Search results for "fission"
showing 10 items of 421 documents
Reactor neutrino background at the proposed LAGUNA sites
2012
Abstract The electron antineutrino background from reactors is estimated in proposed LAGUNA sites using commercial fission reactors operational in 2009. Calculations are made for an input to background studies like e.g. geoneutrino measurement uncertainty estimation.
The probability of prompt and delayed fission of muonic237Np
1991
Fission fragments from the reaction237Np(μ−,γ,f) have been measured in coincidence with muonic X-rays. The efficiency of the fission fragment detector is determined from (μ−,γ,f)-data of the same experiment. The total fission probability perμ-stopPt has been measured as well as the fission probabilities Pf of the non-radiative muonic (3d→1s)- and (2p→1s)-transitions; the latter has been divided into two parts leading to different mean excitation energiesE:P t =(54±17)%,P f (3d→1s)=(41±21)%,P f (2p→1s,E=6.218 MeV)=(61±19)%, andP f (2p→1s,E=6.525 MeV)=(57±18)%. The influence of the muon on the fission barrier is discussed. The fission probability after muon capture is compared with a calculat…
Search for superheavy elements in damped collisions betweenU238andCm248
1986
Negative results for the production of superheavy elements in damped collisions between $^{238}\mathrm{U}$ projectiles and $^{248}\mathrm{Cm}$ targets are reported. This reaction was believed to permit a closer and more widespread approach to the predicted island of stability near Z=114 and N=184 than any practical fusion reaction. Aqueous and gas phase chemistry techniques were used to isolate superheavy element fractions. The fractions were counted for spontaneous fission activity, fragment kinetic energies, and neutron multiplicities. Cross-section limits for half-lives from hours to several years are g4\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}35}$ ${\mathrm{cm}}^{…
Neck fragmentation in fission and quasifission of heavy and superheavy nuclei
2009
The 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 86 Kr + 206 Pb at E Kr = 500 and 600 MeV. It was found th…
Independent Fission Yield Measurements
1986
Various methods to measure independent yields are reviewed and discussed. A survey on actual measurements carried out after 1978 is given.
Fission fragment angular distribution of 232Th(n,f) at the CERN n TOF facility
2014
The angular distribution of fragments emitted in neutron-induced fission of 232Th was measured in the white spectrum neutron beam at the n_TOF facility at CERN. A reaction chamber based on Parallel Plate Avalanche Counters (PPAC) was used, where the detectors and the targets have been tilted 45 degrees with respect to the neutron beam direction in order to cover the full angular range of the fission fragments. A GEANT4 simulation has been developed to study the setup efficiency. The data analysis and the preliminary results obtained for the 232Th(n,f) between fission threshold and 100 MeV are presented here.
(e,e'f) Coincidence experiments on 235U and 238U
1990
Abstract Coincidence experiments for (e, e'f) on the actinide nuclei 235 U and 238 U have been performed at the Mainz Microtron (MAMI A) concentrating on three subjects: multipole strength distributions and form factors for the lowest multipolarities, the mass split in the fission decay of various giant multipole resonances, and the separation of near barrier fission channels. Data were taken at four values of momentum transfer ( q eff ≈ 0.20, 0.28, 0.53, and 0.71 fm −1 for 238 U, q eff ≈ 0.20, 0.44, 0.57, and 0.71 fm −1 for 235 U) for excitation energies ω = 4–22 MeV. The fission fragments have been detected using the Giessen PPAC-Ball. A model-independent multipole analysis yields both fo…
Manifestations of Clustering in Fission of Excited Actinides
2003
A new, graphical way of extracting important physical information from the total kinetic-energy—mass (TKE—M) distributions of the nuclear reaction products is presented. The resulting images indicate for the first time the presence of the Ni—Mo and Ge—Mo fission modes in the fission of Np nuclei at intermediate excitation energies.
New nuclideHa263
1992
A new nuclide $^{263}\mathrm{Ha}$ was produced in the bombardment of a $^{249}\mathrm{Bk}$ target with 93-MeV $^{18}\mathrm{O}$ ions. It was detected via spontaneous fission counting and was shown to have a half-life of about 0.5 min. This activity was also separated from the reaction products by automated rapid chemical separations using cation-exchange chromatography in 0.05M \ensuremath{\alpha}-hydroxyisobutyric acid. After chemical separation, $^{263}\mathrm{Ha}$ was found to decay by spontaneous fission (${57}_{\mathrm{\ensuremath{-}}15}^{+13}$%) and by \ensuremath{\alpha} emission (${\mathit{E}}_{\mathrm{\ensuremath{\alpha}}}$=8.35 MeV, 43%) with a half-life of ${27}_{\mathrm{\ensurem…