THE MOST COMPACT SCISSION CONFIGURATION OF FRAGMENTS FROM LOW ENERGY FISSION OF 234U AND 236U

THE MOST COMPACT SCISSION CONFIGURATION OF FRAGMENTS FROM LOW ENERGY FISSION OF 234U AND 236U Modesto Montoya Zavaleta DOI: https://doi.org/10.33017/RevECIPeru2009.0001/ RESUMEN Usando una técnica de tiempo de vuelo, Signarbieux et al. midieron el valor máximo de la energía cinética total en función de la masa primaria de los fragmentos de la fisión de baja energía de 234U y 236U. De los cálculos de las configuraciones de escisión, puede concluirse que, para esos dos sistemas físiles, el valor máximo de la energía cinética corresponde a las fragmentaciones 42Mo62, 50Sn80 y 42Mo64, 50Sn80), respectivamente, son iguales a los valores disponibles de energía, y sus configuraciones de escisión están compuestas por un fragmento pesado esférico y un fragmento liviano prolato, ambos en sus estados fundamentales. PALABRAS CLAVE: Fisión a baja energía; 234U; 236U; energía cinética de fragmentos; fisión fría. ABSTRACT Using a time of flight technique, the maximal values of kinetic energy as a function of primary mass of fragments from low energy fission of 234U and 236U were measured by Signarbieux et al. From calculations of scission configurations, one can conclude that, for those two fissioning systems, the maximal value of total kinetic energy corresponding to fragmentations (42Mo62, 50Sn80) and (42Mo64, 50Sn80) respectively, are equal to the available energies, and their scission configurations are composed by a spherical heavy fragment and a prolate light fragment both in their ground state. Keywords: Low energy fission; 234U; 236U; fragment kinetic energy; cold fission.

Intermediate Mass Fragments production at low energy: reaction mechanism and isospin influence

In this work, we present a recent study concerning the break-up of the Projectile-Like (PLF) into two fragments, following more violent deep-inelastic collisions in the reactions 78Kr + 40Ca and 86Kr + 48Ca at 10 A MeV, realized at INFN-Laboratori Nazionali del Sud by using the 4π multi detector CHIMERA. For these systems, we have already analyzed the fusion-evaporation and fission-like processes. A selection method has been developed, in order to discriminate PLF break up events from those due to other mechanisms which populate the same region of the phase- space. A preference for PLF aligned break-up, along the direction of the PLF-TLF separation axis with the light fragment emitted in the backward part, has been put in light, suggesting the presence of dynamical effects. Also a comparison between the neutron-rich 86Kr + 48Ca and neutron-poor 78Kr + 40Ca systems is presented, to put in evidence the isospin role in these processes.