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Status of the Dark Energy Survey Camera (DECam) Project

Status of the Dark Energy Survey Camera (DECam) Project. Brenna Flaugher Fermilab Center for Particle Astrophysics DECam Project Manager. The Dark Energy Survey (DES). Proposal: Perform a 5000 sq. deg. survey of the southern galactic cap

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Status of the Dark Energy Survey Camera (DECam) Project

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  1. Status of the Dark Energy Survey Camera (DECam) Project Brenna Flaugher Fermilab Center for Particle Astrophysics DECam Project Manager

  2. The Dark Energy Survey (DES) • Proposal: • Perform a 5000 sq. deg. survey of the southern galactic cap • Measure dark energy with 4 complementary techniques • New Instrument (DECam): • Replace the PF cage with a new 2.2 FOV, 520 Mega pixel optical CCD camera + optics • Time scale: • Approvals and R&D 2004-2008 • Construction 2008-2011 • Commissioning in Oct. 2011 • Survey: • 525 nights Oct.-Feb. 2011-2017 • Area overlap with SPT SZ and VISTA VHS surveys • DECam available for community use the rest of the time Use the Blanco 4M Telescope at the Cerro-Tololo Inter-American Observatory (CTIO)

  3. Dark Energy Survey Science

  4. DES Collaboration 119 Members plus students and postdocs All 6 DES countries made it to the World Cup round of 16 • Fermilab (22 members) • University of Illinois Urbana-Champaign (10) • University of Chicago (9) • Lawrence Berkeley National Lab (9) • University of Michigan (7) • NOAO/CTIO (3) • Spain-DES Consortium: (7) • Institutd’EstudisEspacials de Catalunya, Institut de Fisicad’Altes Energies, CIEMAT • United Kingdom-DES Consortium: (22) • University College London, University of Portsmouth, University of Cambridge, University of Edinburgh, University of Sussex, University of Nottingham • Brazil-DES Consortium (6) • Ohio State University (6) • Argonne National Lab (3) • Santa Cruz-SLAC-Stanford Consortium (7) • Universitats-SternwarteMunchen (6) • Texas A&M University (6) • Funding: • DOE, NSF, STFC (UK), MEC (Spain), FINEP (Brazil), and the Collaborating Institutions

  5. 2 tilings 3 tilings DES Observing Strategy • 80-100 sec exposures • 2 filters per pointing (typically) • gr in dark time • izy in bright time • Multiple overlapping tilings (layers) to optimize photometric calibrations • 2 survey tilings/filter/year • Optimize Dark Energy science within the allotted 525 nights and where possible enable ancillary science, based on simulations • Plan to submit preliminary observing plan to the CTIO Director this Oct. • JP Rheault: Spectrophotometric calibration system for DECam 7735-226 Wednesday, 30 June 2010 Survey Area Overlap with SDSS equatorial Stripe 82 for calibration (200 sq deg) Connector region (800 sq deg) Main survey region (4000 sq deg) Total Area: 5000 sq deg

  6. The DES Instrument: DECam • To meet the DES science requirements, within the allocated time period DECam must have: • 3 sq. deg. field of view (~ 0.5 meter diameter focal plane) • excellent optical image quality, 0.27”/pixel • red sensitive CCDs (from LBNL) • g,r,i,z,y filters • low noise electronics (readout < 15 e noise @ 250kpix/sec) • cryogenic cooling system • After a lengthy review process, DECam was approved by the funding agencies (NSF, DOE, STFC, MEC) for construction in 2008 • Base-line cost to DOE is $35M between 2006-2011, ~ $7M in-kind from Collab. Inst. DECam Focal Plane • 62 2kx4k Image CCDs: 520 MPix • 8 2kx2k Alignment/focus CCDs • 4 2kx2k Guide CCDs • DECam is now 78% complete, integration is in progress on the telescope simulator at Fermilab and staged delivery to CTIO starts next month

  7. DES Instrument: DECam Mechanical Interface of DECam Project to the Blanco CCD Readout Filters Shutter Hexapod Optical Lenses

  8. DECam Mechanics • CCD focal plane is housed in a vacuum vessel (the imager) which is supported by the barrel • LN2 is pumped from the telescope floor to a heat exchanger in the imager: cools the CCDs to -100 C • CCD readout electronic crates are mounted to the outside of the Imager and are actively cooled (UIUC). • Filter changer with 8 filter capacity (UMichigan) • and Bonn shutter fit between 3rd and 4th lenses • Hexapod provides focus and lateral alignment capability for the corrector-imager system • Barrel supports the lenses and imager

