1 B. Flaugher P5 April 2006 The Dark Energy Survey From Scientific Goals to Science Quality Data Brenna Flaugher Fermilab April 2006 P5 Meeting

2 B. Flaugher P5 April 2006 DES Science and Technical Requirements 5000 deg 2 of the So. Galactic Cap in 525 nights (5 yrs) photometric-redshifts to z=1.3 with dz < A small and stable point spread function (PSF) < 0.9'' FWHM median A large camera, on the Blanco 4m – 3 deg 2 camera with ≥ 2.2 deg FOV Data Management system – 300GB/night, automated processing – Publicly available data archive after 1 yr Filters, CCDs, Read noise – SDSS g,r,i,z filters; nm – QE > 50% in the z band ( nm) – Read noise <10 e- Optical Corrector with excellent images – Pixel size <0.3” /pixel – < 0.4” FWHM in the i and z bands The Science Requirements flow to Technical Requirements

3 B. Flaugher P5 April 2006 The DES Instrument: DECam 3556 mm 1575 mm Hexapod Optical Lenses F8 Mirror CCD Read out DECam will replace the prime focus cage on the Blanco Filters Shutter Prime Focus Instrument -in optical path -space and thermal constraints

4 B. Flaugher P5 April 2006 DES: DECam and Data Management 62 2kx4k Image CCDs: 520 MPix 8 2kx2k Guide, focus, alignment DECam will be larger than any existing CCD camera Each image: ~ 20 Galaxy clusters ~ 200,000 Galaxies Each night ~ 300 GB Entire survey ~ 1 PB John Peoples is the DES project director Fermilab leads the DECam project UIUC/NCSA leads the DM project DES Focal Plane OUTLINE of this talk DECam project description cost and schedule Data Management project description cost and schedule

5 B. Flaugher P5 April 2006 DES CCDs LBNL Design: fully depleted 2kx4k CCDs –QE> 50% at 1000 nm, 250 microns thick –15 um pixels, 0.27”/pixel –readout 250 kpix/sec, readout time ~17sec LBNL CCDs in use on WIYN telescope. From S. Holland et al, LBNL IEEE Trans. Elec. Dev. Vol.50, No 1, , Jan LBNL CCDs are much more efficient than the SITE CCDs in Mosaic II at high wave lengths To reach redshifts of ~1.3 DES will spend 46% of survey time in z –band DES CCD design has already been used on telescopes in small numbers (3) SNAP CCDs are the next generation, optimized for space DES is the 1 st production quantity application for LBNL CCDs z band

6 B. Flaugher P5 April 2006 CCD Fabrication and Packaging Follow LBNL business model developed for SNAP: Foundry delivers partially processed wafers to LBNL (~650 microns thick) LBNL finishes wafers (250 microns thick), tests, dices (production rate 5 wafers/month) FNAL builds up the CCD packages and tests CCD – will match CCD delivery rate Preconceptual R&D: 36 Eng. grade 2kx4k CCDs in hand used to develop focal plane packages, characterize CCD performance, test CCD readout electronics Expect 20 more in July 06 Potential Science grade devices expected in Oct. 06 FY07: establish CCD processing and packaging yield –preliminary est. 25% yield (SNAP devices) –implies 18 months and $1.6M for 70 good devices –CCD yield is a cost and schedule driver DES Wafers – June 2005!

7 B. Flaugher P5 April 2006 Front End Electronics: CCD Readout FNAL, Barcelona, Madrid, UIUC Opportunity for large international contribution: Spanish consortium has submitted a proposal to their funding agencies (~$2M). Would provide ~$0.5M for the production FEE. Status: –UIUC funds used to purchase prototype readout systems –have already achieved 6.5e noise at 160kpix/sec, –have a design that fits in 3 temp. controlled crates in PF cage –need to test readout of multiple CCDs Part of Fermilab Team in the testing lab LN2 Dewars Readout racks Filter and shutter controls 3 operational CCD testing setups

8 B. Flaugher P5 April 2006 Camera Vessel Prototype 10 slot thermally controlled crate for CCD readout electronics Cryo and Vacuum controls Focal plane Feed-through board for CCD signals Full size prototype is being built by U. Chicago. It will be ready for CCDs this summer and will be used to test multi- CCD readout

