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Ground-based Observatories Instrumentation and Detector Systems Doug Simons (Gemini Observatory) Paola Amico (Keck Observatory) Scientific Detector Workshop - 2005 Photo Courtesy Akihiko Miyashita, Subaru Telescope Coauthor List Poster Oral Dietrich Baade, European Southern Observatory Sam Barden, Anglo Australian Observatory Randall Campbell,W.M. Keck Observatory Gert Finger, European Southern Observatory Kirk Gilmore, Stanford/SLAC Roland Gredel, Calar Alto Observatory Paul Hickson, University of British Colombia Steve Howell, National Optical Astronomy Observatory Norbert Hubin, European Southern Observatory Andreas Kaufer, European Southern Observatory Ralk Kohley, GranTeCan/ Instituto de Astrofisica de Canarias Philip MacQueen, University of Texas Sergej Markelov, Russian Academy of Sciences Mike Merrill, National Optical Astronomy Observatory Satoshi Miyazaki, Subaru Telescope Hidehiko Nakaya, Subaru Telescope Darragh O'Donoghue, South African Astronimical Observatory Tino Oliva, INAF/ Telescopio Nazionale Galileo Andrea Richichi, European Southern Observatory Derrick Salmon,Canada France Hawaii Telescope Ricardo Schmidt, National Optical Astronomy Observatory Homgjun Su, National Astronomical Observatory of China Simon Tulloch, ISAAC Newton Group/ Instituto de Astrofisica de Canarias Mark Wagner, Large Binocular Telescope Olivier Wiecha, Lowell Observatory Binxun Ye, National Astronomical Observatory of China 2 A World-wide Sample of Instruments 3 Summary Survey conducted world-wide to develop a “snap shot” of instrumentation used today and planned for tomorrow Intent is to use this database to Explore “where we are” now in astronomy Extrapolate to the future Help bridge gap between astronomical community and manufacturers about what types of detectors are needed Not intended to be a detailed description of any institution’s instruments No single observatory is large enough to “dominate” the database 4 Survey Details Instrument name Observing Modes Start of operations Wavelength Coverage Field of View Instrument cost Multiplex gain Spatial [“]/Spectral resolution # Detectors Detector Format Detector size Buttability Pixel size Pixel scale Electronics Noise Readout Time Dark Current Full well Cost per pixel Comments or additional parameters 5 Survey Details 25 institutions polled as part of a world-wide survey of ground-based instrumentation Compiled instrumentation database for telescopes with 3.5 m aperture Compiled data on ~200 instruments through this survey Enough to probe various trends in instrumentation and the detector systems in use today at major astronomy facilities, worldwide Detailed results will be published via the Proceedings of this conference Represents a unique source of information about instrumentation in astronomy, both existing and planned 6 Wavelength Coverage Instrument Number Instrumement The “great divide” between optical and infrared is obvious Basically a bimodal distribution, separated at 1 µm This divide is artificial - it’s technology driven, not science driven 180 90 1 0.1 11 10 Wavelength (µm) 100 7 Optical, Near-Infrared, or Mid-Infrared? 50 40 30 20 10 0 MIR NIR OPT Wavelength Coverage Percent The next-generation of instruments will consist of nearly equal numbers of optical and NIR instruments NOW 60 Percent Currently astronomy is pretty heavily dominated by optical instruments, with ~2 out of 3 instruments using CCDs 70 50 45 40 35 30 25 20 15 10 5 0 FUTURE MIR NIR Wavelength Coverage OPT 8 Optical, Near-Infrared, or Mid-Infrared? This is due to many reasons including 70 50 40 30 20 10 A relatively small MIR community A historically specialized field technically to get into The need for special telescope systems (chopping), etc. 0 MIR NIR OPT Wavelength Coverage Percent The lack of MIR instruments reflects a relatively “untapped” science frontier, not lack of scientific importance NOW 60 Percent In both cases MIR instruments occupy a very small part of the “market” 50 45 40 35 30 25 20 15 10 5 0 FUTURE MIR NIR Wavelength Coverage OPT 9 What Modes are Most Commonly Used? Most spectrometers also have an imaging mode, at least to support a target acquisition mode, so imaging systems are important 70 60 50 Percent Spectrometers