title: Primordial radioelements and cosmogenic radionuclides in lunar samples from apollo 15.
abstract: Two basalts, two breccias, and two soils from Apollo 15 were analyzed by nondestructive gamma-ray spectrometry. The concentrations of potassium, thorium, and uranium in the basalts were similar to those in the Apollo 12 basalts, but the potassium: uranium ratios were somewhat higher. Primordial radioelements were enriched in the soils and breccia, consistent with a two-component mixture of mare basalt and up to 20 percent foreign component (KREEP). The abundance patterns for cosmogenic radionuclides implied surface sampling for all specimens. The galactic cosmic-ray production rate of vanadium-48 was determined as 57 +/- 11 disintegrations per minute per kilogram of iron. Cobalt-56 concentrations were used to estimate the intensity of the solar flare of 25 January 1971.
authors.forename: G D
authors.initials: GD
authors.lastname: O'kelley
authors.forename: J S
authors.initials: JS
authors.lastname: Eldridge
authors.forename: E
authors.initials: E
authors.lastname: Schonfeld
authors.forename: K J
authors.initials: KJ
authors.lastname: Northcutt