학술논문
Sequential fission and the influence of 208Pb closed shells on the dynamics of superheavy element synthesis reactions
Document Type
article
Author
D.Y. Jeung; D.J. Hinde; M. Dasgupta; C. Simenel; E.C. Simpson; K.J. Cook; H.M. Albers; J. Buete; I.P. Carter; Ch.E. Düllmann; J. Khuyagbaatar; B. Kindler; N. Lobanov; B. Lommel; C. Mokry; E. Prasad; J. Runke; C. Sengupta; J.F. Smith; P. Thörle-Pospiech; N. Trautmann; K. Vo-Phuoc; J. Walshe; E. Williams; A. Yakushev
Source
Physics Letters B, Vol 837, Iss , Pp 137641- (2023)
Subject
Language
English
ISSN
0370-2693
Abstract
Measured binary quasifission mass spectra in reactions with actinide nuclides show a large peak in yield near the doubly-magic 208Pb. This has generally been attributed to the enhanced binding energy of 208Pb causing a valley in the potential energy surface, attracting quasifission trajectories. To investigate this interpretation, binary quasifission mass spectra and cross-sections have been measured at near-barrier energies for reactions of 50Ti with actinide nuclides from 238U to 249Cf. Cross-sections have also been deduced for sequential fission (a projectile-like nucleus and two fragments from fission of the complementary target-like nucleus). Binary cross-sections fall from ∼70% of calculated capture cross-sections for 238U to only ∼40% for 249Cf, with a compensating increase in sequential fission cross-sections. The data are consistent with the 208Pb peak originating largely from sequential fission of heavier fragments produced in more mass-asymmetric primary quasifission events. These are increasingly suppressed as the heavy quasifission fragment mass increases above 208Pb. The important role of sequential fission calls for re-interpretation of quasifission characteristics and dynamics in superheavy element synthesis reactions.