title: Rare gas record in the largest apollo 15 rock.
abstract: The spallation krypton data from rock chip 15555,23 indicate a wellshielded location during most of the time during which the rock was exposed to cosmic rays. A krypton-krypton exposure age of 81(+17)(-7) x 10(6) years is calculated, and the gas retention ages are estimated. No evidence for the presence of products from plutonium-244 or iodine-129 was found.
authors.forename: K
authors.initials: K
authors.lastname: Marti
authors.forename: B D
authors.initials: BD
authors.lastname: Lightner