Description:
AbstractX‐ray diffraction, electron diffraction and microscopy, metallography, and thermal methods were utilized to study transmutation effects in a group of crystalline solids. Nearly homogeneous distributions of transmuted species were introduced into small single crystals of Au197, Ag107, and In115, and power samples of Ir193, InO3, and LuO3. The crystals were irradiated in a thermal neutron flux of 4.0 × 1014 neutrons/cm2s at a temperature of ∼ 85 °C for periods of a few days to several months so that considerable fractions of transmuted species were formed.Small metal single crystal spheres were converted to alloy single crystals in their solid solution ranges at temperatures up to several hundred degrees below those required by normal laboratory methods in Au0.82 Hg0.18, Ag0.78 Cd0.22, and In0.95 Sn0.05. A powder sample of Ir193 was transformed into the solid solution alloy Ir0.68 Pt0.32, a high temperature alloy, which would require a temperature in excess of 2000 °C for its formation by laboratory methods.The production of 22.5 at.% Hg198 and Hg199 in Au197 through nuclear transmutation revealed the nucleation of Au3Hg particles with the hcp structure, while the introduction of 29 at.% caused a recrystallization into two unidentified phases. Long range order in single crystals of In115 was completely destroyed when 14 at.% Sn116 was introduced through nuclear transmutation.Powder specimens of In2O3 enriched in In115 were irradiated to produce concentrations of Sn116 as high as 38 (metal) at.% with the result that a new phase with a smaller fluorite structure was formed which contains oxygen vacancies. The original In2O3 structure was largely recovered upon annealing at 1200 °C and SnO2 particles were precipitated. Powder samples of Lu2O3 containing Lu176 were irradiated to produce 74 (metal) at.% Hf177 and the resultant material was cubic (fluorite) with a lattice parameter approximately one‐half that of the original structure. This oxygen deficient lattice was stable at temperatures up to 1200 °C.The results are considered in terms of the original crystal structures and known phase equilibrium systems, and possible future experiments are discussed.