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254
Jul 12, 2010
07/10
by
Money, K. E
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Peripheral Vision Horizon Device (PVHD) theory states that the likelihood of pilot disorientation in flight is reduced by providing an artificial horizon that provides orientation information to peripheral vision. In considering the validity of the theory, three areas are explored: the use of an artificial horizon device over some other flight instrument; the use of peripheral vision over foveal vision; and the evidence that peripheral vision is well suited to the processing of orientation...
Topics: ELECTRON EMISSION, ELECTRON SCATTERING, HOT ELECTRONS, IONIC COLLISIONS, CROSS SECTIONS, ELECTRIC...
407
407
May 23, 2011
05/11
by
Popper, Arthur N
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This paper considers the detection of vibrational signals (including sound) by the two components of the octavolateralis system, the ear and mechanosensory lateral line. Together, these systems provide fishes with a good deal of information about their surrounding environment, and enable fishes to detect both predators and prey. While the mechanisms by which fishes and zooplankton produce and detect signals may differ, it is clear that the physical principles underlying the signals themselves...
Topics: WAVELENGTHS, ELECTRONS, DRAINAGE, DISCRIMINATION, INFRARED RADIATION, HOT ELECTRONS, TRANSISTORS,...
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199
Jun 27, 2010
06/10
by
Taddeo, F. V
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Pulse generating circuit for operation at very high duty cycles and repetition rates
Topics: DISTRIBUTION FUNCTIONS, ENERGY DISTRIBUTION, HOT ELECTRONS, IONOSPHERIC ION DENSITY, PLASMAS...
527
527
May 23, 2011
05/11
by
Lucy, M. H.; Buehrle, R. D.; Woolley, J. P
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Functional shock, safety, overall system costs, and emergence of new technologies, have raised concerns regarding continued use of pyrotechnics on spacecraft. NASA Headquarters-Office of Chief Engineer requested Langley Research Center (LaRC) study pyrotechnic alternatives using non-explosive actuators (NEA's), and LARC participated with Lockheed Martin Missile and Space Co. (LMMSC)-Sunnyvale, CA in objectively evaluating applicability of some NEA mechanisms to reduce small spacecraft and...
Topics: ABSORPTION SPECTRA, CONDUCTION BANDS, ELECTRON TRANSFER, INFRARED ABSORPTION, ULTRAVIOLET...
A design has been proposed for a photodetector that would exhibit a high quantum efficiency (as much as 90 percent) over a wide wavelength band, which would typically be centered at a wavelength of 1.55 m. This and similar photodetectors would afford a capability for detecting single photons - a capability that is needed for research in quantum optics as well as for the practical development of secure optical communication systems for distribution of quantum cryptographic keys. The proposed...
Topics: NASA Technical Reports Server (NTRS), PHOTOMETERS, SUPERCONDUCTORS (MATERIALS), OPTICAL...
253
253
May 28, 2011
05/11
by
Frehlich, Ro
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This report represents the final report for three years of research in the performance of coherent Doppler lidar for use during space missions and the effectiveness of its use for research into wind turbulence. Included are summaries of each year's results, and the publications derived from that years research. The research for year one determined the performance of coherent Doppler Lidar in the weak signal regime, and improved algorithms for extracting the performance velocity estimators with...
Topics: FAR INFRARED RADIATION, MIXERS, HOT ELECTRONS, HIGH FREQUENCIES, BOLOMETERS, HETERODYNING,...
240
240
May 23, 2011
05/11
by
Barber, P. G.; Berry, R. F.; Debnam, W. J.; Fripp, A. L.; Woodell, G.; Simchick, R. T
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Using the advanced technology developed to visualize the melt-solid interface in low Prandtl number materials, crystal growth rates and interface shapes have been measured in germanium and lead tin telluride semiconductors grown in vertical Bridgman furnaces. The experimental importance of using in-situ, real time observations to determine interface shapes, to measure crystal growth rates, and to improve furnace and ampoule designs is demonstrated. The interface shapes observed in-situ, in...
