The Large Synoptic Survey Telescope:The Large Synoptic Survey Telescope:Design and PerformanceDesign and Performance

SPIEMarseille, FranceJune 24th, 2008

Kirk GilmoreLSST Camera ManagerStanford/SLAC/KIPAC

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Science Goals Observational Requirements

Telescope/Camera/Site Requirements

Nature of Dark Energy 1 w to 2%

2 dw/dt to 5%

3 w( over 2

4 correlate with CMB

All sky weak lensing (WL). Rapid revisit SN (2nd param studies)

5 WL shear > 0.001 vs z

6 15,000 sq deg to V=26.5 AB mag (WL)

7 color-z to 0.1(1+z)

8 ~200 exposures per sky patch per filter

9 Photometric calibration: 0.0 2 mag goal

10 900 sec/filter/field/night, repeat every 5 nights o nsmall # of fields ( )SN

11 Ima ge quality: < 0.7” FWH Min V, R, or I bands, PSF q uadmoment stable < 1% per 10

.sec Shear systematics < 0.000 2 in 200 image stack

12 5 bands, for photometri credshifts (WL) & 2nd parameter studies ( )SN : 350 nm to 1 m

13 Southern sit e to ma tchAntarctic SZ ?surveys

14 A 250 , no /ise rea <d 5e

15 Dark sky equa l to best sites

Optical Transients 16 Extreme physics

17 Rare new objects

18 Orphan GR Bstatistics

19 SNe in arcs + lensing

20 Broad coverage in cadence, 20 sec to year time scale

21 Evolution of spectral energ ydistribution

22 Requiresdeep initia lmultiban d template

23 Frequent revisits, max sk ycoverage

24 Requires multi-colors

25 Target latency of <1 min fo ralerts, hi gh throughpu tpipeline

26 A 200 in a single camer a to see even ts as rare as

1/night over 1/5 o f the : skyfast pace. No /ise re <ad 5e.

Solar System 27 PHAs dow n to 100m

28 Smal l KBOs + colors

29 MBA statistics, colors

30 Max covera ge in ecliptic. Magic elongation

31 6 visi , 15 ts min sep, per sky patch per lunation

32 Area coverage > 11000 square degrees

33 Sufficien t A to ge 9t 0% completeness fo r PHAs i n

34 Maximum exposure o 15f se c to avoid trailing losses

35 Ima ge quali <ty 1” FWHM

36 A 200 per camera, /noise read < 5 e.

37 Multiple 500-800nm filters

Science Objectives Drive System Science Objectives Drive System RequirementsRequirements

• Image QualityImage Quality• f/1.25 beamf/1.25 beam• Large focalLarge focal Plane Plane

• Dark Energy / MatterDark Energy / Matter–Weak lensing - PSF Weak lensing - PSF –Shape/ Depth / AreaShape/ Depth / Area–Super Novae + Photo zSuper Novae + Photo z–Filters (ugrizy)Filters (ugrizy)

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Four Main Science Themes for LSST:1. Constraining Dark Energy and Dark Matter2. Taking an Inventory of the Solar System3. Exploring the Transient Optical Sky4. Mapping the Milky Way

Major Implications to the Camera:• Large Etendue• Excellent Image Quality and Control of PSF Systematics• High Quantum Efficiency over the Range 320 – 1,050 nm• Fast Readout

LSST Concept

• 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!

Design Telescope and Camera as a Single Instrument

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________________________________________________LSST Optical DesignLSST Optical Design

• f/1.23 • <0.20 arcsec FWHM images in six bands: 0.3 - 1 m • 3.5 ° FOV Etendue = 319 m2deg2

LSST optical layout

Polychromatic diffraction energy collection

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Detector position ( mm )

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U 80% G 80% R 80% I 80% Z 80% Y 80%

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________________________________________________LSST Camera Optical DesignLSST Camera Optical Design

________________________________________________LSST Deliverable Org Chart

ElectronicsOliver

(Harvard)WBS 3.5.8

Sensor/RaftDevelopment

Radeka/O’Connor(BNL)

WBS 3.5.4

OpticsOlivier (LLNL)

WBS 3.5.5

CryostatAssemblySchindler

(SLAC)WBS 3.5.7

CalibrationBurke(SLAC)

WBS 3.5.1

Camera Body Mechanisms

Nordby(SLAC)

