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The Large Synoptic Survey Telescope

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Title: The Large Synoptic Survey Telescope


1
The Large Synoptic Survey Telescope
A Ground based Facility To Explore Dark
Energy/Dark Matter
Kirk Gilmore SLAC/KIPAC
2
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3
Opportunities
4
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5
Dark Energy Task Force
  • In Feb. 05 the NSF-NASA-DOE Astronomy and
    Astrophysics Advisory Committee (AAAC) and the
    NSF-DOE High Energy Physics Advisory Panel
    (HEPAP) established a Dark Energy Task Force
    (DETF) as a joint subcommittee to advise on the
    future of dark energy research.
  • DETF asked to advise agencies on the optimum near
    and interm. term programs to investigate DE and,
    in cooperation with agency efforts, to advance
    the justification, specification optimimization
    of a ground-based Large Survey Telescope (LST)
    a space-based Joint Dark Energy Mission (JDEM).
  • DETF final report target date is Dec 2005. DETF
    expected to prioritize techniques but probably
    not rank projects.
  • DETF charge
  • Summarize the existing program of funded projects
    by projected capabilities, systematics, risks,
    required documents, and progress-to-date.
  • Summarize proposed and emergent approaches and
    techniques for DE studies that is, characterize
    these approaches and techniques by the added
    value the projected capabilities would provide to
    the investigation of DE.
  • Identify important steps, precursors, RD and
    other projects that are required in preparation
    for JDEM, LST and other existing or planned
    experiments.
  • Identify any areas of DE parameter space that the
    existing or proposed projects fail to address.

6
LSST Concept
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
  • Five Filters
  • 30 Second Cadence
  • Highly Dynamic Structure
  • Highly Parallel Readout
  • Accumulated depth 27 AB mag. in each filter over
    10y
  • Data Storage and Pipelines 18Tb/night!

7
The LSST System Summary
________________________________________________
  • LSST is designed to go wide deep
    fast
  • 10 deg2 per field
  • 6.5m effective collecting aperture
  • m24 AB mag per 10 sec. exposure (2 per pointing)
  • wide coverage gt 20,000 square degrees
  • multiple filters (e.g. grizy - maybe u)
  • accumulated depth of 27 AB magnitude in each
    filter

8
Relative Survey Power
9
The Essence of LSST is To Go Deep, Wide, Fast
Design Driven By The Science
The LSST Concept is Analogous to the Introduction
of 4p Detectors In Particle Physics And We
Anticipate A Similar Revolution in Astrophysics
To Follow. Attack The Dark Energy / Dark Matter
Problem On Many Fronts With the Same Instrument
  • Dark matter/dark energy via weak lensing
  • Dark matter/dark energy via supernovae
  • Strong galaxy cluster lensing physics of dark
    matter
  • Multi-image lensed SN time delays separate test
    of cosmology
  • QSO time delays vs z independent test of dark
    energy

10
Principle LSST Science Missions
_______________________________________________
  • Dark Energy / Matter
  • Weak lensing - PSF Shape/ Depth / Area
  • Super Novae Photo z Filters /
  • Map of Solar System Bodies
  • NEA Cadence
  • KBO
  • Optical Transients and Time Domain
  • GRB Afterglows Image Differencing
  • Unknown transients
  • Assembly of the Galaxy and Solar Neighborhood
  • Galactic Halo Structure and Streams from proper
    motions
  • Parallax to 200pc below H-burning limit

11
LSST and Dark Energy
  • LSST will measure 250,000 resolved high-redshift
    galaxies per square degree! The full survey will
    cover 18,000 square degrees.
  • Each galaxy will be moved on the sky and slightly
    distorted due to lensing by intervening dark
    matter. Using photometric redshifts, we can
    determine the shear as a function of z.
  • Measurements of weak lensing shear over a
    sufficient volume can determine DE parameters
    through constraints on the expansion history of
    the universe and the growth of structure with
    cosmic time.

12
DE science drives short exposures
___________________________________________
  • Weak lensing requires high etendue and thus a
    high photon rate and short exposures.
  • One needs hundreds of exposures per filter per
    sky patch for chopping systematics.
  • Short exposures allow us to optimally weight.

