Mineral powder samples for solar wind ion sputtering experiments relevant for Moon and Mercury

2020 ◽  
Author(s):  
Noah Jäggi ◽  
André Galli ◽  
Peter Wurz ◽  
Herbert Biber ◽  
Paul S. Szabo ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Wind ◽  
The Moon ◽  
Before And After ◽  
First Results ◽  
Powder Samples ◽  
Mineral Powder ◽  
Singly Charged ◽  
Mir Spectra ◽  
Sputtering Yields

<p>The surfaces of Mercury and Moon are thought to be similar in terms of being rocky, regolith covered planetary bodies, dominated by pyroxene and plagioclase (Taylor et al. 1991, McCoy et al. 2018). Contrary to the Moon, Mercury possesses a global dipole magnetic field, resulting in a highly dynamic magnetosphere that varies surface exposure to solar wind ions and energetic electrons (Winslow et al. 2017, Gershman et al. 2015). The energy of these particles is thereby transferred and material is sputtered from the surface (Sigmund 2012), providing the main contributions to the exospheres of the Moon and Mercury. Parametrizing the underlying sputtering processes is of great interest for successfully linking exosphere observations with surface compositions (e.g. Wurz et al. 2010, Merkel et al. 2018).</p><p>The understanding of sputtering from the kinetic energy transfer is sufficient to predict sputter yields of singly charged impinging ions on conducting surfaces (e.g., Stadlmayr et al. 2018). Hijazi et al. (2017) and Szabo et al. (2018) have also made advancements on potential sputtering, investigating the interaction of multiply charged ions with glassy thin films. We expand on their studies and use mineral powder pellets as analogues for sputtering experiments relevant to the surfaces of the Moon and Mercury. The powder pellets include plagioclase, pyroxene, and wollastonite. The latter is a pyroxene-like Ca-rich mineral with Fe contents below detection limits, which allows investigating the effect on reflectivity during sputtering of Fe-free minerals. With these analogues, we strive to supply infrared spectra with a focus on the robust mid infrared (MIR) range for Mercury and sputter yields for both the Moon and Mercury. </p><p>First results of irradiated mineral pellets include MIR spectra of the minerals before and after irradiation as well as sputtering yields and visual alteration effects. So far, no relevant changes in the MIR spectra were observed nor any visual alteration of wollastonite. The first irradiation with 4 keV <sup>4</sup>He<sup>+</sup> reached a fluence of about 29 E+20 ions per m<sup>2</sup> at an angle of 30°. Presumably, the lack of visual alteration is due to the absence of Fe in wollastonite. Further results are expected to bring clarity in the reaction of pellets to irradiation and if their sputtering characteristics differ from those of glassy thin films.</p><p>Gershman, D. J., et al. (2015). J. Geophys. Res.-Space, 120(10).</p><p>Hiesinger, H., & Helbert, J. (2010). Planet. Space Sci., 58(1–2).</p><p>Hijazi, H., et al. (2017). J. Geophys. Res.-Planet, 122(7).</p><p>McCoy, T. J., et al. (2018). Mercury: The View after MESSENGER.</p><p>Sigmund, P. (2012). Thin Solid Films, 520(19).</p><p>Stadlmayr, R., et al. (2018). Nucl. Instrum. Meth. B, 430.</p><p>Szabo, P. S., et al. (2018). Icarus, 314.</p><p>Taylor, G. J., et al. (1991). Lunar sourcebook-A user’s guide to the moon.</p><p>Winslow, R. M., et al. (2017). J. Geophys. Res.-Space, 122(5).</p><p> </p>

A novel setup to examine sputtering characteristics of mineral samples

2021 ◽  
Author(s):  
Herbert Biber ◽  
Paul Stefan Szabo ◽  
Noah Jäggi ◽  
Christian Cupak ◽  
Johannes Brötzner ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Wind ◽  
Outer Space ◽  
High Sensitivity ◽  
Space Environment ◽  
Sample Holder ◽  
Primary Sample ◽  
First Results ◽  
Irradiation Angle ◽  
Sputtering Yields

