Date post: | 15-Jan-2016 |
Category: |
Documents |
View: | 221 times |
Download: | 0 times |
DARK ENERGY DARK ENERGY SURVEY (DES)SURVEY (DES)
Francisco Javier Castander Serentill
All material borrowed from DES collaboration
IEEC/CSIC
Announcement of OpportunityAnnouncement of Opportunity
Blanco Instrumentation PartnershipBlanco Instrumentation Partnership• Develop a major instrument for Blanco 4m CTIO
• Submit a science, technical & management plan
• Community instrument
• Up to 30% of Blanco 4m for 5 years commencing in 2007 or 2008
• Letter of intent March 15, 2004
• Proposals August 15 2004
The Dark Energy Survey
• We propose to make precision measurements of Dark Energy– Cluster counting, weak lensing and
supernovae– Independent measurements
• by mapping the cosmological density field to z=1– Measuring 300 million galaxies– Spread over 5000 sq-degrees
• using new instrumentation of our own design.– 500 Megapixel camera– 2.1 degree field of view corrector– Install on the existing CTIO 4m
Cosmology in 2004
Combine to measure parameters of cosmology to 10%. We enter the era of precision cosmology.
– Confirms dark energy (!)
2003 Science breakthrough of the year
WMAP measures the CMB radiation density field at z=1000
Sloan Digital Sky Survey measures the galaxy density field at z < 0.3
The Big Problems: Dark Energy and Dark Matter
• Dark energy?Who ordered that? (said Rabi about muons)
• Dark energy is the dominant constituent of the Universe
• Dark matter is next
The confirmation of Dark Energy points to major holes in our understanding of fundamental physics
1998 Science breakthrough of the year
95% of the Universe is in forms unknown to us
Dark Energy
1. The Cosmological Constant Problem Particle physics theory currently provides no understanding of why
the vacuum energy density is so small: DE (Theory) /DE (obs) = 10120
2. The Cosmic Coincidence ProblemTheory provides no understanding of why the Dark Energy density
is just now comparable to the matter density.
3. What is it?Is dark energy the vacuum energy? a new, ultra-light particle? a
breakdown of General Relativity on large scales? Evidence for extra dimensions?
The nature of the Dark Energy is one of the outstanding unsolved problems of fundamental physics. Progress requires more precise probes of Dark Energy.
• One measures dark energy through how it affects the universe expansion rate, H(z):
H2(z) = H20 [ M (1+z) 3 + R (1+z) 4 + DE (1+z) 3 (1+w) ]
matter radiation dark energy
• Note the parameter w, which describes the evolution of the density of dark energy with redshift. A cosmological constant has w = 1.
w is currently constrained to ~20% by WMAP, SDSS, and supernovae
• Measurements are usually integrals over H(z) r(z) = dz/H(z)• Standard Candles (e.g., supernova) measure dL(z) = (1+z) r(z)• Standard Rulers measure da(z) = (1+z)1 r(z)• Volume Markers measure dV/dzd = r2(z)/H(z)• The rate of growth of structure is a more complicated function of H(z)
Measuring Dark Energy
DES Dark Energy Measurements• New Probes of Dark Energy
– Galaxy Cluster counting• 20,000 clusters to z=1 with M > 2x1014 M
– Weak lensing• 300 million galaxies with shape measurements
– Spatial clustering of galaxies• 300 million galaxies
• Standard Probes of Dark Energy– Type 1a Supernovae distances
• 2000 supernovae
Supernova
• Type 1a Supernovae magnitudes and redshifts provide a direct means to probe dark energy – Standard candles
• DES will make the next logical step in this program:– Image 40 sq-degree repeatedly
– 2000 supernovae at z < 0.8
– Well measured light curves
SCP EssenceLSST
DES
SNAP
2000 2005 2010 2015 2020
SDSS
Current projects
CFHLSPanStarrs
Proposed projects
New Probes of Dark Energy
• Rely on mapping the cosmological density field
• Up to the decoupling of the radiation, the evolution depends on the interactions of the matter and radiation fields - ‘CMB physics’
• After decoupling, the evolution depends only on the cosmology - ‘large-scale structure in the linear regime’.
