Determination of Fusion Barrier Distributions from Quasielastic Scattering Cross Sections towards Superheavy Nuclei Synthesis

Search for elements 119 and 120

“…The beam energy which we chose for the 50 Ti + 249 Bk and 50 Ti + 249 Cf reactions corresponds to ≈1.05V B (V B = 223.7 MeV) and 1.04V B (V B = 226.2 MeV), respectively. These values are within the above-mentioned energy range where fusion is predicted to be enhanced according to the results from the experiment [58] and the theory [61]. Therefore, it is unlikely that the used beam energy was the major reason for the nonobservation of elements 119 and 120.…”

“…[60]. The recently measured barrier distribution of the 48 Ca + 248 Cm reaction shows that the distribution's centroid is located at an energy slightly greater than V B [58]. This is due to the deformation of the target nucleus, which provides two distinct collision geometries: tip and side.…”

“…3(a) correspond to various projectile energies, each optimal for a given reaction and CN. In fact, in almost every 48 Ca +actinide reaction, ERs were observed at projectile energies up to 10 MeV above the fusion barrier (V B ) [57], i.e., (1.00-1.07)V B [1,58,59]. These energies then correspond to E * in the range of [35][36][37][38][39][40][41][42][43][44][45] MeV.…”

“…One of them is the need to use fusion-evaporation reactions with projectiles heavier than 48 Ca [17][18][19], because of insufficient amounts of materials of elements with appropriate proton numbers, Z > 98, to make a target [20]. With this constraint, the four different reactions 64 Ni + 238 U [21], 58 Fe + 244 Pu [22], 54 Cr + 248 Cm [23], and 50 Ti + 249 Cf [24] have already been examined for the synthesis of SHE with Z = 120. However, none of these experiments provide evidence for the synthesis of the new element.…”

“…48 Ca + 197 Au -249 Cf54 Cr + 248 Cm58 Fe + 244 Pu64 Ni + 238 U50 Ti + 249 Bk50 Ti + 249 Cf 3n or maximum σ 4n of48 Ca-induced reactions with actinide targets[1,[5][6][7][8][9][10][11][12][13][14][15][16]51] and with 197 Au[53]. Present experimental cross-section sensitivities for50 Ti + 249 Bk and50 Ti + 249 Cf are shown together with those of the54 Cr + 248 Cm[23],58 Fe + 244 Pu[22],64 Ni + 238 U[21], and48 Ca + 232 Th[52] reactions. Proton numbers of compound nuclei formed in these reactions are indicated.…”