<p>The surface of bodies without a thick atmosphere in outer space is exposed to the harsh space environment [1]. Space weathering alters its properties and leads to the formation of a tenuous exosphere. This elevated density of particles is coupled to the surface and therefore carries information about the latter. The BepiColombo mission aims to probe the composition of Mercury’s exosphere for the purpose of extracting this information [2]. However, this task requires precise models of exosphere formation [3]. Sputtering by solar wind ions is expected to be one of the main drivers for exosphere formation and models are therefore sensitive to sputtering inputs. So far, mainly simulation data are used, as experimental sputtering data for relevant materials are rare. Furthermore, available measurements have been typically performed with amorphous thin films due to use of the Quartz Crystal Microbalance (QCM) technique for sputtering measurements [4, 5]. Such a QCM is very sensitive to mass changes with resolutions in the sub mono-layer regime and is therefore an ideal tool for quantitative measurements of sputtering yields [6].</p><p>We introduce a new method for determining sputtering yields of more realistic samples, which allows to overcome the limitations of thin films while making use of the high sensitivity of QCMs. For this purpose, pellets pressed from minerals that are relevant for Mercury are used. The primary sample holder is placed on a xyzφ -manipulator, which enables switching between different samples and varying the irradiation angle α. A secondary quartz (C-QCM) is placed on an independently rotatable manipulator. This setup allows probing the angular distribution of sputtered particles by determining the mass change ∆m ion<sup>−1 </sup>in dependence on the angle α<sub>C</sub> between the sample and the C-QCM, which can lead to further improvement of exosphere models. Furthermore, mass changes of the irradiated sample due to ion implantation [7], can be untangled as only deposition of ejected particles contributes to the C-QCM signal. The use of pressed pellets enables a variation in sample parameters not accessible with thin films like crystal structure, surface roughness and porosity. Nonetheless, a QCM coated with the same material is installed on the primary sample holder in addition to the pellet for calibration.<br>First results with the Ca-pyroxenoid wollastonite (CaSiO3) and 2 keV Ar<sup>+</sup> ions are very promising. They indicate no difference in sputtering of the amorphous thin film and the pressed wollastonite pellet for Ar<sup>+</sup> irradiations. In a next step, solar wind ions will be used, which will improve the understanding of sputtering of realistic samples by solar wind ions. </p><p><strong>References</strong></p><p>[1] Hapke B.: J. Geophys. Res. Planet., 106, 10039, 2001.<br>[2] Milillo A., et al.: Planet. Space Sci., 58, 40, 2010.<br>[3] Wurz P., et al.: Planet. Space Sci., 58, 1599, 2010.<br>[4] Szabo P. S., et al.: Astrophys. J., 891, 100, 2020.<br>[5] Hijazi H., et al.: J. Geophys. Res. Planets, 122, 1597, 2017.<br>[6] Hayderer G., et al.: Rev. Sci. Instrum., 70, 3696, 1999.<br>[7] Biber H., et al.: Nucl. Instrum. Methods Phys. Res. B, 480, 10, 2020.</p>

scholarly journals Creation of Lunar and Hermean analogue mineral powder samples for solar wind irradiation experiments and mid-infrared spectra analysis

Icarus ◽  
2021 ◽  
Vol 365 ◽  
pp. 114492
Author(s):  
Noah Jäggi ◽  
André Galli ◽  
Peter Wurz ◽  
Herbert Biber ◽  
Paul Stefan Szabo ◽  
...  
Keyword(s):  
Solar Wind ◽  
Infrared Spectra ◽  
Spectra Analysis ◽  
Mid Infrared ◽  
Powder Samples ◽  
Mineral Powder

Implantation of ions escaping the atmosphere of Mars within the regolith of Phobos, and Phobos’ surface ion weathering

2020 ◽  
Author(s):  
Quentin Nénon ◽  
Andrew R Poppe ◽  
Ali Rahmati ◽  
James P McFadden
Keyword(s):  
Solar Wind ◽  
Atomic Oxygen ◽  
The Moon ◽  
Ion Composition ◽  
Atmospheric Escape ◽  
The Past ◽  
Lunar Samples ◽  
Singly Charged

