Purity of (28)Si-Enriched Silicon Material Used for the Determination of the Avogadro Constant.
At present, counting atoms in a one-kilogram sphere made of (28)Si-enriched silicon allows the determination of the Avogadro constant with the 2.0 × 10(-8) relative standard uncertainty required for the realization of the definition of the new kilogram. With the exception of carbon, oxygen, boron, nitrogen, and hydrogen, the claimed uncertainty is based on the postulation that the silicon material used to manufacture the sphere was above a particular level of purity. Two samples of the silicon were measured using instrumental neutron activation analysis to collect experimental data to test the purity assumption. The results obtained in two experiments carried out using different research reactor neutron sources are reported. The analysis confirmed that the silicon material was of sufficient purity by quantifying the ultratrace concentration of 12 elements and determining the detection limits of another 54 elements.
Istituto Nazionale di Ricerca Metrologica (INRIM) , Strada delle Cacce 91, 10135 Torino, Italy.
Giancarlo
G
D'Agostino
Istituto Nazionale di Ricerca Metrologica (INRIM) , Strada delle Cacce 91, 10135 Torino, Italy.|Department of Chemistry, University of Pavia , Via Taramelli 12, 27100 Pavia, Italy.
Marco
M
Di Luzio
Istituto Nazionale di Ricerca Metrologica (INRIM) , Strada delle Cacce 91, 10135 Torino, Italy.
Giovanni
G
Mana
Department of Chemistry, University of Pavia , Via Taramelli 12, 27100 Pavia, Italy.
Massimo
M
Oddone
Australian Nuclear Science and Technology Organisation (ANSTO) , New Illawarra Road, Lucas Heights, New South Wales 2234, Australia.
John W
JW
Bennett
Australian Nuclear Science and Technology Organisation (ANSTO) , New Illawarra Road, Lucas Heights, New South Wales 2234, Australia.
Attila
A
Stopic