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Results for “ULTRAVIOLET RADIATION”

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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Measurements of the diffuse ultraviolet radiation

The imaging instrumentation on the Dynamics Explorer 1 satellite has been used to measure the intensity of the diffuse ultraviolet radiation on two great circles about the sky. It is found that the isotropic component of the diffuse ultraviolet radiation (possibly of extragalactic origin) has an intensity of 530 + or - 80 units (a unit is 1 photon per sq cm s A sr) at a wavelength of 150 nm. The Galactic component of the diffuse ultraviolet radiation has a dependence on Galactic latitude which requires strongly forward scattering particles if it is produced by dust above the Galactic plane.

Fix, John D.↗
NASA NTRS1974

Generation of ultraviolet and vacuum ultraviolet radiation

The paper describes the use of nonlinear optical techniques for the generation of coherent radiation at ultraviolet, vacuum ultraviolet, and soft X-ray wavelengths. Mixtures of metal vapors and inert gases, and other mixed gas systems, allow generation to regions of the spectrum where nonlinear optical crystals are opaque; and also allow generations at high incident power and energy densities. Progress is reported on programs aimed at efficient conversion from 1.064 microns to 3547 A, and from 3547 A to 1182 A. To date, the shortest wavelength generated by this technique is 887 A. Theoretical considerations indicate that generation into the soft X-ray region should be possible. Using 1182 A radiation, a holographic grating with a fringe spacing of 836 A has been constructed and examined on an electron microscope.

Harris, S. E.↗
NASA NTRS1989

Ultraviolet radiation effects

Solar ultraviolet testing was not developed which will provide highly accelerated (20 to 50X) exposures that correlate to flight test data. Additional studies are required to develop an exposure methodology which will assure that accelerated testing can be used for qualification of materials and coatings for long duration space flight. Some conclusions are listed: Solar UV radiation is present in all orbital environments; Solar UV does not change in flux with orbital altitude; UV radiation can degrade most coatings and polymeric films; Laboratory UV simulation methodology is needed for accelerated testing to 20 UV solar constants; Simulation of extreme UV (below 200 nm) is needed to evaluate requirements for EUV in solar simulation.

Slemp, Wayne S.↗
DOE OSTI2013

Surface photoconductivity of organosilicate glass dielectrics induced by vacuum-ultraviolet radiation

The temporary increase in the electrical surface conductivity of low-k organosilicate glass (SiCOH) during exposure to vacuum-ultraviolet radiation (VUV) is investigated. To measure the photoconductivity, patterned “comb structures” are deposited on dielectric films and exposed to synchrotron radiation in the range of 8–25 eV, which is in the energy range of most plasma vacuum-ultraviolet radiation. The change in photo surface conductivity induced by VUV radiation may be beneficial in limiting charging damage of dielectrics by depleting the plasma-deposited charge.

36 MATERIALS SCIENCE↗
NASA NTRS1972

Ultraviolet radiation effects on the infrared damage rate of a thermal control coating

The effects of ultraviolet radiation on the infrared reflectance of ZnO silicone white thermal coatings were investigated. Narrow band ultraviolet radiation for wavelengths in the 2200A to 3500A range by a monochromator and a high pressure, 150-W Eimac xenon lamp. The sample was irradiated while in a vacuum of at least 0.000001 torr, and infrared reflectance was measured in situ with a spectroreflectometer at 19,500A. Reflectance degradation was studied as a function of wavelength, time, intensity, and dose. Damage was wavelength dependent at constant exposure, but no maximum was evident above the shortest wavelength investigated here. The degradation rate at constant intensity was an exponential function of time and varies with intensity.

Bass, J. A.↗
DOE OSTI2016

Extreme ultraviolet radiation emitted by helium microwave driven plasmas

The extreme ultraviolet radiation emitted by helium microwave-driven (2.45 GHz) plasmas operating at low-pressure conditions was investigated. Novel data regarding emitted spectral lines of excited helium atoms and ions in the 20–33 nm wavelength range and their intensity behavior with variation of discharge operational conditions are presented. The intensity of all the spectral emissions was found to strongly increase with the microwave power delivered to the plasma. Furthermore, the intensity of the ionic spectral emissions decreases by nearly one order of magnitude as the pressure was raised from 0.2 to 0.5 mbar.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1983

Clear Film Protects Against Ultraviolet Radiation

Acrylic film contains screeing agent filtering ultraviolet radiation up to 380 nanometers in wavelength but passes other components of Sunlight. Film used to protect such materials as rubber and plastics degraded by ultraviolet light. Used as protective cover on outdoor sheets or pipes made of such materials as polyethylene or polypropylene and on solar cells.

Gupta, A.↗
NASA NTRS1984

Observed ozone response to variations in solar ultraviolet radiation

During the winter of 1979, the solar ultraviolet irradiance varied with a period of 13.5 days and an amplitude of 1 percent. The zonal mean ozone values in the tropics varied with the solar irradiance, with an amplitude of 0.25 to 0.60 percent. This observation agrees with earlier calculations, although the response may be overestimated. These results imply changes in ozone at an altitude of 48 kilometers of up to 12 percent over an 11-year solar cycle. Interpretation of ozone changes in the upper stratosphere will require measurements of solar ultraviolet radiation at wavelengths near 200 nanometers.

Gille, J. C.↗
NASA NTRS1973

Fluorescence of molecular hydrogen excited by solar extreme-ultraviolet radiation

During trans-earth coast, the Apollo 17 ultraviolet spectrometer was scheduled to make observations of the far ultraviolet background in selected regions of the sky. In the course of one of these observations, the spacecraft fuel cells were routinely purged of excess hydrogen and water vapor. The ultraviolet fluorescence spectrum of the purged molecular hydrogen excited by solar extreme ultraviolet radiation is interpreted by absorption of solar L-beta and L-gamma radiation in the nearly resonant (6, 0) and (11, 0) Lyman bands. The results are deemed significant for ultraviolet spectroscopic investigations of the atmospheres of the moon and planets since Lyman-band fluorescence provides an unambiguous means of identification of molecular hydrogen in upper atmospheres.

Feldman, P. D.↗
NASA NTRS1986

Biologically relevant physical measurements in the ice-free valleys of southern Victoria Land: soil temperature profiles and ultraviolet radiation

As part of the ongoing comprehensive study of the cryptoendolithic microbial community in the ice-free valleys of southern Victoria Land, thermal properties of the soil and the ultraviolet radiation regime were measured. Although soil temperature profiles have been measured in the ice-free valleys (e.g., Cameron et al. 1970; Cameron 1972), these are the first such data from higher elevations. This is apparently the first time the ultraviolet radiation regime has been measured in the Antarctic.

NASA Program Exobiology↗