Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Xenon Isotopes”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1997

NMR of laser-polarized 129Xe in blood foam

Laser-polarized 129Xe dissolved in a foam preparation of fresh human blood was investigated. The NMR signal of 129Xe dissolved in blood was enhanced by creating a foam in which the dissolved 129Xe exchanged with a large reservoir of gaseous laser-polarized 129Xe. The dissolved 129Xe T1 in this system was found to be significantly shorter in oxygenated blood than in deoxygenated blood. The T1 of 129Xe dissolved in oxygenated blood foam was found to be approximately 21 (+/-5) s, and in deoxygenated blood foam to be greater than 40 s. To understand the oxygenation trend, T1 measurements were also made on plasma and hemoglobin foam preparations. The measurement technique using a foam gas-liquid exchange interface may also be useful for studying foam coarsening and other liquid physical properties.

Non-NASA Center↗
NASA NTRS1973

Solar wind xenon in some carbonaceous chondrites.

A table shows the isotopic composition of xenon from several carbonaceous chondrites in which the presence of solar xenon can be demonstrated. The data suggest the presence of a solar xenon component in these carbonaceous chondrites, but solar xenon in these meteorites can be more clearly demonstrated through correlation plots. It is argued that the incorporation of the solar type of noble gases must have occurred during the early history of meteoritic matter when this material consisted of fine-grained particles.

Sabu, D. D.↗
NASA NTRS1998

Isotopic Enrichment of Boron in the Sputtering of Boron Nitride with Xenon Ions

An experimental study is described to measure the isotopic enrichment of boron. Xenon ions from 100 eV to 1.5 keV were used to sputter a boron nitride target. An ion gun was used to generate the ion beam. The ion current density at the target surface was approximately 30 microA/sq cm. Xenon ions impinged on the target surface at 50 deg angle to the surface normal. Since boron nitride is an insulator, a flood electron gun was used in our experiments to neutralize the positive charge buildup on the target surface. The sputtered secondary ions of boron were detected by a quadrupole mass spectrometer. The spectrometer entrance aperture was located perpendicular to the ion beam direction and 10 mm away from the target surface. The secondary ion flux was observed to be enriched in the heavy isotopes at lower ion energies. The proportion of heavy isotopes in the sputtered secondary ion flux was found to decrease with increasing primary ion energy from 100 to 350 eV. Beyond 350 eV, light isotopes were sputtered preferentially. The light isotope enrichment factor was observed to reach an asymptotic value of 1.27 at 1.5 keV. This trend is similar to that of the isotopic enrichment observed earlier when copper was sputtered with xenon ions in the same energy range.

Ray, P. K.↗
NASA NTRS1986

Xenon and other noble gases in shergottites

The isotopic composition of the xenon component trapped in EETA 79001's lithologies B and C has been determined, and other noble gases were measured in some samples. The Xe component was found to have light isotope ratios indistinguishable from those of the terrestrial atmosphere. The trapped component has a Xe-129/Xe-132 ratio of about 2.4, and is enhanced in Xe-134 and Xe-136 relative to the terrestrial atmosphere or the average carbonaceous chondrite. Similarities between values for Ar-40/Ar-36, Xe-129/Xe-132, and N-15/N-14 and the corresponding Martian atmospheric values suggest Martian origin of the trapped gases.

Swindle, T. D.↗
NASA NTRS1974

Studies of K-Ar dating and xenon from extinct radioactivities in breccia 14318; implications for early lunar history

The lunar breccia 14318 is one of three Apollo-14 breccias containing substantial amounts of parentless xenon from the spontaneous fission of extinct Pu-244. The argon and xenon contained in this breccia were studied by stepwise heating of pristine and neutron-irradiated samples. The isotopic composition of xenon from fission, determined by an improved method, is shown to be from Pu-244. Concentrations of this fissiogenic xenon are in substantial excess (15-fold) of what could be produced by spontaneous fission of U-238. The breccia is found to contain abundant trapped argon with an Ar-40/Ar-36 ratio of roughly 14. Otherwise, the argon is radiogenic and gives a convincing K-Ar age of 3.69 plus or minus 0.09 b.y. by the stepwise Ar-40/Ar-39 method, nearly in agreement with ages for other Apollo-14 breccias.

Reynolds, J. H.↗
DOE OSTI2025

Adsorption Studies of Dilute Krypton and Xenon from Nitrogen on SBMOF-1 and Activated Charcoal for Applications in Isotope Harvesting

Adsorptive partitioning of dilute krypton (Kr) and xenon (Xe) onto Stony Brook Metal–Organic Framework (SBMOF-1) and activated charcoal (AC) from carrier nitrogen was experimentally measured at temperatures ranging from 195 to 293 K. For this purpose, a closed-loop system for gas adsorption experiments was developed. From the Kr adsorption measurements, the adsorption equilibrium constant for Kr on SBMOF-1 was calculated, yielding a value for the enthalpy of adsorption of −19 ± 1 kJ·mol –1 . The partition coefficients were utilized to estimate the extraction rates of 76 Kr, 77 Kr, and 122 Xe isotopes during isotope harvesting at the Facility for Rare Isotope Beams (FRIB). We conclude that both materials showed promising results for the extraction of noble gases from FRIB effluents using temperature swing adsorption.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1993