<p>Mars has lost and is losing its atmosphere into space. Strong evidences of this come from the observation of planetary singly charged heavy ions (atomic oxygen, molecular oxygen, carbon dioxide ions) by Mars Express and MAVEN. Phobos, the closest moon of Mars, orbits only 6,000 kilometers above the red planet’s surface and is therefore a unique vantage point of the planetary atmospheric escape, with the escaping ions being implanted within the regolith of Phobos and altering the properties of the moon’s surface.</p> <p>In this presentation, we aggregate all ion observations gathered in-situ close to the orbit of Phobos by three ion instruments onboard MAVEN, from 2015 to 2019, to constrain the long-term averaged ion environment seen by the Martian moon at all longitudes along its orbit. In particular, the SupraThermal and Thermal Ion Composition (STATIC) instrument onboard MAVEN distinguishes between solar wind and planetary ions. The newly constrained long-term ion environment seen by Phobos is combined with numerical simulations of ion transport and effects in matter.</p> <p>This way, we find that planetary ions are implanted on the near side of Phobos (pointing towards Mars) inside the uppermost tens of nanometers of regolith grains. The composition of near-side grains that may be sampled by future Phobos sample return missions is therefore not only contaminated by planetary ions, as seen in lunar samples with the terrestrial atmosphere, but may show a unique record of the past atmosphere of Mars.</p> <p>The long-term fluxes of planetary ions precipitating onto Phobos are so intense that these ions weather the moon’s surface as much as or more than solar wind ions. In particular, Martian ions accelerate the long-term sputtering and amorphization of the near side regolith by a factor of 2. Another implication is that ion weathering is highly asymmetric between the near side and far side of Phobos.</p>

Solar wind sputtering on Mercury and the Moon: effects on mid infrared spectra of mineral powder pellet analogues

2020 ◽  
Author(s):  
Noah Jäggi ◽  
Paul Stefan Szabo ◽  
Herbert Biber ◽  
Klaus Mezger ◽  
Friedrich Aumayr ◽  
...  
Keyword(s):  
Solar Wind ◽  
Infrared Spectra ◽  
The Moon ◽  
Mid Infrared ◽  
Mineral Powder

Ion weathering of the surface of the Martian moon Phobos as inferred from MAVEN ion observations

2020 ◽  
Author(s):  
Quentin Nenon ◽  
Andrew Poppe
Keyword(s):  
Solar Wind ◽  
Molecular Oxygen ◽  
Alpha Particles ◽  
Space Weathering ◽  
The Moon ◽  
Atmospheric Escape ◽  
Flux Measurements ◽  
The One ◽  
Energy Dependent ◽  
Sputtering Yields

<p>Phobos is the closest of the two moons of Mars and its surface is not only exposed to ions coming from the solar wind (mainly protons H+ and alpha particles He<sup>++</sup>), but is also bombarded by ions coming from Mars itself (mainly atomic and molecular oxygen ions O<sup>+</sup> and O<sub>2</sub><sup>+</sup>). Space weathering at Phobos would be intimately linked to the planetary atmospheric escape if Martian ions significantly alter the properties of the moon’s surface.<br />In this presentation, the long-term averaged ion environment seen by the surface of Phobos (omnidirectional and directional fluxes, and composition) is constructed from 4 years of ion measurements gathered in-situ by the NASA MAVEN mission. The MAVEN spacecraft repeatedly crossed the orbit of Phobos from January 2015 to February 2019 and was uniquely suited to unprecedently observe ions there with its three ion instruments: SWIA, STATIC, and SEP. These three experiments together constrain the entire range of ion kinetic energies that impact Phobos, from cold ions of a few eV to solar energetic ions of several MeV. In addition, the STATIC instrument (1 eV to 30 keV) is able to discriminate the mass of the observed ions by measuring their time-of-flight. This capability is important to understand the weathering of the surface of Phobos, as for instance the effect on the surface of a precipitating heavy molecular oxygen ion is significantly different from the one of a proton.<br />The relative importance of Martian and solar wind ions is in turn assessed from the observed ion omnidirectional fluxes for two space weathering effects: (1) surface sputtering, which is computed by using ion specie and energy-dependent sputtering yields available in the literature and (2) the production of vacancies inside the regolith grains, which is estimated with the SRIM software. (1) We find that Martian ions dominate solar wind ions in sputtering the surface of Phobos when the moon crosses the Martian magnetotail. We also reveal that molecular oxygen O<sub>2</sub><sup>+</sup> ions sputter as much as or more from the surface of Phobos than atomic O<sup>+</sup> ions. (2) Martian heavy ions significantly contribute to the production of vacancies in the uppermost nanometer of Phobos regolith grains. Finally, MAVEN directional flux measurements are used to study the anisotropy of the bombarding ion fluxes at Phobos, which we find implies an asymmetric weathering of the surface: the near side (always facing Mars) is primarily weathered by Martian ions, whereas the far side is primarily altered by solar wind ions. </p>