remain the most popular type of instrument in astronomy (~60%), with imagers a distant second (~25%) 30 20 10 0 Imager Spectrometer Other Primary Instrument Modes Among the spectrometers built, not surprisingly the most popular type remains the “simple” long slit spectrometer 80 70 60 Percent An equal number of MOS and IFU based systems are either built or planned Given the large multiplex gain of these systems, MOS and IFU spectrometers tend to require the largest focal planes 40 50 40 30 20 10 0 MOS IFU Long Slit Spectrometer in Use 10 Current Market Share by Various Manufacturers 30 20 15 10 E2V Other E2V Other Rockwell Raytheon SITe Rockwell Manufacturer Raytheon 50 45 40 35 30 25 20 15 10 5 0 SITe 0 MIT/LL 5 MIT/LL Bottom plot tallies all detectors sampled in survey so is a true “head count” of detectors in use Percent of Instruments Effectively assumes 1 detector per instrument “Others” are in many cases are oneoff devices in specialized instruments which together account for ~20% of all instruments 25 Percent of Detectors Top histogram shows dominant manufacturers used in various instruments Manufacturer 11 Current Market Share by Various Manufacturers 30 Regardless of how market share is assessed, E2V detectors are the most commonly used in ground-based astronomy 20 15 10 Other E2V Rockwell Raytheon SITe 0 MIT/LL 5 Manufacturer Other E2V Rockwell Raytheon 50 45 40 35 30 25 20 15 10 5 0 SITe Manufacturer MIT/LL Percent of Detectors Nearly half of all science detectors in instruments sampled are made by E2V Linked to previous plots demonstrating popularity of optical instruments in astronomy Large CCD mosaics that have been built no doubt enable E2V market share compared to NIR manufacturers, where comparably large mosaics have not been built Percent of Instruments 25 12 Plate Scale and Field of View 15 10 Can’t correct over large fields 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 Plate Scale (arcsec/pixel) 40 35 30 Percent Extremely small fields are pretty much exclusively domain of AO 0 0.2 Clearly a “sweet spot” in field size of instruments for fields in the 10-100 arcmin2 range 0.1 5 0 Lack of >1” pixels is probably due to not sampling small telescopes which often have large fields 20 Percent Most instruments use (surprisingly) small pixels, most at ~0.1” 25 25 20 15 10 Field of View (arcmin2) 1E+06 1E+05 10000 1000 100 10 1 0 0.1 5 0.01 Extremely large fields on the right are mainly due to future ultra wide field instruments involving enormous CCD focal planes 14 Drives builders to faster optical systems and reduced tolerances which may be non-trivial to achieve in cryogenic instruments 50 45 40 35 30 25 20 15 10 5 0 CURRENT 18.5 27 30 40 50 75 Pixel Size (µm) 70 FUTURE 60 50 Percent NIR instruments have pretty much locked into 18-27 µm pixel format The the future, pixels of this size will remain popular Likewise MIR instruments have adopted pixels 2-3 times bigger, consistent with larger point spread function at these longer wavelengths Shifting to considerably smaller pixels to reach larger array formats may pose problems for optical designs of infrared instruments Percent Typical Infrared Pixel Size Now and Tomorrow… 40 30 20 10 0 18.5 20 27 40 Pixel Size (µm) 50 15 Typical CCD Pixel Size Now and Tomorrow… 45 40 30 25 20 15 10 86% of current instruments use 13-15 µm pixels In all cases 15 um is the most often used, with 5 0 6.5 13 13.5 15 16 24 Pixel Size (µm) 60 50 Percent 73% of future instruments sampled will use 13-15 um pixels CURRENT 35 Percent Similarly, current and future optical instruments have pretty much “standardized” on 13-15 µm pixels FUTURE 40 30 20 10 0 9 10 12 13 13.5 Pixel Size (µm) 15 24 16 Typical Infrared Array Format, Now and Tomorrow… 1024x1024 is the “standard” format used in NIR arrays today In the future, the community clearly wants to switch to larger format device, with 75% of the future instruments sampled going with 2k NIR arrays Again, astronomers will take advantage of larger format IR detectors, when they become available Percent 50 CURRENT 40 30 20 10 0 128x128 240x320 256x256 512x512 1024x1024 2048x2048 Detector Format 80 70 FUTURE 60 Percent 2048x2048x devices likely have not been around long enough to become well established, with only ~15% of the market