Reliability of Mass Spectrometric Determination of Boron Isotope Abundance

摘要

No statistically significant bias in the determination of boron isotope abundance was observed in 22 mass spectrometric analyses of four carefully prepared standards at nominal B11/B10 ratios of 1:1 and 4:1. The uncertainty in a single determination (including precision and a possible bias of as much as ±0.4%) in this range is ±1.3% of the ratio at the 95% confidence level for carefully handled, clean samples when a comparable amount of data is obtained. This corresponds to ±1 relative per cent uncertainty in measuring the B10 abundance of natural boron. This uncertainty in measurement of the abundance can be reduced by making multiple runs on a sample but is limited by the uncertainty concerning bias. The samples were run as sodium tetraborate in the KAPL single-stage mass spectrometer best adapted for the purpose.