A feasibility study for the measurement of the 30Si mole fraction of the AVO28 material by Instrumental Neutron Activation Analysis

The possibility of using neutron activation to experimentally determine the 30Si mole fraction of the ultra-pure silicon AVO28 material highly enriched in 28Si that being used for the determination of the Avogadro constant has been investigated. Specifically, a 6 g sample of a natural silicon material (WASO04) was irradiated and measured to model the expected signal that would be produced in a sample of the AVO28 material of similar mass and subjected to the same experimental conditions. Data from this experiment has been used to evaluate the contributions which are expected to dominate the measurement uncertainty. The measurement of the 30Si mole fraction of the AVO28 material by neutron activation appears to be feasible and the provisional relative uncertainty is evaluated to be about 3%.