The Isotopic Constitution of Silicon, Germanium, and Hafnium

Abstract

The isotopic constitutions of silicon, germanium, and hafnium have been measured with a mass spectrometer by techniques which are described. Results for silicon are in good agreement with certain of the earlier determinations but are in poor agreement with the values adopted in the recent compilation by Bainbridge and Nier. Results for germanium do not differ significantly from earlier determinations. Results for hafnium differ only slightly from the one previous determination in which electrical detection was used, but in such a way as to suggest that determinations on hafnium which has been fractionally purified with respect to zirconium may not be faithfully representative of the true abundances. An upper limit of 0.003 percent has been placed on the abundance in nature of ${\mathrm{Hf}}^{182}$.