• Eventually the evolution becomes non-linear and complex structures like galaxies and clusters form - ‘non-linear structure formation’.
z = 30 z = 0
Spatial Clustering of Galaxies
• The distribution of galaxy positions on the sky reflects the initial positions of the mass
• Maps of galaxy positions are broken up in photometric redshift bins
• The spatial power spectrum is computed and compared with the CMB fiducial power spectrum.
• The peak and the baryon oscillations provide standard rulers.
• DES will– Image 5000 sq-degrees– Photo-z accuracy of z < 0.1 to z = 1
– 300 million galaxiesCooray, Hu, Huterer, Joffre 2001
LSST
DES
SNAP
2000 2005 2010 2015 2020
PlanckSDSS WMAP
PanStarrs
Weak Lensing
Ds distance to sourceDl distance to lens
Dls distance from lens to source
Light path
Background galaxy shear maps
Lensing galaxies
• Weak lensing is the statistical measurement of shear due to foreground masses
• A shear map is a map of the shapes of background galaxies
Weak Lensing
Shear maps(z)
Galaxy map
z = 1/4z = 1/2
z = 3/4
DeepLens CFHLS
• The strength of weak lensing by the same foreground galaxies varies with the distance to the background galaxies.– Measure amplitude of shear vs. z
– shear-galaxy correlations
– shear-shear correlations
• DES will– Image 5000 sq-degrees
– Photo-z accuracy of z < 0.1 to z = 1
– 10-20 galaxies/sq-arcminute
LSST
DES
SNAP
2000 2005 2010 2015 2020
PlanckSDSS WMAPPanStarrs
Peaks in the Density Field
• Clusters of galaxies are peaks of the density field.
• Dark energy influences the number and distribution of clusters and how they evolve with time.
2 Mpc16 Mpc
Cluster Masses
• Our mass estimators– Galaxy count/luminosity– Weak lensing– Sunyaev-Zeldovich
• The South Pole Telescope project of J. Carlstrom et al.
• DES and SPT cover the same area of sky
• Self calibration– Mass function shape allows
independent checks– Angular power spectrum of clusters– Allows an approach at systematic
error reduction
SZ
OpticalLensing
X-ray
Mass
Cluster Counting
• Locate peaks in the density field using cluster finders– Red sequence methods
– SZ peaks
• DES will– Image 5000 sq-degrees
– Photo-z accuracy z = 0.01 to z = 1
– 20,000 massive clusters
– 200,000 groups and clusters
z = 0 1 3
z
N
LSST
DES
SNAP
2000 2005 2010 2015 2020
PlanckSDSS WMAPPanStarrs
Low mass
High mass
Very massive
13.7 log M < 14.2
14.2 log M
14.5 log M
We aim at ~5% precision on Dark Energy
Cluster Counting Weak Lensing Supernova
The Planck satellite will provide tighter input CMB measurements, and the constraints will improve slightly.
ww w
DEMM
Joint constraints on w and wa are promising: initial results suggest wa ~ 0.5.
