Solopikhin D. High-purity metals for low-background scintillators

Thesis is dedicated to the development of complex processes of deep refining of natural cadmium, cadmium isotopically enriched 106Cd, 116Cd and archaeological Pb which in pure state are components of low- background scintillators. The thesis presents results of computational methods to study distillation process of Cd, 106Cd, 116Cd, аrchPb refinement. Technological methods were established to reduce the composition of volatile and involatile impurities as well as interstitial impurities (gas and carbon) according to the results of computation. The work demonstrates high efficiency of the developed complex method of refinement which includes heating, filtration and distillation, including distillation through getter filter for deep purification of natural and isotope-enriched cadmium and distillation into liquid phase for lead. Pilot sets of high-purity samples of Cd with purity >99.9995 mass% and 106Cd, 116Cd with purity >99.999 mass% and archeological lead with purity >99.9996 mass% were obtained. Problem of non-mechanical grinding of the obtained large-sized distillates is solved. The properties of obtained high-purity samples and single crystals based on them were studied.