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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Optimization of niobium tunnel junctions as X-ray detectors

We report on our ongoing work using Nb/Al/AlO(x)/Nb junctions for the detection of X-rays. Detectors based on superconducting tunneling junctions offer the prospect of resolution over an order of magnitude higher than is obtainable with the current generation of semiconductor-based detectors. Results of measurements taken at 1.85 K (a temperature achievable with current space flight technology) include the current-voltage (I-V) curve, subgap current vs temperature, the dependence of the superconducting current on the applied magnetic field (Fraunhofer pattern), X-ray pulses, and the spectra from a 6 keV X-ray source which gave an intrinsic device resolution of approximately 700 eV. The collection of more than 10 exp 5 electrons per 6 keV photon is established.

Saulnier, Gregory G.↗
NASA NTRS1991

Infrared technology XVII; Proceedings of the Meeting, San Diego, CA, July 22-26, 1991

Recent advances in IR technologies and their application to all types of IR systems are reported focusing on the JPL Space Infrared Telescope Facility (SIRTF), JPL instruments and systems for observation of earth and the atmosphere, staring arrays and thermal imaging, ten-year updates of IR techniques, infrared in the USSR, simulation and testing, focal-plane and optical technologies, and military and scientific applications. Particular attention is given to SIRTF stray light analysis, SIRTF focal-plane technologies, long-wave IR detectors based on III-V materials, IR lidars for atmospheric remote sensing, a firefly system concept, a high-fill-factor monolithic IR image sensor, atmospheric laser-transmission tables simply generated, ORION semiconductor optical detectors, postprocessing of thermograms in IR nondestructive testing, evaluation of the IR signature of dynamic air targets, the current status of InGaAs detector arrays for 1-3 microns, a dual-band optical system for IR multicolor signal processing, and blackbody radiators for field calibration.

Andresen, Bjorn F.↗
NASA NTRS2012

Performance Testing of Lidar Components Subjected to Space Exposure in Space via MISSE 7 Mission

.The objective of the Materials International Space Station Experiment (MISSE) is to study the performance of novel materials when subjected to the synergistic effects of the harsh space environment for several months. MISSE missions provide an opportunity for developing space qualifiable materials. Several laser and lidar components were sent by NASA Langley Research Center (LaRC) as a part of the MISSE 7 mission. The MISSE 7 module was transported to the international space station (ISS) via STS 129 mission that was launched on Nov 16, 2009. Later, the MISSE 7 module was brought back to the earth via the STS 134 that landed on June 1, 2011. The MISSE 7 module that was subjected to exposure in space environment for more than one and a half year included fiber laser, solid-state laser gain materials, detectors, and semiconductor laser diode. Performance testing of these components is now progressing. In this paper, the current progress on post-flight performance testing of a high-speed photodetector and a balanced receiver is discussed. Preliminary findings show that detector characteristics did not undergo any significant degradation.

Prasad, Narasimha S.↗
NASA NTRS1964

Radiation Effects of Protons and Electrons in Silicon Diffused-Junction Detectors

Diffused n-on-p silicon particle detectors were irradiated with 1-Mev electrons, and with 31-Mev and 8.2-Mev protons. The detector capacitance was observed to increase with electron irradiation and to decrease with proton irradiation. A physical interpretation is given in terms of defect energy levels known to be introduced in silicon by irradiation. Defect ionization states are taken to be characteristic of the space-charge region, rather than of bulk silicon. The relation to other studies of damage in semiconductor particle detectors is pointed out, considering differences in the types of detector and irradiation used. The significance of these results is discussed for detector applications where the damage threshold is exceeded.

Scott, R. E.↗
NASA NTRS1998

Quantum Well Infrared Photodetectors for Long Wavelength Infrared Applications

Quantum Well Infrared Photodetectors (QWIPs) offer greater flexibility than usual extrinsically doped semiconductor IR detectors because the wavelength of the peak response and cutoff can be continuously tailored by varying layer thickness (well width), barrier composition (barrier height), and carrier density (well doping density).

