| Popis: |
Absolute values have been obtained for the isotopic abundance ratios of a reference sample of strontium using solid sample thermal ionization mass speelrometry. Samples of independently known isotopic composition prepared from chemically pure and nearly isotopically pure separated strontium isotopes were used to calibrate the mass speelrometry. The resulting absolute 88Sr/86Sr, 87Sr/86Sr, and 84Sr/86Sr ratios are 8.3786 ± 0.0033, 0.71034 ± 0.00026, and 0.05655 ± 0.00014 respectively which yields atom percents of: 88Sr = 82.5845 ± 0.0066, 87Sr = 7.0015 ± 0.0026, 86Sr = 9.8566 ± 0.0034. and 81Sr = 0.5574 ± 0.0015. The atomie weight calculated from these abundances is 87.61681 ± 0.00012. The indicated uncertainties are overall limits of error based on 95 percent confidence limits for the mean and allowances for the effects of possible systematic error. |
