Camera Overview LSST Camera Internal Review with Roger Smith, Cal Tech Kirk Gilmore October 14, 2008

July 7, 2008 SLAC Annual Program Review NSF June 11, FY-09FY-10FY-11FY-12FY-13FY-14 FY-15 FY-16 The current LSST timeline FY-17 FY-07 FY-08 NSF D&D Funding MREFC Proposal Submission NSF CoDR MREFC Readiness NSF PDR NSB NSF CDR NSF MREFC Funding Commissioning Operations DOE R&D Funding DOE CD-0 DOE CD-1 Telescope First Light DOE Operating Funds Camera Ready to Install NSF + Privately Supported Construction (8.5 years) System First Light ORR DOE MIE Funding Camera Delivered to Chile Sensor Procurement Starts DOE CD-3 DOE CD-2 DOE + Privately Supported Fabrication (5 years) DOE CD-4 Privately Supported camera R&D

Camera Lead Scientist Kahn (SLAC) Systems Engineering Gilmore (act.) (SLAC) WBS 3.2 Project Control Price (SLAC) WBS 3.1 Electronics Oliver (Harvard) WBS Sensor/Raft Development Radeka/O’Connor (BNL) WBS Optics Olivier (LLNL) WBS Cryostat Assembly Schindler (SLAC) WBS Calibration Burke (SLAC) WBS Camera Body & Mechanisms Nordby (SLAC) WBS Camera Data Acq. & Control Schalk (UCSC) WBS Camera Integration & Test Planning Nordby (SLAC) WBS 3.6 Performance, Safety and Environmental Assurance (SLAC) WBS 3.3 / 3.4 Observatory Integ., Test & Commission Support (SLAC) WBS 3.7 Corner Raft WFS/Guider Olivier (LLNL) WBS Camera Utilities Nordby (SLAC) WBS Sensor,Elect, Mech. Dev. Antilogus (IN2P3) LPNHE LAL APC Camera Organizational Chart Camera Project Scientist Gilmore (SLAC) Camera Project Manager Fouts (SLAC) WBS 3.1

LSST Camera Deliverable Org Chart Electronics Oliver (Harvard) WBS Sensor/Raft Development Radeka/O’Connor (BNL) WBS Optics Olivier (LLNL) WBS Cryostat Assembly Schindler (SLAC) WBS Calibration Burke (SLAC) WBS Camera Body Mechanisms Nordby (SLAC) WBS Data Acq. & Control Schalk (UCSC) WBS Corner Raft WFS/Guider Olivier (LLNL) WBS Utilities Nordby (SLAC) WBS Sensors/Filters Pain/Antilogus (IN2P3) LPNHE, LAL, APC, LPSC, LMA SLAC/LSST M&S to outside institutions via Financial Plan Transfer

The LSST Camera Team: 72 People from 16 Institutions Brandeis University J. Besinger, K. Hashemi Brookhaven National Lab S. Aronson, C. Buttehorn, J. Frank, J. Haggerty, I. Kotov, P. Kuczewski, M. May, P. O’Connor, S. Plate, V. Radeka, P. Takacs Florida State University Horst Wahl Harvard University N. Felt, J. Geary (CfA), J. Oliver, C. Stubbs IN2P3 - France R. Ansari, P. Antilogus, E. Aubourg, S. Bailey, A. Barrau, J. Bartlett, R. Flaminio, H. Lebbolo, M. Moniez, R. Pain, R. Sefri, C. de la Taille, V. Tocut, C. Vescovi Lawrence Livermore National Lab S. Asztalos, K. Baker, S. Olivier, D. Phillion, L. Seppala, W. Wistler Oak Ridge National Laboratory C. Britton, Paul Stankus Ohio State University K. Honscheid, R. Hughes, B. Winer Purdue University K. Ardnt, Gino Bolla, J, Peterson, Ian Shipsey Rochester Institute of Technology D. Figer Stanford Linear Accelerator Center - G. Bowden, P. Burchat (Stanford), D. Burke, M. Foss, K. Fouts, K. Gilmore, G. Guiffre, M. Huffer, S. Kahn (Stanford), E. Lee, S. Marshall, M. Nordby, M. Perl, A. Rasmussen, R. Schindler, L. Simms (Stanford), T. Weber University of California, Berkeley J.G. Jernigan University of California, Davis P. Gee, A. Tyson University of California, Santa Cruz T. Schalk University of Illinois, Urbana-Champaign J. Thaler University of Pennsylvania M. Newcomer, R. Van Berg

