Raytheon Vision Systems (RVS) has a long history of providing state of the art infrared sensor chip assemblies (SCAs) for the astronomical community. This paper will provide an update of RVS capabilities for the community not only for the infrared wavelengths but also in the visible wavelengths as well. Large format infrared detector arrays are now available that meet the demanding requirements of the low background scientific community across the wavelength spectrum. These detector arrays have formats from 1k x 1k to as large as 8k x 8k with pixel sizes ranging from 8 to 27 μm. Focal plane arrays have been demonstrated with a variety of detector materials: SiPiN, HgCdTe, InSb, and Si:As IBC. All of these detector materials have demonstrated low noise and dark current, high quantum efficiency, and excellent uniformity. All can meet the high performance requirements for low-background within the limits of their respective spectral and operating temperature ranges.
Raytheon Vision Systems (RVS) has been developing high performance low background VisSWIR focal plane arrays suitable for the NASA WFIRST mission. These near infrared sensor chip assemblies (SCAs) are manufactured using HgCdTe on CdZnTe substrates with a 10 micron pixel pitch. WFIRST requirements are for a 4k x 4K format 4-side buttable package to populate a large scale 6 x 3 mosaic focal plane array of 18 SCAs. RVS devices will be compatible with the NASA developed FPA 4-side buttable package, and flight interface electronics. Initial development efforts at RVS have focused on a 2k x 2k format 10 micron pixel design based on an existing readout integrated circuit (ROIC) to demonstrate desired detector material performance at a relevant scale. This paper will provide performance results on the RVS efforts. RVS has successfully developed multiple 4k x 4k 10 micron pixel ROICs and we plan to demonstrate readiness to scale our design efforts to the desired 4k x 4k format for WFIRST in 2016.
Raytheon Vision Systems has achieved significant improvements in VLWIR (very long wavelength infrared) detector materials. These small bandgap detector materials are susceptible to tunneling of carriers across the bandgap via either band-to-band or trap-assisted tunneling phenomena. RVS' new procedures reduce exposure of the highly sensitive p-n junction to possible contamination sources during growth and processing. This reduction in impurities reduces the tunneling component of the detector current and yields high quality detectors out to the VLWIR range. Evidence of a highly uniform detector fabrication process is detailed within spanning the LWIR to VLWIR wavelength range.
The MONSOON Image Acquisition System has been designed to meet the need for scalable, multichannel, high-speed image acquisition required for the next-generation optical and infared detectors and mosaic projects currently under development at NOAO as described in other papers at this proceeding such as ORION, NEWFIRM, QUOTA, ODI and LSST. These new systems with their large scale (64 to 2000 channels) and high performance (up to 1Gbyte/s) raise new challenges in terms of communication bandwidth, data storage and data processing requirements which are not adequately met by existing astronomical controllers. In order to meet this demand, new techniques for not only a new detector controller, but rather a new image acquisition architecture, have been defined. These extremely large scale imaging systems also raise less obvious concerns in previously neglected areas of controller design such as physical size and form factor issues, power dissipation and cooling near the telescope, system assembly/test/ integration time, reliability, and total cost of ownership. At NOAO we have taken efforts to look outside of the astronomical community for solutions found in other disciplines to similar classes of problems. A large number of the challenges raised by these system needs are already successfully being faced in other areas such as telecommunications, instrumentation and aerospace. Efforts have also been made to use true commercial off the shelf (COTS) system elements, and find truly technology independent solutions for a number of system design issues whenever possible. The Monsoon effort is a full-disclosure development effort by NOAO in collaboration with the CARA ASTEROID project for the benefit of the astronomical community.
Wide field-of-view, high-resolution near-infrared cameras on 4-m class telescopes have been identified by the astronomical community as critical instrumentation needs in the era of 8-m and larger telescopes. Acting as survey instruments, they will provide the input source discoveries for large-telescope follow-up observations. The NOAO Extremely Wide Field Infrared Mosaic (NEWFIRM) imaging instrument will serve this need within the US system of facilities. NEWFIRM is being designed for the National Optical Astronomy Observatory (NOAO) 4-m telescopes (Mayall at KPNO and Blanco at CTIO). NEWFIRM covers a 28 x 28 arcmin field of view over the 1-2.4 μm wavelength range with a 4k x 4k pixel detector mosaic assembled from 2k x 2k modules. Pixel scale is 0.4 arcsec/pixel. Data pipelining and archiving are integral elements of the instrument system. We present the science drivers for NEWFIRM, and describe its optical, mechanical, electronic, and software components. By the time this paper is presented, NEWFIRM will be in the preliminary design stage, with first light expected on the Mayall telescope in 2005.
The WIYN One Degree Imager (ODI) will be a well-sampled (0.11” per pixel) imager that provides a full one degree square field of view (32K×32K pixels). ODI will utilize high resistivity, red sensitive, orthogonal transfer (OT) CCDs to provide rapid correction for image motion arising from telescope shake, guider errors, and atmospheric effects. ODI will correct the full field of view by deploying 64 array packages having a total of 4096 independently controllable OTCCDs that can correct individually for local (2 arcmin) image motion. Each array package is an orthogonal transfer array (OTA) of 64 CCDs arranged in an 8×8 grid. Each CCD has 512×512 pixels. We expect the median image quality at the WIYN 3.5m telescope in RIZ to be 0.52”, 0.43”, and 0.35” FWHM. ODI makes optimal use of the WIYN telescope, which has superb optics, excellent seeing characteristics, a natural 1.4 degree field of view (with a new corrector), and can serve as a pathfinder for LSST in terms of detectors, data pipelines, operations strategies, and scientific motivation.
