TVEL, a Rosatom Fuel Company, Successfully Completed Work within the AVOGADRO Project

The main objective of the project is defining the Avogadro Constant with the minimum error of 2x10-8, which is 15 times more precise than the existing physical standard. The physical standard currently used is a platinum-iridium cylinder having relatively unstable parameters that change in the course of time, so that physicists and chemists have to constantly adjust their calculations.
It follows thence, that reducing the measure of inaccuracy in defining the Avogadro constant will allow increasing the precision of the unit of mass, thus making calculations easier for specialists from different fields of applied science. It is not by chance that Centrotech-Spb was chosen to perform one of the key stages in defining the constant.
Specialists from this institute provided a scientific and economic justification for a solution involving calculation of the mass of a certain number of atoms in Si-28 isotope. This material can be created through enrichment of silicon tetrafluoride, a natural isotopic composition. Specialists from the institute designed and manufactured unique equipment – centrifuges for separating stable isotopes, and received isotope-free Si-28. Its isotopic and chemical purity was 10-fold and 50% higher than that required in accordance with the specifications. After that, the crystal was provided to foreign participants of the project for final analyses, treatment and further research.
It is worth mentioning that enriched Si-28 was originally produced for a different task. That was a by-product of heterogeneous technologies for the creation of a quantum super-computer of the future. Besides, during the development of the source material specialists from the institute prepared a range of scientific materials and Si-29, Si-28 and Si-30 samples related to the problem and needed throughout the world for research purposes.
Specialists expect that the new Avogadro constant will be approved and introduced by CIPM International Board of Directors by the end of 2010. Alexei Kaliteyevsky, Director General of Centrotech-Spb CJSC, pointed out: “We have done a most difficult job, indeed. I am proud of all our participants of the project. A great task has been solved! And we are pleased of the fact that it is the involvement of Russian scientists that permitted to find a way out of the complicated situation and teamwise determine the mass of one atom so precisely”.