WBS 3.5.3

Data Acq. & ControlSchalk(UCSC)

WBS 3.5.6

Corner RaftWFS/Guider

Olivier(LLNL)

WBS 3.5.9

UtilitiesNordby (SLAC)

WBS 3.5.2

Sensors/FiltersPain/Antilogus

(IN2P3)LPNHE, LAL,APC, LPSC,

LMA

________________________________________________LSST Camera TeamLSST Camera Team

Brandeis University J. Besinger, K. HashemiBrookhaven 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 WahlHarvard University

N. Felt, J. Geary (CfA), J. Oliver, C. StubbsIN2P3 - France Detailed in IN2P3 section of this reportLawrence Livermore National Lab

S. Asztalos, K. Baker, S. Olivier, D. Phillion, L. Seppala, W. Wistler

Oak Ridge National Laboratory C. Britton, Paul StankusOhio State University

K. Honscheid, R. Hughes, B. WinerPurdue University K. Ardnt, Gino Bolla, J, Peterson, Ian Shipsey

Rochester Institute of TechnologyD. Figer

Stanford Linear Accelerator CenterG. 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 LayoutCamera Layout

Cryostat

L1/L2 Assembly

Filter Changer Filter

Shutter

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CCD

PACKAGEDCCD

RAFT

From sensors to rafts to raft/towers From sensors to rafts to raft/towers The heart of the systemThe heart of the system

TOWER• 3 x 3 submosaic of CCDs• front end electronics• thermal management components

• Tower is an autonomous, fully-testable 144 Mpixel camera

carrier

CCDconnector

alignmentpins

baseplate

thermal straps

FEE boards

housing (cold mass)

3-pt. mount

cooling planes

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LSST focal plane sensors

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BNL and sensor group are providing leadshipFor sensor development

-50V

-10V

X-ray images

• 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

• 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)

________________________________________________32-port CCD

32-port CCD3x3 - 16-port CCDs

Raft tower electronics partitioning/temp zones

Front End Boards (6 per raft):• 144-channels of video signal chain through CDS processing• clock and bias drive• ASIC-based (ASPIC/SCC)

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

~175K

~235K

Flex cables (~ 500 signals)

Cryo Plate (~170k)

Cold Plate (~230k)

~185K

Molecular Flow Barrier

________________________________________________RFP for Prototyping Filters in 08

• 75 cm dia.• Curved surface• Filter is concentric about the chief Filter is concentric about the chief ray so that all portions of the filter see ray so that all portions of the filter see the same angle of incidence range, the same angle of incidence range, 14.2º to 23.6º14.2º to 23.6º

Specs

• Filter RFP being sent out to selected vendors

• Filter prototyping will qualify vendors to fabricate science filters

Filter 1 2 u 330 400 g 402 552 r 552 691 i 691 818 z 818 922 y 950 1070

Half-Maximum Transmission Wavelength

LSST Ideal Filter Set

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u g r i z y

________________________________________________Contamination test chamber at SLACContamination test chamber at SLAC

Fore or Preparation Chamber

Main Chamber

FORE MAIN ANTE

cold finger

Sample Preparation Chamber

Outgassing Analysis Chamber

Optical Transmission Chamber

Sample Entry

Straight-Thru Valve

Straight-Thru Valve

Optical Entry

________________________________________________IN2P3 - France R&D

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CNRS - National Center for Scientific ResearchIN2P3 - 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)

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FinFin

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FY-09 FY-10 FY-11 FY-12 FY-13 FY-14 FY-15 FY-16

The new LSST timeline generated with agency guidance following the successful CoDR in Sep., ‘07

FY-17FY-07 FY-08

NSF D&D FundingMREFC Proposal Submission

NSF CoDRMREFC Readiness

NSF PDRNSB

NSF CDR NSF MREFC Funding

Commissioning

Operations

DOE R&D Funding

DOE CD-0

DOE MIE Funding

DOE CD-1

DOE CD-2

DOE CD-3Sensor Procurement Starts

DOE CD-4Camera Delivered to Chile

Camera Fabrication (5 years)

Telescope First Light

DOE I&CFunding

Camera Ready to Install

NSF + Privately Supported Construction (8.5 years) System First Light

ORR

Privately Supported R&D and Construction (7 years)

________________________________________________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 non-uniformity 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.