13
Color-redshift
14
Color-redshift scatter and expected N(z)
N(z) from degraded HDF
Simulated rms error (0.04-0.07)(1z) per
galaxy Systematic error 0.005(1z) calibratable
to at least 10x better. Need 30,000 spectroscopic
redshifts per z-bin.
15
LSST Measurements of Cosmic Shear
From Takada et al. (2005)
16
Funding and management configuration
DOE
NSF
LSSTC Private
Funding Sources
LSST Collaboration Institutions
LSSTC
PMO
SLAC
BNL
LLNL
NOAO
NCSA
LSSTC Staff
Universities
Relationships established by MoA's
Universities
PMO Program Management Office
17
LSST Management Structure
Board of Directors John Schaefer, President
President John Schaefer
Director Anthony Tyson Steve Kahn, Deputy
Project Manager Donald Sweeney Victor Krabbendam,
Deputy
Science Advisory Committee (SAC)
System Engineering William Althouse
System Scientist Chair of Science
Council Zeljko Ivezic
Education Public Outreach Suzanne Jacoby
Simulation Data Challenge Phil Pinto
Camera Steven Kahn, Sci. Kirk Gilmore, Mgr.
Telescope/Site Charles Claver, Sci. Victor
Krabbendam, Mgr.
Data Management Timothy Axelrod, Sci. Jeffrey
Kantor, Mgr.
18
LSST CAMERA ORGANIZATION CHART
______________________________________________
19
LSST Camera Personnel
First Last Institution First Last Institution
Sam Aronson Brookhaven National Laboratory Morgan May Brookhaven National Laboratory
Steve Asztalos LLNL Martin Nordby SLAC-Stanford
Kevin Baker LLNL Paul O'Connor Brookhaven National Laboratory
Gordon Bowden SLAC-Stanford John Oliver Harvard
David Burke SLAC-Stanford Scot Olivier LLNL
Don Figer STScI John Peterson SLAC-Stanford
John Geary CFA/Harvard Veljko Radeka Brookhaven National Laboratory
Kirk Gilmore SLAC - Stanford Andy Rasmussen Columbia
Layton Hale LLNL Leslie Rosenberg LLNL
Mike Huffer SLAC-Stanford Terry Schalk SLAC-Stanford
Garrett Jernigan UC Berkeley/Space Sciences Lab Rafe Schindler SLAC-Stanford
Steven Kahn SLAC-Stanford Lynn Seppala LLNL
Peter Kim SLAC-Stanford Lance Simms SLAC-Stanford
Eric Lee SLAC-Stanford Chris Stubbs Harvard
Steffen Luitz SLAC-Stanford Jon Thaler U. Illinois
Stuart Marshall SLAC-Stanford Tim Thurston SLAC - Stanford
20
Funding strategy for the LSST
  • Concept and Development Phase (2004 2008) ? Pri
    mirror fab
  • 15M from LSSTC members and private sponsors
  • 15M from the NSF ? 14.5M awarded 9-1-05
  • 18M from the DOE ?Labs providing initial seed
    RD funding
  • Construction Phase (2008 2013)
  • 120M from the NSF
  • 100M from the DOE
  • 50M from private sponsors
  • Operations Phase (2013 2023)
  • 20M/year is estimated as total annual
    operations budget
  • (10M/yr for the observatory and 10M/yr for
    data management)

21
Highest Ranked Technical Risks
_____________________________________________
  • Camera
  • Development of focal plane sensor meeting all
    specifications
  • Assembly of focal plane meeting flatness
    specification - SLAC
  • Design and fabrication of filters with spatially
    uniform passband -SLAC
  • Data Management
  • Interfacing an individual investigator with the
    voluminous LSST data
  • Scientific algorithm development for credible
    prototyping of pipelines
  • Establishing catalog feature set and method for
    querying data base
  • Telescope
  • Implementation of the wavefront sensor and
    stability of the correction algorithm
  • Metrology for the convex, aspheric secondary
  • Achieving 5-sec slew-and-settle specification
  • System Engineering
  • Completing flow-down of scientific mission to
    perfomance specifications
  • Generating a complete end-to-end simulator
  • Establishing link between technical performance,
    cost, and schedule

22
Science Simulator Overview
Simulations
23
G-Band
24
LSST Filter Set
25
Cerro Pachon Atmosphere Experiment
  • Cerro Pachon Facilities
  • SOAR 4.2m Telescope
  • Gemini 8m Telescope
  • MASS
  • DIMM
  • Weather
  • All-sky Camera