IN2P3 - France R&D support for camera development CNRS - National Center for Scientific Research IN2P3 - National Institute for Nuclear Physics and Particle Physics APC - Lab for Astroparticles and Cosmology (Paris) - Calibration/CCS CC-IN2P3 - Computing Center of IN2P3 (Lyon) - Computing Facilities LAL - Lab of Linear Accelerator (Orsay) - Electronics LMA - Lab of Advanced Materials (Lyon) - Filters LPSC - Lab for Subatomic Physics and Cosmology (Grenoble) - Calibration LPNHE - Lab for Nuclear Physics and High Energy (Paris) - Sensors/Elec.

Four Main Science Themes for LSST 1. Constraining Dark Energy and Dark Matter 2. Taking an Inventory of the Solar System 3. Exploring the Transient Optical Sky 4. Mapping the Milky Way Major Implications to the Camera 1.Large Etendue 2.Excellent Image Quality and Control of PSF Systematics 3.High Quantum Efficiency over the Range 330 – 1,070 nm 4.Fast Readout

The camera consists of the camera body and cryostat Access port for Manual Changer L3 Lens Assembly Filter in on-line position Camera Housing Filter Carousel Camera back flange—interface to telescope Cryostat support pedestal Utility Trunk Filter in stored position Lens support ring with light baffles L1 Lens Auto Changer L2 Lens with perimeter light absorber Aperture ring to define Beam Entrance

SLAC Annual Program Review 9 0.6”, 30  m “good” seeing” star image Aspheric surface LSST is a “seeing limited” telescope with ~10 micron (0.2 arc-sec ) diameter images 10  m pixel Camera: Flat 64 cm  CCD array

LSST Optical Design *f/1.23 *<0.20 arcsec FWHM images in six bands:  m *3.5 ° FOV  Etendue = 319 m 2 deg 2 LSST optical layout Polychromatic diffraction energy collection Detector position ( mm ) Image diameter ( arc-sec ) U 80%G 80%R 80%I 80%Z 80%Y 80% U 50%G 50%R 50%I 50%Z 50%Y 50%

Focal plane readout : The challenge *Large focal plane  189 Sensors, 3.2 Gpixels *High speed readout  2 sec goal *Low read noise, sky noise dominated > ~ 5 e rms *High crosstalk immunity ~ 80 db *Fully synchronous readout across entire focal plane *Large number of sensor pads (signals)  150/sensor ~ 30,000 pads total *High vacuum environment  contamination control *Minimization of vacuum feedthroughs

Focal plane readout : The strategy *Utilize highly segmented sensors to allow modest read speed *16 segments (ports) / sensor  500 kHz readout *“Raft” based electronics package  9 x 16 = 144 ports per raft *Electronic package located within Dewar to avoid ~30k Dewar penetrations *FPA electronics packaging requirement  All electronics must live in “shadow” of raft footprint ~ 125 mm x 125 mm *21 rafts  3,024 readout ports (source followers) *Data output on one optical fiber per raft  144 Mpixels/2 sec  ~1.4 Gbps on fiber *All raft electronics controlled by single “Timing & Control Module” for focal plane synchronicity  Timing/Control Port *Timing/Control Port also used for “Engineering Interface” for CCD studies & setup

3X3 CCD “RAFT” 4KX4K Science CCD 10  m pixels Corner area Wavefront sensing and guiding LSST focal plane layout CCD is divided into 16 1Mpix segments with individual readout

