Planetary gamma-ray spectroscopy
The chemical composition of a planet can be inferred from the gamma rays escaping from its surface and can be used to study its origin and evolution. The measured intensities of certain gamma rays of specific energies can be used to determine the abundances of a number of elements. The major sources of these gamma-ray lines are the decay of natural radionuclides, reactions induced by energetic galactic-cosmic-ray particles, capture of low energy neutrons, and solar-proton-induced radioactivities. The fluxes of the more intense gamma-ray lines emitted from 30 elements were calculated using current nuclear data and existing models. The source strengths for neutron-capture reactions were modified from those previously used. The fluxes emitted from a surface of average lunar composition are reported for 288 gamma-ray lines. These theoretical fluxes have been used elsewhere to convert the data from the Apollo gamma-ray spectrometers to elemental abundances and can be used with results from future missions to map the concentrations of a number of elements over a planet's surface. Detection sensitivities for these elements are examined and applications of gamma-ray spectroscopy for future orbiters to Mars and other solar-system objects are discussed.
- Research Organization:
- Los Alamos Scientific Lab., N.Mex. (USA)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6843377
- Report Number(s):
- LA-UR-78-1211; CONF-780314-3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BARYON REACTIONS
CAPTURE
CHARGED-PARTICLE REACTIONS
CHEMICAL COMPOSITION
COSMIC RADIATION
DECAY
ELECTROMAGNETIC RADIATION
GAMMA RADIATION
GAMMA SPECTROSCOPY
HADRON REACTIONS
IONIZING RADIATIONS
ISOTOPES
LUNAR MATERIALS
MARS PLANET
NEUTRON REACTIONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
PLANETARY EVOLUTION
PLANETS
PROTON REACTIONS
RADIATION DETECTION
RADIATION FLUX
RADIATIONS
RADIOACTIVITY
RADIOISOTOPES
SENSITIVITY
SOLAR RADIATION
SOLAR SYSTEM EVOLUTION
SPECTROSCOPY
SURFACES