Isotopic signatures and distribution of nitrogen and trapped and radiogenic xenon in the Acapulco and FRO90011 meteorites

Acapulco metal and silicate show distinct N isotopic signatures. Trapped heavy noble gases are carried by 'magnetic' opx and radiogenic Xe-129 excesses are observed in phosphate and in minor surficial phases on metal grains. N and Xe isotopic signatures in FRO90011 do not agree with those observed in Acapulco. The Acapulco meteorite is unique in having achondritic texture and chondritic composition. Its mineralogical study shows the record of high temperature (1100 C) recrystallization. However, this meteorite shows abundances of volatile elements close to the levels observed in carbonaceous chondrites and concentrations of heavy noble gases comparable to those observed in type 4 ordinary chondrites, not expected for a presumed highly equilibrated object. Nitrogen measurements in bulk Acapulco revealed two different isotopic signatures, in apparent conflict with evidence for a high degree of recrystallization. N and Xe were studied in separated mineral phases to search for the carriers in order to better understand the formation and thermal history of the Acapulco parent body.

Kim, Y.↗
NASA NTRS1972

Fission xenon from extinct Pu-244 in 14,301.

Xenon extracted in step-wise heating of lunar breccia 14,301 contains a fission-like component in excess of that attributable to uranium decay during the age of the solar system. There seems to be no adequate source for this component other than Pu-244. Verification that this component is in fact due to the spontaneous fission of extinct Pu-244 comes from the derived spectrum which is similar to that observed from artificially produced Pu-244. It thus appears that Pu-244 was extant at the time lunar crustal material cooled sufficiently to arrest the thermal diffusion of xenon. Subsequent history has apparently maintained the isotopic integrity of plutonium fission xenon. Of major importance are details of the storage itself. Either the fission component is the result of in situ fission of Pu-244 and subsequent storage in 14,301 material, or the fission xenon was stored in an intermediate reservoir before incorporation into 14,301.

Drozd, R.↗
NASA NTRS1976

Viking to Mars - Profile of a space expedition

The Viking spacecraft, operations, and findings are reviewed and numerous pictures are presented in an attempt to capture the atmosphere of the Viking expedition. The details of the two Viking spacecraft, each consisting of an orbiter and lander combination launched a Titan III/Centaur are described and illustrated, along with the Viking ground-data and communications system. The principal conclusions of the Viking mission to date are: detection of nitrogen, argon, krypton, and xenon; determination of isotopic ratios of carbon, nitrogen, oxygen, and argon; uniform diurnal meteorological conditions; determination of major elemental abundances; complex surface chemistry; no ubiquitous organic material; 4 to 7% of the sampled surface material is magnetic; discovery of ancient extensive fluvial activity; north permanent polar cap made of water ice; and significant variations of the atmospheric water vapor, the summer hemisphere being much more humid than the winter hemisphere.

Martin, J. S., Jr.↗
NASA NTRS1976

Carbonaceous chondritic xenoliths and planetary-type noble gases in gas-rich meteorites

The source of the planetary-type noble gases in gas-rich meteorites is identified as finely divided (submillimeter to millimeter-sized), widely dispersed carbonaceous chondritic fragments. Trace-element abundances, noble-gas elemental abundances and isotopic abundances of xenon are compatible with the hypothesis that the carbonaceous chondritic carrier is present in amounts of a few percent in the gas-bearing portions of gas-rich chondrites and achondrites.

Wilkening, L. L.↗
DOE OSTI2026

FGMS-poster

Idaho National Laboratory (INL) performs post irradiation examination (PIE) of tri-structural isotropic (TRISO)-coated particle fuel to help qualify it for high temperature gas cooled reactors. TRISO fuel compacts are re-irradiated in the Neutron Radiography Reactor (NRAD) to generate the short lived fission products needed for fission product release testing. The Fuel Accident Condition Simulator (FACS) furnace and newly added Screen Neutron Irradiated Fuel for Failure (SNIFF) furnace heat the compacts in helium to temperatures of up to 2,000°C, prompting fission product release—predominantly gaseous xenon and krypton isotopes and condensable products such as cesium—from failed particles. These released isotopes are transported to a fission gas monitoring system (FGMS 1 or FGMS 3), where they accumulate in cryogenic cold traps and are quantified using high-purity germanium (HPGe) detectors. The addition of SNIFF and FGMS 3 increases throughput by enabling simultaneous testing of multiple compacts. Furthermore, automated INL developed software provides continuous, near-real time monitoring of fission product inventories and manages the liquid nitrogen cooling of the traps. These system enhancements improve the efficiency, data quality, and testing capacity of TRISO fuel performance evaluations.