w ~ 5% and DE ~ 3%
The Dark Energy Survey
• We propose the Dark Energy Survey– Construct a 500 Megapixel camera
– Use CTIO 4m to image 5000 sq-degrees
– Map the cosmological density field to z=1
– Make precision measurements of the effects of Dark Energy on cosmological expansion:
• Cluster counting
• Weak lensing
• Galaxy clustering
• Supernovae
5000 sq-degrees
Overlapping SPT SZ survey
4 colors for photometric redshifts
300 million galaxies
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Design of the Dark Energy Survey
James Annis
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Science Goals to Science Objective
• To achieve our science goals:– Cluster counting to z > 1
– Spatial angular power spectra of galaxies to z = 1
– Weak lensing, shear-galaxy and shear-shear
– 2000 z<0.8 supernova light curves
• We have chosen our science objective:– 5000 sq-degree imaging survey
• Complete cluster catalog to z = 1, photometric redshifts to z=1.3• Overlapping the South Pole Telescope SZ survey• 30% telescope time over 5 years
– 40 sq-degree time domain survey• 5 year, 6 months/year, 1 hour/night, 3 day cadence
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
DARK ENERGY SURVEY (DES)DARK ENERGY SURVEY (DES)
Science Goal: measure w=p/ρ, the dark energy equation of state, to a precision of δw ≤ 5%, with
• Cluster Survey
• Weak Lensing
• Galaxy Angular Power Spectrum
• Supernovae
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
DES: Requirements
Science Goals
• Cluster Survey
• Weak Lensing
• Galaxy Angular Power Spectrum
• Supernovae
Science Requirements
redshifts, area, filters, limit mag, red
image quality, area
photometry, area, limit mag
repeat, area, filters, red
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Science Requirements
1. 5000 sq-degrees• Significantly overlapping the
SPT SZ survey area• To be completed in 5 years
with a 30% duty cycle
2. 4 bandpasses covering 390 to 1100 nm• SDSS g,r,i,z• z modified with Y cutoff
3. Limiting magnitudes• g,r,i,z = 24,24,24,23.6• 10σ for small galaxies
4. Photometric calibration to 2%• 1% enhanced goal
5. Astrometric calibration to 0.1”
6. Point spread function• Seeing < 1.1” FWHM
• Median seeing <= 0.9”
• g-band PSF can be 10% worse
• Stable to 0.1% over 9 sq-arcminute scales
From chapter 3 of NOAO proposal; version 3 of requirements.
Version 4, under review, will be a formal science requirements document.
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Limiting Magnitude
Limiting magnitude (10σ for small galaxies) was set by flow down of science goals:
• ½ L* cluster galaxies at redshift 4000A break leaving blue filter
– g,r,i,z = 22.8,23.4,24.0,23.3– Complete cluster catalog
• Galaxy catalog completeness– g,r,i,z = 22.8,23.4,24.0,23.6– Simple selection function
• Blue galaxy photo-z at faint mags– g,r,i,z = 24.0,24.0,24.0,23.6– Photo-z for angular power spectra
and weak lensing
0 redshift 1.5
0 redshift 1.5
Mag of ½ L* galaxy
photo-z – spectro-z
i = 23-24
Red Galaxy
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Galaxy Cluster Redshifts
• the distribution of the number of clusters as a function of redshift is sensitive to the dark energy equation of state parameter, w.
four filters (griz) track 4000 Å break.
Need z band filter to get out to redshift >~ 1
• DES data will enable cluster photometric redshifts with dz~0.02 for clusters out to z~1.3
for M > 2x1014 M
Theory
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Photometric Redshifts
Resulting limiting magnitudes give very good photometric redshifts
• Monte Carlo simulations of photometric redshift precision– Evolving old stellar pop. SED– Redshifted and convolved with
filter curves. Noise added.– Polynomial fit to photo-z– For clusters, averaging all
galaxies in the cluster above limiting magnitude.
• Template fit for photo-z
• These are sufficient to achieve our science goals.
½ L* 2 L*
1.0x1014 M0
Clusters
Red galaxies
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
The Footprint
Requirements• Overlap with SPT SZ survey• Redshift survey overlap
Footprint• -60 <= Dec <= -30• SDSS Stripe 82 + VLT surveys
Overlap target Right Ascension (deg)
Declination (deg)
Area (sq. deg.)
SPT -60 to 105 -75 to -60
-30 to -65-45 to –65
4000
SDSS Stripe 82 -50 to 50 -1.0 to 1.0 200
Connection region
20 to 50 -30 to –1.0 800
DIRBE dust map, galactic coordinates
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Survey Strategy I
• Design decision 1: area is more important than depth– Image the entire survey area multiple times
• Design decision 2: tilings are important for calibration– An imaging of the entire area is a tiling– Multiple tilings are a core means of meeting the photometric
calibration requirement: offset tilings, not dithers
• Design decision 3: substantial science with year 2 data– We will aim for substantial science publications jointly with the
public release of the year 2 data.
