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Results for “Charge-coupled devices (CCDs)”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Effects of radiation on charge-coupled devices

The effects of 1 MeV electron irradiation upon the performance of two phase, polysilicon aluminum gate CCDs are reported. Both n- and p-surface channel and n-buried channel devices are investigated using 64- and 128-stage line arrays. Characteristics measured as a function of radiation dose include: Transfer inefficiency, threshold voltage, field effect mobility, interface state density, full well signal level and dark current. Surface channel devices are found to degrade considerably at less than 10 to the 5th power rads (Si) due to the large increase in fast interface state density caused by radiation. Buried channel devices maintain efficient operation to the highest dose levels used.

Carnes, J. E.↗
NASA NTRS1981

Single photon X-ray imaging with charge-coupled devices /CCDs/

The paper describes a CCD camera facility designed and built for testing and characterization of CCDs in response to single X-ray photons in the 1-10 keV energy range. Results from the frontside-illuminated Fairchild 211 and 221 area imagers are presented; high quantum efficiency over the 3-6 keV range was verified. In order to avoid the problem of charge spreading at the higher energies, deep-depleted CCDs for soft X-ray imaging have been constructed, and good response was obtained at 6 keV. The present results are a first step toward the demonstration of the CCD as an appropriate device for at least the central part of the focal plane of a large X-ray telescope, e.g., the proposed Advanced X-ray Astrophysics Facility.

Griffiths, R. E.↗
NASA NTRS1987

Four-shooter - A large format charge-coupled device camera for the Hale telescope

The Hale telescope has employed an astronomical camera using four 800x800 CCDs in an optical arrangement that allows the imaging of a contiguous 1600-pixel-square region of the sky; reimaging optics are then used to yield a scale of 0.33 arcsec/pixel. Optical coatings are incorporated to yield a throughput at peak efficiency of nearly 50 percent, including telescope losses. This camera can be used in a scanning mode, in which the telescope tracking rate is offset and the charge is clocked in the chips in such a way that the charge image remains aligned with the optical image. Attention is given to the results of a survey for high-redshift quasars using this equipment, which has produced images for the most distant galaxy clusters yet discovered.

Gunn, James E.↗
NASA NTRS1981

Care, feeding, and use of charge-coupled device /CCD/ imagers at Palomar observatory

The paper describes the optical, mechanical, and electronic properties of the TI and RCA CCDs which have been applied to two-dimensional photometry and spectroscopy at Palomar. The drive, processing, and recording techniques are also discussed, and consideration is given to a focal conversion optical system, the Prime Focus Universal Extragalactic Instrument (PFUEI), which is used to more optimally match the Hale 5 meter plate scale. Calibration and data analysis are also examined.

Gunn, J. E.↗
NASA NTRS1985

Potential of CCDs for UV and X-ray plasma diagnostics

A program is under way to develop charge-coupled device (CCD) sensors for space-based X-ray astronomy imaging spectrometers. To date, laboratory line-emission spectra have been acquired throughout the range of 277 to 8000 eV (carbon through copper K-alpha emission) and CCD sensitivity has been demonstrated throughout the range of 1.1 through 8000 eV. Image resolution is excellent, limited almost entirely by the 15 micron pixel size. These results are presented and specialized techniques are described which permit such low energy response, high spectral resolution, and efficient charge collection. Finally, analysis is presented of one particular CCD characteristic which currently limits UV and X-ray performance: charge diffusion.

Janesick, J. R.↗
NASA NTRS1994

Development of CMOS Active Pixel Image Sensors for Low Cost Commercial Applications

JPL, under sponsorship from the NASA Office of Advanced Concepts and Technology, has been developing a second-generation solid-state image sensor technology. Charge-coupled devices (CCD) are a well-established first generation image sensor technology. For both commercial and NASA applications, CCDs have numerous shortcomings. In response, the active pixel sensor (APS) technology has been under research. The major advantages of APS technology are the ability to integrate on-chip timing, control, signal-processing and analog-to-digital converter functions, reduced sensitivity to radiation effects, low power operation, and random access readout.

solid-state image sensors active pixel sensor APS ↗
NASA NTRS2004

Chemical Thinning Process for Fabricating UV-Imaging CCDs

The thinning stage of the postfabrication process reported in the immediately preceding article is notable in its own right. Although the thinning process was described in the preceding article as part of an overall process of fabrication of a supported charge-coupled device (CCD), it is more generally applicable to both free-standing and supported devices that have been fabricated in die and wafer formats. Like the thermocompression bonding process described in the preceding article, the thinning process is compatible with CCD-fabrication processes, as well as postfabrication processes that enhance the response of CCDs to ultraviolet (UV) light, including the delta-doping process. CCDs that are thinned by this process and then delta-doped exhibit high quantum efficiencies that are stable with time and with exposure to the environment.

