Excitation energy partition in fission
(2020) In Physics Letters, Section B: Nuclear, Elementary Particle and HighEnergy Physics 803. Abstract
The transformation of an atomic nucleus into two excited fission fragments is modeled as a strongly damped evolution of the nuclear shape. As in previous studies, it is assumed that the division of mass and charge is frozen in at a critical neck radius of c_{0}=2.5fm. In order to also determine the energetics, we follow the system further until scission occurs at a smaller neck radius, at which point the shapes of the protofragments are extracted. The statistical energy available at scission is then divided on the basis of the respective microscopic level densities. This approach takes account of important (and energydependent) finitesize effects. After the fragments have been fully accelerated and their shapes have relaxed... (More)
The transformation of an atomic nucleus into two excited fission fragments is modeled as a strongly damped evolution of the nuclear shape. As in previous studies, it is assumed that the division of mass and charge is frozen in at a critical neck radius of c_{0}=2.5fm. In order to also determine the energetics, we follow the system further until scission occurs at a smaller neck radius, at which point the shapes of the protofragments are extracted. The statistical energy available at scission is then divided on the basis of the respective microscopic level densities. This approach takes account of important (and energydependent) finitesize effects. After the fragments have been fully accelerated and their shapes have relaxed to their equilibrium forms, they undergo sequential neutron evaporation. The dependence of the resulting mean neutron multiplicity on the fragment mass, ν¯(A), including the dependence on the initial excitation energy of the fissioning compound nucleus, agrees reasonably well with observations, as demonstrated here for ^{235}U(n, f), and the sawtooth appearance of ν¯(A) can be understood from shellstructure effects in the level densities.
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 author
 Albertsson, M. ^{LU} ; Carlsson, B. G. ^{LU} ; Døssing, T. ^{LU} ; Möller, P. ^{LU} ; Randrup, J. ^{LU} and Åberg, S. ^{LU}
 organization
 publishing date
 20200410
 type
 Contribution to journal
 publication status
 published
 subject
 keywords
 Brownian shape evolution method, Fission, Microscopic level densities
 in
 Physics Letters, Section B: Nuclear, Elementary Particle and HighEnergy Physics
 volume
 803
 article number
 135276
 publisher
 Elsevier
 external identifiers

 scopus:85079190033
 ISSN
 03702693
 DOI
 10.1016/j.physletb.2020.135276
 language
 English
 LU publication?
 yes
 id
 7f0a642415bf4030afb1dc7865573363
 date added to LUP
 20200220 11:25:11
 date last changed
 20201229 02:59:43
@article{7f0a642415bf4030afb1dc7865573363, abstract = {<p>The transformation of an atomic nucleus into two excited fission fragments is modeled as a strongly damped evolution of the nuclear shape. As in previous studies, it is assumed that the division of mass and charge is frozen in at a critical neck radius of c<sub>0</sub>=2.5fm. In order to also determine the energetics, we follow the system further until scission occurs at a smaller neck radius, at which point the shapes of the protofragments are extracted. The statistical energy available at scission is then divided on the basis of the respective microscopic level densities. This approach takes account of important (and energydependent) finitesize effects. After the fragments have been fully accelerated and their shapes have relaxed to their equilibrium forms, they undergo sequential neutron evaporation. The dependence of the resulting mean neutron multiplicity on the fragment mass, ν¯(A), including the dependence on the initial excitation energy of the fissioning compound nucleus, agrees reasonably well with observations, as demonstrated here for <sup>235</sup>U(n, f), and the sawtooth appearance of ν¯(A) can be understood from shellstructure effects in the level densities.</p>}, author = {Albertsson, M. and Carlsson, B. G. and Døssing, T. and Möller, P. and Randrup, J. and Åberg, S.}, issn = {03702693}, language = {eng}, month = {04}, publisher = {Elsevier}, series = {Physics Letters, Section B: Nuclear, Elementary Particle and HighEnergy Physics}, title = {Excitation energy partition in fission}, url = {http://dx.doi.org/10.1016/j.physletb.2020.135276}, doi = {10.1016/j.physletb.2020.135276}, volume = {803}, year = {2020}, }