National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Astronomy & Astrophysics Decadal Survey Large Synoptic Survey Telescope (LSST) 6-8m equivalent aperture 3 degree Field of View (FOV) 1-3 Gpixel detector ($30-100M at present costs) Data pipeline, data mining, “National Virtual Observatory” (NVO) The Panoramic Optical Imager

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Science Goals – NEOs Near Earth (“killer”) asteroids Requires whole sky survey, good PSF, <10 sec readout

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Supernovae – The Future of the Universe – is it dominated by dark energy? Science Goals – SNIa

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Supernovae – The Future of the Universe – is it dominated by dark energy? Science Goals – SNIa

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Science Goals – SNIa Supernovae – What is the dark energy, and the future of physics What are the relative roles of  Dark matter  Dark energy (“Quintessence”) What is the dark energy equation of state? Need ~300 SNIa at z~0.7 (Z band ~23 mag)  red response and PSF essential!

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Science Goals – PN From the Main Sequence to the White Dwarfs  will the Sun make a planetary nebula? It will, but only if white dwarf remnant has >0.55 solar masses We don’t know what sort of white dwarf the sun will make  clusters, like M67, fill blanks in our knowledge  need to survey lots of sky (~1 degree) for very faint white dwarfs (V ~ 26)  Need good PSF to separate galaxies from stars

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Many Other Science Goals Near Earth Objects Space junk / fast objects Trans-Neptunian objects / Asteroid belt Variability / microlensing / transients Proper motions / binaries / parallax High-z supernovae (z~0.4, z~0.8, z~1.2) Strong lensing Weak lensing Star properties / galactic structure Galaxy evolution / formation Large-scale structure / clusters z > 6 (first light in the universe) Rare unknown objects

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Traditional Mosaic Imagers Too expensive Too slow Poor red response A  dd M = 2 Figure of merit: Collecting area A may be fixed, but we can improve all three other factors

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Targeted Detector Enhancements Cost  Current mosaics ~0.5 ¢ / pixel CCD only 2-3 ¢ / pixel, with electronics, shutter, filter Speed  Current mosaics have 30 –100 sec readout  NEO searches call for <20 sec exposures Red response  Current mosaics 25% QE at Z band, poor fringing Image motion compensation  Only slow (~1 Hz) telescope guiding, but atmospheric image motion and telescope shake at Hz

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Our Proposed Solution Bring state of the art and system approach to bear Detector  Bring yield to >50%; currently ~25%  Extend red sensitivity by 3x  Add image motion compensation  improve PSF by 20% CCD Packaging -- make it efficient for 100's of detectors Cryostat -- make it efficient for 100's of detectors Electronics -- design a cheap, scalable module Computers -- 1GHz Linux PC per 8K x 8K imager is enough Software -- pay attention to scalability and efficiency

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array The Orthogonal Transfer Array (OTA) – A New Technology CCD Imager A new paradigm in large imagers OTCCD pixel structure Basic OTCCD cell OTA: 8x8 array of OTCCDs

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array One 512x512 CCD Components of an OTA Clock, bias, address lines Output lines o Bond to carrying wafer o Flip over o Thin backside o AR coat One 4K x 4K monolithic OTA

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Detector Details – Overview Each CCD cell of a 4Kx4K OTA Independent 512x512 CCD  Individual or collective addressing  1 arcmin field of view Dead cells excised, yield >50%  Bad columns confined to cells Cells with bright stars for guiding 8 output channels per OTA  Fast readout (8 amps, 2 sec) Disadvantage mm gaps, but gaps and dead cells are dithered out anyway 5cm 12 um pixels

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Detector Details – CCD Output Wrap output amplifier and JFET follower around under serial register. Run clock, bias, and address lines between cells. Limit to ~100 micron gap between cells Good metrology over entire OTA

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Detector Details – Clock and Analog Signals and Cell Addressing Clocks and biases to OTA cells8 channels of output from OTA

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Detector Details – Enhanced Red 45um high-resistivity Si  extended red response  very low fringing

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Detector Details – Orthogonal Transfer Orthogonal Transfer  remove image motion  high speed (few usec) Normal guiding (0.73”) OT tracking (0.50”)

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Detector Details – Image Motion Compensation “Rubber” focal plane permits low order “AO” over degrees  Every 30 msec collect guide star info (Guide stars are plentiful for WIYN)  Compute a “displacement surface” for all cells  Perform OT shifts of all cells Removes image motion from atmosphere and telescope shake on arbitrarily large angular scale Improvement in PSF (20-30%) is very significant  Exposure time to a given S/N decreases by 30-40%

