Towards More Predictive Nuclear Reaction Modelling
11
Fig. 4 Average radiative widths as function of the mass number. Comparison between theoretical
predictions and experiment. The (a) and (b) panels correspond to the traditional analytical
expression SLO and GLO [16], while panels (c) and (d) display the HFB-Gogny QRPA predictions
with two options for the low energy M1 phenomenological correction [20]
top of its ability to reproduce experimental radiative width, the HFB-Gogny QRPA
model has also been tested successfully with respect to other experimental data [21,
22].
4.3 Fission
Despite its fundamental role in nuclear applications as a source of energy, as well
as the fact that it has been discovered many decades ago and intensively studied
since, fission remains probably the least well-understood process in nuclear reaction
modelling. Qualitatively speaking, fission is modelled by a gradual transition of the
nucleus from an initial compact shape to such an elongated shape that the nucleus
breaks into fragments. This evolution is governed by a potential energy landscape
corresponding to nuclear shapes more or less probable depending on the excitation
energy required to reach them. This landscape exhibits features such as valleys and
peaks which help in understanding the major characteristics of the fission process,
and, in particular the fission fragments distributions observed experimentally. For
cross section calculation, one reduces the multidimensional landscape to an effective
one-dimensional (1D) approach. This 1D landscape suggests the concept of fission
barriers through which quantum tunnelling probabilities are computed to determine
fission transmission coefficients.
11
Fig. 4 Average radiative widths as function of the mass number. Comparison between theoretical
predictions and experiment. The (a) and (b) panels correspond to the traditional analytical
expression SLO and GLO [16], while panels (c) and (d) display the HFB-Gogny QRPA predictions
with two options for the low energy M1 phenomenological correction [20]
top of its ability to reproduce experimental radiative width, the HFB-Gogny QRPA
model has also been tested successfully with respect to other experimental data [21,
22].
4.3 Fission
Despite its fundamental role in nuclear applications as a source of energy, as well
as the fact that it has been discovered many decades ago and intensively studied
since, fission remains probably the least well-understood process in nuclear reaction
modelling. Qualitatively speaking, fission is modelled by a gradual transition of the
nucleus from an initial compact shape to such an elongated shape that the nucleus
breaks into fragments. This evolution is governed by a potential energy landscape
corresponding to nuclear shapes more or less probable depending on the excitation
energy required to reach them. This landscape exhibits features such as valleys and
peaks which help in understanding the major characteristics of the fission process,
and, in particular the fission fragments distributions observed experimentally. For
cross section calculation, one reduces the multidimensional landscape to an effective
one-dimensional (1D) approach. This 1D landscape suggests the concept of fission
barriers through which quantum tunnelling probabilities are computed to determine
fission transmission coefficients.