  9. DECam CCDs Juan Estrada: Focal plane detectors for the dark energy survey 7735-61 of Thursday, 01 July 2010 • Red Sensitive CCD wafers are processed at DALSA and LBNL: • QE> 50% at 1000 nm • 250 microns thick • readout 250 kpix/sec • 2 RO channels/device • readout time ~17sec • Bare diced wafers are delivered to Fermilab with test data at -45 deg. C • At Fermilab we package and test the CCDs

  10. CCD ProductionDonna Kubik: DECam CCD testing 7735-311 Monday, 28 June 2010 2kx4k CCDs Tested per week 215 total • Packaging started Nov. 2008 • As of 6/22/10: • 215 2kx4k CCDs packaged and tested • 95 are Science Grade ready for the focal plane! • 62 + 10 spares are required • expect ~ 120 SG : spares in case of damage during final installation/shipping • Total yield is ~ 20% • Also have 14 science grade 2kx2k (out of 24 packaged) need 12 plus spares, expect ~24 SG 120 expected 91 SG complete 72 needed

  11. Front End ElectronicsTerri Shaw: System architecture of the dark energy survey camera readout electronics 7735-123 Monday, 28 June 2010 Javier Castillia: DECam readout electronics 7735-311 Monday, 28 June 2010 • DECam CCD readout started with the Monsoon system developed by NOAO • For the prime focus location, DECam requires higher density boards and actively cooled crates • 12 instead of 8 channel video card • 9 instead of 2 CCD clock cards • SLINK instead of SYSTRAN on MCB • Production of all boards and crates is nearly complete • Currently we are testing the production readout system with 28 eng. grade CCDs in the MultiCCD test Vessel (MCCDTV) Imager Prototype/Multi-CCD Test Vessel

  12. Survey Image System Process Integration (SISPI)Klaus Honscheid: The DECam data acquisition and control system 7740-57 Wed. 30 JuneJacob Eiting: HTML 5, Websockets, and Sproutcore:a web-based user interface for the dark energy camera (DECam) 7740-39 Tuesday, 29 Science Data Flow Aaron Roodman: Focus and alignment using out-of-focus stellar images at the dark energy survey 7735-136 Monday, 28 June 2010 SISPI is in regular use at Fermilab with the MCCDTV and will be used for imager testing Peter Lewis, Rafe Schindler: Design and initial performance of a radiometric all-sky infrared camera (RASICAM) for DES/CTIO7735-119 Monday, 28 Data Transport System

  13. Pin-hole camera on MCCDTV • Using SISPI to take and assemble the images

  14. On-Sky testing • DECam runs on the 1m at CTIO provide calibration information and a test bed for DECam hardware • October 2008, Nov. 2009, Feb. 2010 • 1 DECam CCD • with preproduction electronics • in a small test dewar • on the CTIO 1m (next to the Blanco) • In Nov. 2009 noise from the Dome motors was observed in readout • In Feb. 2010 implemented changes that got rid of the noise. • July 2010: DES filter set will be used • Sept. – Jan. 2011 Precam (2 2kx4k DECam CCDs) on the Schmidt

  15. Optics • Field of view: 2.2o diameter • 2 Aspheres (one surface on C2 and C4) • C1 is the largest: 980mm diameter • C5 is imager window: 500mm diameter • Pixel (15 µm) scale • 0.26”/pixel (1” = 3.8 pix = 57 µm) • Image quality Design FWHM: 0.27” (15 µm) • Status • Blanks complete Jan. 2008 (Corning) • Grinding and polishing is in progress at SESO (STFC funding) • C3 and C5 have been delivered! • C2, C4, and C1 expected next month Attachment ring Bipods Focal plane C5, vacuum window C4 Filters & Shutter C2 - C3 C1

  16. DECam Optical Blanks at Corning (Jan. 2008) C2 C1 Polishing is nearly complete at SESO, removes only ~ 1 mm per side

  17. Lens Fabrication • C3 inspection at SESO April 2010, C3 is now at UCL • C4 Cell inspection at UCL

  18. Filters • Filter contract awarded to Asahi in 2009 • 620mm substrate, 600mm clear aperture • Delivery of all 5 filters (g,r,i,z,y) expected by Dec. 2010 • Asahi has built and commissioned a huge coating chamber as well as custom cleaning, polishing and testing equipment • 100mm square filters from Asahi (for DES calibration) show excellent transmission!

