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Results for “RARE GASES”

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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Mars - Regolith adsorption and the relative concentrations of atmospheric rare gases

Laboratory measurements of Kr and Xe adsorption on samples of ground montmorillonite, limonite and basalt at -77 C have been performed. Results suggest that (1) most degassed martian Xe could be adsorbed on a regolith with a large effective surface area, and (2) if this is the case the elemental composition of martian nonradiogenic rare gas (counting that in the regolith) may be virtually identical to that of ordinary chondrites.

Fanale, F. P.↗
NASA NTRS1975

Rare gases and Ca, Sr, and Ba in Apollo 17 drill-core fines

Trapped gas isotopic compositions and spallation gas concentrations as functions of depth in the Apollo 17 drill core were determined from mass spectrometer studies by means of correlation techniques. The distribution of He, Ne, Ar, Kr, and Xe as well as Ca, Sr, and Ba was investigated, and rare-gas spallation and neutron capture profiles are compared with attention to proposed depositional models for the Taurus-Littrow regolith. The data exclude a sedimentation pattern similar to that found at the Apollo 15 site but are possibly compatible with long-term continuous accretion models or models of very recent rapid accumulation of regolith.

Pepin, R. O.↗
NASA NTRS1972

Ion-atom association reactions in the rare gases.

A simple resonance theory of three-body ion-atom association reactions is presented. The reaction is considered as proceeding through the formation of a long lived orbiting resonance complex between the atom and the ion. The population of these quasi-bound states is estimated assuming thermal equilibrium. A stable molecular ion may then be formed upon deactivation of the complex by collision with a third body. Various simplifying approximations to the potential curves and surfaces are employed. Furthermore, the deactivation cross sections for the relevant complexes are estimated from the corresponding atomic 'sizes.' A simple analytical formula for the three-body rate constant is thus derived. Reasonable agreement with experiment is obtained for He(+) in He and fair agreement for other light systems.

Dickinson, A. S.↗
NASA NTRS1986

Cosmogenic rare gases and 10-Be in a cross section of Knyahinya

The concentrations of cosmogenic nuclides were studied as a function of shielding on samples from a cross section of the 293 kg main fragment of the L5 chondrite Knyahinya. The stone broke into two nearly symmetrical parts upon its fall in 1866. The planar cross section has diameters between 40 and 55 cm. He, Ne, and Ar were measured on about 20 samples by mass spectrometry and the 10-Be activities on aliquots of 10 selected samples were determined by AMS. The 10-Be data are presented and the abundances of spallogenic nuclides are compared with the model calculations reported by Reedy for spherical L chondrites. The 10-Be production rates in Knyahinya are shown versus the shielding parameter 22-Ne/21-Ne.

Wieler, R.↗
NASA NTRS1994

Mantle rare gas relative abundances in a steady-state mass transport model

A model for He and Xe was presented previously which incorporates mass transfer of rare gases from an undegassed lower mantle (P) and the atmosphere into a degassed upper mantle (D). We extend the model to include Ne and Ar. Model constraints on rare gas relative abundances within P are derived. Discussions of terrestrial volatile acquisition have focused on the rare gas abundance pattern of the atmosphere relative to meteoritic components, and the pattern of rare gases still trapped in the Ear,th is important in identifying volatile capture and loss processes operating during Earth formation. The assumptions and principles of the model are discussed in Wasserburg and Porcelli (this volume). For P, the concentrations in P of the decay/nuclear products 4 He, 21 Ne, 40 Ar, and 136 Xe can be calculated from the concentrations of the parent elements U, Th, K, and Pu. The total concentration of the daughter element in P is proportional to the isotopic shifts in P. For Ar, ((40)Ar/(36)Ar)p - ((40)Ar/(36)Ar)o =Delta (exp 40) p= 40 Cp/(exp 36)C where(i)C(sub j) the concentration of isotope i in j. In D, isotope compositions are the result of mixing rare gases from P, decay/nuclear products generated in the upper mantle, and subducted rare gases (for Ar and Xe).

Porcelli, D.↗
NASA NTRS1971

Isotopic studies in returned lunar samples

Analysis of lunar soil samples returned by Apollo 11 and 12 flights are discussed. Isotopic studies of the rare gases from Apollo 11 flight lunar samples are presented. The lunar soil analyses indicated the following: (1) high concentrations of solar wind rare gases, (2) isotopic match between solar wind gases and gas components in gas-rich meteorites, and (3) rare gases attributable to spallation reactions induced in heavier nuclides by cosmic ray particles.

Alexander, E. C., Jr.↗
NASA NTRS1975

Agglutinates as indicators of lunar soil maturity - The rare gas evidence at Apollo 16

The weight percent of lunar agglutinic glass (glass-welded aggregates resulting from micrometeorite impacts) in Apollo 16 bulk soils is considered with respect to quantities of trapped rare gases, e.g., He-4, Ne-20, Ar-36, Kr-84, and Xe-132, in an effort to determine the cumulative time a given soil sample has spent exposed on the lunar surface. The agglutinic glass, which reacts strongly in a magnetic field, is obtained by the standard fluid (methanol)-magnetic technique. It is noted that the absolute concentrations of trapped rare gases all show a linear relationship with increasing agglutinic glass content.

Charette, M. P.↗
NASA NTRS1972

On the origins of trapped helium, neon and argon isotopic variations in meteorites. I - Gas-rich meteorites, lunar soil and breccia. II - Carbonaceous meteorites.

Data are presented from stepwise heating experiments and total extractions on five meteorites: Kapoeta, Fayetteville, Holman Island, Cee Vee, and Pultusk. These data reveal the presence of four isotopically distinct trapped neon components. A comparison of trapped neon with trapped helium and argon in bulk analyses indicates the existence of correlated helium, neon and argon isotopic structures. Component B is attributed primarily to direct implantation of rare gas ions by the present day solar wind. Component C is identified with directly implanted low energy (1-10 Mev/n) solar flare rare gases. Component D is associated with rare gas ions implanted in meteoritic material by the primitive, pre-main sequence, solar wind. A fourth component, observed only in Kapoeta and the lunar fines and breccia, is tentatively attributed to parent body 'atmospheric' ions implanted in surface material by a solar wind induced electric field.

Black, D. C.↗