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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Fast Single-Quantum Measurement with a Multi-Amplifier Sensing Charge-Coupled Device

A novel readout architecture that uses multiple non-destructive floating-gate amplifiers to achieve sub-electron readout noise in a thick, fully-depleted silicon detector is presented. This Multi-Amplifier Sensing Charge-Coupled Device (MAS-CCD) can perform multiple independent charge measurements with each amplifier; measurements with multiple amplifiers can then be combined to further reduce the readout noise. The readout speed of this detector scales roughly linearly with the number of amplifiers without requiring segmentation of the active area. The performance of this detector is demonstrated, emphasizing the ability to resolve individual quanta and the ability to combine measurements across amplifiers to reduce readout noise. The unprecedented low noise and fast readout of the MAS-CCD make it a unique technology for astronomical observations, quantum imaging, and low-energy interacting particles.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS2019

Maturing Electron Multiplying Charge Coupled Device Photon-Counting with Variable Multiplication Gain Imaging for a Coronagraphic Instrument

This is an introduction to a US Government Program that conducted high-contrast imaging experiments with an Electron Multiplying Charge Coupled Device (EMCCD) in an interferometric coronagraph. This report will introduce the concepts of “Charge Blooming” and “Starlight Saturation” in the context of high-contrast astronomical imaging. These phenomena adversely affect the performance of high-contrast photon-counting instruments that do not use a mask to physically block starlight in the science channel of the coronagraph. The problems will be presented with the help of images taken with a commercial EMCCD camera in the Visible Nulling Coronagraph at the Goddard Space Flight Center (GSFC). A new clocking scheme for EMCCDs – Variable Multiplication Gain Clocking – will be proposed as a means for suppressing horizontal blooming and starlight saturation in an astronomical camera. This opening report from the program will conclude with an introduction to a new controller for high-contrast imaging with EMCCDs in coronagraphs. This controller is being designed to allow a single frame from an EMCCD to be scanned in multiple modes – photon counting and digitization – to enable direct imaging of an exo-planet and wavefront control of a coronagraph, simultaneously.

Udayan Mallik↗
NASA NTRS1982

Differential imaging using charge-coupled device (CCD) imagers with on-chip charge storage

A CCD technique is described which allows long integration periods between readouts together with moderate chopping rates. During each phase of a differential chopping cycle, one set of charge images is shifted to the center of the chip, which is light sensitive. At the same time, the other set of charge images is shifted under one of two masked areas which serve as charge-storage sites. Since the vertical shifting between phases can be accomplished in much less time than the typical exposure per phase, there is negligible image smearing. For a given light level and chopping rate the performance of this technique is limited primarily by the readout noise and the vertical charge transfer inefficiency. If many transfer cycles are required between readouts, the charge transfer inefficiency will diffuse the accumulated charge images along the vertical columns. Laboratory and astronomical data obtained with this technique using a CCD camera and the 2.3 m telescope on Kitt Peak are presented.

Stockman, H. S.↗
NASA NTRS1992

Growth of a delta-doped silicon layer by molecular beam epitaxy on a charge-coupled device for reflection-limited ultraviolet quantum efficiency

Low-temperature silicon molecular beam epitaxy is used to grow a delta-doped silicon layer on a fully processed charge-coupled device (CCD). The measured quantum efficiency of the delta-doped backside-thinned CCD is in agreement with the reflection limit for light incident on the back surface in the spectral range of 260-600 nm. The 2.5 nm silicon layer, grown at 450 C, contained a boron delta-layer with surface density of about 2 x 10 exp 14/sq cm. Passivation of the surface was done by steam oxidation of a nominally undoped 1.5 nm Si cap layer. The UV quantum efficiency was found to be uniform and stable with respect to thermal cycling and illumination conditions.

Hoenk, Michael E.↗
DOE OSTI2024

Sixteen multiple-amplifier sensing charge-coupled devices and characterization techniques targeting the next generation of astronomical instruments

We present a candidate sensor for future spectroscopic applications, such as a Stage-5 Spectroscopic Survey Experiment or the Habitable Worlds Observatory. This type of charge-coupled device (CCD) sensor features multiple in-line amplifiers at its output stage allowing multiple measurements of the same charge packet, either in each amplifier or in the different amplifiers. Recently, the operation of an eight-amplifier sensor has been experimentally demonstrated, and we present the operation of a 16-amplifier sensor. This new sensor enables a noise level of ∼1 erms− with a single sample per amplifier. In addition, it is shown that sub-electron noise can be achieved using multiple samples per amplifier. In addition to demonstrating the performance of the 16-amplifier sensor, we aim to create a framework for future analysis and performance optimization of this type of detectors. New models and techniques are presented to characterize specific parameters, which are absent in conventional CCDs and Skipper CCDs: charge transfer between amplifiers and independent and common noise in the amplifiers and their processing.