  19. DECam Imager • Focal plane support plate is painted black to reduce scattered light between CCDs • DECam imager with three readout crates on the handling cart • June 26th First cool down with two engineering grade CCDs installed, production LN2 and crate cooling systems: read out with low noise! • Next step: install ~25 eng. grade CCDs • Greg Derylo: Assembly of the dark energy survey CCD image 7739-163 01 Jul 2010 • Jiangang Hao: Measuring the flatness of focal plane for very large mosaic CCD camera 7735-137 28 Jun 2010

  20. Hexapod • Factory • acceptance of • the Hexapod • On May 3rd • Arrived at • Fermilab • June10th

  21. Shutter Arrived at Fermilab May 12th : Successfully operated May 14th! Shutter Owners manual

  22. Filter Changer Mechanism (FCM) Arrived at Fermilab May 12thGreg Tarle: Large format filter changer mechanism and shutter for the dark energy survey 7739-162 Thursday, 01 July 2010

  23. DECam imager will be cooled by a Closed Loop LN2 System 200L Reservoir LN2 pump, 300 W Gifford McMahon GN2 condenser Bypass valve to Pre-cool transfer lines Transfer Line Length ~31 meters Pump to Polar axis ~34 meters Polar axis to Imager Dec Axis Hose Wrap Polar Axis Hose Wrap

  24. LN2 Cooling systemHerman Cease: Cooling the dark energy camera CCD array using a closed-loop two-phase liquid nitrogen system 7739-16 01 Jul 2010 • The LN2 system for CTIO will be commissioned at Fermilab and used to cool the imager on the telescope simulator • It was assembled and hooked up to the imager (on the floor) on June 18th. Testing and commissioning are in progress. • Note – two cryo coolers provide cooling to condense the return fluid/gas, only one is required. • The prototype cooling system will continue to provide cooling to the MCCDTV

  25. DECam Telescope Simulator at FermilabTom Diehl: Testing the dark energy camera on a telescope simulator 7735-125 Monday, 28 June 2010 • Provides platform for testing all components of DECam in all orientations • also tests installation • Filter changer and shutter • Imager into the cage at the service platform • F/8 handling • Cage onto the telescope spiders

  26. Conclusions DES Collaboration formed and DECam project began in 2004 June 2010: Major components of DECam are complete Integration is in progress at Fermilab on the telescope simulator Full system testing planned for the next year DECam is on budget and on schedule for delivery and first light at CTIO in 2011

  27. Extra Slides Cerro Tololo Inter-American Observatory

  28. Telescope Simulator and F/8 handing system White Rings match the rings on the Blanco (except they are bolted instead of welded) Fins and fin attachments made from NOAO drawings (1970) Yellow rings were designed by Fermilab to allow us to reach any orientation Fake F/8 and counterweight used for installation tests

  29. DECam Talks and Posters • Talks: • Juan Estrada: Focal plane detectors for the dark energy survey 7735-61 of Thursday, 01 July 2010 • Klaus Honscheid: The DECam data acquisition and control system 7740-57 Wednesday, 30 June 2010 • Jacob Eiting: HTML 5, Websockets, and Sproutcore:a web-based user interface for the dark energy camera (DECam) 7740-39 Tuesday, 29 • Posters: •  Greg Derylo: Paper Title: Assembly of the dark energy survey CCD image 7739-163 01 Jul 2010 • JiangangHao: Paper Title: Measuring the flatness of focal plane for very large mosaic CCD camera 7735-137 28 Jun 2010 • Herman Cease: Paper Title: Cooling the dark energy camera CCD array using a closed-loop two-phase liquid nitrogen system 7739-16 01 Jul 2010 • Rafe Schindler: Design and initial performance of a radiometric all-sky infrared camera (RASICAM) for DES/CTIO7735-119 Monday, 28 June • Tom Diehl: Testing the dark energy camera on a telescope simulator 7735-125 Monday, 28 June 2010 • Aaron Roodman: Focus and alignment using out-of-focus stellar images at the dark energy survey 7735-136 Monday, 28 June 2010 • Terri Shaw: System architecture of the dark energy survey camera readout electronics 7735-123 Monday, 28 June 2010 • Donna Kubik: DECam CCD testing 7735-311 Monday, 28 June 2010 • Greg Tarle: Large format filter changer mechanism and shutter for the dark energy survey 7739-162 Thursday, 01 July 2010 • Javier Castillia: DECam readout electronics 7735-311 Monday, 28 June 2010 • JP Rheault: Spectrophotometric calibration system for DECam 7735-226 Wednesday, 30 June 2010

  30. DES Deliverables • An MOU outlining the nature of the partnership between NOAO and the DES collaboration was finally executed in May, 2008. Goals stated in the MOU: • Successful deployment of the new instrument (DECam) and the community pipeline • Successful completion of the scientific goals of the DES collaboration • To complete the science program, the DES collaboration requested 525 nights during Oct – Feb. over a 5 year period (105 nights/year) • In exchange for the telescope time, the DES collaboration will deliver • The DECam Instrument (details will follow) • The Community Pipeline: will remove the instrumental signatures and provide astrometric and rough photometric calibration for images taken under well defined observing modes. • One year after routine observations have been established, the DES data will become public.