Jones, TOdd↗
NASA NTRS1982

The development and applications of charge-coupled devices for space astronomy

The developments in charge-coupled device technology over the past decade are reviewed, with emphasis on the relevance of these developments to astronomical applications. The characteristics and limitations of current commercial devices are described, and the future requirements on CCDs for space astronomy are summarized for the X-ray and near UV, optical, and infrared wavelength ranges. Emphasis is placed on the commonality of technological development which is called for, including the issues of quantum detection efficiency (photon entrance and depletion depth), charge transfer efficiency, modulation transfer function, output noise level, and array size. The system requirements on focal plane instrumentation for space astronomy are summarized, and shown to have much in common for the different wavelength bands. These requirements are discussed in terms of CCD mosaicing, cryogenic cooling, and electronics. The overlap in CCD developments in the defense, astronomical and commercial arenas is summarized.

Griffiths, R. E.↗
NASA NTRS1994

Ground-Based Fabry-Perot Interferometry of the Terrestrial Nightglow with a Bare Charge-Coupled Device: Remote Field Site Deployment

The application of Fabry-Perot interferometers (FPIs) to the study of upper atmosphere thermodynamics has largely been restricted by the very low light levels in the terrestrial airglow as well as the limited range in wavelength of photomultiplier tube (PMT) technology. During the past decade, the development of the scientific grade charge-coupled device (CCD) has progressed to the stage in which this detector has become the logical replacement for the PMT. Small fast microcomputers have made it possible to "upgrade" our remote field sites with bare CCDs and not only retain the previous capabilities of the existing FPls but expand the data coverage in both temporal and wavelength domains. The problems encountered and the solutions applied to the deployment of a bare CCD, with data acquisition and image reduction techniques, are discussed. Sample geophysical data determined from the FPI fringe profiles are shown for our stations at Peach Mountain, Michigan, and Watson Lake, Yukon Territory.

Niciejewski, Rick↗
NASA NTRS1987

Ultraviolet and extreme ultraviolet response of charge-coupled-device detectors

Results of a program to enhance the ultraviolet and extreme ultraviolet response of charge-coupled devices are presented. The ultimate goal of the program is to develop a large format device with both high and stable quantum efficiency from 100 to 3000 A that can be used as a windowless imaging detector in a space environment. Ultraviolet quantum efficiency measurements have been made for several ion-implanted and laser-annealed test CCDs. Quantum efficiencies as high as 22 percent at 2500 A, where the absorption depth in silicon is about 55 A, have been observed in one such test CCD. Quantum efficiency measurements of standard back-illuminated CCDs are also presented.

Stern, R. A.↗
NASA NTRS1980

Dual charge-coupled device /CCD/, astronomical spectrometer and direct imaging camera. II - Data handling and control systems

The data collection system for the MASCOT (MIT Astronomical Spectrometer/Camera for Optical Telescopes) is described. The system relies on an RCA 1802 microprocessor-based controller, which serves to collect and format data, to present data to a scan converter, and to operate a device communication bus. A NOVA minicomputer is used to record and recall frame images and to perform refined image processing. The RCA 1802 also provides instrument mode control for the MASCOT. Commands are issued using STOIC, a FORTH-like language. Sufficient flexibility has been provided so that a variety of CCDs can be accommodated.

Dewey, D.↗
NASA NTRS1998

Composite x-ray image assembly for large-field digital mammography with one- and two-dimensional positioning of a focal plane array

To demonstrate the feasibility of a novel large-field digital mammography technique, a 1024 x 1024 pixel Loral charge-coupled device (CCD) focal plane array (FPA) was positioned in a mammographic field with one- and two-dimensional scan sequences to obtain 950 x 1800 pixel and 3600 x 3600 pixel composite images, respectively. These experiments verify that precise positioning of FPAs produced seamless composites and that the CCD mosaic concept has potential for high-resolution, large-field imaging. The proposed CCD mosaic concept resembles a checkerboard pattern with spacing left between the CCDs for the driver and readout electronics. To obtain a complete x-ray image, the mosaic must be repositioned four times, with an x-ray exposure at each position. To reduce the patient dose, a lead shield with appropriately patterned holes is placed between the x-ray source and the patient. The high-precision motorized translation stages and the fiber-coupled-scintillating-screen-CCD sensor assembly were placed in the position usually occupied by the film cassette. Because of the high mechanical precision, seamless composites were constructed from the subimages. This paper discusses the positioning, image alignment procedure, and composite image results. The paper only addresses the formation of a seamless composite image from subimages and will not consider the effects of the lead shield, multiple CCDs, or the speed of motion.