share 60 50 40 30 20 10 0 256x256 240x320 1024x1024 Detector Format 2048x2048 17 Typical CCD Format, Now and Tomorrow… 60 77% of future instruments expect to use either 2x4k or 4x4k CCDs Clearly astronomers are eager to use ever larger CCDs… Percent 50 CURRENT 40 30 20 10 0 1024x1024 2048x2048 2048x4096 Other Detector Format 45 40 35 Percent 2x4k building block is, not surprisingly, by far the most popular current CCD format Future planned instruments will baseline 4x4k detectors as much as the more established 2x4k detectors FUTURE 30 25 20 15 10 5 0 1024x1024 2048x2048 2048x4096 4096x4096 Detector Format Other 18 Optical Infrared Number of Pixels in Focal Plane (10 6) 18 16 More 100 90 80 70 60 50 40 30 20 10 CURRENT 0 50 45 40 35 30 25 20 15 10 5 0 FUTURE 14 12 10 8 Number of Pixels in Focal Plane (10 6) More 100 90 80 70 60 50 40 30 20 2 0 10 6 4 0 Essentially all IR focal planes are <10 Mpixel Most optical focal planes are also <10 Mpixel, though some are much larger Have merged NIR+MIR into “Infrared” Number of Focal Planes Total of ~1.9 Gpixels found in current instruments sampled by this survey Number of Focal Planes Total Pixel “Inventory”, Now and Tomorrow… 19 Optical Infrared 18 16 More 100 90 80 70 60 50 40 30 20 10 CURRENT 0 50 45 40 35 30 25 20 15 10 5 0 Number of Pixels in Focal Plane (10 6) FUTURE 14 12 10 8 Number of Pixels in Focal Plane (10 6) More 100 90 80 70 60 50 40 30 20 2 0 10 6 4 0 Number of Focal Planes The future looks similar in the infrared with most instruments having modest size focal planes The future at optical wavelengths include a lot more large focal planes The future market includes ~7.7Gpixels of science grade detectors, >90% of which is in the form of CCDs in the future “More” category (>100 Mpixel focal planes) Note that lack of planned IR large format focal planes isn’t due to lack of ambition on the part of IR astronomers - it’s due to lack of money… Number of Focal Planes Total Pixel “Inventory”, Now and Tomorrow… 20 Controller Types 25 20 15 10 MPI Monsoon MCE SDSU IRACE FIERA 0 ARCON 5 AAO2 Percent Includes all instruments (current and future) in survey SDSU clearly the most commonly used controller in astronomy, with ~1 in 4 controllers being an SDSU system Huge range in controllers being used - total of 44 different controllers identified in survey This is an area where we would all benefit from an “industry standard” Manufacturer Closest thing we have is SDSU 21 Instrument Costs Most participants in the survey did not include a cost and, in general, it is difficult to make a detailed “apples to apples” comparisons due to various assumptions Does cost include labor, overhead, all parts, etc? Instead, have only assessed median costs of current and future instruments to look for basic trends Median Instrument Cost Summary Optical Infrared Current $400,000 $3,750,000 Future $6,600,000 $5,000,000 22 Future Trends in Science and Technology… “Cosmic Convergence” Tracing the physical origin, evolution, and large scale structure of matter and energy, from the Big Bang, to present, remains one of highest priority research areas in all of science Many organizations are working in this field in a global effort to unravel the most fundamental aspects of the universe 24 Key Epochs in the Early Universe Photons from this scattering surface are what we now see as the Cosmic Microwave Background (CMB) Universe Neutral Universe Ionized Reionization in the Early Universe 25 “First Light” in a Dark Universe Using current and/or next-gen telescopes, we will, for the first time, detect the first luminous objects in the universe – the “First Light” The discovery and analysis of the first stars is arguably one of the “holy grails” in astronomy The light from these distant objects is red shifted to 1-2 µm, hence the need for large format, low noise, NIR detectors in the future Simulation of an Ultra Deep NIR Image of the First Stars 26 Boundaries on Research Frontiers Astronomy is fundamentally a technology driven and limited field of science and detectors always have and always will play a central role in what we can learn about the universe As an example… 27 The Galactic Center: Discovery Strip Chart 28 The Galactic Center: Becklin & Neugebauer 1975 29 The Galactic Center: Forrest et al. 1986 30 The Galactic Center: Rigaut et al. 1997 31 The Galactic Center: Recent ESO Results Zeroing in on a Massive Black Hole… 32 Our basic understanding of key areas in astronomy is clearly a function of current technology What took us perhaps 25 years to achieve before, may only take ~10 years with the rapid acceleration of technology available to astronomers Advancements in science detectors have made this all possible… 25 yrs The 25 Year “Evolution” of the Galactic Center... 