Topics: SUPERCONDUCTING DEVICES, ELECTRON PHONON INTERACTIONS, MIXERS, DIFFUSION, COOLING, BOLOMETERS, HOT...
444
444
May 23, 2011
05/11
by
Schelman, David A.; Jenkins, Phillip P.; Brinker, David J.; Appelbaum, Josep
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Past NASA missions to Mars, Jupiter and the outer planets were powered by radioisotope thermal generators (RTG's). Although these devices proved to be reliable, their high cost and highly toxic radioactive heat source has made them far less desirable for future planetary missions. This has resulted in a renewed search for alternate energy sources, some of them being photovoltaics (PV) and thermo-photovoltaics (TPV). Both of these alternate energy sources convert light/thermal energy directly...
Topics: SOLAR WIND, IONS, INNER RADIATION BELT, GEOMAGNETIC TAIL, SATELLITE INSTRUMENTS, MAGNETICALLY...
444
444
May 31, 2011
05/11
by
Ellis, Stephen R.; Adelstein, Bernard D.; Reisman, Ronald J.; Schmidt-Ott, Joelle R.; Gips, Jonathan; Krozel, Jimm
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An optical see-through, augmented reality display was used to study subjects' ability to detect aircraft maneuvering and landing at the Dallas Ft. Worth International airport in an ATC Tower simulation. Subjects monitored the traffic patterns as if from the airport's western control tower. Three binocular fields of view (14 deg, 28 deg and 47 deg) were studied in an independent groups' design to measure the degradation in detection performance associated with the visual field restrictions. In a...
Topics: SPECTROSCOPIC ANALYSIS, NITRIC ACID, BACKWARD WAVES, FREQUENCY MEASUREMENT, SUBMILLIMETER WAVES,...
This report summarizes work done under NASA Grant NAG2-1062 awarded to the University of Colorado. The project goal was to evaluate the scientific capabilities and technical requirements for a far-infrared heterodyne spectrometer suitable for the SOFIA Airborne Observatory, which is now being developed by NASA under contract to the Universities Space Research Association (USRA). The conclusions detailed below include our specific recommendations for astronomical observations, as well as our...
Topics: NASA Technical Reports Server (NTRS), SPECTROMETERS, SOFIA (AIRBORNE OBSERVATORY), HETERODYNING,...
666
666
May 29, 2011
05/11
by
Han, Jongil; Arya, S. Pal; Shaohua, Shen; Lin, Yuh-Lan
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Algorithms are developed to extract atmospheric boundary layer profiles for turbulence kinetic energy (TKE) and energy dissipation rate (EDR), with data from a meteorological tower as input. The profiles are based on similarity theory and scalings for the atmospheric boundary layer. The calculated profiles of EDR and TKE are required to match the observed values at 5 and 40 m. The algorithms are coded for operational use and yield plausible profiles over the diurnal variation of the atmospheric...
Topics: BANDWIDTH, MICROWAVE FREQUENCIES, INTERMEDIATE FREQUENCIES, LOW NOISE, SIDEBANDS, SUBMILLIMETER...
A batch of experimental diffusion-cooled hot-electron bolometers (HEBs), suitable for use as mixers having input frequencies in the terahertz range and output frequencies up to about a gigahertz, exploit the superconducting/normal-conducting transition in a thin strip of tantalum. The design and operation of these HEB mixers are based on mostly the same principles as those of a prior HEB mixer that exploited the superconducting/normal- conducting transition in a thin strip of niobium and that...
Topics: NASA Technical Reports Server (NTRS), BOLOMETERS, HOT ELECTRONS, TANTALUM, TRANSITION TEMPERATURE,...
