/sup 10/Be profiles in lunar surface rock 68815
Cosmic ray produced /sup 10/Be (t/sub 1/2/ = 1.6 x 10/sup 6/ years) activities have been measured in fourteen carefully ground samples of lunar surface rock 68815. The /sup 10/Be profiles from 0 to 4 mm are nearly flat for all three surface angles measured and show a very slight increase with depth from the surface to a depth of 1.5 cm. These depth profiles are in contrast to the SCR (solar cosmic ray) produced /sup 26/Al and /sup 53/Mn profiles measured from these same samples. There is no sign of SCR produced /sup 10/Be in this rock. The discrepancy between the data and the Reedy-Arnold theoretical calculation (about 2 dpm /sup 10/Be/kg at the surface) can be explained in two ways: (1) the low energy proton induced cross sections for /sup 10/Be production from oxygen are really lower than those used in the calculations or, (2) compared to the reported fits for /sup 26/Al and /sup 53/Mn, the solar proton spectral shape is actually softer (exponential rigidity parameter Ro less than 100 MV), the omnidirectional flux above 10 MeV is higher (more than 70 protons/cm/sup 2/ s), and the erosion rate is higher (greater than 1.3 mm/My). /sup 10/Be, as a high energy product, is a very useful nuclide for helping to obtain the SCR spectral shape in the past. 23 refs., 3 figs., 1 tab.
- Research Organization:
- California Univ., San Diego, La Jolla (USA). Dept. of Chemistry; Tokyo Univ., Tanashi (Japan). Inst. for Nuclear Study; Nihon Univ., Tokyo. Coll. of Humanities and Sciences; Tokyo Univ. (Japan). Research Center for Nuclear Science and Technology; Tokyo Univ. (Japan). Faculty of Science; Los Alamos National Lab., NM (USA)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6460601
- Report Number(s):
- LA-UR-87-1995; CONF-870396-4; ON: DE87011776
- Country of Publication:
- United States
- Language:
- English
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71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALKALINE EARTH ISOTOPES
ALUMINIUM 26
ALUMINIUM 26 TARGET
ALUMINIUM ISOTOPES
BARYON REACTIONS
BARYONS
BERYLLIUM 10
BERYLLIUM 10 TARGET
BERYLLIUM ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CHARGED-PARTICLE REACTIONS
COSMIC PROTONS
COSMIC RADIATION
DATA
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTARY PARTICLES
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
FERMIONS
HADRON REACTIONS
HADRONS
INFORMATION
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
ISOTOPES
LIGHT NUCLEI
LUNAR MATERIALS
MANGANESE 53
MANGANESE 53 TARGET
MANGANESE ISOTOPES
MATERIALS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUCLEONS
NUMERICAL DATA
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
PROTON REACTIONS
PROTONS
RADIATIONS
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
SOLAR PARTICLES
SOLAR PROTONS
SOLAR RADIATION
STELLAR RADIATION
TARGETS
YEARS LIVING RADIOISOTOPES