Study of fusion reactions forming Cf nuclei

Abstract

Abstract. The formation of a compound nucleus in different projectile and target combinations is a powerful method for investigating the fusion process. Recently, the dominance of quasi-fission over fusion-fission has been inferred for 34 S+ 208 Pb in comparison to 36 S+ 206 Pb; both reactions lead to the compound nucleus 242 Cf * . The mass and angle distributions of the fission fragments from these reactions were studied in order to further investigate the presence of quasi-fission.

Nuclear structure dependence of fusion hindrance in heavy element synthesis

“…Likewise, it confirms the earlier conclusions on the presence of slow QF in the S + Pb reactions made in Refs. [23,26,27].…”

“…Fusion-evaporation cross sections of the 36 S + 206 Pb reaction have been found to be ≈10-10 2 times greater than those of 34 S + 208 Pb over a wide range of CN excitation energies [23,25]. Based on a series of experimental studies on evaporation-residue and fission cross sections [23,[25][26][27], a higher QF contribution for 34 S + 208 Pb has been proposed to conserve Bohr's hypothesis [19] that W CN is the same for both reactions.…”

“…No evidence for an increased presence of QF in 34 S + 208 Pb has been observed in experimental mass-angle distributions (MADs) of fission fragments [23,26,27]. It has been suggested, therefore, that collisions in the S + Pb reactions that result in QF have long sticking times (slow QF), causing a strong overlap between QF and FF observables and rendering any QF dominance in the 34 S + 208 Pb reaction impossible to detect [23,26,27]. Thus, experimental signatures of differing fusion probabilities in very similar reactions forming the same CN, which would uniquely resolve these issues, have been urgently sought.…”