Mn-53 and Al-26 evidence for solar cosmic ray constancy - An improved model for interpretationA general, numerical method for calculating activities of solar cosmic ray produced radionuclides at any point within an irregularly shaped lunar rock of known surface contour and lunar surface orientation is described. This method is then used to predict the activities of Mn-53 andAl-26 as a function of postion within lunar rock 68815 for various assumed values of solar cosmic ray flux (J), rigidity (R sub 0), and rock erosion rate (ER). The predicted activities agree with the measured activities of Kohl et al. (1978) when values of R sub 0 = 100 MV, J = 70 p/sq cm-sec (4 pi, E greater than 10 MeV), ER not greater than 1 mm/m.y. and a total exposure time of 2 m.y. are assumed. These values are in agreement with those found for rocks exposed for not less than 10 m.y. and provide no evidence for variation of the average solar cosmic ray parameters between the last 2 and 10 m.y. intervals. When interpreted with the improved model the activity vs. depth profiles for three faces of 68815 show no evidence of SCR anisotropy or differential erosion.
Document ID
19810064424
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Russ, G. P., III (Hawaii, University; Hawaii Institute of Geophysics, Honolulu, HI, United States)
Emerson, M. T. (Hawaii, University; Hawaii Institute of Geophysics, Honolulu, HI; Alabama, University, Huntsville, AL, United States)
Date Acquired
August 11, 2013
Publication Date
January 1, 1980
Subject Category
Lunar And Planetary Exploration
Meeting Information
Meeting: Conference on The ancient sun: Fossil record in the earth, moon and meteorites