This PDF file contains the front matter associated with SPIE Proceedings Volume 6690, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

A new class of CMOS imagers that compete with scientific CCDs is presented. The sensors are based on deep depletion backside illuminated technology to achieve high near infrared quantum efficiency and low pixel cross-talk. The imagers deliver very low read noise suitable for single photon counting - Fano-noise limited soft x-ray applications. Digital correlated double sampling signal processing necessary to achieve low read noise performance is analyzed and demonstrated for CMOS use. Detailed experimental data products generated by different pixel architectures (notably 3TPPD, 5TPPD and 6TPG designs) are presented including read noise, charge capacity, dynamic range, quantum efficiency, charge collection and transfer efficiency and dark current generation. Radiation damage data taken for the imagers is also reported.

Inter-Pixel capacitance (IPC) is an effect that can occur in bump-bonded hybrid CMOS pixel arrays that employ a source follower pixel amplifier. IPC can result in the signal in one pixel being sensed by adjacent pixels that are capacitively coupled. IPC effect is more pronounced in full-depletion silicon hybrid CMOS focal plane arrays than infrared arrays because of the stronger coupling path through the silicon detector layer. IPC can degrade the image resolution and it can cause an overestimation of conversion gain (electrons per mV) determined from conventional photon-transfer method because the IPC "blur" reduces the variance of photon noise. However, the IPC effect can be minimized with improvements in pixel design, and the conversion gain can be properly calculated, and image resolution can be restored with deconvolution techniques. In this paper, we report the results of a recent effort to reduce IPC in Teledyne's visible silicon hybrid CMOS focal plane arrays through pixel design improvements.

The conversion gain in hybridised near infrared detectors with Source Follower per Detector unit cells changes non-linearly as the signal integrates on the junction capacitance of the detector diodes[1,2]. However, the non-linearity in the measured conversion gain as calculated from the conventional photon transfer technique (~15% in VIRGO-2K for example) is higher than the non-linearity noticed at the detector output (~4% in the same detectors). This paper presents experimental data from the VIRGO-2K, Aladdin-III and Hawaii-1RG detectors which is used to highlight this discrepancy and thus show the shortcomings of the use of the photon transfer technique with such non-linear detectors. The mechanism for the changing detector node capacitance with integrating signal is explained. A method for correcting the measured conversion gain to account for this non-linearity has been implemented on the data from the same detectors and will be presented. If not corrected, this non-linearity can be another source of error that could cause an over-estimation of the detector performance parameters (as is the case with the inter-pixel capacitance).

We compare a more complete characterization of the low temperature performance of a nominal 1.7um cut-off wavelength 1kx1k InGaAs (lattice-matched to an InP substrate) photodiode array against similar, 2kx2k HgCdTe imagers to assess the suitability of InGaAs FPA technology for scientific imaging applications. The data we present indicate that the low temperature performance of existing InGaAs detector technology is well behaved and comparable to those obtained for state-of-the-art HgCdTe imagers for many space astronomical applications. We also discuss key differences observed between imagers in the two material systems.

We describe our programme to develop a large-format, science-grade, monolithic CMOS active pixel sensor for future space science missions, and in particular an extreme ultra-violet spectrograph for solar physics studies on ESA's Solar Orbiter. Our route to EUV sensitivity relies on adapting the back-thinning and back-illumination techniques first developed for CCD sensors. Our first large-format sensor consists of 4kx3k 5 μm pixels fabricated on a 0.25 μm CMOS imager process. Wafer samples of these sensors have been thinned by e2v technologies with the aim of obtaining good sensitivity at EUV wavelengths. We present results from both front and back-illuminated versions of this sensor. We also present our plans to develop a new sensor of 2kx2k 10 μm pixels which will be fabricated on a 0.35 μm CMOS process. In progress towards this goal, we have designed a test structure consisting of six arrays of 512x512 10 μm pixels. Each of the arrays has been given a different pixel design to allow verification of our models and progress towards optimising a design for minimal system readout noise and maximum dynamic range. These sensors will also be back-thinned for characterisation at EUV wavelengths.

A full-wafer, 10,580 × 10,560 pixel (95 × 95 mm) CCD was designed and tested at Semiconductor Technology Associates (STA) with 9 μm square pixels and 16 outputs. The chip was successfully fabricated in 2006 at DALSA and some performance results are presented here. This program was funded by the Office of Naval Research through a Small Business Innovation in Research (SBIR) program requested by the U.S. Naval Observatory for its next generation astrometric sky survey programs. Using Leach electronics, low read-noise output of the 111 million pixels requires 16 seconds at 0.9 MHz. Alternative electronics developed at STA allow readout at 20 MHz. Some modifications of the design to include anti-blooming features, a larger number of outputs, and use of p-channel material for space applications are discussed.

SOI-based active pixel image sensors have been built in both monolithic and vertically interconnected pixel technologies. The latter easily supports the inclusion of more complex pixel circuitry without compromising pixel fill factor. A wafer-scale back-illumination process is used to achieve 100% fill factor photodiodes. Results from 256 x 256 and 1024 x 1024 pixel arrays are presented, with discussion of dark current improvement in the differing technologies.

