Hopping diffusion of helium isotopes from samples of lunar soil

Anufriev, G. S.

doi:10.1134/s1063783410100082

Cited by 5 publications

(3 citation statements)

References 1 publication

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“…The first one (53.692 kJ/mol), determined from the 200-400 ℃ range, is higher than that for the 500-1 300 ℃ range (11.290 kJ/mol). The former one agrees with E a for 4 He in Luna 24 soil (Anufriev, 2010). …”

Section: Diffusion Experimentssupporting

confidence: 73%

Noble gas diffusion mechanism in lunar soil simulant grains: Results from 4He+ implantation and extraction experiments

Zou

Zheng

et al. 2011

J. Earth Sci.

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Experiments on ion implantation were performed in order to better characterize diffusion of noble gases in lunar soil. 4 He + at 50 keV with 5×10 16 ions/cm 2 was implanted into lunar simulants and crystal ilmenite. Helium in the samples was released by stepwise heating experiments. Based on the data, we calculated the helium diffusion coefficient and activation energy. Lunar simulants display similar 4 He release patterns in curve shape as lunar soil, but release temperatures are a little lower. This is probably a consequence of long-term diffusion after implantation in lunar soil grains. Variation of activation energy was identified in the Arrhenius plots of lunar simulants and Panzhihua (攀枝花)ilmenite. We conclude that noble gas release in lunar soil cannot be described as simple thermally activated volume diffusion. Variation of diffusion parameters could be attributed to physical transformation during high temperature. Radiation damage probably impedes helium diffusion. However, bubble radius growth during heating does not correlate with activation energy variation. Activation energy of Panzhihua ilmenite is 57.935 kJ/mol. The experimental results confirm that ilmenite is more retentive for noble gas than other lunar materials.

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Section: Diffusion Experimentssupporting

confidence: 73%

Noble gas diffusion mechanism in lunar soil simulant grains: Results from 4He+ implantation and extraction experiments

Zou

Zheng

et al. 2011

J. Earth Sci.

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“…where No is the initial concentration of gas (Xe‐P3), Nr is the concentration of gas (Xe‐P3) after heating for time t , k— Boltzmann constant, and T— temperature of heating (in K). This equation has been derived from the equation of the first‐order chemical reaction (see, e.g., Anufriev ). On the Arrhenius plot lnln( N o / N r ) versus 1/ T the slope of the line determines the activation energy and the value of the intercept with the ordinate axis—the frequency factor, which in this model is a proxy of diffusion coefficient.…”

Section: Kinetics Of the Xe‐p3 Releasementioning

confidence: 99%

Kinetics of Xe‐P3 release during pyrolysis of the coarse‐grained fractions of Orgueil (CI) meteorite nanodiamonds

Fisenko

Verchovsky

Semjonova

2014

Meteorit & Planetary Scien

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Abstract-The kinetics of the release of the Xe-P3 component from coarse-grained fractions of Orgueil (CI) meteorite nanodiamonds has been investigated using stepped and isothermal pyrolysis. It has been shown that a first-order chemical reaction diffusion model with a single activation energy cannot provide a satisfactory explanation for the observed retention of Xe-P3 during parent body thermal metamorphism and the kinetics of Xe-P3 release from nanodiamonds during isothermal pyrolysis. Using the activation energy and frequency factor calculated according to this model, it is shown that in the course of thermal metamorphism of the Orgueil meteorite almost the entire Xe-P3 component must have been lost in a very short time (<4 yr at approximately 100°C). However, the calculated retention of Xe-P3 increases significantly if a diffusion model with a spectrum of activation energies is used. In this case, the model can explain not only a high retention of Xe-P3 in the Orgueil nanodiamonds but also the release pattern of the Xe-P3 from Semarkona and Bishunpur nanodiamonds that have experienced a significant gas loss during parent body metamorphism as well as the release of Xe-P3 during isothermal pyrolysis of the Orgueil nanodiamonds. The energetically complicated Xe-P3 distribution is most likely caused by structural damage to the nanodiamond grains or a complex phase composition of carbon in the surface layer of the diamond grains. It is supposed that the structural damage of the diamond grains can have a radiation origin, while the variations of the carbon phase composition in the grain's mantle can be caused by the radiation-induced reactions and/or a thermal effect.

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“…Anufriev investigated the diffusion of helium isotopes in lunar soil samples from Luna-24 and found that due to the radiation damage, the diffusion of helium isotopes in lunar soil did not obey Fick's law. Helium atoms were bound in the damaged mineral crystals, and extra energy was required to cause the displacement of helium-3 atoms [31]. Harris-Kuhlman et al studied the forms and diffusion of helium in simulated lunar soil, which was represented by ilmenite.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study on Thermal Release of Helium-3 in Lunar Ilmenite

et al. 2021

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The in-situ utilization of lunar helium-3 resource is crucial to manned lunar landings and lunar base construction. Ilmenite was selected as the representative mineral which preserves most of the helium-3 in lunar soil. The implantation of helium-3 ions into ilmenite was simulated to figure out the concentration profile of helium-3 trapped in lunar ilmenite. Based on the obtained concentration profile, the thermal release model for molecular dynamics was established to investigate the diffusion and release of helium-3 in ilmenite. The optimal heating temperature, the diffusion coefficient, and the release rate of helium-3 were analyzed. The heating time of helium-3 in lunar ilmenite under actual lunar conditions was also studied using similitude analysis. The results show that after the implantation of helium-3 into lunar ilmenite, it is mainly trapped in vacancies and interstitials of ilmenite crystal and the corresponding concentration profile follows a Gaussian distribution. As the heating temperature rises, the cumulative amounts of released helium-3 increase rapidly at first and then tend to stabilize. The optimal heating temperature of helium-3 is about 1000 K and the corresponding cumulative release amount is about 74%. The diffusion coefficient and activation energy of helium-3 increase with the temperature. When the energy of helium-3 is higher than the binding energy of the ilmenite lattice, the helium-3 is released rapidly on the microscale. Furthermore, when the heating temperature increases, the heating time for thermal release of helium-3 under actual lunar conditions decreases. For the optimal heating temperature of 1000 K, the thermal release time of helium-3 is about 1 s. The research could provide a theoretical basis for in-situ helium-3 resources utilization on the moon.

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Hopping diffusion of helium isotopes from samples of lunar soil

Cited by 5 publications

References 1 publication

Noble gas diffusion mechanism in lunar soil simulant grains: Results from 4He+ implantation and extraction experiments

Noble gas diffusion mechanism in lunar soil simulant grains: Results from 4He+ implantation and extraction experiments

Kinetics of Xe‐P3 release during pyrolysis of the coarse‐grained fractions of Orgueil (CI) meteorite nanodiamonds

Theoretical Study on Thermal Release of Helium-3 in Lunar Ilmenite

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