07 - ISOTOPES AND RADIATION SOURCES↗
NASA NTRS1999

An experimental study of the isotopic enrichment in Ar, Kr, and Xe when trapped in water ice

The isotopic enrichment of argon, krypton, and xenon, when trapped in water ice, was studied experimentally. The isotopes were found to be enriched according to their (m1/m2)1/2 ratio. These enrichment factors could be useful for comparison among the uncertain cosmic or solar isotopic ratios, the hopeful in situ cometary ratio, and those in Earth's atmosphere, in the context of cometary delivery of volatiles to Earth.

NASA Discipline Exobiology↗
NASA NTRS1985

Noble gas component organization in Apollo 14 breccia 14318 I-129 and Pu-244 regolith chronology

Drozd et al. (1972) have first detected the presence of Xe-129 in lunar material. Bernatowicz et al. (1979, 1980) established that this xenon component resides exclusively on grain surfaces and confirmed previous observations that it is less tightly bound than other surface components. The present investigation extends many of the observations made on the basis of a study of the 14301 to 14318, which is the only other lunar regolith breccia for which the isotopic structure of 'parentless xenon' has been accurately resolved. Actually this isotope has two parents, including Pu-244 and I-129, which are both now extinct. Attention is given to the analyzed samples, the employed analytical methods, the petrology and chemistry of the grain size separates, and stepwise heating experiments. On the basis of the obtained results, it is concluded that the I-Pu-Xe system can be used as a chronometer.

Swindle, T. D.↗
NASA NTRS1976

The atmosphere of Mars - Detection of krypton and xenon

Krypton and xenon have been discovered in the Martian atmosphere with the mass spectrometer on the second Viking lander. Krypton is more abundant than xenon. The relative abundances of the krypton isotopes appear normal, but the ratio of xenon-129 to xenon-132 is enhanced on Mars relative to the terrestrial value for this ratio. Some possible implications of these findings are discussed.

Owen, T.↗
NASA NTRS1987

Evidence for interstellar SiC in the Murray carbonaceous meteorite

Silicon carbide has been identified in two separates from the Murray carbonaceous chondrite that are enriched 20,000-fold in isotopically anomalous neon and xenon. The SiC is present in the form of crystalline grains 0.1-1 micron in size. Cubic and 111-plane-twinned cubic are the most common ordered polytypes observed so far. The anomalous isotopic composition of its carbon, nitrogen, and silicon indicates a presolar origin, probably in the atmospheres of red giants. An additional silicon- and oxygen-rich phase shows large isotropic anomalies in nitrogen and silicon, also associated with a presolar origin.

Bernatowicz, Thomas↗
DOE OSTI2024

Supernova electron-neutrino interactions with xenon in the nEXO detector

Electron-neutrino charged-current interactions with xenon nuclei were modeled in the nEXO neutrinoless double-𝛽 decay detector (∼5 metric ton, 90% 136 Xe, 10% 134 Xe) to evaluate its sensitivity to supernova neutrinos. Predictions for event rates and detectable signatures were modeled using the Model of Argon Reaction Low Energy Yields (MARLEY) event generator. We find good agreement between MARLEY’s predictions and existing theoretical calculations of the inclusive cross sections at supernova neutrino energies. The interactions modeled by MARLEY were simulated within the nEXO simulation framework and were run through an example reconstruction algorithm to determine the detector’s efficiency for reconstructing these events. The simulated data, incorporating the detector response, were used to study the ability of nEXO to reconstruct the incident electron-neutrino spectrum and these results were extended to a larger xenon detector of the same isotope enrichment. We estimate that nEXO will be able to observe electron-neutrino interactions with xenon from supernovae as far as 5–8 kpc from Earth, while the ability to reconstruct incident electron-neutrino spectrum parameters from observed interactions in nEXO is limited to closer supernovae.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1972

Rare-gas analyses on neutron irradiated Apollo 12 samples.

Argon, krypton, and xenon from stepwise heating of five Apollo 12 rocks that had been irradiated to a neutron fluence of about 10 to the 19th neutrons/sq cm were analyzed mass-spectrometrically. The Ar40-Ar39 ages were determined and range from 3.18 plus or minus 0.06 x 10 to the 9th years to 3.32 plus or minus 0.06 x 10 to the 9th years. Trace elements Ba, Br, I, and U were measured via the neutron-induced reactions that produce isotopes of krypton and xenon. The following concentration ranges were observed: Ba, 46 to 70 ppm; Br, 48 to 146 ppb; I, 16 to 73 ppb; and U, 170 to 247 ppb.

Alexander, E. C., Jr.↗
NASA NTRS1993

Xenological constraints on the impact erosion of the early Martian atmosphere

This paper considers impact erosion as the agent of the early Martian atmophere escape, by examining xenon-related constraints imposed on the impact erosion. It is found that, if impact erosion of a planetary atmosphere is important, the remnant atmosphere is likely to fall into one of two qualitatively distinct categories: (1) cometary xenon has an unexpected isotopic composition or (2) factors other than impacts, such as outgassing or recycling, are needed. Neither of these categories can readily account for the present Martian atmosphere.

Zahnle, Kevin J.↗