ΓnΓffor actinide nuclei using (

Transfer reactions in inverse kinematics: An experimental approach for fission investigations

“…The scattering of these particles off the collimator lead to an overestimation of N f (E x ), although with a more moderated effect because, in this case, the cross-section below the fission barrier is considerably smaller than for 238 U. The restrictions applied in the azimuthal and polar angles of target-like nuclei provided 239 Np fission probabilities in good agreement with previous data [1], without need for a correction factor. Figure 12 shows the fission probabilities obtained in this work, as a function of the total excitation energy available in the exit channel.…”

“…The contributions to the graphical cuts that we used to select the different target-like nuclei are given in Table I. The presence of 16 1 H reactions, as a result of contaminants in the target. The fact that 16 O and 1 H were mostly detected in anticoincidence with a fission fragment, together with the angular distributions measured for these nuclei, suggests that they mainly emerged from elastic reactions.…”

Role of transitional levels inNp237(γ,f): Perspectives for studying highly deformed systems

“…Therefore, the experimental observation of these structures is not an "unexpected" finding, as pointed out elsewhere [10]; (ii) put in evidence the angular momenta selectivity in a photoreaction, which generates a modulation in the transition levels spectra (alternating compression and rarefaction of levels). With hadronic probes, on the contrary, a plethora of uniformly distributed transition levels shows up and, therefore, no structure is observed in low-energy fission cross section, as, e.g., in the reaction 236 U( 3 He,df ) [8,9]. Thus, the argument presented by Soldatov et al [10] to rule out the fission nature of the 5.7-to 5.8-MeV structure in 237 Np (see above) should not be valid at all; (iii) suggest that the Bremsstrahlung derived wide structure at 5.6-6.0 MeV [10] is in fact two unresolved sharper structures, also supported by higher resolution data [15]-see Figs.…”

“…(iv) In the detailed 237 Np (γ,f ) study of Soldatov et al [10], the fission nature of the 5.7-5.8 MeV structure was ruled out, based on the argument that the fission probability of 237 Np measured with other projectiles, as, e.g., in the reaction 236 U ( 3 He, df) [8,9], shows no "irregularity" in this energy region.…”

“…At energies above (but close to) the barrier, structures could be originated from the fission and neutron emission competing channels. However, the most interesting physics is contained in the cross-section irregularities caused by the transition spectrum structure, but the observation of low-energy structures in the fission cross section of odd heavy nuclei, or at least for odd-Z nuclei, has been discarded by means of both experimental and theoretical arguments related to the absence of pairing gap of levels and the high level densities for these nuclei at low energies [8][9][10].…”