Title: The Large Synoptic Survey Telescope
1The Large Synoptic Survey Telescope
A Ground based Facility To Explore Dark
Energy/Dark Matter
Kirk Gilmore SLAC/KIPAC
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3Opportunities
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5Dark 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.
6LSST 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!
7The 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
8Relative Survey Power
9The 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
10Principle 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
11LSST 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.
12DE 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.
13Color-redshift
14Color-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.
15LSST Measurements of Cosmic Shear
From Takada et al. (2005)
16Funding 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
17LSST 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.
18LSST CAMERA ORGANIZATION CHART
______________________________________________
19LSST 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
20Funding 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)
21Highest 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
22Science Simulator Overview
Simulations
23G-Band
24LSST Filter Set
25Cerro 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
26LSST Final Three Sites
San Pedro Martir
Cerro Pachon
Las Campanas
Site Evaluation
27Telescope Development
LSSTs Ohara E-6 Glass
Facility and Dome Definition
M2
Camera interface
LBTs are Done GMT In Casting, LSST Cast Nov 05
28Optical Design
0.6
29Why 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
30Camera Development
31LSST camera slice
sensors
raft base
front-end electronics
integrating structure
cold sink 1
cold sink 2
back-end electronics
32LSST 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
34LSST 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)
35Multi-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
36Current baseline Detector/WFS Layout
20 Curvature Sensors
3.5 FOV ? 64 cm ?
X
X
X
X
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X
X
X
X
X
X
X
Shack Hartman Sensor
Raft
X
X
X
X
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37FPA 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
38Monte-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
40AlN
UP
41LAB 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
42FREQUENCY 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
43Some 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
44Laser 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
45Science 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
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47LSST Style Detector
_____________________________________________
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49 LSST Data Rates
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- 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
50Stuart is adding one slidehere summarizingthe
DM F2F meeting
51Project 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
52Where do you fit in?
- Camera
- Optics
- Electronics
- Mechanical
- Calibration
- Modeling
- Motion Control
- Data Management/DAQ
53Extra Slides
54Science Objectives Drive System Requirements
- Image Quality
- Is Key
- f/1.25 beam
- Large focal Plane
- Construction
- Techniques
55NSF 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
56Potential 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)
57P5 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.
58The 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