SGER: Redetermining the Half-Life of 187 Re

与许多广泛使用的地质年代计相比，实验测定的187 Re半衰期的不确定性（4.23 ± 0.13 x 10 E10年; Lindner等人，1986年，1989年）是大（~3%）。这种不确定性目前限制了Re-Os系统作为精密计时器的应用。该提案要求支持使用Lindner等人（1986年，1989年）在实验测定187 Re半衰期时最初使用的1 kg Re进行187 Re半衰期的实验测定。将等分试样密封在配有密封条的玻璃蒸馏器中，以防止储存期间挥发性Os损失。储存期为0.5-2.5年足以产生187 Os/ 188 Os 1在所有除第一个实验，确保187 Os/ 188 Os的精度是不受限制的丰度放射性187 Os。五个独立的测定187 Re半衰期将使用等离子体电离多集电极质谱法对最初的Os-自由过氧酸。使用这种方法的187 Re半衰期的预期总体不确定性为0.4%。

Peucker-EhrenbrinkEAR-0228307In contrast to many widely used geochronometers, the uncertainty in the experimentally determined half-life of 187 Re (4.23 plus or minus 0.13 x 10E10 yr; Lindner et al., 1986, 1989) is large (~3%). This uncertainty currently limits the application of the Re-Os system as a precise chronometer. This proposal requests support for an experimental determination of the 187 Re half-life using 1 kg of Re originally used by Lindner et al. (1986, 1989) in their experimental determination of the 187 Re half-life. The aliquots will be sealed in glass stills equipped with break seals to prevent loss of volatile Os during storage. Storage periods of 0.5-2.5 years are sufficient to generate 187 Os/ 188 Os 1 in all except the first experiment, ensuring that the precision on the 187 Os/ 188 Os is not limited by the abundance of radiogenic 187 Os. Five independent determinations of the 187 Re half-life will be made using plasma ionization multicollector mass spectrometry on initially Os-free perrhenic acid. The expected overall uncertainty of the 187 Re half-life using this approach is 0.4%.