A document proposes the development of hot-electron photon counters (HEPCs) for detecting terahertz photons in spaceborne far-infrared astronomical instruments. These would be superconducting- transition-edge devices: they would contain superconducting bridges that would have such low heat capacities that single terahertz photons would cause transient increases in their electron temperatures through the superconducting- transition range, thereby yielding measurable increases in electrical...
Topics: NASA Technical Reports Server (NTRS), BOLOMETERS, PHOTONS, COUNTERS, TRANSITION TEMPERATURE, HOT...
The millimeter and the submillimeter wavelengths of the electromagnetic spectrum hold a wealth of information about the evolution of the universe. In particular, cosmic microwave background (CMB) radiation and its polarization carry the oldest information in the universe, and provide the best test of the inflationary paradigm available to astronomy today. Detecting gravity waves through their imprint on the CMB polarization would have extraordinary repercussions for cosmology and physics. A...
Topics: NASA Technical Reports Server (NTRS), BOLOMETERS, HOT ELECTRONS, INTEGRATED CIRCUITS, COSMIC...
The project goal was to evaluate the scientific capabilities and technical requirements for a far-infrared heterodyne spectrometer suitable for the SOFIA Airborne Observatory, which is now being developed by NASA under contract to the Universities Space Research Association (USRA). The conclusions detailed below include our specific recommendations for astronomical observations, as well as our intended technical approach for reaching these scientific goals. These conclusions were presented to...
Topics: NASA Technical Reports Server (NTRS), FAR INFRARED RADIATION, HETERODYNING, SPECTROMETERS,...
The relaxation dynamics of hot electrons in the X6 and X7 satellite and upper conduction bands in GaP was directly measured by femtosecond UV-pump-IR-probe absorption spectroscopy. From a fit to the induced IR-absorption spectra the dominant scattering mechanism giving rise to the absorption at early delay times was determined to be intervalley scattering of electrons out of the X7 upper conduction-band valley. For long delay times the dominant scattering mechanism is electron-hole scattering....
Topics: NASA Technical Reports Server (NTRS), ABSORPTION SPECTRA, CONDUCTION BANDS, ELECTRON TRANSFER,...
A superconducting hot-electron bolometer has been built and tested as a prototype of high-sensitivity, rapid-response detectors of submillimeter-wavelength radiation. There are diverse potential applications for such detectors, a few examples being submillimeter spectroscopy for scientific research; detection of leaking gases; detection of explosive, chemical, and biological weapons; and medical imaging. This detector is a superconducting-transition- edge device. Like other such devices, it...
Topics: NASA Technical Reports Server (NTRS), SUBMILLIMETER WAVES, SUPERCONDUCTING DEVICES, HOT ELECTRONS,...
Bell System Technical Journal, 30: 4. October 1951 pp 990-1034. Hot Electrons in Germanium and Ohm's Law. (Shockley, W.)
Topics: energy, electron, electrons, optical, phonon, modes, germanium, velocity, phonons, drift, free...
The toroidal ring of plasma contained in the NASA Lewis bumpy-torus superconducting magnet facility may be biased to positive or negative potentials approaching 50 kilovolts by applying direct-current voltages of the respective polarity to 12 or fewer of the midplane electrode rings. The electric fields which are responsible for heating the ions by E/B drift then point radially outward or inward. The low-frequency fluctuations below the ion cyclotron frequency appeared to be dominated by...
Topics: NASA Technical Reports Server (NTRS), PLASMA GENERATORS, TOROIDAL PLASMAS, DEUTERIUM, ELECTRIC...
A time-of-flight mass spectrometer (TOF-MS) like the one mentioned in the immediately preceding article has been retrofitted with an ionizer based on a surface spontaneous-desorption process. This ionizer includes an electron multiplier in the form of a microchannel plate (MCP). Relative to an ionizer based on a hot-filament electron source, this ionizer offers advantages of less power consumption and greater mechanical ruggedness. The current density and stability characteristics of the...
