Search results for "Fission"
showing 10 items of 421 documents
Experiments on Fission Dynamics with Relativistic Heavy-ion Beams
2002
[Abstract] At GSI, Darmstadt, an experimental program on fission with relativistic heavy-ion beams is in progress. A large range of excitation energies, combined with low angular momentum and small shape distortion is accessible. Full nuclide identification of the reaction residues is achieved by applying inverse kinematics. The nuclide production and the kinematics of fission fragments from a variety of primordial and radioactive projectiles reveal new insight into the influence of shell effects and dissipation on the fission process. The present contribution gives an overview on the experimental methods, the experimental results and the prospects for future progress.
Fragment mass distribution in superasymmetric region in proton-induced fission of U and Th
1998
Fission fragment mass distributions down to super-asymmetric mass region and both pre- and post-scission neutron multiplicity for238U(p,fission) reaction atEp = 20, 35, 50, 60 MeV and for232Th(p, fission) reaction atEp = 50, 60 MeV were measured using HENDES set-up. The results indicate enhancement for super-asymmetric mass division at intermediate excitation energies.
Ca48+Bk249Fusion Reaction Leading to ElementZ=117: Long-Livedα-DecayingDb270and Discovery ofLr266
2014
The superheavy element with atomic number Z=117 was produced as an evaporation residue in the 48Ca+249Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allowed measuring decays of single atomic nuclei with half-lives between sub-μs and a few days. Two decay chains comprising seven α decays and a spontaneous fission each were identified and are assigned to the isotope 294-117 and its decay products. A hitherto unknown α-decay branch in 270Db (Z=105) was observed, which populated the new isotope 266Lr (Z=103). The identification of the long-liv…
Superasymmetric fission at intermediate energy and production of neutron-rich nuclei with A < 80
1997
Abstract The yields of neutron-rich Ni, Cu, Zn, Ga and Ge-isotopes were measured in 25 MeV proton induced fission of 238 U using the ion guide-based isotope separator technique. The results indicate enhancement for superasymmetric mass division at intermediate excitation energy of the fissioning nucleus and show the potential of this reaction for the production of neutron-rich exotic nuclei around Z = 28.
Levels in104Ru populated by the ??-decay of104Tc
1978
Theβ− — andγ-activities of 18.4 min104Tc have been studied with singles and coincidence measurements. Sources were prepared by chemical separation of technetium from the fission products of thermal-neutron-induced fission of235U. A revised level scheme of104Ru up to an excitation energy of 4.26 MeV is proposed. Fromβ-γ coincidence measurements, aQβ-value of 5.62±0.07 MeV has been obtained.
Cross section systematics for the lightest Bi and Po nuclei produced in complete fusion reactions with heavy ions
2005
The production of the very neutron-deficient nuclides $^{184\ensuremath{-}192}\mathrm{Bi}$ and $^{186\ensuremath{-}192}\mathrm{Po}$ in the vicinity of the neutron midshell at N = 104 has been studied by using heavy-ion-induced complete fusion reactions in a series of experiments at the velocity filter SHIP. The cross sections for the xn and pxn evaporation channels of the $^{46}\mathrm{Ti}$+$^{144}\mathrm{Sm}$$\ensuremath{\rightarrow}^{190}\mathrm{Po}{}^{*},$$^{98}\mathrm{Mo}$+$^{92}\mathrm{Mo}$$\ensuremath{\rightarrow}^{190}\mathrm{Po}{}^{*},$$^{50,52}\mathrm{Cr}$+$^{142}\mathrm{Nd}$$\ensuremath{\rightarrow}^{192,194}\mathrm{Po}{}^{*}$, and $^{94,95}\mathrm{Mo}$+$^{93}\mathrm{Nb}$$\ensurem…
Decay of the heaviest isotope of neodymium:154Nd
1985
The neutron-rich isotope154Nd has been separated from235U fission products with the HELIum-jet On-line mass Separator HELIOS and investigated by γ-singles, γγ- and γX-coincidence measurements. The Z- and A-assignment have been confirmed by the observation of promethium KX-rays and by the genetic relationship to the daughter product 1.7-min154Pm. A half-life of 26±2 s has been obtained for154Nd, and a partial decay scheme is proposed. A 40 s activity previously assigned to154Nd could not be confirmed.
A study of fusion - fission atZ= 107
1997
An experiment was performed with the EUROGAM II array to investigate the reaction channels that are open in the fusion of a beam on the actinide target at a series of energies around the Coulomb barrier. The symmetric fission products identified from the level structures seem to suggest that a proton and neutrons are emitted prior to fission.
The collective structure of106,108Ru
1984
Levels in106,108Ru have been studied by measuringγγ coincidences andγγ directional correlations of theγ-rays following theβ−-decay of 36 s106Tc and 5 s108Tc. Tc activities were separated chemically from the fission products of thermal neutron induced fission of239Pu by the continuously running system “SISAK 2” and theγ-radiation was measured on-line. An extended level scheme for108Ru, spin assignments,E2/M1 multipole mixing ratios andB(E2) ratios for106Ru and108Ru have been obtained. The collective structure of the two nuclei is discussed in the framework of different nuclear models.
Neutron-rich nuclei and fission; recent developments and future aspects
2002
Production 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 accelarated beams of fission products are discussed.