Quantum↗
NASA NTRS1971

NASA multidisciplinary research grant

Research is discussed in the multidisciplinary areas of space and planetary science; materials and radiation; systems, instrumentation, and structures; and technology and man. Highlights are identified as an alpha-recoil track method of archeological dating; infrared astronomical telescope; reaction rates data, semiconductor radiation detectors, and analysis of time-dependent systems; Gunn effect devices for microwave generation and detection, mode-locked lasers, and radiation theory; and the application of a satellite communication system to educational development. Detectors to be flown on Apollo 16 to measure heavy particle flux in the solar wind and to be part of the HEAO-A experiment on extremely heavy nuclei in cosmic rays were developed. The impact of the multidisciplinary research on university activities is described, and individual departmental reports are included.

Source record↗
NASA NTRS1974

Separation of surface and bulk minority-carrier lifetimes in silicon

A photoexcitation technique is suggested which is direct and convenient, requiring little special equipment. No change in the dimensions of the crystal sample is necessary. Although related to the technique of interposing a filter between the light source and the sample, it differs in that the filter is part of the crystal itself. Basically, one of the electrodes is split into two electrodes, one collecting charge from carriers excited in the bulk. This phenomenon in which the carriers follow very closely the electric field lines has been used in position-sensitive semiconductor radiation detectors (Norbeck and Carlson, 1963) but has not been applied to lifetime measurements. In a sense, the split electrode creates a sample without a surface.

Carroll, K. A.↗
NASA NTRS1975

Nuclear Science Symposium, 21st, Scintillation and Semiconductor Counter Symposium, 14th, and Nuclear Power Systems Symposium, 6th, Washington, D.C., December 11-13, 1974, Proceedings

Papers are presented dealing with latest advances in the design of scintillation counters, semiconductor radiation detectors, gas and position sensitive radiation detectors, and the application of these detectors in biomedicine, satellite instrumentation, and environmental and reactor instrumentation. Some of the topics covered include entopistic scintillators, neutron spectrometry by diamond detector for nuclear radiation, the spherical drift chamber for X-ray imaging applications, CdTe detectors in radioimmunoassay analysis, CAMAC and NIM systems in the space program, a closed loop threshold calibrator for pulse height discriminators, an oriented graphite X-ray diffraction telescope, design of a continuous digital-output environmental radon monitor, and the optimization of nanosecond fission ion chambers for reactor physics. Individual items are announced in this issue.

Source record↗
NASA NTRS2002

Multi-Band GaAs/AlGaAs Quantum Well Infrared Photodetector (QWIP) Focal Plane Arrays

The GaAs/AlGaAs based Quantum Well Infrared Photodetectors (QWIPs) afford greater flexibility than the usual extrinsically doped semiconductor IR detectors because the wavelength of the peak response and cutoff can be continuously tailored over any wavelength between 6-20 micrometers. The spectral band width of these detectors can be tuned from narrow (DELTA)lamba/lamba approx. 10 %)) to wide (DELTA)lamba/lamba approx. 50 %) allowing various applications. Also, QWIP offers multi-color infrared cameras which is capable of simultaneously acquiring images in different infrared bands. Each pixel of such array consists of vertically stacked, independently readable, QWIP detectors sensitive in different narrow infrared bands. In this article, we discuss the development and results of the 640 x 512 dual-band and four-band QWIP FPAs.

Bandara, S. V.↗
NASA NTRS2003

High Sensitivity Long-Wavelength Infrared QWIP Focal Plane Array Based Instrument for Remote Sensing of Icy Satellites

GaAs based Quantum Well Infrared Photodetector (QWIP) technology has shown remarkable success in advancing low cost, highly uniform, high-operability, large format multi-color focal plane arrays. QWIPs afford greater flexibility than the usual extrinsically doped semiconductor IR detectors. The wavelength of the peak response and cutoff can be continuously tailored over a range wide enough to enable light detection at any wavelength range between 6 and 20 micron. The spectral band-width of these detectors can be tuned from narrow (Deltalambda/lambda is approximately 10%) to wide (Deltalambda/lambda is approximately 40%) allowing various applications. Furthermore, QWIPs offer low cost per pixel and highly uniform large format focal plane arrays due to mature GaAs/AlGaAs growth and processing technologies. The other advantages of GaAs/AlGaAs based QWIPS are higher yield, lower l/f noise and radiation hardness (1.5 Mrad). In this presentation, we will discuss our recent demonstrations of 640x512 pixel narrow-band, broad-band, multi-band focal plane arrays, and the current status of the development of 1024x1024 pixel long-wavelength infrared QWIP focal plane arrays.

