G.G.Devyatykh Institute of Chemistry of High-Pure Substances of RAS

Abstracts：
Feasibility study of  the recovery of stable isotopes  of silicon, germanium and molybdenum from their isotope-enriched volatile fluorides in hydrogen plasmas sustained by different discharges is discussed. The starting substances in all cases are volatile fluorides SiF4, GeF4 and MoF6. The enrichment is carried out by centrifugal method. The results of deposition of 28Si, 74Ge and 72Ge isotopes in form of films and bulk material (“flakes”) in ECR, RF-IC and RF-Arc discharges are discussed. Method is more appropriated for production of germanium because of higher efficiency of its fluoride decomposition in plasma, relative low melting temperature and less chemical activity of germanium. Samples of single crystals of  74Ge and 72Ge isotopes of semiconductor grade were obtained due to Czokhralski growth. In the second part of the report application of developed plasma-chemical method to manufacturing of 98Mo from its hexafluoride is discussed. This isotope is important from point of view of production of radioactive 99Mo and after the following decay of 99mTc isotope for medical applications. Synthesis of 98Mo and its carbide nanoparticles  in hydrogen plasma as well as their characterization is discussed.

Brief bio:
Professor Petr G. Sennikov is a Head of Laboratory for Plasma-Chemical preparation of high-purity substances at Institute of Chemistry of High-Purity Substances of Russian Academy of Sciences (IChPS RAS) in Nizhny Novgorod. He graduated from Nizhny Novgorod State University, Chemistry Department, in 1973 and received a PhD at this University in 1980 in the field of molecular spectroscopy of organo-metallic compounds.
He received next academic degree D.Sc. (chem.) in 1994 at IChPS RAS in the field of IR spectroscopy of liquefied hydrides of IV-VI Group elements using in electronic industry.
Since 1993 he is engaged in different aspects of preparation and characterization of isotopic-enriched silicon and later germanium by CVD method. He was the manager of the first international Avogadro project in 2000-2003 with the scope of development of silicon based mass reference.
Since 2007 he is engaged in the development of plasma-chemical approach for one-step preparation of different stable isotopes from their volatile compounds, first and foremost from their fluorides.
He has published more than 200 papers.

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