DIMM Integrated Measurement
MASS Structure above 500m
26
LSST Final Three Sites
San Pedro Martir
Cerro Pachon
Las Campanas
Site Evaluation
27
Telescope Development
LSSTs Ohara E-6 Glass
Facility and Dome Definition
M2
Camera interface
LBTs are Done GMT In Casting, LSST Cast Nov 05
28
Optical Design
0.6
29
Why is the LSST unique?
Primary mirror diameter
Field of view (full moon is 0.5 degrees)
0.2 degrees
10 m
3.5 degrees
Keck Telescope
30
Camera Development
31
LSST camera slice
sensors
raft base
front-end electronics
integrating structure
cold sink 1
cold sink 2
back-end electronics
32
LSST Camera
33
From LSST Science Reqts to Sensor Reqts
  • High QE to 1000nm ? thick silicon (gt
    75 µm)
  • PSF ltlt 0.7 (0.2) ? high
    internal field in the sensor
  • ? high resistivity substrate (gt 5
    kohmcm)
  • ? high applied voltages (30 - 50
    V)
  • ?
    small pixel size (0.2 10 µm)
  • Fast f/1.2 focal ratoi ? sensor
    flatness lt 5µm
  • ? package with piston, tip,
    tilt adj. to 1µm
  • Wide FOV ? 3200 cm2 focal plane
  • ? gt 200-CCD mosaic (16 cm2 each)
  • ? industrialized production process required
  • High throughput ? gt 90 fill
    factor
  • ? 4-side buttable package, sub-mm gaps
  • Fast readout (1 - 2 s) ? segmented sensors (6400
    TOTAL output ports)
  • ?
    150 I/O connections per sensor

34
LSST Camera sensor development
  • sensor modeling
  • characterization of test devices and prototypes
  • packaging investigation
  • readout electronics (incl. ASIC) design
  • focal plane mechanical and thermal engineering
  • optical metrology (sensor flatness)

35
Multi-port 4K x 4K 16M Pixel CCD strawman
32 segments/port
Strawman has 208 bonding pads total
J. Geary, LSST Strawman CCD Design, Dec. 2004
36
Current baseline Detector/WFS Layout
20 Curvature Sensors
3.5 FOV ? 64 cm ?
X
X
X
X
X
X
X
X
X
X
X
X
Shack Hartman Sensor
Raft
X
X
X
X
X
X
X
X
X
X
X
X
37
FPA Flatness Allocations Established
Sensor Module 5mm p-v flatness over entire
sensor surface
Raft Assembly 6.5mm p-v flatness over entire
surfaces of sensors
Focal Plane Assembly 10mm p-v flatness over
entire surfaces of sensors
38
Monte-Carlo simulation of long-wavelength light
absorption in silicon sensor. Right-hand
figures show the simulated points where 10,000
photons are absorbed. Left-hand panels show the
projections onto the charge-collection plane.
39
MATERIAL EVALUATION FOR INTEGRATING STRUCTURE OF
LSST FPA
FPA Deflection Under Gravity Silicon
Carbide-30 Option
0.45 mm max
SiC Focal-Plane for the Gaia Space Telescope
(courtesy of CoorsTek)
0.20 mm min
0.25 mm P-V
DZ mm?
support
1 mm Thick Walls
support
support
40
AlN
UP
41
LAB FOCAL PLANE ALIGNMENT USING NON-CONTACT LASER
TRIANGULATION
Reference Surface
Hi-Precision Shrt Rng. Head
XY Stage
Reflectivity Test with HIRES/Keck CCDs with AR
Coatings Keyence 30mm Head at 15mm Range
Long Range Head
L3 or WINDOW
L3
Received-light Waveform sobs 0.5 mm
  • Proposed Full Scale Metrology Setup

42
FREQUENCY SCANNING INTERFEROMETRY (Ala ATLAS
_at_LHC) FOR MEASURING RAFT POSITION DURING OPERATION
Quills
Mirror or Retro-Reflecter on IS
  • LSST IMPLEMENTATION
  • 4 Fiber PairsQuills on _at_ Raft (100 Tot)
  • Retroreflector or Flat Mirror on IS
  • Measure D 7mm to Top of IS
  • 100 Points 0.5mm in 1 Minute
  • Passive No In-Camera Electronics
  • Lasers Ref. Spectr. Off Telescope
  • Optical Multiplexing To Reduce Fiber

43
Some Techniques Explored For In-Situ Cold
Metrology
  • A laser and 2D diffraction grating projects
    unique pattern of ellipses onto FPA. Ellipses
    centroided by CCD to 1/3 mm. Spot motion and/or
    pattern distortion, determine flatness and/or
    other changes.
  • 2x2mm2 Diff. Gratings, 50 lines/mm
  • x 150 lines/mm, _at_ 100nm wide,
  • made at Nano-Fab. Lab at Stanford
  • Prototype Cold-Test Facility Under Construction

intensity
44
Laser Straightedge
  • Location on Integrating Structure of
  • Diode Laser With Actuators
  • Camera Receives Fully Transmitted Signal for
    Adjusting Actuators (not shown)

