The Large Synoptic Survey Telescope:
Design and Performance
SPIE
Marseille, France
June 24th, 2008
Kirk Gilmore
LSST Camera Manager
Stanford/SLAC/KIPAC
Science Objectives Drive System
Requirements
________________________________________________
• Dark Energy / Matter
–Weak lensing - PSF
–Shape/ Depth / Area
–Super Novae + Photo z
–Filters (ugrizy)
• Image Quality
• f/1.25 beam
• Large focal
Plane
Four Main Science Themes for LSST:
1. Constraining Dark Energy and Dark Matter
2. Taking an Inventory of the Solar System
3. Exploring the Transient Optical Sky
4. Mapping the Milky Way
Major Implications to the Camera:
1.
2.
3.
4.
Large Etendue
Excellent Image Quality and Control of PSF Systematics
High Quantum Efficiency over the Range 320 – 1,050 nm
Fast Readout
3
LSST Concept
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Design Telescope and Camera
as a Single Instrument
• 8.4 Meter Primary Aperture
– 3.4 M Secondary
– 5.0 M Tertiary
• 3.5 degree Field Of View
• 3 Gigapixel Camera
– 4k x 4k CCD Baseline
– 65 cm Diameter
– Six Filters
• 30 Second Cadence
– Highly Dynamic Structure
– Highly Parallel Readout
• Accumulated depth ~27 mag.
in each filter over 10y
• Data Storage and Pipelines ~
18Tb/night!
LSST Optical Design
________________________________________________
Image diameter ( arc-sec )
• f/1.23
• <0.20 arcsec FWHM images in six bands: 0.3 - 1 mm
• 3.5 ° FOV  Etendue = 319 m2deg2
Polychromatic diffraction energy collection
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0
80
160
240
320
Detector position ( mm )
U 80%
G 80%
R 80%
I 80%
Z 80%
Y 80%
U 50%
G 50%
R 50%
I 50%
Z 50%
Y 50%
LSST optical layout
LSST Camera Optical Design
________________________________________________
LSST Deliverable Org Chart
________________________________________________
Electronics
Oliver
(Harvard)
WBS 3.5.8
Optics
Olivier
(LLNL)
WBS 3.5.5
Sensor/Raft
Development
Radeka/O’Connor
(BNL)
WBS 3.5.4
Cryostat
Assembly
Schindler
(SLAC)
WBS 3.5.7
Camera Body
Mechanisms
Nordby
(SLAC)
WBS 3.5.3
Calibration
Burke
(SLAC)
WBS 3.5.1
Data Acq. &
Control
Schalk
(UCSC)
WBS 3.5.6
Utilities
Nordby
(SLAC)
WBS 3.5.2
Corner Raft
WFS/Guider
Olivier
(LLNL)
WBS 3.5.9
Sensors/Filters
Pain/Antilogus
(IN2P3)
LPNHE, LAL,
APC, LPSC,
LMA
LSST Camera Team
________________________________________________
Brandeis University
J. Besinger, K. Hashemi
Brookhaven National Lab
S. Aronson, C. Buttehorn, J. Frank, J.
Haggerty, I. Kotov, P. Kuczewski, M. May, P.
O’Connor, S. Plate, V. Radeka, P. Takacs
Florida State University
Horst Wahl
Harvard University
N. Felt, J. Geary (CfA), J. Oliver, C. Stubbs
IN2P3 - France
Detailed in IN2P3 section of this report
Lawrence Livermore National Lab
S. Asztalos, K. Baker, S. Olivier, D. Phillion,
L. Seppala, W. Wistler
Oak Ridge National Laboratory
C. Britton, Paul Stankus
Ohio State University
K. Honscheid, R. Hughes, B. Winer
Purdue University
K. Ardnt, Gino Bolla, J, Peterson, Ian
Shipsey
Rochester Institute of Technology
D. Figer
Stanford Linear Accelerator Center
G. Bowden, P. Burchat (Stanford), D. Burke,
M. Foss, K. Gilmore, G. Guiffre, M. Huffer, S.
Kahn (Stanford), E. Lee, S. Marshall, M.
Nordby, M. Perl, A. Rasmussen, R.