9 B. Flaugher P5 April 2006 Survey Image System Process Integration (SISPI) CTIO will upgrade the Telescope Control System (TCS) Data Management (DM): U. Illinois-Astro/NCSA U Illinois-HEP (J. Thaler) is leading the SISPI development - similar to HEP-DAQ systems

10 B. Flaugher P5 April 2006 Optical Corrector Design Preliminary Design complete (UMich, FNAL, UCL) –Image quality fwhm: ~ 0.33” (<0.4” required) Opportunity now for international collaboration: –March 05, the UK Consortium submitted a proposal to PPARC to lead the procurement of the optics –1.47 M pound proposal to cover cost of polishing, mounting, and alignment of the lenses in the barrel –P. Doel at U. College London Optical Science Lab will manage the procurement and fabrication March 2006, PPARC Council announced that it “will seek participation in DES Additional UK funding ($0.5M ) available through Portsmouth (SRIF3): ~60% of the blanks US University funding could cover the rest. Procurement of the optics is ~2 years CRITICAL PATH filter Dewar window C1 has 940 mm diameter C2 C3 C4 5 elements, fused silica

11 B. Flaugher P5 April 2006 U. Michigan will –handle procurement and testing of the filters –match SDSS – g,r,i,z and introduce a well defined cut-off at high wavelength –design and fabricate or procure a combined filter changer and shutter DES Filters Filter changer will be a cartridge system similar to PanStarrs design

12 B. Flaugher P5 April 2006 Image Quality: An observed PSF pattern optical model = * Elliptical PSFCircular PSF whisker DES optics Primary Mirror Blanco Primary mirror –excellent figure: D80 <0.25” –radial position controlled by counterweights –Upgrades in Oct. 5 reduced the mirror motion from ~1.5mm to < 0.4mm, further reduction expected 24 Radial Supports 3 Hard Points 33 Pressure Pads Ray tracing model of existing mirror, camera and corrector qualitatively reproduces PSF patterns seen in data In this model the primary was misaligned by 0.2 mm x and mm y Primary Mirror Support cell

13 B. Flaugher P5 April 2006 CTIO and the Blanco Telescope Have produced some of the best Weak Lensing measurements Cerro Tololo Image Quality Sept-Feb – site median PSF 0.65” FWHM – Prime Focus (PF) delivered median PSF 0.9” FWHM (used in all DES constraint forecasts) DES/CTIO upgrades will stabilize the PSF and should improve the median FWHM: DES – focus and alignment sensors on focal plane: generate focus and lateral alignment information with each image – active control of camera position: hexapods will provide focus and lateral adjustments of corrector + camera system – improved thermal environment: heat dissipation will be actively controlled CTIO is planning additional upgrades to the radial supports

14 B. Flaugher P5 April Level 0 Image Simulations → DM Challenge 0: Done! –Reformatted SDSS data used to simulate DES images Level 1 Catalog &Image Sim. → DM Chal. 1: Done! –500 sq. deg. catalog; 500 GB of images; FNAL and UChicago computing used Level 2 Catalog and Image Sim. In progress –5000 sq. deg. catalog; 5 TB of images –FermiGrid & MareNostrum SuperComputer (Barcelona) –Higher resolution N-body simulation, more realistic galaxy properties, and more sophisticated atmosphere and instrument models (noise, ghosts) –Recover input cosmology from catalogs using 4 DES key project methods Level 3 Catalog and Image Simulations –Suite of full-DES catalogs (i.e., different input cosmologies) –Synergy with DOE SciDAC proposal (with many DES collaborators) to produce large cosmological simulations for dark energy studies –1 year of DES imaging data –Recovery of input cosmologies from catalogs and images –Stress test of full data processing system DES Simulations Feed DM Challenges

15 B. Flaugher P5 April 2006 DECam critical paths: CCDs & Optics CCDs: LBNL can deliver CCDs at a rate of 20/month after 3 month startup We need 70 CCDs for the FP including spares Preliminary yield estimate of 25% implies ~18 months Cost is ~$23k/wafer, 25% yield implies $1.6M Construction start of Oct. 07 implies last CCD is finished March ’09 Install last CCD and test full camera ~ 2 months Ready to ship to Chile ~ May 09 Optics: Blanks ~ $0.8M, 8 month delivery Polishing ~ $1.5M, 18 month delivery Assembly and alignment into corrector ~ 6 months Ready to ship to Chile ~ 2.75 yrs after procurement begins (Oct. 06 → May 09)