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Survey Strategy II
• Year 2– g,r,i,z 100 sec exposures– g,r,i,z =24.6, 24.1, 23.6, 23.0– Calibration: abs=2.5% rel=1.2%– Clusters to z=0.8– Weak lensing at 12 gals/sq-arcmin
• Year 5– z 400 sec exposures– g,r,i,z =24.6, 24.1, 24.3, 23.9– Calibration: abs=<2% rel=<1%– Clusters to z=1.3– Weak lensing at 28 gals/sq-arcmin
• Two tilings/year/bandpass
• In year 1-2, 100 sec/exp• In year 3, drop g,r and devote
time to i,z: 200 sec/exp• In year 5, drop i and devote
time to z: 400 sec/exp
• If year 1 or 2 include an El Nino event, we lose ~1 tiling, leaving three tilings at the end of year 2. This is sufficient to produce substantial key project science.
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
DES Time Allocation Model
September: 4 bright+ 4 dark nights 22 nights October: 4 bright+ 5 dark nights 22 nights
November: 4 bright+ 4 dark nights 22 nights
December: 4 bright+ 4 dark nights 21 nights Telescope shut down Dec 25, 31
January: 4 bright+ 5 dark nights 11 nights and the 2nd half of all nights
February: 3 bright+ 3 dark nights 11 nights and the 2nd half of all nights
March – August all none
Total 257 nights 108 nights
Time to the Community and to the Dark Energy Survey
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Time Allocation
• Analytic calculation of time available– 30 year CTIO weather statistics– 5 year moving averages– Calculate photometric time– Can complete imaging survey and
time domain survey with 3 sq-degree field of view camera
• Simulations of observing process– Use mean weather year – Survey geometry– Observing overhead– NOAO time allocation model– High probability of completing core
survey area in time allocated
Probability of obtaining 8 tilings per year over survey area. Dark is 100%, light yellow ~50%
=> DES time allocation model just sufficient to achieve science objective.
CTIO mean weather year
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Photometric Calibration Strategy
• Calibrate system response– Convolve calibrated spectrum
with system response curves to predict colors to 2%
– Dedicated measurement response system integrated into instrument
• Absolute calibration– Absolute calibration should be
good to 0.5%– Per bandpass: magnitudes,
not colors– Given flat map, the problem
reduces to judiciously spaced standard stars
• Relative calibration– Photometry good to 2%– Per bandpass: mags, not colors– Use offset tilings to do relative
photometry• Multiple observations of same
stars through different parts of the camera allow reduction of systematic errors
• Hexagon tiling:– 3 tilings at 3x30% overlap– 3 more at 2x40% overlap
– Aim is to produce rigid flat map of single bandpass
– Check using colors• Stellar locus principal colors
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Survey Simulation
• We plan a full scale simulation effort– Led by Huan Lin– Centered at Fermilab and Chicago– Using analytic, catalog and full
image simulation techniques
• Over 4 years– Underway, starting with photometric
redshift simulations
• Use the simulations in 3 ways:– Check reduction code
• Mock data reduction challenge• Chris Stoughton
– Prepare analysis codes• Mock data analysis challenge• Josh Frieman
– Prepare for science
• Survey simulations– Jim Annis
• Catalog level simulations– Lin, Frieman, students for photo-z and
galaxy distributions – Risa Weschler’s Hubble Volume n-body– Albert Stebbins’s multi-gaussian
approximation– Mike Gladder’s empirical halo model
• Image level simulations– Erin Sheldon for weak lensing– Doug Tucker and Chris Stoughton
• Terapix skyMaker• Massey’s Shapelets code
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Survey Planning Summary
• We have well defined science goals and a well defined science objective– A 5000 sq-degree survey substantially overlapping the SPT survey– A time domain survey using 10% of time
• The science requirements are achievable.– A good seeing, 4 bandpass, 2% calibration, i ~ 24 survey
• Multiple tilings of the survey area the core of the survey strategy and photometric calibration.
