Elemental characterization of the Avogadro silicon crystal WASO 04 by neutron activation analysis
arXiv:1301.2693 · doi:10.1088/0026-1394/49/6/696
Abstract
Analytical measurements of the 28Si crystal used for the determination of the Avogadro constant are essential to prevent biased results or under-estimated uncertainties. A review of the existing data confirms the high-purity of silicon with respect to a large number of elements. In order to obtain a direct evidence of purity, we developed a relative analytical method based on neutron activation. As a preliminary test, this method was applied to a sample of the Avogadro crystal WASO 04. The investigation concerned twenty-nine elements. The mass fraction of Au was quantified to be 1.03(18) x 10-12. For the remaining twenty-eight elements, the mass fractions are below the detection limits, which range between 1 x 10-12 and 1 x 10-5.
11 pages, 1 figure, 4 tables