºC ºC Tube 8000 W/mTube 8000 W/m22K K 0.25W/chip Q (Si)=00.25W/chip Q (Si)=0

Bridge foam and tube foam 45W/mk, density ~0.2 g/cm3(no POCO foam) Peak detector temp -24.2ºC

Sandwich foam core 3W/mK, density ~0.06 g/cm3

Peak chip=-21.8ºC

Wire bonds 97W/mK