• The survey can be completed using:– 22 nights a month between September and October– 21 nights in December– 22 half nights a month in January and February
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
DES Instrument Project
OUTLINE• Science and Technical
Requirements• Instrument Description• Cost and Schedule
Prime Focus Cage of the Blanco Telescope
We plan to replace this and everything inside it
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
DES Instrument Reference Design
3556 mm
1575 mmCamera
Filters
Optical Lenses
ScrollShutter
The Reference Designrepresents our current design choices and may change with more analysis
1.2.1 CCDs1.2.2 CCD Packaging1.2.3 Front End Electronics1.2.4 CCD Testing1.2.5 Data Aquisition1.2.6 Camera Vessel1.2.7 Cooling1.2.8 Optics1.2.9 Prime Focus Cage1.2.10 Auxiliary Components1.2.11 Assembly and Testing
Instrument Construction Organization
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Optics Design
• 2.2 deg. FOV Corrector – 5 powered elements (Fused Silica)– one aspheric surface (C4)
• four filters – griz needed for DES– others can be used
• More details of the design in the next talk (Steve Kent)
• Cost for the glass ~ 660k$• Cost for figuring ~ $1M• ~ 1.5 yr delivery
Corrector
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Dark Energy Survey:Optical Design and Issues
2.2 Deg. Field of View Corrector
• Requirements• Performance• Issues
Steve Kent, Fermilab, for the DES CollaborationDark Energy SurveyBIRP, Aug 12, 2004
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
2.2 Deg. Field of View Corrector
● 14 requirements total
– 0.39 to 1.1 μ (SDSS filter bandpasses)
– Scale 17.7 arcsec/mm
– Field size 450 mm diameter (2.2 degrees)
– D80 < 0.64 arcsec everywhere (FWHM < .4 arcsec)
– No ADC (Atmospheric Dispersion Corrector)
– Minimize ghosting
– Space for filter, shutter
– Design choices should minimize procurement, fabrication schedule.
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Gladders may11 design
Features:
•Flat focal plane•Five lenses + Filter
• (including dewar window)•All fused silica•One aspheric surface•Largest diameter 1.1 meters•Flexibility spacing elements•Low distortion (<1%)•Good ghosting properties
• star halos• exit pupil image
Filter
Shutter
C1
C2
C3
C4
C5
Filter
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
CCDs
• Reference Design: LBNL CCDs– QE> 50% at 1000 nm – 2k x 4k– 15 micron pixels– 250 microns thick– fully depleted (high resistivity)– back illuminated– 4 side buttable– readout 250 kpix/sec– 2 RO channels/device– readout time ~17sec– fringing eliminated– PSF controlled by bias voltage
R&D on LBNL CCDs nearly finished. LBNL CCDs have been used at LICK and on the WIYN Telescopeand on the Mayall
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
CCD QE and Read noise
1
10
100
0 1 10 100
Sample time (ms)
Noi
se (
elec
tron
s)
Read noise for a recently finished DALSA 2k x 4k
250 kHz → 7e-
To get redshifts of ~1 we spend ~50% of survey time in z-band.
LBNL CCDs are much more efficient in the z band than the current devices in Mosaic II
DECam / Mosaic II QE comparison
0
10
20
30
40
50
60
70
80
90
100
300 400 500 600 700 800 900 1000 1100
Wavelength (nm)
QE, LBNL (%)QE, SITe (%)
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
CCD Wafers:• Existing masks have 2/wafer• to be cost efficient we will make new masks with 4/wafer
CCD Acquisition Model
Reference Design Acquisition Model• Order CCDs through LBNL – good relationship with commercial foundry• Foundry delivers wafers to LBNL (~650 microns thick)• LBNL
– applies backside coatings for back illuminated operation– oversees thinning (~ 250 microns thick) and dicing– tests all devices on cold probe station
• LBNL delivers all tested, unpackaged devices to FNAL• FNAL packages and tests CCDs• Prepared to package ~ 160 CCDs (spares, yield)
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Packaging
• CCD Packaging will be done at Fermilab
• LICK and LBNL have already successfully packaged small quantities.
• We are developing a working relationship with R. Stover at LICK (we visited in July) to learn packaging techniques
CCD Packaging is very similar to building the components of silicon vertex detectors. Fermilab has built many vertex detectors for CDF and D0, and is contributing to CMS
CCD packaged at LBNL
Invar Foot
AlN circuit board
Wirebonds to CCD
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Packaging and Testing Process
• Packaging and testing keep up with anticipated CCD delivery rate of 20/month (5 wafers).
