Determination of the silicon content of geological materials by reactor fast neutron activation analysis

Determining the silicon concentration of geological materials is desirable because the silica (SiO₂) content is an important criterion often used in their classification and in assessing petrogenesis. A rapid, non-destructive, approach for measuring silicon in rocks by reactor fast NAA using a B₄C shield and the transmutation reaction ²⁹Si(n, p)²⁹Al is presented that is competitive with other commonly applied analytical techniques. In addition to quantifying silicon the simultaneous determination of U and Co (largely by epithermal NAA), and Mn and V (by activation predominantly with the residual thermal neutron flux) is also generally possible. Silicon, Mn, U, V and Co concentrations are reported for a number of rock standards demonstrating the utility of the method.