1st Order Inner Layer Layout

1
1st Order Inner Layer Layout

• Salient points
• Constraint stay clear zone around beam pipe
• 70mm diameter
• Support split into two halves
• Requires equal modules around perimeter for
  grouping two cooling tubes, inlet and exit same
  end
• Heat load assumption for 800mm length120W
• Two pass for each cooling tube 5mm ID to limit
  pressure drop to lt200mbar
• Issues under study cooling and structural
  support for minimum radiation length
• Material Support Goal lt1

37.5mm
24.4mm
88mm
2
Preliminary Pixel Inner Layer Study

• Solid Models
• Examined various options for single and double
  layer pixels
• Initial objective was to combine both layers with
  on support structure
• Castellated and non-castellated design
• One layer design selected to quantify issues
• Cooling solution looks OK
• Proceeding to structural model

3
Pixel Thermal Solution-1st Order

• Description
• Isotropic carbon foam 50W/mK
• Specialized low density (0.14g/cc) foam enhanced
  to high conductivity
• Interface resistance from bonding chip to foam
  equal to 0.8W/mK 4mil thickness
• Pixel chip heating 0.6W/cm2
• Simulated tube wall temperature-22ºC
• Results
• Peak chip edge temperature-17.25 ºC
• Next slide illustrates chip temperature beneath
  detector

4
Thermal Solution (Continued)

• Surface temperature of electronic chip, detector
  removed for clarity

5
Structural Model of Inner Pixel Layer

• Model length 800mm, with supports at two end
• Will address gravity sag fully loaded with
  modules and cooling tubes
• Assess benefit, or need, of connecting two halves
  to form circular structure
• Examine prospect of using carbon foam to tie
  tubes into a common structure as was as acting as
  high conductivity media
• Anticipate need for single layer composite to
  enhance stiffness applied to outer and inner
  foam surface
• Limit material radiation length to 0.13 for both
  surfaces