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Focal Plane Array - Integration update -
Focal plane working group Bill Althouse John
Geary Kirk Gilmore Layton Hale Paul OConnor John
Oliver Veljko Radeka Chris Stubbs Tim Thurston
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Focal Plane Array

• Based on Raft structures
• Multiple (e.g. 9) CCD modules on local stiff
  raft structures
• Each CCD module kinematically mounted to raft
• CCD modules adjusted by vendor (preferred) for
• Parallel
• Height
• Raft features
• Optically flat (lt 1u)
• Kinematically mounted to FPA Structure
• Raft mount adjustability
• Manual (vernier screws, )
• Actuated (Piezo, )

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Focal Plane Array - Integration -
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Focal Plane Array - Integration -
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CCD Module/Raft assembly
CCD
Wire bonds
Aluminum nitride carrier/pwb
High density interconnects
Invar frame
Assembly tool holes
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CCD Module/Raft assembly
CCD
Aluminum nitride carrier/pwb
Kinematic mounts
Invar frame
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(No Transcript)
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CCD Module
-Tim Thurston-
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Raft assy detail
-Tim Thurston-
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Assembly detail guide pins
-Tim Thurston-
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Focal plane power (CCD only) (For 2 sec readout
on 12 sec cadence)
Energy Instantaneous power Average power 220 sensor total ave power Location
Radiation 726 mW 726 mW 160 W On chip
Parallel clocks 16 mJ 8 mW 1.3 mW 0.3 W Off chip
Serial clocks 256 mJ 128 mW 21.3 mW 4.7 W Off chip
Source followers 80 mW 80 mW 17.6 Off chip
Source followers 80 mW 80 mW 17.6 On chip
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Raft conceptual design - Thermal modeling -
-Tim Thurston-

• Thermal modeling in progress
• Detailed CCD module model with heat sources
• Heat removal through kinematic mounting studs
  (MIT-LL)
• Heat removal through direct strap to CCD module

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FPA Temperature profile
Raft Boundary
CCD
Temperature Drop from CCD to Cold Sink
Raft
Center Raft
Edge Raft
HX Straps
.5 C
.5 C
15 C
Raft Cage
10 C
Structural Strong Back
3 C
3 C
Cold Plate
16 C
11 C
Cold Sink
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FPA Structure design/FEA - Layton Hale-

• Modeling
• Deflections, gravity
• Normal modes
• Thermal
• x-y motions

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4 FOV ? 74 cm ?
WFS
8/5/04 workshop CCDs 3x3
3.5 FOV ? 64 cm ?
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• 4096x4096 pixels
• 10 µm pixels
• 1678 mm2 active
• 41.7 mm x 41.7 mm Si
• 42 mm pitch (0.3 mm gaps)
• 95 fill factor
• 25 x 3x3 225 chips
• If allow dummies outside 64cm, then?21 rafts
  with 9 live4 corners with 3 live ea
• 201 live chips total

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• wea 8/6/04

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Important outstanding issues

• Wavefront sensors
• How many?
• How big? ? footprint
• Special locations or sacrifice imager
  locations?
• Fill factor budget for WFSs
• Bandwidth, read rate?
• Who specifies?
• WFS Group?
• FP Group
• Other?
• Guide sensors
• Same questions
• Calibration sensors
• Ditto