Changes in perceived size of high luminance targets.
Luminescence effects on apparent size and shape of foveally fixated targets of various forms
Haines, R. F.↗
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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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Semiconductor physics
Irradiation effects on semiconductor properties, luminescence, and p-i-n diode electrical properties
Arora, B.↗
The use of single photon counting methods in solving basic problems in chemiluminescent reactions
Single photon counting and fast coincidence system in nuclear physics experiment involving two body luminescent reaction
Emerson, J. A.↗
Recent advances in cathode-ray-tube display devices
CRT display devices and R and D, discussing electron generation, luminescent materials, resolution, brightness, etc
Davis, J. A.↗
Carrier injection electroluminescence
Carrier injection luminescence properties useful for display medium applications, discussing group II-VI compounds as injection host crystal materials
Haas, R. W.↗
The formation of defect centers in MgO
Defect F centers formation in MgO, discussing optical absorption bands, oscillator strengths, luminescence band, impurity centers, etc
Kroes, R. L.↗
Study of the zinc-silver oxide battery system Quarterly report, Oct. - Dec. 1970, Jan. - Mar. 1971
Optical luminescence in reaction detection at rear of porous electrodes and comparison of interface reaction resistance and electrolyte ohmic resistance in zinc-silver oxide batteries
Nanis, L.↗
Photometry of asteroids
Photographic and photoelectric photometry of asteroids, discussing luminescence, reflectivities, light curves, colors and phase variations observations
Gehrels, T.↗
Application of optical fluorescence for the characterization of lunar materials
Optical fluorescence of lunar transients in UV to IR range for rock forming silicates, using electron microprobe with cathode luminescence capability
Greer, R. T.↗
A reusable prepositioned ATP reaction chamber
Luminescence biometer detects presence of life by means of light-emitting chemical reaction of luciferin and luciferase with adenosine triphosphate (ATP) that occurs in all living cells. Amount of light in reaction chamber is measured to determine presence and extent of life.
Hoffman, D. G.↗
Improving the efficiency of GaP LED's which emit green light
A study of techniques for preparing n-type material and junctions which yield the most consistent high diode efficiency values high lighted the role that Ga vacancies and/or associated defects play in reducing the green luminescent efficiency of n-type GaP. A useful method for obtaining good quality material was developed. It is shown that junction formation at high temperatures in a process where the n to p transition occurs without removing the substrate from the furnace yields devices superior to those obtained by diffusion or double epitaxy in the conventional manner previously used for GaP junction formation.
Ladany, I.↗
Photoemf in cadmium sulfide
Theoretical and experimental investigations on CdS single crystals and CuxS:CdS photovoltaic cells prepared from CdS single crystals by a chemical-dip procedure are described. The studies are aimed at clarifying cell mechanisms which affect key cell properties (efficiency, reliability, and lifetime) by examining the properties of intrinsic and extrinsic defects in the junction and surface regions and their effects on carrier transport through these regions. The experimental research described includes studies of thermal, infrared, and field quenching of acceptor-doped CdS crystals; investigation of optical and electrical properties of CuxS:CdS photovoltaic cells (current-voltage characteristics, spectral distribution of photocurrent and photovoltage) and the dependence of these properties on temperature and light intensity; measurement of changes, as a result of heat treatment in ultrahigh vacuum, in the spectral distribution of photoconductivity at room temperature and liquid nitrogen temperature, the luminescence spectrum at liquid nitrogen temperature, and the thermally stimulated current curves of CdS crystals; determination of the effect of irradiation with 150 keV (maximum) X-rays on the spectral distribution of photoconductivity and thermally-stimulated current of CdS crystals; and studies of the effect of growth conditions on the photoconductive properties of CdS crystals.
Boeer, K. W.↗
Tape Cassette Bacteria Detection System
The design, fabrication, and testing of an automatic bacteria detection system with a zero-g capability and based on the filter-capsule approach is described. This system is intended for monitoring the sterility of regenerated water in a spacecraft. The principle of detection is based on measuring the increase in chemiluminescence produced by the action of bacterial porphyrins (i.e., catalase, cytochromes, etc.) on a luminol-hydrogen peroxide mixture. Since viable as well as nonviable organisms initiate this luminescence, viable organisms are detected by comparing the signal of an incubated water sample with an unincubated control. Higher signals for the former indicate the presence of viable organisms. System features include disposable sealed sterile capsules, each containing a filter membrane, for processing discrete water samples and a tape transport for moving these capsules through a processing sequence which involves sample concentration, nutrient addition, incubation, a 4 Molar Urea wash and reaction with luminol-hydrogen peroxide in front of a photomultiplier tube. Liquids are introduced by means of a syringe needle which pierces a rubber septum contained in the wall of the capsule. Detection thresholds obtained with this unit towards E. coli and S. marcescens assuming a 400 ml water sample are indicated.
