Neutron activation analysis of the 30Si content of highly enriched 28Si:   proof of concept and estimation of the achievable uncertainty
  We investigated the use of neutron activation to estimate the 30Si mole fraction of the ultra-pure silicon material highly enriched in 28Si for the measurement of the Avogadro constant. Specifically, we developed a relative method based on Instrumental Neutron Activation Analysis and using a natural-Si sample as a standard. To evaluate the achievable uncertainty, we irradiated a 6 g sample of a natural-Si material and modeled experimentally the signal that would be produced by a sample of the 28Si-enriched material of similar mass and subjected to the same measurement conditions. The extrapolation of the expected uncertainty from the experimental data indicates that a measurement of the 30Si mole fraction of the 28Si-enriched material might reach a 4% relative combined standard uncertainty. 
Giancarlo D'Agostino, Giovanni Mana, Massimo Oddone, Michele Prata,   Luigi Bergamaschi, Laura Giordani
physics.chem-ph physics.ins-det