Topics: NASA Technical Reports Server (NTRS), IONIZERS, TIME OF FLIGHT SPECTROMETERS, MASS SPECTROMETERS,...
The Twelfth International Symposium on Space Terahertz Technology was held February 14-16, 2001 in San Diego, California, USA. This symposium was jointly sponsored by the National Aeronautics and Space Administration (NASA) and the Jet Propulsion Laboratory, California Institute of Technology. The symposium featured sixty nine presentations covering a wide variety of technical topics relevant to Terahertz Technology. The presentations can be divided into five broad technology areas: Hot...
Topics: NASA Technical Reports Server (NTRS), AEROSPACE ENGINEERING, BOLOMETERS, CONFERENCES, SIS...
Geotail was launched on 24 July 1992 as the first new spacecraft of the International Solar Terrestrial Physics Program (ISTP). A primary objective of the Geotail mission is the acquisition of particles and fields measurements in the tail region of the magnetosphere. Some of the specific scientific objectives of the Geotail mission are; (1) assessment of the relative importance of solar-wind and ionospheric sources to the plasmas of the magnetotail, (2) a search for plasmoids and flux ropes,...
Topics: NASA Technical Reports Server (NTRS), SOLAR WIND, GEOMAGNETIC TAIL, SATELLITE INSTRUMENTS,...
Both external and internal phenomena impact the terrestrial magnetosphere. For example, solar wind and particle precipitation effect the distribution of hot plasma in the magnetosphere. Numerous models exist to describe different aspects of magnetosphere characteristics. For example, Tsyganenko has developed a series of models (e.g., [TSYG89]) that describe the magnetic field, and Stern [STER75] and Volland [VOLL73] have developed an analytical model that describes the convection electric...
Topics: NASA Technical Reports Server (NTRS), ELECTRIC FIELDS, GEOMAGNETISM, HIGH TEMPERATURE PLASMAS, HOT...
Frequency band broadening takes place just outside of the nighttime plasmasphere, where the density of cold plasma is known to be very low during the later phase of a geomagnetic storm. Instead of the gradual broadening of several hours duration, a burst type broadening of VLF emission lasting less than ten minutes was observed by Explorer 45 in a similar location. The magnetic field component of this emission is very weak and the frequency spreads below the local half electron cyclotron...
Topics: NASA Technical Reports Server (NTRS), BROADBAND, ELECTRON EMISSION, MAGNETIC STORMS, RADIO BURSTS,...
Currently, millimeter-wave and submillimeter-wave spectroscopy is conducted in our laboratory on several different types of spectrometers. Our standard spectrometer utilizes the output of a phase-locked klystron operating in the 40-60 GHz region, which is sent into a crossed-waveguide harmonic generator, or "multiplier". The high frequency millimeter-and submillimeter-wave radiation is transmitted via quasi-optical techniques through an absorption cell and then onto a detector, which...
Topics: NASA Technical Reports Server (NTRS), SPECTROSCOPIC ANALYSIS, SUBMILLIMETER WAVES, SPECTROMETERS,...
Thin-film electroluminescent (TFEL) devices are studied for a possible means of achieving a high resolution, light weight, compact video display panel for computer terminals or television screens. The performance of TFEL devices depends upon the probability of an electron impact exciting a luminescent center which in turn depends upon the density of centers present in the semiconductor layer, the possibility of an electron achieving the impact excitation threshold energy, and the collision...
Topics: NASA Technical Reports Server (NTRS), DATA PROCESSING TERMINALS, DISPLAY DEVICES,...
Superlattice photodetectors were investigated. A few major physical processes in the quantum-well heterostructures related to the photon detection and electron conduction mechanisms, the field effect on the wave functions and the energy levels of the electrons, and the optical absorption with and without the photon assistance were studied.
Topics: NASA Technical Reports Server (NTRS), ELECTRIC FIELDS, ELECTROMAGNETIC ABSORPTION, ELECTRON...
