FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W1668733390> ?p ?o ?g. }

• W1668733390 startingPage "3155" @default.
• W1668733390 abstract "Introduction: The Alpha Proton X-ray Spectrometer (APXS) on the Pathfinder mission to Ares Vallis on Mars in July, 1997, provided data that were used to determine the geochemistry and infer the petrology of the rocks and soils at the landing site. The previously reported preliminary X-ray results [1] were based on calibration data before instrumental biases were determined and before a minor instrumental difference between the laboratory and flight instrument was corrected. Also, these preliminary results [1] did not include alpha and proton results. The alpha mode in particular reveals the amounts of carbon and oxygen, important for understanding of the volatile contents of the Pathfinder samples. In order to determine the abundances from the alphaproton modes, a technique for atmosphere subtraction from the spectra was developed [2]. The flight duplicate has been used to determine the accuracy of analysis under Martian conditions with all three modes of the APXS [2, 3]. We have now finished the re-analysis of all the Pathfinder APXS data, both the alphaproton and the x-ray modes. Two papers, one on the calibration of the APXS [4] and another one on the final results of the martian samples at the Pathfinder landing site [5], have been written and sent for publication to JGR. This work was also the basis for a Ph.D. degree awarded at the University of Chicago [6]. Pathfinder Chemical Results: Pathfinder sample abundances as now determined by the X-ray mode are listed in table I. The alpha-proton modes yield similar bulk abundances, on a volatile free basis (table II) to the X-ray mode for Pathfinder rocks. However, the alpha-proton mode abundances for soils, on a volatile free basis, are approximately 20 relative % lower than X-ray for iron and approximately 2 relative % higher for silicon. The preferred Pathfinder sample abundances, as determined from all modes, are listed in table III. Similar results to our X-ray values have been obtained independently by analyses of the X-ray mode of the instrument by the group at Mainz [7]. The accuracy of our chemical results is supported by the agreement of the three modes of the instrument for most samples on a volatile-free basis. Since the X-ray mode is the most independent of the three modes, its elemental abundances are used together with the carbon, sodium, and water contents from the alpha-proton joint mode to derive the final preferred bulk sample abundances. These results, normalized to 100%, are listed in table III. The errors listed were derived from the laboratory measurements of accuracy and from counting statistics. Alpha-Proton Mode Carbon and Oxygen: No carbon is detected in the Pathfinder samples. Therefore, the abundance of sample carbon is below the APXS detection limit of 0.3 wt% [3, 7]. The bulk oxygen determination from the alpha mode has yielded some excessive amounts of oxygen possibly indicating the presence of chemically bound water. Excess oxygen: The bulk oxygen content of most soils is accounted for by assuming that all iron is in the 3+ oxidation state and all sulfur is in the 6+ oxidation state. In some rocks, however, the oxygen excess remains unaccounted for even if we assume the highest oxidation state for all detected elements. Our ability to detect excess oxygen (above stoichiometry for the measured elements), due to oxygen from water (for which the APXS can not detect H), is illustrated in figures 1 and 2. Clearly there is a significant difference in the spectra within figures 1 and 2 if no sample water is present. Figure 3 shows a typical Pathfinder soil (A-15) which appears to have no excess oxygen, while figure 4 shows a rock (A-17) which appears to have a significant amount of excess oxygen." @default.
• W1668733390 created "2016-06-24" @default.
• W1668733390 creator A5007193214 @default.
• W1668733390 creator A5029374016 @default.
• W1668733390 creator A5032176497 @default.
• W1668733390 date "2003-07-01" @default.
• W1668733390 modified "2023-09-23" @default.
• W1668733390 title "The Chemical Composition of Martian Samples — Final Results from the Pathfinder Alpha Proton X-Ray Spectrometer" @default.
• W1668733390 hasPublicationYear "2003" @default.
• W1668733390 type Work @default.
• W1668733390 sameAs 1668733390 @default.
• W1668733390 citedByCount "2" @default.
• W1668733390 crossrefType "journal-article" @default.
• W1668733390 hasAuthorship W1668733390A5007193214 @default.
• W1668733390 hasAuthorship W1668733390A5029374016 @default.
• W1668733390 hasAuthorship W1668733390A5032176497 @default.
• W1668733390 hasConcept C120665830 @default.
• W1668733390 hasConcept C121332964 @default.
• W1668733390 hasConcept C127313418 @default.
• W1668733390 hasConcept C161191863 @default.
• W1668733390 hasConcept C165838908 @default.
• W1668733390 hasConcept C185544564 @default.
• W1668733390 hasConcept C2778600265 @default.
• W1668733390 hasConcept C2778940482 @default.
• W1668733390 hasConcept C33390570 @default.
• W1668733390 hasConcept C39432304 @default.
• W1668733390 hasConcept C41008148 @default.
• W1668733390 hasConcept C45095769 @default.
• W1668733390 hasConcept C54516573 @default.
• W1668733390 hasConcept C62520636 @default.
• W1668733390 hasConcept C62649853 @default.
• W1668733390 hasConcept C83260615 @default.
• W1668733390 hasConcept C87355193 @default.
• W1668733390 hasConceptScore W1668733390C120665830 @default.
• W1668733390 hasConceptScore W1668733390C121332964 @default.
• W1668733390 hasConceptScore W1668733390C127313418 @default.
• W1668733390 hasConceptScore W1668733390C161191863 @default.
• W1668733390 hasConceptScore W1668733390C165838908 @default.
• W1668733390 hasConceptScore W1668733390C185544564 @default.
• W1668733390 hasConceptScore W1668733390C2778600265 @default.
• W1668733390 hasConceptScore W1668733390C2778940482 @default.
• W1668733390 hasConceptScore W1668733390C33390570 @default.
• W1668733390 hasConceptScore W1668733390C39432304 @default.
• W1668733390 hasConceptScore W1668733390C41008148 @default.
• W1668733390 hasConceptScore W1668733390C45095769 @default.
• W1668733390 hasConceptScore W1668733390C54516573 @default.
• W1668733390 hasConceptScore W1668733390C62520636 @default.
• W1668733390 hasConceptScore W1668733390C62649853 @default.
• W1668733390 hasConceptScore W1668733390C83260615 @default.
• W1668733390 hasConceptScore W1668733390C87355193 @default.
• W1668733390 hasLocation W16687333901 @default.
• W1668733390 hasOpenAccess W1668733390 @default.
• W1668733390 hasPrimaryLocation W16687333901 @default.
• W1668733390 hasRelatedWork W1656739181 @default.
• W1668733390 hasRelatedWork W19272893 @default.
• W1668733390 hasRelatedWork W1964786960 @default.
• W1668733390 hasRelatedWork W2043655962 @default.
• W1668733390 hasRelatedWork W2071749311 @default.
• W1668733390 hasRelatedWork W2087099887 @default.
• W1668733390 hasRelatedWork W3128466026 @default.
• W1668733390 hasRelatedWork W42927829 @default.
• W1668733390 hasRelatedWork W1667105746 @default.
• W1668733390 isParatext "false" @default.
• W1668733390 isRetracted "false" @default.
• W1668733390 magId "1668733390" @default.
• W1668733390 workType "article" @default.