33 Boundaries on Research Frontiers ELT’s and the next generation of ultra wide field instruments are examples of nextgeneration ground-based facilities that will revolutionize our understanding of the universe The years ahead in astronomy will include explorations of very large and very small structures In either case, large scale, high performance, affordable optical and infrared science detectors will be necessary 34 The Future is Both Large and Small The next generation of ELT’s will provide unprecedented “views” of the universe Given the extreme apertures of these telescopes, when coupled with AO systems that allow ELT’s to work at their diffraction limits, they will yield data with spatial resolutions far greater than what is possible with the current generation of 8-10 m telescopes OWL TMT 35 The ELT’s Window on the Universe... ~1” ~1” Target: Galactic Cores Objective: Detect signatures of black holes in compact galactic nuclei Target: Io Objective: Remote seismic monitoring & planetary mineralogy Target: Forming Planetary Systems Objective: Measure SED of forming stars, planets & surrounding gas, binary fractions, disk evolution, Dust & gas dynamics, MF, etc. Target: First Stars Objective: Morphology, spectra, and luminosity of first luminous objects in the universe Target: -ray bursters Objective: Identify and measure distance & SED of hosts; detect the “first” GRBs in the universe Target: Extra-solar planets Objective: Direct imaging and spectroscopy of planetary systems beyond our own Future Wide Field Facilities LAMOST Project The Large Sky Area Multi-Object Fiber Spectroscopic Telescope Pan-STARRS LSST Hyper-SUPRIME + WFMOS 44 Future Research These facilities will be used to perform enormous surveys to answer major questions in astronomy and fundamental physics, of interest to all of humanity Galaxy Genesis Dark Matter Dark Energy 45 The Destiny of the Universe Matter/Gravity Overcome the Initial Expansion from the Big Bang 46 The Destiny of the Universe Universe “Coasts” Outward, with Matter/Gravity In Approximate Equilibrium with Big Bang Expansion 47 The Destiny of the Universe Expansion of the Universe Accelerates, Ultimately Shredding Its Material Contents 48 The Destiny of the Universe With the discovery of Dark Energy this now appears to be possible. Next-generation detectors will play a key role in solving this mystery Expansion of the Universe Accelerates, Ultimately Shredding Its Material Contents 49 Summary Thoughts Detectors in 180 instruments in use today have been surveyed to perform a “bottom-up” assessment of detector systems in use now or planned in the near future in astronomy Optical detectors currently dominate those used in ground-based astronomy, and will remain the most commonly used detector throughout the next ~decade Planned future instruments will need Gpixel class optical focal planes and many are migrating to 40962 format Most infrared detectors used now have a 10242 format, but many instrument builders are migrating to the buttable 20482 format detectors now available 50 Summary Thoughts A “top-down” approach is used to forecast the future in ground based astronomy (~5-15 years) ELTs: Large infrared focal planes will be needed to sample diffraction limited fields of enormous telescopes of the future Wide Field Facilities: Large optical focal planes will be used to survey millions of stars and galaxies at modest to high spectral resolution Cosmology: Frontier science is being red shifted to the near-infrared as telescopes get larger, which will drive NIR detectors to have low noise and low dark current in often “photon starved” applications The science horizon in astronomy is exciting and compelling, but our discoveries will only be as remarkable as the science detectors we use to explore the universe 51