A hot-electron transition-edge superconducting bolometer with adjustable thermal relaxation speed is proposed. The bolometer contacts are made from a superconductor with high critical temperature which blocks the thermal diffusion of hot carriers into the contacts. Thus electron-phonon interaction is the only mechanism for heat removal. The speed of thermal relaxation for hot electrons in a nanometer-size superconducting bolometer with T(sub c) = 100-300 mK is controlled by the elastic electron...
Topics: NASA Technical Reports Server (NTRS), BOLOMETERS, HOT ELECTRONS, RADIO ASTRONOMY, ELECTRON PHONON...
A new theoretical model is introduced to describe heterodyne mixer conversion efficiency and noise (from thermal fluctuation effects) in diffusion-cooled superconducting hot-electron bolometers. The model takes into account the non-uniform internal electron temperature distribution generated by Wiedemann-Franz heat conduction, and accepts for input an arbitrary (analytical or experimental) superconducting resistance-versus- temperature curve. A non-linear large-signal solution is solved...
Topics: NASA Technical Reports Server (NTRS), FREQUENCY DOMAIN ANALYSIS, CONDUCTIVE HEAT TRANSFER,...
The development of electric fields in an expanding plasma was studied. With regard to the polar wind, it was found that hot magnetospheric electrons have a pronounced effect on the polar wind. In addition, there is no O(+) charge exchange barrier and substantial fluxes of O(+) ions can escape with the polar wind. In the auroral plasma physics area, the excitation of electrostatic waves by field aligned auroral electron beams was examined. It was demonstrated that the auroral field aligned...
Topics: NASA Technical Reports Server (NTRS), AURORAS, ELECTRIC FIELDS, ELECTROSTATIC WAVES, HOT ELECTRONS,...
We report on the first heterodyne measurements with a diffusion-cooled hot-electron bolometer mixer in the submillimeter wave band, using a waveguide mixer cooled to 2.2 K. The best receiver noise temperature at a local oscillator frequency of 533 GHz and an intermediate frequency of 1.4 GHz was 650 K (double sideband). The 3 dB IF roll-off frequency was around 1.7 to 1.9 GHz, with a weak dependence on the device bias conditions.
Topics: NASA Technical Reports Server (NTRS), BOLOMETERS, BANDWIDTH, SUPERCONDUCTIVITY, SUBMILLIMETER...
Spacecraft charging is well known threat to successful long term spacecraft operations and instrument reliability in orbits that spend significant time in hot electron environments. In recent years, spacecraft charging has increasingly been recognized as a potentially significant engineering issue for launch vehicles used to deploy spacecraft using (a) low Earth orbit (LEO), high inclination flight trajectories that pass through the auroral zone, (b) geostationary transfer orbits that require...
Topics: NASA Technical Reports Server (NTRS), SPACECRAFT CHARGING, LAUNCH VEHICLES, RISK, LOW EARTH ORBITS,...
We proposed to perform a comprehensive design study of a 16-element heterodyne array receiver for SOFIA. The array was designed to utilize hot-electron bolometers in an efficient, low-cost waveguide mount to achieve low noise performance between approx. 1500 and 2400 GHz. Due to the prevailing physical conditions in the interstellar medium, this frequency range is one of the richest in the FIR portion of the spectrum. An array designed for this wavelength range will make excellent use of the...
Topics: NASA Technical Reports Server (NTRS), DESIGN ANALYSIS, HETERODYNING, ARRAYS, RECEIVERS, HOT...
This final report describes a three-year research effort, aimed at developing new types of THz low noise receivers, based on bulk effect ('hot electron') nonlinearities in the Two-Dimensional Electron Gas (2DEG) Medium, and the inclusion of such receivers in focal plane arrays. 2DEG hot electron mixers have been demonstrated at 35 and 94 GHz with three orders of magnitude wider bandwidth than previous hot electron mixers, which use bulk InSb. The 2DEG mixers employ a new mode of operation,...