Mammography/methods/statistics & numerical data↗
NASA NTRS2005

Characterization of Custom-Designed Charge-Coupled Devices for Applications to Gas and Aerosol Monitoring Sensorcraft Instrument

Custom-designed charge-coupled devices (CCD) for Gas and Aerosols Monitoring Sensorcraft instrument were developed. These custom-designed CCD devices are linear arrays with pixel format of 512x1 elements and pixel size of 10x200 sq m. These devices were characterized at NASA Langley Research Center to achieve a full well capacity as high as 6,000,000 e-. This met the aircraft flight mission requirements in terms of signal-to-noise performance and maximum dynamic range. Characterization and analysis of the electrical and optical properties of the CCDs were carried out at room temperature. This includes measurements of photon transfer curves, gain coefficient histograms, read noise, and spectral response. Test results obtained on these devices successfully demonstrated the objectives of the aircraft flight mission. In this paper, we describe the characterization results and also discuss their applications to future mission.

Refaat, Tamer F.↗
NASA NTRS1983

Evaluation of a virtual phase charged-coupled device as an imaging X-ray spectrometer

The X-ray response of an 800 x 800 Texas Instruments virtual phase charge-coupled device (CCD) has been measured in the range 1-8 keV. In the single-photon counting mode, excellent energy resolution (approximately 250 eV FWHM is found for single-pixel Fe-55 X-ray events at a spatial resolution of 15 microns. The detector quantum efficiency for all events is 65% at 2.3 keV (S K line) and approximately 34% at 5.9 keV (Mn K line from Fe-55). The CCD response is linear in energy to a few percent over the 1-8 keV energy range. These results demonstrate that virtual phase CCDs are superior imaging X-ray spectrometers with applications for X-ray astronomy and laboratory plasma research.

Stern, R. A.↗
NASA NTRS1985

Nondispersive X-ray spectroscopy and imaging of plasmas using a charge-coupled device

A virtual-phase charge-coupled device (CCD) was used to obtain pinhole images and X-ray spectra of laser-produced, solid target plasmas. With the CCD used in the single-photon counting mode, the spectrum in the energy range 2-10 keV was obtained without a dispersive element. Typical spectra reveal two distinct temperatures: a cold component of approximately 200 eV and a hot component of approximately 5 keV. Also, multiline spectra comprising characteristic line emission (K alpha, K beta) from a multilayer target bombarded by beta-rays were recorded using a three-phase CCD. The results demonstrate the potential of CCDs as imaging spectrometers with application in space, laboratory, and fusion-plasma research.

Marsh, K.↗
DOE OSTI2025

Multiple-amplifier sensing charged-coupled device: model and improvement of the node removal efficiency

The multiple-amplifier sensing charge-coupled device (MAS-CCD) has emerged as a promising technology for astronomical observation, quantum imaging, and low-energy particle detection due to its ability to reduce the readout time for the same readout noise level compared with its predecessor, the skipper-CCD, by reading out the same charge packet through multiple inline amplifiers. Previous works identified a new parameter in this sensor, called node removal inefficiency (NRI), related to inefficiencies in charge transfer and residual charge removal from the sense node of each amplifier after readout. These inefficiencies can lead to distortions in the measured signals similar to those produced by the charge transfer inefficiencies in standard CCDs. We introduce more details in the mathematical model of the NRI mechanism and provide techniques to quantify its magnitude from the measured data. It also proposes a new operation strategy that significantly reduces its effect with minimal alterations of the timing sequences or voltage settings for the other signals of the sensor. The proposed technique is demonstrated experimentally on a 16-amplifier MAS-CCD. At the same time, the experimental data demonstrate that this approach minimizes the NRI effect to levels comparable with other sources of distortion such as the charge transfer inefficiency in scientific devices.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1985

CCD charge collection efficiency and the photon transfer technique

The charge-coupled device (CCD) has shown unprecendented performance as a photon detector in the areas of spectral response, charge transfer, and readout noise. Recent experience indicates, however, that the full potential for the CCD's charge collection efficiency (CCE) lies well beyond that which is realized in currently available devices. A definition of CCE performance is presented and a standard test tool (the photon transfer technique) for measuring and optimizing this important CCD parameter is introduced. CCE characteristics for different types of CCDs are compared; the primary limitations in achieving high CCE performance are discussed, and the prospects for future improvement are outlined.

Janesick, J.↗
NASA NTRS1987

Scientific charge-coupled devices

The charge-coupled device dominates an ever-increasing variety of scientific imaging and spectroscopy applications. Recent experience indicates, however, that the full potential of CCD performance lies well beyond that realized in devices currently available.Test data suggest that major improvements are feasible in spectral response, charge collection, charge transfer, and readout noise. These properties, their measurement in existing CCDs, and their potential for future improvement are discussed in this paper.

Janesick, James R.↗