Under View
  • Locations in Rafts of
  • Light channels
  • Beam splitter
  • /cameras plug
  • Cross Section of Beam Splitter/Camera Plug
  • Beam Splitter
  • Camera
  • Adjustment Mechanism

45
Science Camera Electronics Layout
  • Front end cards
  • Analog signal processing
  • -100C
  • Back end cards
  • A/D conversion
  • Control / timing signal transmission
  • Data collection transmission
  • -20C 0C

46
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47
LSST Style Detector
_____________________________________________
48
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49
LSST Data Rates
________________________________
  • 3.2 billion pixels read out in 2 sec (15 second
    integration)
  • 1 pixel 2 Bytes (raw)
  • Over 3 GBytes/sec peak raw data from camera
  • Real-time processing and transient detection lt
    10 sec
  • Dynamic range 4 Bytes / pixel
  • gt 0.6 GB/sec average in pipeline
  • 5000 floating point operations per pixel
  • 2 TFlop/s average, 9 TFlop/s peak
  • 20-30 Tbytes/night

50
Stuart is adding one slidehere summarizingthe
DM F2F meeting
51
Project Baseline Schedule Plans
NSF D D Phase
MREFC Construction Phase
CommScience
First Light
Submit MREFC
Mirror Fabrication/ Cell Assembly
Telescope
Site Preparation
Mount/Dome
System Integration
Camera fabrication integration
Camera Design
Camera
Sensor Devl and protoype
Sensor Fabrication
Software Preliminary Design
Software Final Design
Data Mngt
SoftwareValidation
Software Integration
52
Where do you fit in?
  • Camera
  • Optics
  • Electronics
  • Mechanical
  • Calibration
  • Modeling
  • Motion Control
  • Data Management/DAQ

53
Extra Slides
54
Science Objectives Drive System Requirements
  • Image Quality
  • Is Key
  • f/1.25 beam
  • Large focal Plane
  • Construction
  • Techniques

55
NSF DD funding started Sept 1, 2005
  • 4 years, 14.1M
  • Basis for distribution of NSF funding
  • MREFC proposal preparation / baseline definition
  • Maintain first-light schedule
  • Risk reduction
  • NSF allocation TeleSite 40
  • Data Management 40
  • Project Office 20

56
Potential Contributions for the LSST
  • Concept and Development Phase (2004 2008)
  • 15M from LSSTC members and private sponsors
  • 15M from the NSF
  • 18M from the DOE
  • Construction Phase (2008 2013)
  • 120M from the NSF
  • 100M from the DOE
  • 50M from private sponsors
  • Operations Phase (2013 2023)
  • 20M/year is estimated as total annual
    operations budget
  • (10M/yr for the observatory and 10M/yr for
    data management)

57
P5 Charge
  • Letter From DOE NSF to Abe Seiden, Chair, P5,
    6-05
  • Role of P5 to Advise and prioritize specific
    projects at the request of the DOE and NSF and
    to maintain the roadmap for the field.
  • We would like P5 to begin the task of
    constructing a roadmap for the next decade..
    based on input from various HEPAP subpanels
    formed over the few months..
  • There are major opportunities ahead of us . a
    number of subpanels have laid out opportunities
    in other non-PEP-II, non-Tevatron areas such as
    neutrinos, dark energy and dark matter.
  • Draft recommendation by Oct. 05 on disposition
    of Tevatron and PEP-II, programs in context of a
    preliminary roadmap..
  • Final roadmap will be separately requested
    following conclusion of work of various
    subpanels.

58
The Essence of LSST is Deep, Wide, Fast!
  • Dark matter/dark energy via weak lensing
  • Dark matter/dark energy via supernovae
  • Galactic Structure encompassing local group
  • Dense astrometry over 30,000 sq.deg rare
    moving objects
  • Gamma Ray Bursts and transients to high redshift
  • Gravitational micro-lensing
  • Strong galaxy cluster lensing physics of dark
    matter
  • Multi-image lensed SN time delays separate test
    of cosmology
  • Variable stars/galaxies black hole accretion
  • QSO time delays vs z independent test of dark
    energy
  • Optical bursters to 25 mag the unknown
  • 5-band 27 mag photometric survey unprecedented
    volume
  • Solar System Probes Earth-crossing asteroids
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