Topics: NASA Technical Reports Server (NTRS), ELECTRON GAS, FABRICATION, FOCAL PLANE DEVICES, RECEIVERS,...
The goal of this project was to fabricate and test planar arrays of superconducting mixers for the 2-6 THz band. The technology is intended for multi-beam receivers aboard Explorer-class missions and the SOFIA Airborne Observatory. The mixer technology is the superconducting transition-edge microbolometer, which is more commonly known as the Hot-Electron micro-Bolometer (HEB). As originally proposed, two superconducting technologies were to be developed: (1) low-Tc niobium HEBs which could...
Topics: NASA Technical Reports Server (NTRS), FABRICATION, PERFORMANCE TESTS, PLANAR STRUCTURES, ARRAYS,...
Diffusion-cooled Nb hot-electron bolometer (HEB) mixers have the potential to simultaneously achieve high intermediate frequency (IF) bandwidths and low mixer noise temperatures for operation at THz frequencies (above the superconductive gap energy). We have measured the IF signal bandwidth at 630 GHz of Nb devices with lengths L = 0.3, 0.2, and 0.1 micrometer in a quasioptical mixer configuration employing twin-slot antennas. The 3-dB EF bandwidth increased from 1.2 GHz for the 0.3 gm long...
Topics: NASA Technical Reports Server (NTRS), BANDWIDTH, BOLOMETERS, DIFFUSION, HOT ELECTRONS, NIOBIUM,...
Topics covered include: Dual Cryogenic Capacitive Density Sensor; Hail Monitor Sensor; Miniature Six-Axis Load Sensor for Robotic Fingertip; Improved Blackbody Temperature Sensors for a Vacuum Furnace; Wrap-Around Out-the-Window Sensor Fusion System; Wide-Range Temperature Sensors with High-Level Pulse Train Output; Terminal Descent Sensor Simulation; A Robust Mechanical Sensing System for Unmanned Sea Surface Vehicles; Additive for Low-Temperature Operation of Li-(CF)n Cells; Li/CFx Cells...
Topics: NASA Technical Reports Server (NTRS), ANTENNA ARRAYS, BRIGHTNESS TEMPERATURE, CARBON NANOTUBES,...
Spacecraft charging is well known threat to successful long term spacecraft operations and instrument reliability in orbits that spend significant time in hot electron environments. In recent years, spacecraft charging has increasingly been recognized as a potentially significant engineering issue for launch vehicles used to deploy spacecraft using (a) low Earth orbit (LEO), high inclination flight trajectories that pass through the auroral zone, (b) geostationary transfer orbits that require...
Topics: NASA Technical Reports Server (NTRS), LAUNCH VEHICLES, SPACECRAFT CHARGING, LONG DURATION SPACE...
The lowest noise temperature for any receiver in the 0.5 to 1 THz range has been achieved with the bulk InSb hot electron mixer, which unfortunately suffers from the problem of having a very narrow bandwidth (1-2 MHz). We have demonstrated a three order of magnitude improvement in the bandwidth of hot electron mixers, by using the two-dimensional electron gas (2DEG) medium at the hetero-interface between AlGaAs and GaAs. We have tested both inhouse MOCVD-grown material, and MBE materials, with...
Topics: NASA Technical Reports Server (NTRS), ALUMINUM GALLIUM ARSENIDES, BOLOMETERS, ELECTRON GAS, GALLIUM...
In one fo the most exciting areas of progress, we have now developed a dynamic semikinetic model for examining the synergistic effects of waves and magnetospheric hot plasma populations on the outflowing ionospheric plasma. We have done this by imposing hot biMaxwellian ion and electron distributions at the top of our auroral simulation flux tube (4 R(sub e)), as well as a spectrum of waves with altitude which perpendicularly heats the ionospheric ions. We have also addressed the...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC MODELS, DYNAMIC MODELS, EARTH MAGNETOSPHERE,...
