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Measuring excitation functions needed to interpret cosmogenic nuclide production in lunar rocksRadionuclides produced in lunar rocks by cosmic ray interactions are measured using Accelerator Mass Spectrometry or gamma-ray spectroscopy. From these measurements, estimates of the solar proton flux over time periods characterized by the half-life of the isotope under study can be made, if all the cross sections for all the reactions of all cosmic ray particles with all elements found in lunar rocks are known. Proton production cross sections are very important because (approximately) 98% of solar cosmic rays and (approximately) 87% of galactic cosmic rays are protons in the lunar environment. Many of the needed cross sections have never been measured. Targets of C, Al, Si, SiO2, mg, K, Ca, Fe and Ni have been irradiated using three accelerators to cover a proton energy range of 25-500 MeV. Excitation functions for Be-7, Be-10, Na-22, and Al-26 production from Mg and Al will be reported, and the consequences of using these new cross section values to estimate solar proton fluxes discussed.
Document ID
19970034842
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Sisterson, J. M.
(Harvard Univ. Cambridge, MA United States)
Kim, K.
(San Jose State Univ. CA United States)
Beverding, A.
(San Jose State Univ. CA United States)
Englert, P. A. J.
(San Jose State Univ. CA United States)
Caffee, M. W.
(Lawrence Livermore National Lab. Livermore, CA United States)
Vincent, J.
(British Columbia Univ. Vancouver, British Columbia Canada)
Castaneda, C.
(California Univ. Davis, CA United States)
Reedy, R. C.
(Los Alamos National Lab. NM United States)
Date Acquired
August 17, 2013
Publication Date
January 1, 1997
Subject Category
Lunar And Planetary Exploration
Report/Patent Number
NAS 1.26:205619
DE97-003394
NASA-CR-205619
CONF-961110-24
LA-UR-97-79
Meeting Information
Meeting: Application of Accelerators In Research and Industry
Location: Denton, TX
Country: United States
Start Date: November 6, 1996
End Date: November 9, 1996
Accession Number
97N30065
Funding Number(s)
CONTRACT_GRANT: NAGw- 4609
CONTRACT_GRANT: W-7405-eng-48
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
Radiation Flux
Solar Protons

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