arXiv subjects

G. A. Shafeev

Publications and source records attributed to G. A. Shafeev.

21 records · Page 2Linked to original sources

arXiv2009

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

Laser exposure of suspension of either gold or palladium nanoparticles in aqueous solutions of UO2Cl2 of natural isotope abundance was experimentally studied. Picosecond Nd:YAG lasers at peak power from 1011 to 1013 W/cm2 at the wavelength of 1064 and 355 nm were used as well as a visible-range Cu vapor laser at peak power of 1010 W/cm2. The composition of colloidal solutions before and after laser exposure was analyzed using atomic absorption and gamma spectroscopy between 0.06 and 1 MeV range of photon energy. A 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 238U and 235U nuclei via different channels in H2O and D2O. The influence of saturation of both the liquid and nanoparticles by gaseous H2 and D2 on the kinetics of nuclear transformations was found. Possible mechanisms of observed processes are discussed.

physics.gen-ph↗

arXiv2009

Influence of intensity distribution of laser beam on the properties of nanoparticles obtained by laser ablation of solids in liquids

Control over the properties of nanoparticles obtained by laser ablation in liquids is experimentally demonstrated via modulation of the beam intensity profile on the target. Mask projection scheme was used with either a copper laser (wavelength of 510. 6 nm, pulse duration of 10ns) or with a Ti:sapphire laser (wavelength of 800 nm and pulse duration of 200 fs). Si and ZnSe were chosen as target materials. Obtained nanoparticles were characterized using Transmission Electron Microscopy (TEM), optical absorption spectroscopy and photoluminescence. It was shown that that size of Si nanoparticles depends on the spatial profile of the laser beam.

cond-mat.mes-hall↗

arXiv2009

Initiation of nuclear reactions under laser irradiation of Au nanoparticles in the presence of Thorium aqua-ions

Initiation of nuclear reactions in Thorium nuclei is experimentally studied under laser exposure of Au nanoparticles suspended in the aqueous solution of Th(NO3)4 (232Th). It is found that the reaction pathway depends in which water, either H2O or D2O, the laser exposure is carried out. Saturation of the liquids (H2O or D2O) with gaseous H2 or D2, respectively, enhances the nuclear reactions under laser exposure allowing their excitation at peak intensity as low as 1010 W/cm2. Enhanced gamma-activity of the probe is observed after the end of laser exposure for several hours.

physics.gen-ph↗