The Precipitation of Si in AlCuSi Thin Films

1973 ◽  
Vol 31 ◽  
pp. 34-35 ◽  
Author(s):  
R. M. Anderson
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Heat Treatment ◽  
Solid Solution ◽  
Integrated Circuit ◽  
Copper Film ◽  
Solution Concentration ◽  
X Ray ◽  
Silicon Thin Films ◽  
Before And After

Aluminum-copper-silicon thin films have been considered as an interconnection metallurgy for integrated circuit applications. Various schemes have been proposed to incorporate small percent-ages of silicon into films that typically contain two to five percent copper. We undertook a study of the total effect of silicon on the aluminum copper film as revealed by transmission electron microscopy, scanning electron microscopy, x-ray diffraction and ion microprobe techniques as a function of the various deposition methods.X-ray investigations noted a change in solid solution concentration as a function of Si content before and after heat-treatment. The amount of solid solution in the Al increased with heat-treatment for films with ≥2% silicon and decreased for films <2% silicon.

Fem Simulation of Micro-Rotating-Structures and Their Applications in Measurement of Residual Stresses in Thin Films

1997 ◽  
Vol 505 ◽  
Author(s):  
Xin Zhang ◽  
Tong-Yi Zhang ◽  
Yitshak Zohar
Keyword(s):  
Thin Films ◽  
Residual Stresses ◽  
Fem Simulation ◽  
Sensitivity Factor ◽  
Local Measurement ◽  
Micro Structure ◽  
Micro Raman Spectroscopy ◽  
Before And After ◽  
Polysilicon Films ◽  
Simulation Results

ABSTRACTFEM simulation of micro-rotating-structures was performed for local measurement of residual stresses in thin films. A sensitivity factor is introduced, studied and tabulated from the simulation results. The residual stress can be evaluated from the rotating deflection, the lengths of rotating and fixed beams, and the sensitivity factor. The micro-structure technique was applied to measure residual stresses in both silicon nitride and polysilicon thin films, before and after rapid thermal annealing (RTA), and further confirmed by wafer curvature method. Residual stresses in polysilicon films at different RTA stages were also characterized by micro-Raman spectroscopy (MRS). The experimental results indicate that micro-rotating-structures indeed have the ability to measure spatially and locally residual stresses in MEMS thin films with appropriate sensitivities.

Structural, electrical and optical characterizations of yttrium doped aluminum nitride thin films before and after ions irradiation

2021 ◽  
Vol 116 ◽  
pp. 111097
Author(s):  
Asmat Ullah ◽  
Muhammad Usman ◽  
Wang Qingyu ◽  
Iftikhar Ahmad ◽  
Muhammad Maqbool
Keyword(s):  
Thin Films ◽  
Aluminum Nitride ◽  
Before And After

scholarly journals Mid-Infrared Spectroscopy as a Rapid Tool to Qualitatively Predict the Effects of Species, Regions and Roasting on the Nutritional Composition of Australian Acacia Seed Species

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1879
Author(s):  
Oladipupo Q. Adiamo ◽  
Yasmina Sultanbawa ◽  
Daniel Cozzolino
Keyword(s):  
Principal Component ◽  
Nutritional Composition ◽  
Human Consumption ◽  
Mid Infrared ◽  
Mir Spectroscopy ◽  
As Species ◽  
Before And After ◽  
Mir Spectra ◽  
Main Components ◽  
Rapid Tool

In recent times, the popularity of adding value to under-utilized legumes have increased to enhance their use for human consumption. Acacia seed (AS) is an underutilized legume with over 40 edible species found in Australia. The study aimed to qualitatively characterize the chemical composition of 14 common edible AS species from 27 regions in Australia using mid-infrared (MIR) spectroscopy as a rapid tool. Raw and roasted (180 °C, 5, 7, and 9 min) AS flour were analysed using MIR spectroscopy. The wavenumbers (1045 cm−1, 1641 cm−1, and 2852–2926 cm−1) in the MIR spectra show the main components in the AS samples. Principal component analysis (PCA) of the MIR data displayed the clustering of samples according to species and roasting treatment. However, regional differences within the same AS species have less of an effect on the components, as shown in the PCA plot. Statistical analysis of absorbance at specific wavenumbers showed that roasting significantly (p < 0.05) reduced the compositions of some of the AS species. The results provided a foundation for hypothesizing the compositional similarity and/or differences among AS species before and after roasting.

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