• Packaging:– one CCD takes ~ 1 week to complete– Plan to have capabilities to start 2/day
• Testing: – estimate 2 days/CCD– 3 identical test stands needed to keep up with 5 CCDs/week
• LBNL cold probe test results will guide which CCDs to package 1st
• Assume 60 good devices from production run and up to 18 good devices from preproduction run
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
CCD Test Stand and Acceptance Criteria
• Testing– linearity, full well depth, QE, CTE,
readnoise, dark current
• Testing and acceptance criteria will be defined as we gain experience with LBNL CCDs
• Will also consider impact of acceptance criteria on community
• Multiple tilings reduces impact of bad regions
• Study with 100 consecutive bad columns found ~1.5% of tiling area was imaged less than 3 times after 5 complete tilings
Broadband, High-Intensity
Light Source(~300 to 1100 nm) S
hu
tte
r
Monochromator(~300 nm to 1100 nm) F
ilte
rs
CCDelectronics Integrating
Sphere CalibratedPhotodiode
Light Tight Box
Fe55 Source
Cryostat withCCD
CCDQuartz Window
DAQ and InstrumentControl Computer
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Camera Reference Design
Focal Plane
62 2k x 4k CCDs for main image, 4-side buttable, 15 micron pixels
8 1k x 1k CCDs for guiding and focus
Camera Design
Focal Plane
feed throughboard
Frontendelectronics
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Camera Vessel
• Vacuum feed through board brings signals out of cryostat
Camera is separated into two spool pieces: one for signal feed throughsone for cooling and vacuum services
Removal of cooling spool piece allows access to back of focal plane and cables
Cooling/ Vacuum spool piece
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Cooling and Integration
• Reference Design has LN2 reservoir inside cryostat
• Fill from recondensing dewars on floor
• investigating alternative: Gifford-McMahon cryo coolers on cooling spool piece which condense N2 directly into reservoir
Will fully assemble prime focus cage at FNAL and test all systems together (corrector, focal plane,cooling, data acquisition, data management....)before shipping to Chile
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Front End Electronics and DAQ
• Large focal plane implies long cables between CCD and electronics crates• Reference design has clock drivers and preamps as part of the cable assembly • Goals are noise < 5 e-, linearity <0.25%, support a readout rate of 250 kpix/sec• Reliable operation requires careful consideration of internal and external components• Minimize heat generated in the PF cage by locating DAQ off telescope
off the cage
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Data Acquisition
DAQ Parameters
62 (+4)
2k x 4k (1k x 1k)
2
250 kHz (17 s)
971 MB
57 MB/s
4
1k x 1k
2
1 MHz (0.5 s)
8 MB
16 MB/s
# CCDs
Pixels/CCD
Amps/CCD
Digitization rate
Bytes/image
Data rate FEDAQ
Image CCDs Guide CCDs
DES data rates are relatively high by astronomy standards, but not for particle physics.
• We will use the Monsoon data acquisition system, developed by NOAO.
• We will modify it to separate digital and analog functionality.
Using Monsoon shortens development time and enables collaboration with NOAO and other Monsoon users.
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
DES Modifications:ADCs will reside on the telescope.The rest of the electronics will be off the telescope.
• Save space and power on the telescope.
• Reduce noise (ADCs are closer to the CCDs).
• Save money.
Data Acquisition
LINUX PCPCI FIBER CARD
Ethernet Link100Mb/s
1Gb/s Fiber(50Mpixel/s)
1Gb/s Fiber(50Mpixel/s)
LINUX PCPCI FIBER CARD
1Gb/s Fiber(50Mpixel/s)
SYNC
Ethernet Link100Mb/s
SYNC
Ethernet Link100Mb/s
N NODES
SUPERVISORY NODELINUX PC
LINUX PCPCI FIBER CARD
CCDor
FPA
10Mb/sEthernet
10Mb/sEthernet
10Mb/sEthernet
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
SYNC SYNCN NODES
SUPERVISORY NODELINUX PC
CCDor
FPA
10Mb/sEthernet
10Mb/sEthernet
10Mb/sEthernet
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
PIXEL ACQUISITION NODE 1
DETECTOR HEADELECTRONICSNODE 1
SYNC SYNCN NODES
SUPERVISOR NODELINUX PC
CCDor
FPA
10Mb/sEthernet
10Mb/sEthernet
10Mb/sEthernet
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
CCDor
FPA
PIXEL ACQUISITION NODE 2 PIXEL ACQUISITION NODE 3
DETECTOR HEADELECTRONICSNODE 2
DETECTOR HEADELECTRONICSNODE 3
We will modify this
part.
