Ceramic Focal Plane Components For SNAP B. C. Bigelow, UM Physics 4/13/05

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Ceramic Focal Plane Components For SNAPB. C.
Bigelow, UM Physics4/13/05
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Ceramic Detector Packages

• AlN detector package material already
  demonstrated
• Ground and space heritage well established
• Cryo epoxies known, package assembly procedures
  established
• See Oluseyi, Bercovitz, et. al. (LBNL)
• Package assembly to set height, flatness to /-
  5 microns
• See Miyazaki, et al, PASJ
• AlN CTE close match to Si, SiC, Invar
• Natural match to Si CCD sensor material
• Near-match to HgCdTe Si MUX material
• Can be machined, polished, epoxy-inserted, etc.
• AlN -gt near match for SiC
• SiC package material base-lined for GAIA mission
• More later!

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CTE for Focal Plane Materials

• CTE plot courtesy of Pat Jelinsky

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Subaru Suprime Camera

• On Subaru 8.2m telescope, Mauna Kea, Hi
• See Miyazaki, et al
• 5 x 2 mosaic of LL-MIT 2K x 4k CCDs - 83
  Megapixels
• AlN CCD packages
• AlN cold-plate
• Assembled mosaic is flat to approx. /- 5 microns
• Threaded studs epoxied into AlN packages
• Flat interface between packages and cold-plate

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Subaru Suprime Camera
Miyazaki, et al
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Subaru Suprime Camera
AlN cold-plate
120mm x 150mm mosaic
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Subaru Suprime Camera
AlN package and buffer block
Stud is epoxied into AlN buffer block
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Subaru Suprime Camera
AlN buffer block and spacer shims in assembly jig
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Subaru Suprime Camera
AlN CCD package epoxied to buffer block
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GAIA mission SiC focal plane

• Boostec SiC material
• Sintered fabrication process
• Less than 3 porosity
• Pure, alpha phase SiC, no free silicon
• Boostek SiC Moly
• Density 3100 kg/m3 10,200 kg/m3
• Youngs modulus 420 GPa 330 GPa
• Flexural strength 450 Mpa 415 Mpa
• CTE (room temp) 4.0 PPM/C 5.35 PPM/C
• Thermal conductivity 180 W/mk 138 W/mk

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GAIA mission SiC cold-plate
Boostec/Astrium GAIA focal plane demonstrator
model Sintered SiC, 770mm by 580mm by 36mm, 8kg.
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GAIA mission SiC cold-plate
GAIA cold-plate - detector mounting detail.
Note finished bores on mounting holes
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Ceramic CCD Packages for SNAP

• CCD package features
• All dimensions and mounting features per ICD
  00065-AC14A (HDH)
• Hypertonics KA series connectors per ICD
• All vented hardware but not always shown!
• AlN PCB interfaces between detectors and
  connectors
• Integral filter/aperture assemblies
• AlN or SiC package and mount material
  (interchangeable)

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Ceramic CCD package
Invar inserts with internal threads for M3
mounting screws
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Ceramic CCD package
Round insert, diamond insert, undersized insert
provide kinematic constraint of in-plane DOF X,
Y, and rot Z.
Ground pads define tip, tilt, and piston of
package
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Ceramic CCD assembly
AlN or SiC mount
AlN or SiC CCD package
epoxy
Ribbon cable
Invar insert, epoxied in
PCB
Invar insert, epoxied in
Hypertronics KA series, 72 pins
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Ceramic CCD package
CTE-matching filter frame, with filter and
aperture mask
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Ceramic MCT Packages

• MCT package features
• All dimensions and mounting features per ICD
  00065-AC14A (HDH)
• Hypertonics KA series connectors per ICD
• All vented hardware but not always shown!
• AlN PCB interfaces between detectors and
  connectors
• Integral filter/aperture assemblies
• AlN or SiC package and mount material
  (interchangeable)

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Ceramic MCT package
Near-copy of CCD PCB, but wraps around for
wire-bonding to sensor MUX on top surface
AlN/SiC PCB isolates detector package from
connector thermal stresses
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Ceramic MCT package
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Ceramic MCT package
Filter frame clearance for wire-bonds
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Ceramic MCT package
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SNAP ¼ CCDMCT mosaic
CCD MCT
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SNAP ¼ CCDMCT mosaic
Section showing mounting interface details
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SNAP ¼ CCDMCT mosaic
Section showing mounting interface details
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SNAP ¼ CCDMCT mosaic
Back side of FP mosaic showing mounting screws
and access to connector