Initiation of nuclear reactions under laser irradiation of Au nanoparticles in the aqueous solution of Uranium salt

摘要

Laser exposure of a suspension of either gold or palladium nanoparticles in aqueous solutions of UO_2Cl_2 of natural isotope abundance was experimentally studied. Picosecond Nd:YAG lasers at peak power of 10~(11)-10~(13) W/cm~2 at the wavelength of 1.06-0.355 μm were used as well as a visible-range Cu vapor laser at a peak power of 10~(10) W/cm~2. The composition of colloidal solutions before and after laser exposure was analyzed using atomic absorption and gamma spectroscopy in the 0.06-1 MeV range of photon energy. Real-time gamma spectroscopy was used to characterize the kinetics of nuclear reactions during laser exposure. It was found that laser exposure initiated nuclear reactions involving both ~(238)U and ~(235)U nuclei via different channels in H_2O and D_2O. The influence of saturation of both the liquid and nanoparticles by gaseous H_2 and D_2 on the kinetics of nuclear transformations was found. Possible mechanisms of observed processes are discussed.