16 B. Flaugher P5 April 2006 DECam Schedule Dependent on DOE funding and international participation Opportunity exists to capitalize on international interest in DES UK consortium would lead and fund procurement of optical elements Spanish Consortium would lead and fund procurement of production FEE Important for DOE to provide timely assurance that it intends to proceed with DES (we will be ready technically to proceed with optics procurement by Aug. 06) A positive recommendation from P5 would help in this process DOE Critical Decision Process schedule FY06 Preconceptual R&D; CD1 Paper review Sept.06 FY07 R&D, CD2 Review March 07, CD3 Review Sept. 07 FY08 MIE Construction start FY09-10: Assemble and test camera vessel and corrector –Ship to Chile and install on Blanco, first DES observations Dec. 09

17 B. Flaugher P5 April 2006 DECam Funding Need Profile (then yr $, Overhead included) Total Project Cost: (FY07-FY10) = $19.7 M Total DOE Project cost: $16.7 M DOE Major Item of Equipment (MIE) total of $12.6 M includes M&S equipment ($7M), technical labor ($5.6M) and a total of ~35% contingency * Additional $1M in External funds in FY06,Total External Funds = $4M *

18 B. Flaugher P5 April 2006 DES Data Management Project U. Illinois and NCSA lead the DM project –Joe Mohr (U. Illinois) is the project leader –Cristina Beldica (NCSA) is the project manager DM System Requirements –Reliably transfer ~300GB/night for 525 nights from CTIO to U.Illinois/National Center for Supercomputing Applications (NCSA) –Automatically process data with built-in quality assurance –Archive the data products and serve the processed data to collaboration –Provide community access to the archive 1 year after images were collected DM Team –U Illinois/NCSA, Fermilab and NOAO –Additional DES collaborators Deliverables to DES and astronomical community –DM System ( High Performance Computing platforms and workstations )  Pipeline middleware  Astronomy modules  Catalog database  Image Archive –Archived science ready DES data U Illinois/NCSA DES DM Team

19 B. Flaugher P5 April 2006 This grid-based, modular and flexible data management system was deployed and tested in Data Challenge 1 (Oct ‘05-Jan ‘06)

20 B. Flaugher P5 April 2006 DM Schedule and Status Pursuing iterative development strategy ‘04-’09 –Yearly data challenges Oct-Jan ‘05-’08 –Development targets full delivery in 2009  DC1: base level system in place  DC2: data quality, stress test  DC3: deploy and test outside NCSA  DC4: final validation and stress test Data Challenge 1 Results (Oct 1 ‘05-Jan 31 ‘06) –DM system deployed and tested –Automated reduction (500GB raw reduced into 5TB) –Catalogued and calibrated 50 million objects –Confirmed photometry and astrometry Reduced, pseudo-color DC1 Image

21 B. Flaugher P5 April 2006 DES DM Funding Sources (then yr $, OH included) DM System Construction (‘04-’09)$5.1M U Illinois/NCSA (seed funding, incl. 2.5FTE/yr) $1.40M NOAO (NOAO Science Archive, 1.5FTE/yr) $1.00M Fermilab* (1.5FTE/yr) $1.00M Total to date$3.40M Pending NSF DES CyberInfrastructure proposal($1.70M) Model is for NSF to fund proposed Data Management system * Contributions by Fermilab scientists (DOE supported)

22 B. Flaugher P5 April 2006 Conclusions DES provides the next logical step in both technology and science –Builds on existing technology and infrastructure, and capitalizes on collaboration experience with large DAQ systems, silicon vertex detectors, and data handling –3 deg 2 camera: x7 larger area and x7 faster readout than existing Mosaic camera on the Blanco –1PB total processed images available to the public; data released 1 year after images taken –Development and implementation of data analysis techniques for photo-z’s, cluster masses, weak lensing, baryon oscillations, and supernovae are the next step towards the science of the Stage IV projects of the future (LSST, SNAP)

23 B. Flaugher P5 April 2006 extras

24 B. Flaugher P5 April 2006 CCD Requirements

25 B. Flaugher P5 April 2006 CCD testing results Good news: with 5 thin CCDs tested it looks likely that they can be grouped together ( need more statistics) Have all the testing infrastructure running – now need more analysis! Horizontal Charge Transfer Inefficiency for different voltages

26 B. Flaugher P5 April 2006 Side view

27 B. Flaugher P5 April 2006 Front view

28 B. Flaugher P5 April 2006 Isometric view camera end