Distribution of iron&titanium on the lunar surface from lunar prospector gamma ray spectra

Conference · Mon Jan 01 04:00:00 EST 2001

OSTI ID:975127

Prettyman, T H ^[1]; Feldman, W C ^[2]; Elphic, R C ^[3]; Gasnault, O M ^[4]; Maurice, S ^[5]; Moore, K R ^[6]; Binder, A B

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1. Thomas H.
2. William C.
3. Richard C.
4. Olivier M.
5. Sylvestre
6. Kurt R.

Gamma ray pulse height spectra acquired by the Lunar Prospector (LP) Gamma-Ray Spectrometer (GRS) contain information on the abundance of major elements in the lunar surface, including O, Si, Ti, Al, Fe, Mg, Ca, K, and Th. With the exception of Th and K, prompt gamma rays produced by cosmic ray interactions with surface materials are used to determine elemental abundance. Most of these gamma rays are produced by inelastic scattering of fast neutrons and by neutron capture. The production of neutron-induced gamma rays reaches a maximum deep below the surface (e.g. {approx}140 g/cm{sup 2} for inelastic scattering and {approx}50 g/cm{sup 2} for capture). Consequently, gamma rays sense the bulk composition of lunar materials, in contrast to optical methods [e.g. Clementine Spectral Reflectance (CSR)], which only sample the top few microns. Because most of the gamma rays are produced deep beneath the surface, few escape unscattered and the continuum of scattered gamma rays dominates the spectrum. In addition, due to the resolution of the spectrometer, there are few well-isolated peaks and peak fitting algorithms must be used to deconvolve the spectrum in order to determine the contribution of individual elements.

• Research Organization: Los Alamos National Laboratory
• Sponsoring Organization: DOE
• OSTI ID: 975127
• Report Number(s): LA-UR-01-0536; LA-UR-01-536
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ABUNDANCE
ALGORITHMS
CAPTURE
DISTRIBUTION
FAST NEUTRONS
INELASTIC SCATTERING
IRON
LUNAR MATERIALS
NEUTRON REACTIONS
PRODUCTION
RESOLUTION
SPECTRA
SPECTRAL REFLECTANCE
SPECTROMETERS
TITANIUM