Rare gas measurements in three mineral separates of rock 12013,10,31
Microprobe measurements of rare gas composition for lunar rock 12013,10,31 mineral separates, noting cosmic ray bombardment role in K and Ar production
Kaiser, W. A.↗
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Charge transfer and dissociative charge transfer between rare-gas ions and molecular nitrogen.
Low collision energy charge transfer and dissociative charge transfer between rare gas ions and molecular nitrogen, measuring nitrogen ion kinetic energy distributions
Champion, R. L.↗
Pressure dependence of the melting temperature of solids - Rare-gas solids
A method presented by Schlosser et al. (1989) for analyzing the pressure dependence of experimental melting-temperature data is applied to rare-gas solids. The plots of the logarithm of the reduced melting temperature vs that of the reduced pressure are straight lines in the absence of phase transitions. The plots of the reduced melting temperatures for Ar, Kr, and Xe are shown to be approximately straight lines.
Schlosser, Herbert↗
Rare gas analysis of size fractions from the Fayetteville meteorite
Eight size separates of grains from the Fayetteville meteorite ranging from less than 20 microns to greater than 1 millimeter are being analyzed for their rare gas elemental and isotopic composition. Measurements on five samples were performed. All five reveal a mixture of solar, planetary, cosmic ray produced and radiogenic gases. The solar component is of particular interest since it suggest that the meteorite may represent a fragment of an ancient protoplanetary regolith which was exposed to the solar wind. Solar wind elements are implanted in the outer few hundred Angstroms of exposed grains and are therefore expected to be surface correlated. At present the data do not suggest that such a correlation exists, but the final conclusion must await further analyses and data reduction.
Jordan, Jim L.↗
Vacuum ultraviolet light source utilizing rare gas scintillation amplification sustained by photon positive feedback
A source of light in the vacuum ultraviolet (VUV) spectral region includes a reflective UV-sensitive photocathode supported in spaced parallel relationship with a mesh electrode within a rare gas at low pressure. A high positive potential applied to the mesh electrode creates an electric field which causes drifting of free electrons occurring between the electrodes and producing continuous VUV light output by electric field-driven scintillation amplification sustained by positive photon feedback mediated by photoemission from the photocathode. In one embodiment the lamp emits a narrow-band continuum peaked at 175 nm.
Aprile, Elena↗
Physical adsorption of rare gas on terrigenous sediments
Heavy rare gases adsorption on terrigenous sediments, comparing earth atmospheric composition with meteoritic planetary primordial component
Cannon, W. A.↗
Origin of planetary primordial rare gas - The possible role of adsorption.
The degree of physical adsorption of Ne, Ar, Kr, and Xe on pulverized samples of the Allende meteorite at 113 K has been measured. The observed pattern of equilibrium enrichment of heavy rare gases over light on the pulverized meteorite surfaces relative to the gas phase is similar to the enrichment pattern exhibited by planetary primordial rare gas when compared with the composition of solar rare gas. Results indicate that, at 113 K, a total nebular pressure of from .01 to .001 atm would be required to explain the Ar, Kr, and Xe abundances in carbonaceous chondrites with an adsorption mechanism. This pressure estimate is compatible with the range of possible nebular pressures suggested by astrophysical arguments. However, the subsequent mechanism by which initially adsorbed gas might have been transferred into the interiors of grains cannot be identified at present.
Fanale, F. P.↗
Irradiation records of Acapulco and other small meteorites derived from Mn-53 and rare gas measurements
Attempts have been made recently to resolve the problem of depth and size dependences of the production rates of cosmogenic radionuclides within meteorites. The present investigation is concerned with Mn-53 and Al-25 measurements in samples of eight meteorite falls with small recovered masses. The recovered masses of the chondrites lie in the range from 0.35 to 8.4 kg, which corresponds to effective postatmospheric radii in the range from 2.9 to 8.3 cm. The He-3/Ne-21 ratios observed in these stones lie in the range from 6.33 to 8.62, and the Ne-22/Ne-21 ratios lie in the range from 1.132 to 1.248, thus generally indicating lightly shielded samples. The obtained results together with rare gas data are used as a basis for the discussion of the irradiation histories.
Englert, P.↗
Light-dark structure and rare gas content of the carbonaceous chondrite Nogoya.
Nogoya type II carbonaceous chondrite noting cosmogenic, radiogenic and primordial noble gas components
METEORITIC COMPOSITION↗
Clues in the rare gas isotopes to early solar system history
Rare gases in meteorites and lunar samples are discussed stimulating the discovery of the solar wind. Radioactive isotopes are examined, making a correlation to the origin of the solar system. It is shown that the heights of the peaks above the horizontal lines represent the spectrum of the fissiogenic sample. Nuclear tracks of iodine, xenon, and plutonium detected in lunar rocks are also explained.
