Absolute isotopic abundance ratios and the atomic weight of a reference sample of chromium

摘要: An absolute value has been obtained for the isotopic abundance ratio of a reference sample rhenium, using surface emission mass spectrometry. Samples known composition, prepared from nearly isotopically pure separated rhenium isotopes, were used to calibrate spectrometers. The resulting 185Ke/187Re is 0.59738±0.00039, which yields atom percents 185Re = 37.398±0.016 and 187Re 62.602±0.016. atomic weight calculated this composition 186.20679±0.00031. indicated uncertainties are overall limits error based on 95 percent confidence mean allowances effects sources possible systematic error.