Alpha-Scattering Experiment on Surveyor 7: Comparison with Surveyors 5 and 6

Patterson, J. Herbert; Franzgrote, Ernest J.; Turkevich, A.; Anderson, Wayne A.; Economou, T.; Griffin, H.E.; Grotch, Stanley L.; Sowinski, Kenneth P.

doi:10.1029/jb074i025p06120

Cited by 33 publications

(7 citation statements)

References 15 publications

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“…Some 50 particles from a radioactive source (this time the transuranium nuclide 242Cm) and measurement of the energy distribution of these particles by means of solid-state detectors after they had been scattered by the target atoms through angles close to 180 ø (therefore the term "backscattered"). They designed instruments that flew on three Surveyor missions (Surveyor V, VI, and VII) in the years 1967 and 1968 and yielded the first complete and accurate chemical analysis of lunar soils [Turkevich et al, 1969;Franzgrote et al, 1970;Patterson et al, 1970]. In addition to the measurement of backscattered alpha particles, these instruments already contained detectors to measure the energy distribution of protons, generated by (a, p) reactions on certain medium-heavy elements (F, Na, Mg, A1, Si, S, and C1), thus enhancing their resolution capability for these elements.…”

Section: Introductionmentioning

confidence: 99%

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Determination of the chemical composition of Martian soil and rocks: The alpha proton X ray spectrometer

Rieder¹,

Wänke²,

Economou³

et al. 1997

J. Geophys. Res.

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Abstract. The alpha proton X ray spectrometer (APXS) for the Mars Pathfinder mission is designed to provide a complete and detailed analysis of chemical elements in Martian soil and rocks near the landing site. The APXS instrument is carried on the Pathfinder Microrover, which will provide transportation to places of interest on the Martian surface. It consists of a complex sensor head, mounted on a simple but sophisticated APXS deployment mechanism (ADM) outside the warm electronics box (WEB) of the Microrover, and the instrument electronics, mounted inside the WEB. The ADM permits the instrument sensor head to be placed against soil and rock samples in arbitrary positions, ranging from horizontal to vertical, in order to perform in situ analysis. The possibility to transport the APXS to an arbitrary location, preselected on Earth, and to perform in situ analysis there, constitutes one of the most exciting aspects of the Pathfinder mission. The principle of the APXS technique is based on three interactions of alpha particles from a radioisotope source with matter: simple Rutherford backscattering, production of protons from (c•, p) reactions on light elements, and generation of characteristic X rays upon recombination of atomic shell vacancies created by c• bombardment. Measurement of the intensities and energy distributions of these three components yields information on the abundance of chemical elements in the sample. In terms of sensitivity and selectivity, data are partly redundant and partly complementary: alpha backscattering is superior for light elements (C, O), while proton emission is mainly sensitive to Na, Mg, A1, Si, S, and X ray emission is more sensitive to heavier elements (Na to Fe and beyond). A combination of all three measurements enables determination of all elements (with the exception of H and He) present at concentration levels above typically a fraction of 1%.

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Section: Introductionmentioning

confidence: 99%

“…The use of alpha backscattering and related techniques for obtaining the chemical composition of planetary bodies was described in detail in the past [Turkevich, 1961;Patterson et al, 1969;Economou et al, 1970Economou et al, , 1973. The following is a brief review for easy reference.…”

Section: Alpha Backscattering (Alpha Mode)mentioning

confidence: 99%

Determination of the chemical composition of Martian soil and rocks: The alpha proton X ray spectrometer

Rieder¹,

Wänke²,

Economou³

et al. 1997

J. Geophys. Res.

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“…Results of the Surveyor VII alpha scattering experiment [Patterson et al, 1969] and early observations on lunar samples led to the speculation that the moon's highland crust was anorthositic [e.g., Smith et al, 1970;Wood et al, 1970]. Discovery of large fragments of anorthosite consisting almost entirely of plagioclase in the Apollos 15 and 16 collections [Lunar Sample Preliminary Examination Team (LSPET), 1972a,b] and prevalence of anorthosite in the early list of 'pristine' rocks [Warren and Wasson, 1977] led to speculation that one manifestation of plagioclase enrichment in the moon's Crust might be an anorthositic shell (>90% plagioclase) [Wood et al, 1970;Wasson, 1979, 1980;Longhi, 1980], although the best estimates of average highlands surface composition indicated a substantial mafic component.…”

Section: Introductionmentioning

confidence: 99%

Stillwater Anorthosites: A lunar analog?

Salpas¹,

Haskin²,

McCallum³

1983

J. Geophys. Res.

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Samples of anorthosite from Stillwater Complex units AN‐I and AN‐II (terminology of McCallum et al (1980)) were analyzed by instrumental neutron activation analysis (INAA) for FeO, CaO, Na2O, REE, and other trace elements. No compositional trend with stratigraphic position was observed. Mean concentrations for most elements are about the same for three traverses (two for AN‐II) but CaO, FeO, and Sr concentrations are slightly different for the three traverses. The elements are not normally or lognormally distributed among samples from a single traverse. Strong interelement correlations can be understood in terms of sample mineralogy. Little evidence for compositional evolution of minerals during precipitation of the entire Middle Banded Zone is apparent. As in lunar anorthosites, the component of trapped residual liquid is relatively insignificant (less than 5%). In addition to plagioclase, which makes up, on average, 90% of the anorthosites, the rocks contain interstitial pyroxene (augite and inverted pigeonite) and, in some cases, quartz, titano‐magnetite, sulfides, and rare apatite and allanite. There is an inverse relationship between the amounts of pyroxene and quartz. General compositional trends, exemplified by La‐Sc systematics, indicate that the bulk of the poikilitic pyroxene appears to be cumulus‐adcumulus, presumably formed at the crystallization front from a magma saturated in plagioclase and pyroxene. A small fraction of the pyroxene and plagioclase plus all the quartz and other trace minerals formed from the minor trapped liquid component. The irregular distribution of pyroxene oikocrysts indicates that interstitial melt migrated substantially prior to final consolidation of the rock.

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“…The comparison of the lunar analyses results provided by the ASI on the Surveyor 5 and Surveyor 7 with those analyses of lunar material brought back from the Moon by the Apollo 11 astronauts is shown in Fig. 4 [6]. a b Fig.…”

Section: Fig 2 the Alpha Scattering Instrument Deployed On The Surfmentioning

confidence: 99%

History of Applications of Radioactive Sources in Analytical Instruments for Planetary Exploration

Economou¹

2011

Radioisotopes - Applications in Physical Sciences

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Alpha-Scattering Experiment on Surveyor 7: Comparison with Surveyors 5 and 6

Cited by 33 publications

References 15 publications

Determination of the chemical composition of Martian soil and rocks: The alpha proton X ray spectrometer

Determination of the chemical composition of Martian soil and rocks: The alpha proton X ray spectrometer

Stillwater Anorthosites: A lunar analog?

History of Applications of Radioactive Sources in Analytical Instruments for Planetary Exploration

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