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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 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Modulation of cosmic-ray protons and helium nuclei near solar maximum

Balloon observations of proton and helium spectra in 1970, 1971 and 1972, reveal a factor of approximately 1.85 deviation from a single valued regression at low rigidities. This deviation decreases with increasing rigidity for both species. The period 1969-1970 is unique because time variations at low and high energies were anti-correlated. When satellite observations are used to extend the balloon observations to energies below 100 MeV/Nucleon, the proton spectrum showed a steeper slope in 1970 and 1972 than the characteristic J = AT spectrum observed during 1965-1969. The slope of the helium spectrum became continuously flatter during the same period (1970-1972). Computer generated spectra based on simple two parameter modulation models describe the basic features of the observations if one of the variable parameters is used to characterize the rigidity dependence of the diffusion coefficient. Models which do not allow such a variation are not consistent with the observations.

Rygg, T. A.↗
NASA NTRS1973

Comments on 'Elastically scattered recoil nuclei in solid-state detectors'

Horn and Von Oertzen (1967) have shown that tracks in mica are produced by an irradiation with 32-MeV O-16 ions. These tracks were attributed to K and Fe recoils produced by elastic scattering of the incident oxygen beam. In the present work an alternate explanation of their observations is provided. The measured characteristics of the tracks are shown to be compatible with theoretical predictions for production of tracks by inelastic (mostly compound nucleus) reactions with silicon and to be inconsistent with the previously proposed elastic scattering process. The possibility that the tracks are produced by contaminant ions in the beam cannot be ruled out.

Maurette, M.↗
NASA NTRS1974

Composition of Z greater than or equal to 5 nuclei at 1.3 GeV/n and 23 GeV/n

Measurements made with a balloon-borne counter telescope having an exposure factor of 842 sq m-ster-sec are reported. The telescope was flown from Palestine, Texas, during the fall of 1971 for a total of ten hours under an average residual atmospheric depth of 4.5 g/sq cm. The analysis indicates that the integral flux ratios above 1.3 and 23 GeV/nucleon are consistent with energy independence.

Badhwar, G. D.↗
NASA NTRS1974

The chemical composition of cosmic ray nuclei above 1.3 GeV per nucleus and 23 GeV per nucleus

Measurements made with a balloon-borne counter telescope are reported. The telescope was flown from Palestine, Tex., during the fall of 1971 for a total of 10 hours under an average residual atmospheric depth of 4.4 g per sq cm. The data analysis indicates that the integral flux ratios above 1.3 GeV per nucleus and 23 GeV per nucleus are consistent with energy independence.

Badhwar, G. D.↗
NASA NTRS1974

Observations of the infrared radiation from the nuclei of NGC 1068 and NGC 4151

Data resulting from monitoring the flux of radiation at 11 microns from NGC 1068 and NGC 4151 are presented. There is some evidence for changes of flux of 50% on a time scale of approximately 100 days from NGC 4151. This evidence is suggestive but not compelling. Limits are set on the possible change of the 11-micron flux from NGC 1068. The energy distribution of radiation from NGC 1068 between 8 and 13 microns has been shown to have no spectral features within the accuracy and resolution of our measurement. This is in contrast to energy distributions observed from galactic sources in which the source of energy is generally interpreted as thermal reradiation from grains.

Stein, W. A.↗
NASA NTRS1974

The effect of suprathermal protons on the physical conditions in Seyfert galaxy nuclei

The physical conditions in a high density hydrogen gas heated and ionized by suprathermal protons were investigated, with application to the gas in the nuclear region of Seyfert galaxies. The gas is assumed optically thick to Lyman and Balmer line radiation. Mechanisms by which the radiation from the gas can balance the heating by the fast protons were investigated, and minimum values for the mass of gas were estimated. Under certain conditions, the suprathermal atoms themselves can cool the ambient gas by rescattering the line radiation into the optically thin region in the wings of the line. This mechanism, called optical reverberation, can enhance the broad component of the hydrogen lines produced by inelastic atomic collisions and yield line widths consistent with those observed in Seyfert and quasar spectra. Also discussed is the possibility of achieving dynamic equilibrium of the ambient gas by balancing the momentum transfer from the suprathermals with gravitational attraction of a massive central source.

Ptak, R.↗