Astromat

Accelerator mass spectrometry analysis of 36Cl concentrations in six sub-samples from aggregate sample OEX-803014-0. The samples include one bulk aggregate sample, OREX-803047-0, and 5 individual mm-sized particles (OREX-803048-0, OREX-803049-0, OREX-803050-0, OREX-803051-0, OREX-803052-0). For comparison, we also measured two aliquots of the Orgueil CI chondrite. The samples were dissolved in HF/HNO3 and a small aliquot of the dissolved sample was taken for chemical analysis by ICP-OES. The 36Cl concentrations in the particles range from 78 to 157 dpm/kg, compared to a 36Cl concentration of 91 dpm/kg in the aggregate sample. The high 36Cl concentrations indicate that 36Cl is dominated by neutron-capture production on 35Cl in the top 1-2 m of Bennu's surface.