87 research outputs found
Neck fragmentation in fission and quasifission of heavy and superheavy nuclei
No full textThe generalized approach is proposed for the ternary fission and the neck fragmentation of the dinuclear system formed in the heavy ion quasifission reactions. The light-charged-particles accompanied the fission and quasifission are the valuable probes for studies of the dynamics of the hyperdeformed nuclear configurations with neck. The developed model describes well the light-charged-particle emission probabilities and their mass distributions in the ternary fission of actinide nuclei. The model is also applied to analyze the double differential distributions of the protons and α-particles accompanied fragmentation in the reaction 86Kr + 206Pb at EKr = 500 and 600 MeV. It was found that the near scission emission multiplicities of α-particles are and 0.070 ± 0.005 at lower and higher energies, respectively. The neck emission of the protons was not detected
Independent isotopic yields in 25 MeV and 50 MeV proton-induced fission of natU
No full textIndependent isotopic yields for elements from Zn to La in the 25 MeV proton-induced fission of natUnatU were determined with the JYFLTRAP facility. In addition, isotopic yields for Zn, Ga, Rb, Sr, Zr, Pd and Xe in the 50 MeV proton-induced fission of natUnatU were measured. The deduced isotopic yield distributions are compared with a Rubchenya model, the GEF model with universal parameters and the semi-empirical Wahl model. Of these, the Rubchenya model gives the best overall agreement with the obtained data. Combining the isotopic yield data with mass yield data to obtain the absolute independent yields was attempted. The result depends on the mass yield distribution.peerReviewe
Light Particle Accompanied Quasifission in Superheavy Composite Systems
No full textThe dynamics of the excited superheavy system with Z = 118 in the reaction Kr-86 + Pb-208 at E-Kr = 460, 500, and 600 MeV has been investigated. The mass and kinetic energy of binary fragments were measured by the time-of-flight method. Double-differential distributions of protons and a particles were measured in coincidence with fragments. The proton spectra can be described considering only evaporation from fragments. Evidence of the neck fragmentation was obtained from analysis of double-differential a spectra. Properties of the alpha-particle neck fragmentation component are close to those known from the tertiary fission of actinide nuclei, but the multiplicity is much larger than can be expected from extrapolation of the ternary fission data
Fragment mass distribution in 238U(d,pf) reaction at Ed = 124 MeV
No full textMass‐energy distributions of fission fragments in the deuteron induced fission of 238U at deuteron energy 124 MeV have been measured. For better understanding of the reaction mechanism, the inclusive proton spectra and proton spectra in coincidence with fission fragments were measured in the experiment
Neutron-rich nuclei and fission: recent developments and future aspects
No full textProduction and studies of neutron-rich nuclei produced in fission are reviewed. Some recent experiments performed with the ISOL technique at the IGISOL and the ISOLDE facilities are reviewed. The manipulation of neutron-rich nuclei is discussed with a special focus on radioactive ion cooling and trapping techniques under construction worldwide. Perspectives of obtaining intense post accelerated beams of fission products are discussed. (50 refs)
Proton induced fission of 232Th at intermediate energies
No full textThe mass-energy distributions and cross sections of proton-induced fission of Th-232 have been measured at the proton energies of 7, 10, 13, 20, 40, and 55 MeV. Experiments were carried out at the proton beam of the K-130 cyclotron of the JYFL Accelerator Laboratory of the University of Jyvakyla and U-150m cyclotron of the Institute of Nuclear Physics, Ministry of Energy of the Republic of Kazakhstan. The yields of fission fragments in the mass range A = 60- 170 a.m.u. have been measured up to the level of 10(-4)%. The three humped shape of the mass distribution up has been observed at higher proton energies. The contribution of the symmetric component grows up with increasing proton incident energy; although even at 55 MeV of proton energy the shoulders in the mass energy distribution clearly indicate the asymmetric fission peaks. Evolution of shell structure was observed in the fission fragment mass distributions even at high excitation energy
- …
