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Title: Results on the Influence of Neutron-Richness on Quasifission in Intermediate Mass Reactions

Abstract

Superheavy elements are primarily formed through heavy ion fusion reactions(1-3). Formation of a fully equilibrated compound nucleus is a critical step in this reaction mechanism but can be hindered by orders of magnitude by quasifission, a process in which the dinuclear system breaks apart prior to full equilibration(1'4-8). To provide a complete description of heavy-ion fusion it is important to characterize the quasifission process. The interplay between the fusion-fission and quasifission reaction channels was explored by measuring fission mass distributions in eight different combinations of Cr+W reactions, with varying neutron-richness, at the Australian National University. The reactions were measured in two energy regimes: one at 13% above the Bass fusion barrier(9) and one at 52.0 MeV of excitation energy in the compound nucleus, E-CN*. For the systems measured at E-c.m./V-Bass = 1.13 the dependence on the neutron-richness is clear(10). However, for the reactions at E-CN* = 52.0 MeV, the dependence is less clear and additional factors are shown to play a vital role, especially the influence of deformation on the effective fusion barrier. The present work demonstrates that quasifission is an important process in competition with heavy-ion fusion in reactions with intermediate mass projectiles, particularly with more neutron-rich systems.

Authors:
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Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Nuclear Physics; National Science Foundation (NSF); Australian Research Council; USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1467895
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Conference
Resource Relation:
Conference: 6th International Conference on Fission and Properties of Neutron-Rich Nuclei, 11/06/16 - 11/12/16, Sanibel Island, FL, US
Country of Publication:
United States
Language:
English
Subject:
Heavy-ion reactions; quasifission

Citation Formats

Hammerton, K. M., Morrissey, D. J., Kohley, Z., Wakhle, A., Stiefel, K., Hinde, D. J., Dasgupta, M., Williams, E., Carter, I. P., Cook, K. J., and Greene, J. Results on the Influence of Neutron-Richness on Quasifission in Intermediate Mass Reactions. United States: N. p., 2018. Web. doi:10.1142/9789813229426_0053.
Hammerton, K. M., Morrissey, D. J., Kohley, Z., Wakhle, A., Stiefel, K., Hinde, D. J., Dasgupta, M., Williams, E., Carter, I. P., Cook, K. J., & Greene, J. Results on the Influence of Neutron-Richness on Quasifission in Intermediate Mass Reactions. United States. doi:10.1142/9789813229426_0053.
Hammerton, K. M., Morrissey, D. J., Kohley, Z., Wakhle, A., Stiefel, K., Hinde, D. J., Dasgupta, M., Williams, E., Carter, I. P., Cook, K. J., and Greene, J. Mon . "Results on the Influence of Neutron-Richness on Quasifission in Intermediate Mass Reactions". United States. doi:10.1142/9789813229426_0053.
@article{osti_1467895,
title = {Results on the Influence of Neutron-Richness on Quasifission in Intermediate Mass Reactions},
author = {Hammerton, K. M. and Morrissey, D. J. and Kohley, Z. and Wakhle, A. and Stiefel, K. and Hinde, D. J. and Dasgupta, M. and Williams, E. and Carter, I. P. and Cook, K. J. and Greene, J.},
abstractNote = {Superheavy elements are primarily formed through heavy ion fusion reactions(1-3). Formation of a fully equilibrated compound nucleus is a critical step in this reaction mechanism but can be hindered by orders of magnitude by quasifission, a process in which the dinuclear system breaks apart prior to full equilibration(1'4-8). To provide a complete description of heavy-ion fusion it is important to characterize the quasifission process. The interplay between the fusion-fission and quasifission reaction channels was explored by measuring fission mass distributions in eight different combinations of Cr+W reactions, with varying neutron-richness, at the Australian National University. The reactions were measured in two energy regimes: one at 13% above the Bass fusion barrier(9) and one at 52.0 MeV of excitation energy in the compound nucleus, E-CN*. For the systems measured at E-c.m./V-Bass = 1.13 the dependence on the neutron-richness is clear(10). However, for the reactions at E-CN* = 52.0 MeV, the dependence is less clear and additional factors are shown to play a vital role, especially the influence of deformation on the effective fusion barrier. The present work demonstrates that quasifission is an important process in competition with heavy-ion fusion in reactions with intermediate mass projectiles, particularly with more neutron-rich systems.},
doi = {10.1142/9789813229426_0053},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {1}
}

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