Neutro-capture 128Xe in the Sam Juan mass of the Campo del Cielo IAB Iron meteorite: Evidence for a high fluence of thermalized neutrons

PRAVDIVTSEVA O.; MESHIK A.; HOHENBERG C.; VARELA M.E.; GARADUZZI M.F.

Hosuton

Conferencia; Lunar and Planetary Science Conference; 2017

Galactic Cosmic Rays (GCR)- induced effects provide a means to study the history ofmeteorites as small objects in space or in the top fewmeters of their parent body. Most important are cosmogenic nuclides, produced by interactions of primaryand secondary cosmic ray particles with target atoms.Interactions with high-energy neutrons and protonsusually result in spallogenic nuclides of a lower massthan the original target. Neutron capture of thermal(?¬0.6 eV) or epithermal (up to hundreds of eV) secondary neutrons produces heavier nuclides. Cosmogenic 128Xe produced by capture of low-energy neutrons on 127I has been previously observed in AllendeCAIs [1], lunar dust [2], and the El Taco fragment ofCampo del Cielo [3]. Here we report cosmogenic 128Xefrom neutron capture on 127I in the San Juan fragmentof Campo del Cielo and its correlation with 129Xe fromextinct 129I, a natural I-Xe study.