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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Further studies of the isotopic composition of cosmic ray Li, Be and B nuclei - Implications for the cosmic ray age

The isotopic compositions of Li, Be, and B nuclei were investigated by using balloon flight data and the dE/dx X(E) mode of analysis. 600 Be nuclei were considered, including 24 (Be-10) isotopes; the effect of solar modulation of the surviving fraction of (Be-10) measured in this experiment and limits on the age of cosmic rays are discussed. The isotopic composition of all Li, Be, and B nuclei is examined with respect to the fragmentation origin of these particles and the effects of solar modulation.

Webber, W. R.↗
NASA NTRS1980

Cosmic ray exposure ages of chondrites, pre-irradiation and constancy of cosmic ray flux in the past

Calibration of the production rate of the Ne-21 nuclide was accomplished by 4 methods based on (Al-26)-age, (Mn-53)-age, Kr-81/Kr-83, and Na-22/Ne-22. These production rates are normalized to a shielding parameter ratio Ne-22/Ne-21 = 1.11 and to the chemical composition of L chondrites; a value of P(21)(1.11) = 0.31 is suggested, and a production rate equation derived in terms of the 'F' parameters for L, LL, and H chondrites. The Al-26 half-life measurements are considered to evaluate the effects resulting from preirradiation of meteorites and to examine the data on the constancy of the cosmic ray flux in the light of current astronomical observations.

Nishizumi, K.↗
NASA NTRS1981

Cosmic ray drift, shock wave acceleration, and the anomalous component of cosmic rays

A model of the anomalous component of the quiet-time cosmic ray flux is presented in which ex-interstellar neutral particles are accelerated continuously in the polar regions of the solar-wind termination shock and then drift into the equatorial regions of the inner heliosphere. The observed solar-cycle variations, radial gradient, and apparent latitude gradient of the anomalous component are a natural consequence of this model.

Pesses, M. E.↗
NASA NTRS1981

Cosmic ray neutrino tests for heavier weak bosons and cosmic antimatter

A program for using high energy neutrino astronomy with large neutrino detectors to directly test for the existence of heavier weak intermediate vector bosons (ivb) and cosmic antimatter is described. Such observations can provide a direct test of baryon symmetric cosmologies. Changes in the total cross section for nu(N) yields mu(X) due to additional propagators are discussed and higher mass resonances in the annihilation channel bar-nu sub e e(-) yields X are analyzed. The annihilation channel is instrumental in the search for antimatter, partcularly if heavier IVB's exist.

Brown, R. W.↗
NASA NTRS1982

OB associations and the nonuniversality of the cosmic abundances - Implications for cosmic rays and meteorites

The formation of the solar system inside an OB association is examined with particular attention to the elemental abundances which would have been ejected by the association's first few supernovae. It is found that the solar system material may have been significantly contaminated by these supernovae and thus the average interstellar composition may differ from the solar system composition. In particular, we find that many of the so-called isotopic and elemental abundance anomalies (e.g., Ne, C, O, s-process/r-process, etc.) found in meteoritic inclusions and in cosmic rays may be more representative of the average interstellar abundance. In other words, it may be that the average solar system abundances are what is 'anomalous'.

Olive, K. A.↗
NASA NTRS1984

Observations of cosmic ray acceleration in solar system shock waves - Implications for galactic cosmic ray acceleration

Many models of galactic cosmic ray acceleration utilize supernova shock waves to accelerate ambient ions and electrons to very high energies. Although the supernova shock acceleration process cannot be directly observed, the interplanetary shock acceleration process has been observed in situ for 20 years. The main features of solar system shock acceleration observations are briefly reviewed and their implications for supernova acceleration models discussed.

Pesses, M. E.↗
NASA NTRS1990

A preliminary measurement of the cosmic microwave background spectrum by the Cosmic Background Explorer (COBE) satellite

A preliminary spectrum is presented of the background radiation between 1 and 20/cm from regions near the north Galactic pole, as observed by the FIRAS instrument on the COBE satellite. The spectral resolution is 1/cm. The spectrum is well fitted by a blackbody with a temperature of 2.735 + or - 0.06 K, and the deviation from a blackbody is less than 1 percent of the peak intensity over the range 1-20/cm. These new data show no evidence for the submillimeter excess previously reported by Matsumoto et al. (1988) in the cosmic microwave background. Further analysis and additional data are expected to improve the sensitivity to deviations from a blackbody spectrum by an order of magnitude.

Mather, J. C.↗
NASA NTRS1990

Cosmic impacts, cosmic catastrophes. II

The role of extraterrestrial impacts in shaping the earth's history is discussed, arguing that cosmic impacts represent just one example of a general shift in thinking that has made the idea of catastrophes respectable in science. The origins of this view are presented and current catastrophic theory is discussed in the context of modern debate on the geological formation of the earth. Various conflicting theories are reviewed and prominent participants in the ongoing scientific controversy concerning catastrophism are introduced.

Chapman, Clark R.↗
NASA NTRS1993

Biological effects and physics of solar and galactic cosmic radiation, Part B; Proceedings of a NATO Advanced Study Institute on Biological Effects and Physics of Solar and Galactic Cosmic Radiation, Algarve, Portugal, Oct. 13-23, 1991

Since there is an increasing interest in establishing lunar bases and exploring Mars by manned missions, it is important to develop appropriate risk estimates and radiation protection guidelines. The biological effects and physics of solar and galactic cosmic radiation are examined with respect to the following: the radiation environment of interplanetary space, the biological responses to radiation in space, and the risk estimates for deep space missions. There is a need for a long-term program where ground-based studies can be augmented by flight experiments and an international standardization with respect to data collection, protocol comparison, and formulation of guidelines for future missions.

Swenberg, Charles E.↗
NASA NTRS2004

Propagation of Cosmic Rays: Nuclear Physics in Cosmic-ray Studies

The nuclei fraction in cosmic rays (CR) far exceeds the fraction of other CR species, such as antiprotons, electrons, and positrons. Thus the majority of information obtained from CR studies is based on interpretation of isotopic abundances using CR propagation models where the nuclear data and isotopic production cross sections in p- and alpha-induced reactions are the key elements. This paper presents an introduction to the astrophysics of CR and diffuse gamma-rays and dimsses some of the puzzles that have emerged recently due to more precise data and improved propagation models. Merging with cosmology and particle physics, astrophysics of CR has become a very dynamic field with a large potential of breakthrough and discoveries in the near fume. Exploiting the data collected by the CR experiments to the fullest requires accurate nuclear cross sections.

Moskalenko, Igor V.↗
NASA NTRS1972

Cosmic ray experiment. Part A: Composition and energy spectra of solar cosmic ray nuclei

The GE experiment consisted of two types of detectors: plastics and glasses located in panel 2 and the lower half of panel 3. In panel 2, the entire exposed detector area of 14.7 by 22.6 cm was composed of 31 sheets of 0.025-cm polycarbonate plastic 9070-112. In panel 3, 39 sheets of 0.02-cm cellulose triacetate with no plasticizer made up the major volume fraction. The lower part of panel 3 contained five types of glass detectors. Particles that entered the array after it was folded were recognized, if they crossed from one sheet to another, by means of a 2-mm relative shift of alternate sheets.

Fleischer, R. L.↗