Abstract
Pure tin metals were centrifuged at 1 × 106g and at 220°C for 100 hours, at 0.40 × 106g at 220–230°C for 24 hours, and at 0.25 × 106g at 220°C for 24 hours. Their isotopic compositions were measured by a secondary ion mass spectrometer (SIMS). 116Sn/120Sn and 124Sn/120Sn ratios of the 1.02 × 106g sample were considerably different than the initial compositions, and the magnitude of isotopic fractionation reached 2.6 ± 0.1%. A three-isotope diagram of 116Sn/120Sn vs.124Sn/120Sn shows conclusively that isotopic fractionation caused by a gravitational field depended only on the isotopic mass.