1' Telescope

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1. Telescope
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Enclosure Design Studies
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LSST Strawman design short-tube 3.5 degree
diameter field

• Modified Paul-Baker, Willstrop Mercenne-Schmidt
  or Laux design
• 8.36 m aperture primary mirror f / 1.25
• 3.5 degree full field of view
• Three aspheric mirror design
• Primary and tertiary mirror are a continuous
  surface 4.0 cm separation between beams
• Three fused silica spherical corrector lenses
• L1 is 1.6 m diameter
• Five interchangeable fused silica filters,
  13.5-22.0 mm thick
• CCD in vacuum, L3 is vacuum barrier
• 25 mm space CCD-L3
• Vertex of secondary mirror is 1.1 m from CCD
  array
• Effective etendue 230 (m-deg)2
• including all losses obstruction and
  vignetting, coatings and detector fill

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2. Camera
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Shutter design

• Requirements
• Shutter fits between the filter and L3
• Aperture diameter .76m

L1
Shutter
Detector array
1.6m
Filter
L3
L2
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Filter exchange mechanism

• New optical design
• 3.5º field of view ? optics and detector array
  are larger
• Includes shutter
• Due to space constraints, single pivot mechanism
  no longer fits

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Filter exchange mechanism

• 4-bar linkage allows filter to move past shutter
  and fit inside the outer camera Dewar

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Filter exchange mechanism
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Camera optics
1600
1120.346
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L2

• mechanical stop
• thermal barrier
• soft support
• filters

L3

• Camera integration issues
• FPA / elx assembly
• elx access

Secondary mirror
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External services

• DC-DC converters, power conditioning, ..
• misc environmental / commercial components
• Temp controllers
• Vacuum monitors / controllers
• etc.

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3. Focal Plane Assembly
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Conceptual design giga-bit serial data link

• 32 channel analog signal processing (ASIC)
• CCD clock buffer bias (ASIC or discrete)

sensor
FEE

• Intermediate cable for signals, clocks, misc
  control, thermal standoff
• 90 conductors

Timing ADCs

• Features
• No digital activity (except clocks) in FEE
• Differential analog signals to ADC
• Maximal separation of ADCs digital from FEE
  sensors
• High immunity to digital/analog x-talk.

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Conceptual design giga-bit serial data link
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Thermal zones
Zone-1 -100 to -60 degC
Zone-2 -20 to 20 degC

• Zone-1
• Sensors Front end electronics
• High stability loop DT few 0.1s degC

• Zone-2
• Data collection, etc
• Lower stability loop DT few degC

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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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FPA Structure design/FEA - Layton Hale-

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

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4. Raft
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Focal Plane Array - Integration -
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Focal Plane Array - Integration -
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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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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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Raft assy detail
-Tim Thurston-
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Assembly detail guide pins
-Tim Thurston-
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FPA raft with electronics
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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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Sloan Digital Sky Survey
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5. CCD package
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Mosaic Packaging
140 K plate attached to space radiator.
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CCD Subassembly
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CCD Module
-Tim Thurston-
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LBNL 4-Side Buttable AlN Pattern
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LBNL 4-Side Buttable Package
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PanSTARRS CCID45 OTA Package Exploded View of
Package
3-point mount foot with integral pin and shim disk
Ceramic retainer clips
Moly Base
Wirebond Ceramic PGA
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PanSTARRS CCID45 OTA Package Wirebond Ceramic PGA

• 74 pins used
• Includes temperature sensing diode
• JFETS SST309 in SOT-23 package
• Caps 0.22uF in 0603 size package
• Resistors 100K ohm in 0603 package

• Manufacturer Kyocera
• Material Alumina A440
• Multilayer 4 internal layers top ledge and
  bottom side.
• 94-pin interstitial PGA

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PanSTARRS CCID45 OTA Package Package Design
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PanSTARRS CCID45 OTA Package Photos of first
packaged OTA
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PanSTARRS CCID45 OTA Package Package Dimensions
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Focal plane power (CCD only) (For 2 sec readout
on 12 sec cadence)
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SDSS