16 multiple-amplifer sensing CCD (MAS-CCD)↗
NASA NTRS1977

Charge-coupled device data processor for an airborne imaging radar system

Processing of raw analog echo data from synthetic aperture radar receiver into images on board an airborne radar platform is discussed. Processing is made feasible by utilizing charge-coupled devices (CCD). CCD circuits are utilized to perform input sampling, presumming, range correlation and azimuth correlation in the analog domain. These radar data processing functions are implemented for single-look or multiple-look imaging radar systems.

Arens, W. E.↗
NASA NTRS1976

Test results on intensified charge coupled devices

CCD imaging arrays were evaluated for a photon counting astronomical sensor. Results show noise corresponding to less than 100 rms electrons and gains of approximately 1000 at 10kV accelerating voltage (greater than 5000 at 25kV). Measured charge transfer efficiencies are in excess of 0.9999, signal saturation levels are as high as 990000 electrons per pixel and peak quantum efficiencies are greater than 75%. Successful proximity focussed intensified charge coupled devices (ICCD) have been fabricated, although problems still exist with contamination and possible structural failures in the CCD's during tube manufacture.

Williams, J. T.↗
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 NTRS1979

800 x 800 charge-coupled device /CCD/ camera for the Galileo Jupiter Orbiter mission

During January 1982 the NASA space transportation system will launch a Galileo spacecraft composed of an orbiting bus and an atmospheric entry probe to arrive at the planet Jupiter in July 1985. A prime element of the orbiter's scientific instrument payload will be a new generation slow-scan planetary imaging system based on a newly developed 800 x 800 charge-coupled device (CCD) image sensor. Following Jupiter orbit insertion, the single, narrow-angle, CCD camera, designated the Solid State Imaging (SSI) Subsystem, will operate for 20 months as the orbiter makes repeated encounters with Jupiter and its Galilean Satellites. During this period the SSI will acquire 40,000 images of Jupiter's atmosphere and the surfaces of the Galilean Satellites. This paper describes the SSI, its operational modes, and science objectives.

Clary, M. C.↗
NASA NTRS1976

MIDAS prototype Multispectral Interactive Digital Analysis System for large area earth resources surveys. Volume 2: Charge coupled device investigation

MIDAS is a third-generation, fast, low cost, multispectral recognition system able to keep pace with the large quantity and high rates of data acquisition from large regions with present and projected sensors. MIDAS, for example, can process a complete ERTS frame in forty seconds and provide a color map of sixteen constituent categories in a few minutes. A principal objective of the MIDAS Program is to provide a system well interfaced with the human operator and thus to obtain large overall reductions in turn-around time and significant gains in throughput. The need for advanced onboard spacecraft processing of remotely sensed data is stated and approaches to this problem are described which are feasible through the use of charge coupled devices. Tentative mechanizations for the required processing operations are given in large block form. These initial designs can serve as a guide to circuit/system designers.

Kriegler, F.↗
NASA NTRS2019

Standard Component Commodity Usage Guides (CUGs) for Charge-Coupled Devices (CCDs)

Communicating risk and reliability information within NASA Goddard’s missions is crucial to continuing the development of new technology and ensuring GSFC missions achieve their science objectives. The Reliability and Risk Assessment Branch (Code 371) within the SMA directorate is one of GSFC’s leaders in communicating this information to missions, and one tool 371 engineers use to provide this information is the Commodity Usage Guides (CUGs). CUGs are helpful in compiling various critical parameters and heritage information for standard payload components, ensuring project personnel inherit the lessons learned from previous experiences. The purpose of this project was to create CUGs for CCDs used within GSFC missions. To formulate a CUG applicable data was aggregated into the CUG template for Charge-Coupled Devices (CCDs)--electro-optical components used to convert photons into digital images and data. CCDs can easily be adapted to a variety of mission requirements making them widely used at GSFC, and therefore suitable for CUGs. Once the CUGs for CCDs are completed the information can be distributed to engineers, scientists and other project members to ensure the lessons learned are passed on to the next mission.