32-port CCD 3x port CCDs Raft tower electronics partitioning Front End Boards (6 per raft): 144-channels of video signal chain through CDS processing clock and bias drive ASIC-based (ASPIC/SCC) BEE motherboard and backplane: differential receiver signal chain ADC (16+ bits) buffers data transport to optical fiber clock pattern generation clock and bias DACs temperature monitor / control ~175K ~235K Flex cables (~ 500 signals) Cryo Plate (~170k) Cold Plate (~230k) ~185K Molecular Flow Barrier

CCD PACKAGED CCD RAFT From sensors to rafts to raft/towers - All being prototyped in TOWER 3 x 3 submosaic of CCDs front end electronics thermal management components Tower is an autonomous, fully-testable 144 Mpixel camera carrier CCD connector alignment pins baseplate thermal straps FEE boards housing (cold mass) 3-pt. mount cooling planes

Corner raft tower - Prototype in 09 at Purdue Guider sensor packages FE double-board unit for Guiders Vee-block and spring mount system from standard Rafts WFS sensor package FE double-board unit for WFS CCD Curvature Sensor CMOS Guide Sensor

17 Thermal control engineering model being developed Design approach –Create isolated zones for controlling the camera environments –Control zones independently to produce the environments needed –Allow for on-telescope cool-down/warm-up Thermal zones: 5 thermal zones in the camera 1.Focal plane array Cooled by Cryo plate 2.Cryo Plate Cools Cryo plate, shroud, FEE modules 3.Back end Cools Cold plate, BEE modules No temperature stability requirements 4.Camera body Actively controlled to match ambient temp 5.Utility trunk Actively controlled to match ambient temp Zone 5: Utility Trunk Zone 4: Camera Body BEE Module FEE Module Cryo Plate Cold Plate Power, Timing, Comm, Control ActuatorsControllers Valve Box Zone 3: Back End Utility Room Chillers Facility A.C. Facility Water Grid Zone 1: Focal Plane Array Zone 2: Cryo Plate L2 L1 Rafts Therm Strap Htr BEE Module FEE Module Rafts Therm Strap Htr Rafts Therm Strap Htr Filter L3

Auto Changer module Filter exchange mechanism in prototyping Filter exchange time = 120s Filter exchange consists of 3 assemblies – Carousel Stores up to five filters out of the field of view Moves chosen filter into exchange position –Auto Changer Supports filter in the field of view Moves filter from storage position into field of view –Manual Changer Used for filter exchange from outside the camera

Shutter design being prototyped in 08 *Shutter is comprised of two stacks of 3 blades each –One stack retracts to start an exposure, and the second stack extends to stop it This ensures uniform exposure time for all pixels 1s close to open time 1s open to close time Housing for Shutter mechanisms Drive timing belts Motors with 3 drive pulleys of different diameters Blades are contoured to fit around convex crown of L3 to save Z-space Blades stack beyond field of view when not in use Guide rail channel tracks cam followers in blades to reduce sagging of blades

Cryostat design overview Cold Plate Raft Tower Cryo Plate L3 Assembly Feedthrough Flange Back flange Cryostat Housing Mounting flange Support Tube Cryo Line

A camera integration plan is complete Camera Body Cryostat L1/L2 assy Utility Trunk

LSST will build on successes and resources available at SLAC for I&T GLAST - LAT Built at SLAC LSST Camera

Camera risk mitigation plan prior to construction R&D EffortPlan Status Demonstrate sensor performance Establish all specs are met: Flatness, high fill factor, electrical parameters, Study phase sensors received and being evaluated Efficient sensor procurement Establish cost, yield and performance of sensors PO’s being drafted that address risk areas. Prototype phase starting Establish reliability of shutter/filter excahnge mechanism Build prototype and testDesign completed. Procurement of parts begun Evaluate outgassing properties of cryostat components Contamination control demonstrated in engineering cryostat Contamination testing started. Materials selection process begun. 75cm filter w/multilayer coatings produced with non-uniformity of <1%. Fabrication of samples in large coating chamber to evaluate uniformity of filter transmission Passbands defined. Total system throughput modeled. Some witness samples already produced. RFP to potential vendors under review.

Summary of sub-system risk mitigation activities Mechanical Contamination Metrology

Summary of sub-system risk mitigation activities Optics CCS CCD Electronics