Progress report, Chemistry and Materials Division

New results have been obtained by time-of-flight studies for the stopping powers for heavy ions (Ne,Ar) transmitted at O0 through tin, copper and gold foils. It has been shown that complexes formed between vacancies and solute ions can be dissolved by MeV He+ ion irradiation at 70 K. An improved optical absorption spectrum of hypoiodite ion has been obtained. Studies of the radiolysis of gadolinium solutions covered with a vapour space are continuing. Research on hydrogen isotope separation by laser photochemistry and catalytic chemical exchange is going forward. A method for the determination of trace quantities of hexavalent uranium in groundwater and urine has been found. Preliminary experiments have been carried out on zone refining and electrotransport purification of zirconium. Irradiation creep and growth are bieng examined, and an experimental study of recovery in Zircaloy-2 from mechanical deformation has been completed. (LL)