Monsoon architecture:
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
We Can Do This!
The Silicon facility at Fermilab has experience building the Run 0, I, & II silicon vertex detectors:
° Micron precision assembly ° Wirebonding ° Thermal Management ° CleanroomsBuilding a CCD focal plane uses many of the same skills, but has many fewer devices.
LBNL has extensive experience with CCD development and packaging for SNAP/JDEM
UIUC has experience building large, high rate data acquisition systems at SLAC, Fermilab, and Cornell.
U Chicago has experience with optical design and optical systems on SDSS° DES does not depend on pioneering development work.° The main issues are cost, schedule, and integration.
The DES collaboration has assembled a team of experienced scientists, engineers, designers and technicians
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Schedule Milestones
• Optics and CCDs are the most Challenging tasks• CCDs: Preproduction run: FY05, Production run: FY06 and FY07• Optics: Order glass in FY06, Figuring/polishing in FY07
ID Task Name Start
10 Funds available (Fermilab R&D, external) Fri 10/29/04
38 Ready to submit masks to Dalsa Thu 12/2/04
40 Order 24 wafers of devices Thu 12/30/04
43 1st fu lly processed CCDs (8) in hand Thu 10/6/05
46 Submit order for final processing of remaing 1st batch wafers Thu 10/13/05
58 First production CCDs in hand Thu 7/6/06
17 FY07 funding available Tue 10/31/06
363 Order Corrector elements Tue 10/31/06
146 CCDs Ready for mounting on focal p lane Tue 1/15/08
368 Lenses and filters complete Mon 1/21/08
335 Dewar closed, ready for testing Tue 3/11/08
265 Camera testing complete - ready for corrector Tue 8/26/08
423 corrector, fi lters and cage ready for camera Mon 9/1/08
453 Prime focus cage complete Mon 10/27/08
455 Testing complete Mon 1/5/09
457 Ready to Ship to Chile Mon 1/19/09
489 Ready to Mount on Blanco Mon 3/16/09
491 1st light Mon 4/27/09
493 1st useful data Mon 5/25/09
Qtr 3 Qtr 1 Qtr 3 Qtr 1 Qtr 3 Qtr 1 Qtr 3 Qtr 1 Qtr 3 Qtr 1 Qtr 3 Qtr 12004 2005 2006 2007 2008 2009
Fully Commissioned byJune 2009!
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Total Cost profile in Then Yr $(excluding institutional overhead)
FY04 FY05 FY06 FY07 FY08 FY09 TotalM&S 0 1,097 3,321 3,362 520 68 8,368M&S Contingency 0 0 379 338 1,580 782 3,079Total M&S 0 1,097 3,700 3,700 2,100 850 11,447
Labor 609 1062 955 1150 560 299 4,635Labor Contingency 304 531 478 575 280 150 2,318Total Labor 913 1593 1433 1724 839 449 6,953
Total (M&S + Labor) 913 2,690 5,133 5,424 2,939 1,299 18,400
The Reference Design represents our current choices for meeting the science goals
Total cost for the Instrument project is $18.4 M excluding institutional overheads and 22.5M$ with overhead in then year $.
We will be ready for observations by June 2009. This schedule is funding limited.
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Instrument Project Organization
Brenna Flaugher for the DES Collaboration BIRP Meeting August 12, 2004 TucsonFermilab, U Illinois, U Chicago, LBNL, CTIO/NOAO
Conclusions
• We have a strong collaboration with a wide variety of skills that cover all aspects of this project
• With this collaboration we can complete the instrument and start survey operations on the telescope in 2009