Reynolds, J. H.↗
Ionisation cross sections of rare-gas atoms by electron impact
A pulsed electron beam and ion extraction method is used to measure normalized values of partial ionization cross sections for rare gases from threshold to 1000 eV. Cross sections obtained for singly ionized species are used to calibrate the mass transmission efficiency of the ion extraction/analyzer/detection system by the relative flow technique, and this mass transmission curve is then used to determine the absolute cross sections of the multiply ionized species. Total ion cross sections are found by summation of the individual partial cross sections with proper weighting for charge.
Krishnakumar, E.↗
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.↗
Selective removal of either metastable species from a mixed 3P 0,2 rare-gas metastable beam
A tunable CW laser has been used to selectively remove either of the two metastable species, 3P 0,2, which are initially present in a neon metastable beam. The method is applicable to other rare gases and provides the opportunity for separate investigation of effects due to atoms in either the 3P 0 or 3P 2 state.
Dunning, F. B.↗
Rare-gas effects on metabolism and inert gas narcosis
The detailed examination is reported of the theory that narcosis results from expansion of the cell membrane under high partial pressures. The research is partially based on the hypothesis that, like oxygen toxicity, the mechanism of metabolic effects of rare gases may be similar at both low and high pressures and are simply more observable at high pressures. Using adult female goats, the parameters measured include oxygen consumption, CO2 production, respiration rate, heart rate, rectal and skin temperatures and the analysis of electroencephalograms and evoked response. Additionally, the specific activity is measured of plasma glucose subsequent to injection of glucose-UL-C-14, intravenous infusion, specific activity of expired CO2, unesterified fatty acid levels and whole blood lactate-to-pyruvate ratios. Also studied were the effects of acetylsalicylic acid, vitamin E and cationic detergents (which alleviate narcosis) upon metabolic changes induced by high pressure narcosis.
Source record↗
Energetic binary collisions in rare gas plasmas
Calculations have been made of cross sections for energy and momentum transfer in binary collisions between like pairs of Ar, Kr, and Xe atoms in the energy range from about 1 to 1000 eV. These calculations were made using a classical model with pair interaction potentials for the rare gases developed from experimental sources, e.g., investigations of specific heats, viscosities, solid-state parameters, and scattering data. Cross sections in this energy range have not been available. The cross sections exhibit a rapid decrease from accepted values at thermal energies as the interaction energy increases. This behavior can be used to understand directed beam propagation limits as well as particle propagation within a plasma. Experimental data have also been fit to a theoretical expression for the Ar resonance charge exchange cross section over the same energy range.
Robinson, R. S.↗
A rare gas optics-free absolute EUV photon spectrometer for solar system studies
We have developed a prototype spectrometer for space applications which require long term absolute EUV photon flux measurements. In this recently developed spectrometer, the energy spectrum of the incoming photons is transformed directly into an electron energy spectrum by taking advantage of the photoelectric effect in one of several rare gases at low pressures. Using an electron energy spectrometer operating at a few eV, and followed by an electron multiplying detector, pulses due to individual electrons are counted. The overall efficiency of this process is essentially independent of gain drifts in the signal path, and the secular degradation of optical components which is often a problem in other techniques is avoided.
Daybell, M. D.↗
A rare gas optics-free absolute photon flux and energy analyzer to provide absolute photoionization rates of inflowing interstellar neutrals
A prototype spectrometer has been developed for space applications requiring long term absolute EUV photon flux measurements. The energy spectrum of the incoming photons is transformed directly into an electron energy spectrum by taking advantage of the photoelectric effect in one of several rare gases at low pressures. Using an electron energy spectrometer, followed by an electron multiplier detector, pulses due to individual electrons are counted. The overall efficiency of this process can be made essentially independent of gain drifts in the signal path, and the secular degradation of optical components which is often a problem in other techniques is avoided. A very important feature of this approach is its freedom from the problem of overlapping spectral orders that plagues grating EUV spectrometers. An instrument with these features has not been flown before, but is essential to further advances in our understanding of solar EUV flux dynamics, and the coupled dynamics of terrestrial and planetary atmospheres. The detailed characteristics of this optics-free spectrometer are presented in the publications section.
Judge, Darrell L.↗
A rare gas optics-free absolute photon flux and energy analyzer for solar and planetary observations
We have developed a prototype spectrometer for space applications requiring long term absolute EUV photon flux measurements. In this recently developed spectrometer, the energy spectrum of the incoming photons is transformed directly into an electron energy spectrum by taking advantage of the photoelectric effect in one of several rare gases at low pressures. Using an electron energy spectrometer, followed by an electron multiplier detector, pulses due to individual electrons are counted. The overall efficiency of this process can be made essentially independent of gain drifts in the signal path, and the secular degradation of optical components which is often a problem in other techniques is avoided. A very important feature of this approach is its freedom from the problem of overlapping spectral orders that plagues grating EUV spectrometers. An instrument with these features has not been flown before, but is essential to further advances in our understanding of solar EUV flux dynamics, and the coupled dynamics of terrestrial and planetary atmospheres. The detailed characteristics of this optics-free spectrometer are presented in the publications section.
Judge, Darrell L.↗