The LSST Instrument is a wide-field optical (0.3 to 1um) imager designed to provide a three degree field-of-view with better than 0.2 arcsecond sampling. The image surface of the LSST is approximately 55cm in diameter with a curvature radius of 25 meters to flat. The detector format is currently defined to be a circular mosaic of 568 2k × 2k devices faceted to synthesize this surface within the constraints of LSST's f/1.25 focal ratio. This camera will provide over 2.2 Gigapixels per image with a 2 second readout time. With an expected typical exposure time of as short as 10s, this will yield a nightly data set on order of 3 terapixels. The scale of the LSST Instrument is equivalent to a square mosaic of 47k × 47k. The LSST Instrument will also provide a filter mechanism, as well as optical shuttering capability. Imagers of this size pose interesting challenges in many design areas including detectors, interface electronics, data acquisition and processing pipelines, dewar construction, filter and shutter mechanisms. Further more, the LSST 3 mirror optical system places this instrument in a highly constrained volume where these challenges are compounded. Specific focus is being applied to meeting defined scientific performance requirements with an eye to total cost, system complexity, power consumption, reliability, and risk. This paper will describe the current efforts in the LSST Instrument Concept Design.
CFH12K is a 12,228 by 8,192 pixel wide-field imaging camera in operation at the 3.6m Canada-France-Hawaii Telescope (CFHT) since January 1999. It still remains the largest close-packed array in use in astronomy today. The mosaic consists of twelve MIT Lincoln laboratories 2K by 4K thinned backside illuminated CCID-20 devices. The camera is used in broad-band and narrow-band filter direct imaging mode which constrains the devices' operating parameters to ensure the best data quality. Adaptation to the 20-year old CFHT prime focus environment included modifications to reduce the scattered light seen by the camera. Computer facilities have been upgraded and new software has been developed to handle the large amount of data generated. The two terabytes of scientific data taken by the camera in 1999 has proven the success of CFHT's new capability for 42 by 28 square arcminute imaging with high resolution subarcsecond seeing.
The CFH12K is a 12K by 8K CCD mosaic camera for the Canada- France-Hawaii Telescope (CFHT), a 3.6 m telescope located on Mauna Kea, Hawaii. The CFH12K is comprised of twelve 4K by 2K thinned backside-illuminated CCDs, arrange din a close- packed array of two rows each containing six CCDs. Located at the CFHT Prime Focus, the CFH12K provides a 42 by 28 arcminute field-of-view, 0.206 arcsecond per pixel sampling, with a resulting data file of more than 200Mbytes per image. The camera has been designed to exploit the exceptional wide-field imaging capability provided by the CFHT. At the time of its commissioning in January 1999, the CFH12K is the largest thinned close-packed CCD mosaic in astronomy. This paper describes the system architecture, and some of the relevant issues associated with the construction, evaluation, and operation of very large mosaic cameras. Emphasis is given to system design issues, illustrating the CFHT12K as part of a larger system: the CFHT.
The CFHTIR is a large format near IR camera based on the Rockwell HAWAII Array. CFHTIR is designed for both direct imaging at the f/8 Cassegrain focus, as well as spectroscopy on the OSIS multiobject spectrograph. The camera provides 0.21 inch/pixel sampling in both applications with a single set cold transfer optics and pupil mask. The camera includes two eight-position filterwheels driven by cryogenic stepper motors with position control using a novel Hall effect sensor technique. CFHTIR also uses a novel dewar wiring technique employing flexible circuit vacuum feedthrus. CFHTIR is the second large format IR camera based on the Hawaii array constructed at CFHT, the first being the KIR camera for the CFHT Adaptive Optics Bonnette which was commissioned in 1997. This paper describes the system architecture of the CFHTIR highlighting key design concepts and detailing the physical elements.
The CFH12K is a 12k X 8k CCD mosaic camera for the Canada-France-Hawaii Telescope (CFHT), a 3.6 m telescope located on Mauna Kea, Hawaii. The CFH12K is comprised of twelve 4k X 2k thinned backside-illuminated CCDs, arranged in a close-packed array of two rows each containing six CCDs. Located at the CFHT Prime Focus (f/4.2), the CFH12K provides a 42 by 28 arcminute field-of-view, 0.206 arcsecond per pixel sampling, with a resulting data file of more than 200 Mbytes per image. The camera has been designed to exploit the exceptional wide-field imaging capability provided by the CFHT. At the time of it's commissioning in January 1999, the CFH12K is the largest thinned close-packed CCD mosaic in astronomy. This paper describes the system architecture, and some of the relevant issues associated with the construction, evaluation, and operation of very large mosaic cameras. Emphasis is given to system design issues, illustrating the CFH12k as part of a larger system: the CFHT.
KIR is a 1024 by 1024 near-IR camera used with the adaptive optics Bonnette (PUEO) of the Canada-France-Hawaii Telescope. The camera houses a 1024 by 1024 HgCdTe and simple refractive optics providing diffraction-limited images with an image scale of 0.035 inch/pixel. First light was obtained in December 1997. The throughput of the camera, from the top of the atmosphere down to the atmosphere down to the detector including PUEO, is 19 percent, 20 percent and 21 percent at J, H and K, respectively. This project is a collaboration between the Universite de Montreal, the Observatoire Midi Pyrenees and the Canada-France-Hawaii Telescope. The design and performance of the instrument are presented in this paper.