Cosmogenic and Primordial Radionuclides in Lunar Samples by Nondestructive Gamma-Ray Spectrometry

The (7)Be, (22)Na, (26)Al, (44)Ti, (46)SC, (48)V (51)Cr, (54)Mn, (56)Co, (57)Co, (57)CO, (40)K, (238)U, and (232)Th were measured in lunar fines and portions of three rocks. Major production of cosmogenic radionuclides is due to solar protons, thus their concentrations are far different than those in meteorites. Surface exposures of the rocks and fines are long compared with the 0.74 million year half-life of (26)Al. Lunar fines show substantially higher concentrations of low energy reaction products. The ratios of thorium to uranium are extremely constant at 3.8, which indicates very little geochemical differentiation and are in good agreement with a common nucleosynthesis for lunar and earth materials.

Radionuclide Composition of the Allende Meteorite from Nondestructive Gamma-Ray Spectrometric Analysis

The concentrations of beryllium-7, sodium-22, aluminum-26, potassium-40, scandium-46, vanadium-48, chromium-51, manganese-54, cobalt-57, cobalt-60, and thorium-232 (thallium-208) have been measured in the Allende meteorite by nondestructive gamma-ray spectrometry. The high cobalt-60 content of the meteorite is indicative of a preatmospheric body with a minimum effective radius of 50 centimeters and a weight of 1650 kilograms; the aluminum-26 activity indicates a minimum exposure age of 3 million years.

Microsome-associated DNA

Deoxyribonucleic acid has been isolated from the microsomes of mouse liver homogenates under conditions designed to prevent or greatly reduce mitochondrial and nuclear contamination. The DNA rapidly incorporates tritiated thymidine, and this, together with its reannealing characteristics after thermal denaturation, shows that it is not mitochondrial or typically nuclear DNA.