The astronomic mission Gaia is a cornerstone mission of the European Space Agency, due for launch in the 2011 time frame. Requiring extremely demanding performance, Gaia calls for the development of an unprecedented large focal plane featuring innovative technologies. For securing the very challenging Gaia Focal Plane Assembly (FPA) development, technology activities have been led by EADS Astrium from 2002 to 2005. After EADS Astrium selection for the development of the Gaia satellite, the program started in early 2006. The all-Silicon Carbide FPA hosts all the mission scientific functions for Astronometry, Photometry and Radial Velocity Spectrometry, encompassing 106 large scientific CCDs operated in TDI mode with windowing readout. With a sensitive area of about half a square meter, the FPA includes more than 935 millions of 10 μm x 30 μm pixels. To fulfill all the requirements, the CCDs feature a specific design with a Silicon Carbide package and on-chip functions such as TDI dynamic gain control and pulsed charge injection. Main development issues are related to the mass production of CCDs, and extremely low noise and miniaturized focal plane electronics. Finally, the major challenge of the overall focal plane mechanical and thermal accommodation is to allow full modularity while providing perfectly stable temperature and efficient thermal decoupling between the CCDs area (160 K - 170 K) and electronics operated in standard temperature conditions.

Following its launch in August, 2005 and a year of interplanetary cruise and aero-braking, the successful Mars Reconnaissance Orbiter (MRO) mission is currently orbiting Mars and down-linking imagery from the High Resolution Imaging Science Experiment (HiRISE) camera. The primary objectives of the MRO mission are to characterize the present climate of Mars, look for evidence of water-related activities, and characterize potential landing sites. After only four months in the Primary Science Phase (PSP) of the mission, MRO has returned more data than any other previous Mars mission. Approximately one-third of this data volume is from the HiRISE camera, built by Ball Aerospace & Technologies Corporation (BATC), for the University of Arizona (UofA), Department of Planetary Sciences. With a 0.5-meter primary mirror, the HiRISE instrument includes the largest optical telescope ever sent beyond Earth's orbit, and is producing images with unprecedented resolution. It has detected objects of less than one meter size from the nominal orbit of 250 x 320 km. The highest resolution images have a scale of 25 to 32 cm per pixel (1.0 microradian IFOV). HiRISE is a "push-broom" camera with a swath width of 6 km in a broad red spectral band and 1.2 km in blue-green and near infrared bands. There are 14 CCD detector chips (2048 x 128 TDI elements each) on the focal plane. The HiRISE camera was designed to minimize use of spacecraft resources. Even with a half-meter primary mirror, through the use of lightweight glass optics and graphite-composite structures the final mass of the instrument is only 64.2 kg. It maintains a nearly uniform telescope temperature of 20°C yet its orbital average power consumption is less than 60 W. An overview is given of the NASA MRO mission and the HiRISE instrument. Pre-launch activities are detailed and the launch time discussed. An account is given of the cruise events, along with a description of aerobraking and the primary science phase. A sample of science results are presented, including a wealth of imagery.

The HAWAII-2RG based focal plane arrays represent one the most advanced imaging sensor technologies for near-infrared and visible astronomy. Since its introduction a few years ago, the HAWAII-2RG has been selected for a large number of space and ground-based instruments, including the James Webb Space Telescope. In addition, the SIDECAR ASIC, a fully integrated FPA controller system-on-a-chip, has been matured and is now being implemented in many of the next generation instruments. As a result of the SIDECAR ASIC, the detector system becomes a fully digital unit that is superior to the conventional discrete focal plane electronics with respect to power consumption, mass, volume and noise immunity. This paper includes an introductory description of the HAWAII-2RG and the SIDECAR ASIC, and presents the latest test results. It also discusses the latest generation of astronomy FPAs: the HAWAII-4RG. This new multiplexer contains all of the HAWAII-2RG features, but provides 4 times as many pixels at a pixel pitch of 10μm. Preliminary HAWAII-4RG test data is presented.

We present both laboratory and telescope testing results describing the performance of the H4RG-10 CMOS-Hybrid detector. The H4RG-10 is the largest visible hybrid array currently in existence and shows great potential for use in future space missions. We report read noise, dark current, pixel connectivity, persistence, and inter-pixel capacitance measurements for the temperature range 110-240 K. We report on quantitative astrometric and qualitative photometric performance of the instrument based on observations made at USNO's Flagstaff Station observatory and establish an upper limit to the astrometric performance of the detector. We discuss additional testing and future work associated with improving detector performance.