Source record↗
Photoluminescence and optical transmission of diffusion-pump oils.
The photoluminescence and optical transmission of the four widely used diffusion-pump oils, DC-705, DC-704, Convalex-10, and Convoil-20, were measured. Each of the oils was found to be transparent throughout the visible region, showed some absorption in the near-UV region, and became very opaque below approximately 300 nm. Both Convalex-10 and Convoil-20 turned yellow after exposure to UV light. No such change was noted in DC-705 or DC-704. Photoluminescence was produced in each of the four oils when irradiated with UV light. Both DC-705 and DC-704 had a nearly identical luminescence spectra that peaked at 350 nm. The spectra of Convalex-10 and Convoil-20 were fairly complex, with several peaks in the visible region.
Kroes, R. L.↗
NO and O3 measurements in the lower stratosphere from a U-2 aircraft
In situ measurements of nitric oxide and ozone were carried out at altitudes up to 21 km during two flights of a U-2 aircraft on Dec. 6 and 18, 1973, over the west coast of the United States. A chemiluminescent detector based on the luminescent reaction of nitric acid with excess ozone was used in nitric acid measurements. Ozone concentration measurements were based on the absorption of the Hg line at 2,537 A in the Hartley continuum. The results are compared with available data.
Loewenstein, M.↗
Ion-implanted epitaxially grown ZnSe
The use of ZnSe to obtain efficient, short wavelength injection luminescence was investigated. It was proposed that shorter wavelength emission and higher efficiency be achieved by employing a p-i-n diode structure rather than the normal p-n diode structure. The intervening i layer minimizes concentration quenching effects and the donor-acceptor pair states leading to long wavelength emission. The surface p layer was formed by ion implantation; implantation of the i layer rather than the n substrate permits higher, uncompensated p-type doping. An ion implanted p-n junction in ZnSe is efficiency-limited by high electron injection terminating in nonradiative recombination at the front surface, and by low hole injection resulting from the inability to obtain high conductivity p-type surface layers. While the injection ratio in p-n junctions was determined by the radio of majority carrier concentrations, the injection ratio in p-i-n structures was determined by the mobility ratios and/or space charge neutrality requirements in the i layer.
Chernow, F.↗
Plasma flow and fast particles in a hypervelocity accelerator - A color presentation
A new concept for particle acceleration for micrometeoroid simulation was developed at NASA Marshall Space Flight Center, using a high-density self-luminescent fast plasma flow to accelerate glass beads (with a diameter up to 1.0 mm) to velocities between 15-20 km/sec. After a short introduction to the operation of the hypervelocity range, the eight-converter-camera unit used for the photographs of the plasma flow and the accelerated particles is described. These photographs are obtained with an eight-segment reflecting pyramidal beam splitter. Wratten filters were mounted between the beam splitter and the converter tubes of the cameras. The photographs, which were recorded on black and white film, were used to make the matrices for the dye-color process, which produced the prints shown.
Igenbergs, E. B.↗
Effects of 1- and 2-MeV electrons on photomultiplier tubes
Various types of photomultiplier tubes useful for space applications were irradiated with 1- and 2-MeV electrons at Van Allen radiation belt fluxes of 100,000 to 10 millions electrons/sq cm-sec. The increase in the dark current due to electron irradiation was observed at various bias voltages under worst-case conditions (no shielding). Results were presented in the form of dark current plotted against electron flux. All the tubes tested showed extremely large increases in dark current. Tube types 541A, 6217, 6199, and 6903 exhibited the largest increases under irradiation, whereas type 1P22 was affected the least. All the damage observed was transient. The luminescence produced in the optical window probably accounts for a large part of the dark-current increases, but there were some effects possibly due to direct irradiation of the photocathode and dynode chain.
Beatty, M. E., III↗