  31. DES Timeline • 2004: Fermilab and National Optical Astronomy Observatory (NOAO) approvals • 2005: Nov. DOE approved CD-0 (Mission Need) for a ground based DE project • 2006: P5 and the Dark Energy Task Force • Dark Energy Task Force report recommended projects like DES • P5 recommendation to proceed with DES. Reiterated this in 2008 • 2007: Oct. CD-1 approval • 2008: April/May CD2/3a approval (Baseline and long lead procurements start for $35M project) • 2008: Oct. CD-3b (construction) approval • 2009: July Status review by DOE and NSF • 2010: June Status review by DOE and NSF • 2011: First light – Start of commissioning! • Sept. 2012: CD-4 Baseline for DECam project complete

  32. Spectroscopic Redshift Training Sets for DES Training Sets to the DES photometric depth in place (advantage of a `relatively’ shallow survey)

  33. Forecast Constraints DETF FoM • DES+Stage II combined = Factor 4.6 improvement over Stage II combined • Consistent with DETF range for Stage III DES-like project • Large uncertainties in systematics remain, but FoM is robust to uncertainties in any one probe, and we haven’t made use of all the information

  34. Dark Energy Survey History • In December 2003 NOAO issued an Announcement of Opportunity which offered up to 30% of the Blanco telescope time over five years (525 scheduled nights) in exchange for a major new instrument • The DES collaboration formed at that time and has been proceeding through a plethora of review processes (NSF, DOE, STFC, etc) • In Aug/Sept 2004, the NOAO Blanco Instrumentation Review panel (BIRP) reviewed the DES proposal and recommended that NOAO and the DES collaboration move the project forward.

  35. Photometric Redshifts Elliptical galaxy spectrum • Measure relative flux in multiple filters: track the 4000 A break • Estimate individual galaxy redshifts with accuracy (z) < 0.1 (~0.02 for clusters) • Precision is sufficient for Dark Energy probes, provided error distributions well measured. • Good detector response in z band filter needed to reach z>1

  36. Galaxy Photo-z Simulations +VHS* DES DES griz DES griZY +VHS JHKs on ESO VISTA 4-m enhances science reach 10 Limiting Magnitudes g 24.6 r 24.1 i 24.0 z 23.9 +2% photometric calibration error added in quadrature Key: Photo-z systematic errors under control using existing spectroscopic training sets to DES photometric depth: low-risk J 20.3 H 19.4 Ks 18.3 Z 23.8 Y 21.6 *Vista Hemisphere Survey PI: R. McMahon, Cambridge DES collaborator (approved by ESO 11/06) +Developed improved Photo-z & Error Estimates and robust methods of outlier rejection

  37. 3 Techniques for Cluster Selection and Mass Estimation: Optical galaxy concentration Weak Lensing Sunyaev-Zel’dovich effect (SPT) Cross-compare these techniques to reduce systematic errors Additional cross-checks: shape of mass function N(M,z) cluster spatial correlations M(r;z) Cluster Cosmology with DES

  38. DECam Monsoon Block Diagram provides readout of 6 CCDs provides clocks for 9 CCDs 39

  39. DECam Changes to Monsoon Electronics • Due to space constraints, in order to use the Monsoon System for production DECam electronics, we have had to design denser modules and have customized the new boards to meet our specific application: • 12 channel CCD Acq Module provides customized bias voltages, RTD readout, and Vsubstrate ramp control and provides readout for 6 instead of 4 CCDs (FNAL) • Customized Clock Board to better address our clocking needs; services 9 instead of 2 CCDs, greater fanout ability (135 clock outputs vs 32) to drive more clocks. (CIEMAT- Madrid) • Master Control Board modified to work with S-Link and to enhance multi-crate synchronization (IFAE - Barcelona)

  40. FE Electronics Packaging • Each crate will contain two backplanes; one with 6 slots and one with 4 slots. • A single 4-slot section would provide for readout the 4 guide CCDs • The remaining backplane sections will provide readout of up to 72 science and alignment CCDs. • Active cooling will hold electronics temperature stable to within +/-2°C. Crate is designed to radiate less than 20Watts.

  41. The Crate w/o Shields Vicor Power Supply 60mm Fans Fan 12vDC PS 92mm Fans Chiller water in/out Water Chiller Heat Exchangers

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