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Package and Demonstration Camera (QUOTA) 4-side buttable package with multilayer ceramic substrate Flexprint to hermetic or through wall Cryocooled bars Four OTAs = QUOTA (8K x 8K = 15 x 15 arcmin)

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Electronics – Signal Chain SDSU dual channel video board  2 channels  150 kpixel/sec  CDS, 16 bit ADC  15 W power Analog Devices 9826  3 channels (RGB)  15 Mpixel/sec  CDS, 16 bit ADC  250 mW power

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Electronics – OTA Control Motherboard with OTA acquisition board(s)  Gain  CDS/ADC  FPGA controller Addresses cells Interprets commands Generates clock patterns

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Electronics – Computer Communications Four OTA served by an Interface Unit and Gbit fiber  Decodes computer commands  Synchronizes readout  Formats data for computer transmission 64 Mpixel = 128 Mb

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Electronics – Block Diagram Scalable system architecture QUOTA

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Acquisition Software Tasks Observation shift and guide loop

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Reduction Software Tasks Read out science arrays; organize data Flat fielding: OT shifting integrates over many pixels Adding dithered images  Determine offsets (Continuous? Piecewise constant?)  Remove bad data (dead cells, gaps, etc)  Remove cosmic rays  Combine (Remap? Piecewise constant? Integer pixel?) Ideally want many dithers but only one final image

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array The WIYN One Degree Imager (ODI) PI-driven science for WIY (U. Wisconsin, Indiana U., Yale) and the US community (via NOAO) Pathfinder for LSST detector and data pipeline Why WIYN?  Excellent “seeing”; median ~ 0.7”  1 degree FOV, inherent to telescope  Hydra spectrograph – 1 degree FOV  US access NGC 7620 in R, I Seeing = 0.38” Sky Survey

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array WIYN One Degree Imager Instrumentation goal for WIYN 64 OTAs = ODI (32K x 32K = 1 x 1 deg) QUOTA does the R&D, different funding for large cryostat, additional devices, filters, shutter, etc. Deployment in ”

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array The OTA Team CCD Design and Fabrication: Barry Burke (Lincoln Labs), John Tonry (IFA) – CCDs for 20+ years, inventors of OTCCD Project management: George Jacoby (WIYN) – 20+ years of instrumentation at NOAO, Director of WIYN Observatory Package and Cryostat design: Gerry Luppino (IFA) – 8K, 12K CCD mosaics for CFHT, UH Electronics, device testing: Barry Starr (NOAO) – 12K at CFHT Optics, filter, shutter, commissioning: Chuck Claver (NOAO) – WIYN optics, AO, George Jacoby (WIYN) Software: John Tonry (IFA)

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Experience OTCCD camera used at MDM (Tonry, Burke, Schechter 1997) Extensive modelling of image motion compensation (Kaiser, Tonry, Luppino 2000)

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Experience OTCCD camera used at MDM (Tonry, Burke, Schechter 1997) Extensive modelling of image motion compensation (Kaiser, Tonry, Luppino 2000) OPTIC camera nearing completion (two 2K x 4K OTCCDs)

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Timeline to Deployment

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Budget QUOTA (Quad OTA Camera)  ~$700K + Detectors ($750K)  2 ¢ / pixel (but large R&D costs) ODI (WIYN One Degree Imager)  additional $3.7M  0.4 ¢ / pixel (includes corrector, shutter, and filters) Additional funding now would allow  Multiple foundry runs to reduce risk, produce more devices  Additional engineering for improved hardware and software design, earlier and more reliable implementation  On-chip shuttering  Integrated CMOS ASICs for focal plane controllers (read out NxN CCDs of OTA instead of N)

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Budget Details: ODI Total -- $3.7M  Detectors (2 add’l foundry runs)$1000K  Hardware Design$ 300K  Dewar plus cooling system$ 300K  Shutter plus BVRIZ filters$ 400K  Software Design$ 200K  Acquisition computers/software$1000K  Optical corrector for WIYN$ 500K

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Additional Applications LSST Earth imaging Surveillance Medical imaging High energy physics detectors

National Science Foundation, July 23, 2001 The Orthogonal Transfer Array Summary 4” 16” QUOTA: 8K ODI: 32K (~$4M) LSST: 48K