Zhemenik V. Kr and Xe isotopes yield in the low-energy photofission of light actinides

The thesis is devoted to research the patterns in yield distributions at photofission of the actinide targets, in the region of light mass peak - krypton isotopes, and heavy mass peak- xenon isotopes. For measurements the original method was developed, with separation of stopped in the buffer gas gaseous products of nuclear reactions, followed by aerosol-free gas transport and activity condensation in cryostat, filled with liquid nitrogen. The yields are calculated using the spectrum of just krypton and xenon isotopes measured in on-line mode, and using the spectrum of their beta-decay products, measured off-line. Corrections are determined, associated with activity decay during transport and with its uneven distribution during freezing along the collector, the absorption of gamma rays in the walls of the collector are considered. Pumping coefficients are determined for process of isobaric chain decay and freezing coefficients and their time dependence from the half-life of the isotopes of krypton and xenon. A study of the processes taking place in a gaseous medium, when intense beam of heavy ions pass through it, is performed. The mechanism of plasma effect in the ion guide ion source is described.