As part of the early development for NASA's Mars Laser Communication Demonstration (now canceled), we exposed two InGaAs focal plane arrays (FPAs) to 22 krad(Si) dose at a rate of 4.6 rad(Si)/s using a ⁶⁰Co gamma-ray source. Both the SU320MS from Sensors Unlimited and the ISC9809 from FLIR Systems, Inc. operated throughout the test. The FPA electronics were shielded from radiation; only the photosensitive InGaAs and its readout integrated circuit (ROIC) were exposed. Background levels on both FPAs increased during the test. The SU320MS saturated and failed to respond to infrared light after the test. The ISC9809's background increased but did not saturate. Phenomena exhibited during the test included both isolated single-pixel hits and increased mean over the full FPA. Tests of the ISC9809 after irradiation indicate no change in gain but an increase in mean dark current. In addition, 91% of the ISC9809 pixels also had increased temporal noise. As a result of these tests, the ISC9809 was chosen for flight, but shielding was added to reduce the level seen by the FPA to an estimated 6 krad(Si) for a 10-year lifetime in Mars orbit.

The Wide-field Infrared Survey Explorer (WISE) is a NASA MidEx mission which will survey the entire sky at 3.3, 4.7, 12 and 23 microns. As with most all-sky surveys, WISE results will address many fundamental topics, but the passbands and sensitivity are particularly well suited to study the distribution and evolutionary history of brown dwarfs and ultra-luminous IR galaxies. The two long wavelength bands will use 1024x1024 Si:As BIB detectors manufactured by DRS Sensors & Targeting Systems. NASA ARC has optimized the operating parameters as well as conducted detailed cryogenic performance and radiation testing of a prototype array. Dark current, noise performance, and radiation test results will be reported.

We present the first astronomical results from a 4K² Hybrid Visible Silicon PIN array detector (HyViSI) read out with the Teledyne Scientific and Imaging SIDECAR ASIC. These results include observations of astronomical standards and photometric measurements using the 2.1m KPNO telescope. We also report results from a test program in the Rochester Imaging Detector Laboratory (RIDL), including: read noise, dark current, linearity, gain, well depth, quantum efficiency, and substrate voltage effects. Lastly, we highlight results from operation of the detector in window read out mode and discuss its potential role for focusing, image correction, and use as a telescope guide camera.

This paper presents the radiometric and noise characteristics of 12-bit SI-1920HD cameras built from the AltaSens ProCamHD 3560 FPA as a function of integration time and temperature. Our measurements are for two integration time regions: 1 to 50 millisecond, which is standard for video operation; and 1 to 240 seconds, of possible use for stellar observations. For 1 to 50 millisecond integration times, the cameras are extremely linear with a Gaussian-like dark frame. As we increased to seconds-long integration times, the camera initially remains radiometrically linear, but develops a dark frame with the vast majority of pixels at dn=5. Further increases in integration time eventually result in a saturated dark frame with all pixels at dn=4095. Reducing the operating temperature to -7.2°C increased the integration times at which the camera's two transitions occur by a factor of 20. The calibration parameters determined from our measurements were applied to the image data collected by Dorland et al. (these proceedings).

CMOS-based focal planes have many potential advantages over CCDs for use in space for star mapping/star tracking applications. These include more flexible readout circuitry and improved radiation tolerance. There are also weaknesses, including noise performance, quantum efficiency, and potential systematics introduced by the presence of circuitry on the photosensitive side of the detector. In this paper, we measure the effects of these sources of error on centroiding and photometry for the HDTV (1k x 2k) SI-1920HD camera by observing stellar reference fields using USNO's 8-inch Twin Astrograph telescope in Flagstaff, AZ. This camera serves as an archetype for the entire family of related TIS detectors, including the 3k x 4k V12M and the 7.6k x 7.6k V59M. We determine an upper limit for the astrometric centroiding performance for this class of detector to be ~1/30^th of a pixel. There are indications that better performance may be possible if improvements are made to the temperature control system used for this first set of observations.

The e2v CCD212 was designed and developed explicitly to support very high accuracy astrometric observations in moderate radiation environments in space. One of the major new innovations in the detector is the use of "charge canals", i.e. regions of raised potential walls rather than notches or channels, in order to mitigate bulk damage effects without the CTI discontinuities associated with spilling over the notch capacity. We report on both pre- and post-radiation performance test results for this detector.

We present early results from the performance test development for the Detector Subsystem of the Near-Infrared Spectrograph (NIRSpec). NIRSpec will be the primary near-infrared spectrograph on the James Webb Space Telescope (JWST). The Detector Subsystem consists of a Focal Plane Assembly containing two Teledyne HAWAII-2RG arrays, two Teledyne SIDECAR cryogenic application specific integrated circuits, and a warm Focal Plane Electronics box. The Detector Characterization Laboratory at NASA's Goddard Space Flight Center will perform the Detector Subsystem characterization tests. In this paper, we summarize the initial test results obtained with engineering grade components.

The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) incorporates two 5 μm cutoff (λ_co =5 μm) 2048×2048 pixel Teledyne HgCdTe HAWAII-2RG sensor chip assemblies. These detector arrays, and the two Teledyne SIDECAR application specific integrated circuits that control them, are operated in space at T ~ 37 K. In this article, we provide a brief introduction to NIRSpec, its detector subsystem (DS), detector readout in the space radiation environment, and present a snapshot of the developmental status of the NIRSpec DS as integration and testing of the engineering test unit begins.