Records of ancient cosmic radiation in extraterrestrial rocks

Bhandari, Narendra (1991) Records of ancient cosmic radiation in extraterrestrial rocks Proceedings of the Indian Academy of Sciences - Earth and Planetary Sciences, 90 (3). pp. 359-382. ISSN 0253-4126

PDF - Publisher Version

Official URL:

Related URL:


Recent results on cosmic ray interactions in lunar samples and meteorites resulting in production of stable and radionuclides, particle tracks and thermoluminescence are reviewed. A critical examination of26A1 depth profiles in lunar rocks and soil cores, together with particle track data, enables us to determine the long term average fluxes of energetic solar protons (>10 MeV) which can be represented by (J s,R o) = (125, 125). The lunar rock data indicate that this flux has remained constant for 5 × 105 to 2 × 106 years. Production rates of stable and radionuclides produced by galactic cosmic rays is given as a function of size and depth of the meteoroid. Radionuclide (53Mn,28Al) depth profiles in meteorite cores, whose preatmospheric depths are deduced from track density profiles are used to develop a general procedure for calculating isotope production rates as a function of meteoroid size. Based on the track density and 22Ne/21Ne production rates, a criterion is developed to identify meteorites with multiple exposure history. 22Ne/21Ne ratio <1.06 is usually indicative of deep shielded exposure. An examination of the available data suggests that the frequency of meteorites with multiple exposure history is high, at least 15% for LL, 27% for L and 31% for H chondrites. The epi-thermal and the thermal neutron density profiles in different meteorites are deduced from 60Co and track density data in Dhajala, Kirin and Allende chondrites. The data show that the production profile depends sensitively on the size and the chemical composition of the meteoroid. Cosmic ray-induced thermoluminescence in meteorites of known preatmospheric sizes has been measured which indicates that its production profile is nearly flat and insensitive to the size of the meteoroid. Some new possibilities in studying cosmic ray implanted radionuclides in meteorites and lunar samples using resonance ionisation spectroscopy are discussed.

Item Type:Article
Source:Copyright of this article belongs to Indian Academy of Sciences.
Keywords:Solar Cosmic Rays; Meteorites; Particle Tracks; Thermoluminescence; Lunar Samples; Radioactivity; Resonance Ionisation Spectroscopy
ID Code:18432
Deposited On:17 Nov 2010 09:09
Last Modified:17 May 2016 03:09

Repository Staff Only: item control page