Schindler, L. Simms (Stanford), T. Weber
University of California, Berkeley
J.G. Jernigan
University of California, Davis
P. Gee, A. Tyson
University of California, Irvine
D. Kirkby
University of California, Santa Cruz
T. Schalk
University of Illinois, Urbana-Champaign
J. Thaler
University of Pennsylvania
M. Newcomer, R. Van Berg
Wayne State University
David Cinabro
Camera Layout
________________________________________________
Cryostat
Filter Changer
Filter
L1/L2
Assembly
Shutter
From sensors to rafts to raft/towers
The heart of the system
________________________________________________
CCD
thermal straps
FEE boards
PACKAGED
CCD
cooling
planes
connector
CCD
housing
(cold mass)
carrier
alignment
pins
TOWER
RAFT
• 3 x 3 submosaic of CCDs
• front end electronics
• thermal management components
baseplate
3-pt. mount
• Tower is an autonomous,
fully-testable 144 Mpixel
camera
LSST focal plane sensors
________________________________________________
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BNL and sensor group are providing leadship
For sensor development
________________________________________________
• Request for proposals for
prototype science CCDs
– issued Feb. 2008
– contract award June 2008
• 5 high-resistivity, thick CCDs
from study program have
been extensively characterized
– design models validated
– behavior of dark current, quantum efficiency, and
point spread function vs. thickness, temperature,
and electric field
– flatness and surface morphology
– antireflection coating
-50V
• CCD controllers for 4 new test labs under
construction
– UC Davis, SLAC, Paris, Purdue
– allows full-speed testing of segmented sensors
• Components for CCD/electronics chain testing
in assembly (Raft/Tower electronics)
X-ray images
-10V
Raft tower electronics partitioning/temp zones
________________________________________________
Molecular Flow Barrier
32-port CCD
32-port CCD
3x3 - 16-port CCDs
~185K
~175K
Front End Boards (6 per raft):
• 144-channels of video signal
chain through CDS processing
• clock and bias drive
• ASIC-based (ASPIC/SCC)
Cryo Plate (~170k)
Flex cables (~ 500 signals)
Cold Plate (~230k)
~235K
BEE motherboard and backplane:
• differential receiver
• signal chain ADC (16+ bits)
• buffers
• data transport to optical fiber
• clock pattern generation
• clock and bias DACs
• temperature monitor / control
RFP for Prototyping Filters in 08
________________________________________________
Specs
Half-Maximum Transmission Wavelength
• 75 cm dia.
• Curved surface
• Filter is concentric about the chief
ray so that all portions of the filter see
the same angle of incidence range,
14.2º to 23.6º
LSST Ideal Filter Set
100.0
System Throughput (%)
90.0
80.0
70.0
• Filter RFP being sent out to
selected vendors
60.0
50.0
u
g
r
i
z
y
40.0
• Filter prototyping will qualify
vendors to fabricate science
filters
30.0
20.0
10.0
0.0
300
400
500
600
700
800
Wavelength (nm)
900
1000
1100
Contamination test chamber at SLAC
________________________________________________
Sample
Preparation
FORE
Chamber
Outgassing
Analysis
Main
MAIN
Chamber
Chamber
Optical
Transmission
ANTE
Chamber
Sample
Entry
Fore or
Preparation
Chamber
Optical
Entry
StraightThru
Valve
StraightThru
Valve
cold
finger
IN2P3
France
R&D
________________________________________________
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decompressor
are needed to see this picture.
CNRS - National Center for Scientific Research
IN2P3 - National Institute for Nuclear Physics and Particle Physics
APC - Lab for Astroparticles and Cosmology (Paris)
CC-IN2P3 - Computing Center of IN2P3 (Lyon)
LAL - Lab of Linear Accelerator (Orsay)
LMA - Lab of Advanced Materials (Lyon)
LPSC - Lab for Subatomic Physics and Cosmology (Grenoble)
LPNHE - Lab for Nuclear Physics and High Energy (Paris)
________________________________________________
________________________________________________
Fin
The new LSST timeline generated with agency
guidance
following the successful CoDR in Sep., ‘07
________________________________________________
FY-07
FY-08
FY-09
FY-10
FY-11
FY-12
FY-13
FY-14
FY-15
FY-16
FY-17
NSF D&D Funding
MREFC Proposal Submission
NSF CoDR
MREFC Readiness
NSF PDR
NSB
NSF CDR
NSF MREFC Funding
Telescope First Light
NSF + Privately Supported Construction (8.5 years)
System First Light
Commissioning
ORR
Operations
Privately Supported R&D and Construction (7 years)
DOE I&C
Funding
DOE MIE Funding
Camera Fabrication (5 years)
DOE R&D Funding
Sensor Procurement Starts
DOE CD-3
DOE CD-2
DOE CD-0
DOE CD-1
DOE CD-4
Camera Delivered to Chile
Camera Ready to Install
Camera
Construction
Costs
________________________________________________
Request to DOE
$87M
Camera risk mitigation plan prior to construction
________________________________________________
R&D Effort
Plan
Status
Demonstrate sensor
performance
Establish all specs are met:
Flatness, high fill factor,
electrical parameters,
Study phase sensors
received and being
evaluated
Efficient sensor
procurement
Establish cost, yield and
performance of sensors
PO’s being drafted that
address risk areas.
Prototype phase starting
Establish reliability of
shutter mechanism
Build prototype shutter and
test
Design completed.
Procurement of parts begun
Evaluate outgassing
properties of cryostat
components
Contamination control
demonstrated in engineering
cryostat
Contamination testing
started. Materials selection
process begun.
75cm filter w/multilayer
coatings produced with nonuniformity of <1% .
Fabrication of samples in
large coating chamber to
evaluate uniformity of filter
transmission
Passbands defined. Total
system throughput modeled.
Some witness samples
already produced. RFP to
potential vendors ready.