The Miniaturized Mössbauer Spectrometer MIMOS II for Extraterrestrial and Outdoor Terrestrial Applications: A Status Report

Klingelhöfer, G.; Bernhardt, B.; Foh, J.; Bonnes, U.; Rodionov, D.; Souza, P. A. de; Schröder, C.; Gellert, R.; Kane, S. N.; Gütlich, Philipp; Kankeleit, E.

doi:10.1007/978-94-010-0045-1_36

Cited by 5 publications

(5 citation statements)

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“…The advantage of the sample bags was that there was no need to open them for the Mössbauer measurements, which was important to prevent reoxidation. The Mössbauer measurements were carried out with a modified transmission Mössbauer spectrometer produced by Wissenschaftliche Elektronik GmbH Starnberg/Germany (WissEl) using a self-build drive control and data acquisition unit at 77 and 298 K. The detectors were a proportional counter as well as a Si-PIN-photodiode …”

Section: Methodsmentioning

confidence: 99%

About the Corrosion Mechanism of Metal Iron in Contact with Bentonite

Kaufhold

Klimke

Schloemer

et al. 2020

ACS Earth Space Chem.

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Anaerobic corrosion at the metal/bentonite interface determines the performance of bentonite-based high-level radioactive waste (HLRW) barriers. Both magnetite and Fe-silicate formation were previously observed as well as higher corrosivity of bentonites containing low-charged smectites. In the present study, six different bentonites containing differently charged smectites were selected and used for laboratory corrosion tests. The extent of corrosion could be quantified based on the mass loss of Fe0, the increase of Fe2+ in the bentonite, and the increase of the total amount of Fe in the bentonite, which was liberated by the native Fe and found in the bentonite afterward. Magnetite and H2 were found, which can be explained, e.g., by the Schikorr reaction, which is often proposed in this context. However, as soon as Si is available in solution, Fe-silicates form. The corrosion is controlled by diffusion, but the extent of the corrosion could be understood based on reactions involving electrons, H2, and Fe2+. An electron reduces water to H2, which then may be consumed by reduction of Fe3+ of the smectites. The reduction of structural Fe3+ in turn can lead to destabilization (dissolution) of the smectites, hence providing Si into solution, which in turn reacts with Fe2+. Based on this finding, it is now possible to explain the previously observed correlation: The correlation with the layer charge density may result from the fact that low-charged smectites are easier to reduce, becoming less stable, hence consuming more H2 and Fe2+, which accelerates the corrosion. Based on this model, it is also possible to explain why sometimes an Fe-silicate coating forms and sometimes magnetite because this depends on the amount of reactive silica, which is naturally present in some bentonites and absent in others.

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Section: Methodsmentioning

confidence: 99%

About the Corrosion Mechanism of Metal Iron in Contact with Bentonite

Kaufhold

Klimke

Schloemer

et al. 2020

ACS Earth Space Chem.

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“…Therefore, information about the distribution of Fe‐bearing phases with depth (depth sensitive or selective), is possible if two or more resonant radiations are measured for the same sample. Depth‐sensitive information is possible for the MER MIMOS II instruments because both the resonant 14.4 keV γ rays and the resonant 6.4 keV X rays are simultaneously detected [ Klingelhöfer et al , 2002, 2003; de Souza , 2004; Fleischer , 2006; Fleischer et al , 2007]. Analysis of 14.4 keV and 6.4 keV backscatter Mössbauer spectra is discussed by Bara [1980] and Mei et al [1988].…”

Section: Depth Selectivity In Mössbauer Spectramentioning

confidence: 99%

Depth selective Mössbauer spectroscopy: Analysis and simulation of 6.4 keV and 14.4 keV spectra obtained from rocks at Gusev Crater, Mars, and layered laboratory samples

et al. 2008

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The miniaturized Mössbauer spectrometer (MIMOS) II Mössbauer spectrometers on the Mars Exploration Rovers (MER) simultaneously obtained 6.4 keV and 14.4 keV Mössbauer spectra from rock and soil targets. Because photons with lower energy have a shallower penetration depth, 6.4 keV spectra contain more mineralogical information about the near‐surface region of a sample than do 14.4 keV spectra. The influence of surface layers of varying composition and thickness on Mössbauer spectra was investigated by Monte Carlo simulation and by measurement using a copy of the MER MIMOS II instrument and samples with one or two layers of known thicknesses. Thin sections of minerals or metallic Fe foil on top of a thick mineral sample were used to produce samples with thin layers of known thickness on a thick substrate. Monte Carlo simulation of MER spectra obtained on the rock Mazatzal, which displays a coating on a basaltic substrate, and other Adirondack Class rocks results in a calculated thickness of 10 μm for the Mazatzal surface layer. The 6.4 keV spectra obtained on Adirondack Class rocks, on laboratory samples, and in Monte Carlo calculations show an apparent olivine enrichment which is not related to any observable surface layer.

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“…In the field of Mössbauer spectroscopy, a few cases of remote control of the spectrometer have been reported by Silaev and coworkers [8], Zhou and coworkers [9] and Klingelhöfer and coworkers [10], being this last implementation developed for the mini spectrometer MIMOS II for Mars exploration. Remote platforms for the control of Mössbauer spectrometers assisted by learning objects seem to be a topic little explored, being this methodology a good option to allow cooperative work between researchers of different laboratories, bring young researchers closer to the Mössbauer technique, take advantage of the useful life of the radioactive source of the spectrometer, offer online courses and services of Mössbauer spectroscopy, among other benefits.…”

Section: Introductionmentioning

confidence: 99%

Implementation of a platform for the remote access to a transmission Mössbauer spectrometer

Torres

2019

Hyperfine Interact

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This platform was developed looking for a proper use of the radioactive source of 57 Co(Rh) during recess periods of the staff of the laboratory, reduction of exposure of the users to the ionizing radiation coming from radioactive source, as well as spread Mössbauer spectroscopy between new researchers during their academic formation in materials characterization. The application is executed from the server "Neutrón" of the "Laboratorio para la Innovación y el Aprendizaje" of Universidad EAFIT of Medellín. Through a web application based on the e-learning platform Moodle, the user can access, after registration, to a web site with a series of introductory contents related to Mössbauer spectroscopy, a field with remote connection to the Mössbauer spectrometer and other fields with support materials, among them: suggested papers, video of the experiment through an IP camera, chat with the administrator of the spectrometer and access to the file with the experimental spectra. Details of the design of the platform are presented through the sections of this paper.

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The Miniaturized Mössbauer Spectrometer MIMOS II for Extraterrestrial and Outdoor Terrestrial Applications: A Status Report

Cited by 5 publications

References 5 publications

About the Corrosion Mechanism of Metal Iron in Contact with Bentonite

About the Corrosion Mechanism of Metal Iron in Contact with Bentonite

Depth selective Mössbauer spectroscopy: Analysis and simulation of 6.4 keV and 14.4 keV spectra obtained from rocks at Gusev Crater, Mars, and layered laboratory samples

Implementation of a platform for the remote access to a transmission Mössbauer spectrometer

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