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Alpha-Scattering Surface Analyzer

NSSDCA ID: 1967-084A-02

Mission Name: Surveyor 5
Principal Investigator:Prof. Anthony L. Turkevich


The alpha-scattering surface analyzer was designed to measure directly the abundances of the major elements of the lunar surface. The instrumentation consisted of six alpha sources (curium 242) collimated to irradiate a 10-cm-diameter opening in the bottom of the instrument where the sample was located and two parallel but independent charged particle detector systems. One system, containing two sensors, detected the energy spectra of the alpha particles scattered from the lunar surface, and the other, containing four sensors, detected energy spectra of the protons produced via reactions (alpha and proton) in the surface material. Each detector assembly was connected to a pulse height analyzer. A digital electronics package, located in a compartment on the spacecraft, continuously telemetered signals to earth whenever the experiment was operating. The spectra contained quantitative information on all major elements in the samples except for hydrogen, helium, and lithium. The experiment provided 83 hr of high quality data during the first lunar day. During the second lunar day, 22 hr of data were accumulated. However, detector noise posed a problem in the reduction of data from this second day.

Alternate Names

  • Surveyor5/Alpha-ScatteringSurfaceAnalyzer


  • Planetary Science: Geology and Geophysics

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Mr. Ernest J. FranzgroteOther InvestigatorNASA Jet Propulsion Laboratory
Prof. Anthony L. TurkevichPrincipal InvestigatorUniversity of Chicago

Selected References

  • Turkevich, A. L., et al., Chemical analysis of the moon at the Surveyor V landing site, Science, 158, 635-637, doi:10.1126/science.158.3801.635, Nov. 1967.
  • Turkevich, A. L., et al., Alpha radioactivity of the lunar surface at the landing sites of Surveyors 5, 6, and 7, Science, 167, No. 3926, 1722-1724, doi:10.1126/science.167.3926.1722, Mar. 1970.
  • Turkevich, A. L., et al., Chemical analysis of the Moon at Surveyor V landing site: Preliminary results, in Surveyor V, Prelim. Rept., NASA SP-163, Wash., DC, Dec. 1967.
  • Turkevich, A. L., et al., The alpha-scattering chemical analysis experiment on the Surveyor lunar missions, Surveyor Program Results, NASA SP-184, Wash., DC, 1969.
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