Gunapala, S.↗
NASA NTRS2002

Multi-band quantum well infrared photodetectors

The GaAs/AlGaAs based Quantum Well Infrared Photodetectors (QWIPs) afford greater flexibility than the usual extrinsically doped semiconductor IR detectors because the wavelength of the peak response and cutoff can be continuously tailored over any wavelength between 6-20 mu m.

IR quantum well thermal imaging multi-spectral↗
NASA NTRS2006

Cryogenic Cooling for Myriad Applications-A STAR Is Born

Cryogenics, the science of generating extremely low temperatures, has wide applicability throughout NASA. The Agency employs cryogenics for rocket propulsion, high-pressure gas supply, breathable air in space, life support equipment, electricity, water, food preservation and packaging, medicine, imaging devices, and electronics. Cryogenic liquid oxygen and liquid hydrogen systems are also replacing solid rocket motor propulsion systems in most of the proposed launch systems, a reversion to old-style liquid propellants. In the late 1980s, NASA wanted a compact linear alternator/motor with reduced size and mass, as well as high efficiency, that had unlimited service life for use in a thermally driven power generator for space power applications. Prior development work with free-piston Stirling converters (a Stirling engine integrated with a linear actuator that produces electrical power output) had shown the promise of that technology for high-power space applications. A dual use for terrestrial applications exists for compact Stirling converters for onsite combined heat and power units. The Stirling cycle is also usable in reverse as a refrigeration cycle suitable for cryogenic cooling, so this Stirling converter work promised double benefits as well as dual uses. The uses for cryogenic coolers within NASA abound; commercial applications are similarly wide-ranging, from cooling liquid oxygen and nitrogen, to cryobiology and bio-storage, cryosurgery, instrument and detector cooling, semiconductor manufacturing, and support service for cooled superconducting power systems.

Source record↗
NASA NTRS2014

Post-Flight Test Results of Acousto-Optic Modulator Devices Subjected to Space Exposure

The objective of the Materials International Space Station Experiment (MISSE) is to study the performance of novel materials when subjected to the synergistic effects of the harsh space environment for several months. MISSE missions provide an opportunity for developing space qualifiable materials. Several laser and lidar components were sent by NASA Langley Research Center (LaRC) as a part of the MISSE 7 mission. The MISSE 7 module was transported to the international space station (ISS) via STS 129 mission that was launched on Nov 16, 2009. Later, the MISSE 7 module was brought back to the earth via the STS 134 that landed on June 1, 2011. The MISSE 7 module that was subjected to exposure in a space environment for more than one and a half years included fiber laser, solid-state laser gain materials, detectors, and semiconductor laser diode. Performance testing of these components is now progressing. In this paper, the results of performance testing of a laser diode module sent by NASA Langley Research Center on MISSE 7 mission will be discussed. This paper will present the comparison of pre-flight and post-flight performance of two different COTS acousto-optic modulator (AOM) devices. Post-flight measurements indicate that these two devices did not undergo any significant performance degradation.

Prasad, Narasimha S.↗
NASA NTRS2013

Post-Flight Test Results of Seed Laser Module Subjected to Space Exposure

The objective of the Materials International Space Station Experiment (MISSE) is to study the performance of novel materials when subjected to the synergistic effects of the harsh space environment for several months. MISSE missions provide an opportunity for developing space qualifiable materials. Several laser and lidar components were sent by NASA Langley Research Center (LaRC) as a part of the MISSE 7 mission. The MISSE 7 module was transported to the international space station (ISS) via STS 129 mission that was launched on Nov 16, 2009. Later, the MISSE 7 module was brought back to the earth via the STS 134 that landed on June 1, 2011. The MISSE 7 module that was subjected to exposure in space environment for more than one and a half year included fiber laser, solid-state laser gain materials, detectors, and semiconductor laser diode. Performance testing of these components is now progressing. In this paper, the results of performance testing of a laser diode module sent by NASA Langley Research Center on MISSE 7 mission will be discussed. This paper will present the comparison of pre-flight and post-flight performance curves and discuss the effect of space exposure on the laser diode module. Preliminary findings on output power measurements show that the COTS laser diode characteristics did not undergo any significant performance degradation.

Prasad, Narasimha S.↗