Christman, Jerika H.↗
NASA NTRS1982

Intensified charge coupled devices for use as a spaceborne spectrographic image-plane detector system

An instrument that has been developed for studies of atmospheric emissions from the Space Shuttle comprises an array of imaging spectrometers to observe features over the 300-12,000-A wavelength range. Each spectrometer has a 2-D image-plane detector system on which spectral information is dispersed in one direction and spatial information is resolved in the other. The detectors consist of CCD arrays which are coupled to proximity focused image intensifiers. The intensifier in each case is selected for the wavelength range covered by the particular spectrometer. The result is a compact low-power spectrographic detector system. In the course of building the five flight detector systems, there was occasion to evaluate a larger number of the charge coupled devices and the proximity focused image intensifiers. Various characteristics, advantages, and shortcomings of these devices and the overall intensified CCD system are reported.

Torr, M. R.↗
NASA NTRS1982

Visible charge-coupled device (CCD) focal plane design considerations for multispectral applications

The typical Multispectral Linear Array (MLA) Instrument mission would be to gather high-resolution, radiometrically accurate earth resources data in several spectral bands over a prolonged period of time. These bands would include the visible (VIS), near infrared (NIR) and short wavelength infrared. Silicon charge-coupled imaging devices (CCDs) can be assembled into contiguous pixel focal planes which will cover the VIS/NIR region and operate reliably for several years in a space environment. A typical MLA focal plane would have approximately 12,000 pixels, with a pixel-to-pixel registration requirement on the order of + or - 0.1 pixel. The technology to assemble such focal planes has been developed and is described. The problem of polarization sensitivity associated with certain types of focal plane assemblies is addressed. Radiation effects on CCDs are also discussed, and a practical solution to the problem through the use of shielding is described.

Sadowski, H.↗
NASA NTRS1987

Electro-optical characterization of the Tektronix TK512M-011 charge-coupled device

An electrooptical characterization encompassing linearity, blooming, dark-count rate, charge-transfer efficiency (CTE), and quantum efficiency, is presented for a front/side-illuminated CCD with 512x512 format and 27x27-micron pixels. The detailed noise characteristics of the CCD-output FET are reported. While very good low light level CTE is obtained in the parallel-shift direction, CTE problems arise in the serial direction. The output FET noise is equivalent to 5-12 electrons, depending on FET operating conditions and system bandwidth.

Epperson, Patrick M.↗
NASA NTRS1981

Subtleties in the flat-fielding of charge-coupled device /CCD/ images

Astronomical photometry with CCDs will often involve relatively low signal levels (less than 1000 charge carriers per pixel), at which nonlinear effects sometimes become significant. These effects will probably play a role in the processing of Space Telescope data. The problem apparently arises because signal charges are not read out equally completely from all columns and all pixels. It is shown that, although a first-order correction can be made by subtracting a low-level flat field from all frames before conventional processing, higher accuracy can be achieved by modeling the response with a nonlinear function.

Baum, W. A.↗
NASA NTRS1987

Charge-coupled-device parallel-to-serial converter

A CCD parallel-to-serial converter comprising two successions of charge transfer stages, recurrently side-loaded with respective ones of parallelly supplied charge packets, then serially unloaded by time-interleaved respective shift register operations. The charge packets converted to time-division-multiplexed serial form are supplied to a shared electrometer, and the electrometer response is de-multiplexed. Preferably, shift register operations are carried forward concurrently at the same rate, but with the final charge transfer stages clocked in phases staggered in time.

Tower, John R.↗
DOE OSTI2020

Charge collection efficiency in back-illuminated Charge-Coupled Devices

Low noise CCDs fully-depleted up to 675 micrometers have been identified as a unique tool for Dark Matter searches and low energy neutrino physics. The charge collection efficiency (CCE) for these detectors is a critical parameter for the performance of future experiments. We present here a new technique to characterize CCE in back-illuminated CCDs based on soft X-rays. This technique is used to characterize two different detector designs. The results demonstrate the importance of the backside processing for detection near threshold, showing that a recombination layer of a few microns significantly distorts the low energy spectrum. The studies demonstrate that the region of partial charge collection can be reduced to less than 1 micrometer thickness with adequate backside processing.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1976

Charge coupled device integration-time coding for detection of images moving with unknown velocities

Existing techniques for the detection of a moving low light level image by a CCD array have required velocity synchronism between the image and the photogenerated charges. This was necessary to prevent blurring during the long duration of charge integration. A new detection scheme is described which causes the image to be convolved with a clock modulation signal as the photocharges are collected. The charge accumulating from each image point will now be spread over many photoelements due to the absence of velocity synchronism, but the output is not blurred in the usual sense. Instead the charge is distributed through the array in a controlled way so that the image can be reconstructed.

White, J. M.↗