14
S. Hilaire and S. Goriely
5 Conclusions
The modelling of a nuclear reaction is a complicated task, sometimes challenging.
Several models and nuclear ingredients have to be linked together to be able
to predict the outcome of a nuclear reaction. Although significant improvements
have been made during the last decades, there are still many challenges to face.
Pre-equilibrium and fission modelling are certainly among these. In the case of
pre-equilibrium, the main reason is that the flexibility of semi-classical approaches
makes it possible to obtain at small computational price results which satisfy the
quality required for applications. It is only recently that the need for better models
has become timely, in particular while studying “subtle” processes such as (n,xnγ)
transitions in actinides [8]. For fission, the problem is more complicated. The
models used are far too simple compared to the most fundamental approaches
which evidence a need to account for multidimensional energy landscapes. If future
developments consist, without any doubt, in adding more and more microscopic
approaches in the nuclear reaction models, this will be a very long-term project.
For now, such microscopic approaches can only provide guidelines for nuclear data
evaluations but offer the only alternative to empirical expressions whose predictive
power far from the valley of stability cannot be trusted given the number of
phenomenological parameters they rely on.
References
1. G. Audi et al., The NUBASE 2016 evaluation of nuclear properties. Chin. Phys. C 41(3),
030001 (2017)
2. A. Sobiczewski, Y. Litvinov, Predictive power of nuclear-mass models. Phys. Rev. C 90,
017302 (2014)
3. G. Audi et al., The AME2003 atomic mass evaluation. Nucl. Phys. A 729, 337–676 (2003)
4. G. Audi et al., The Ame2012 atomic mass evaluation. Chin. Phys. C 36(12), 1287–1602 (2012)
5. A.J. Koning, J.P. Delaroche, Local and global nucleon optical models from 1 keV to 200 MeV.
Nucl. Phys. A 713, 231–310 (2003)
6. E. Bauge et al., Lane-consistent semi-microscopic nucleon-nucleus optical model. Phys. Rev.
C 63, 024607 (2001)
7. A.J. Koning, J.M. Akkermans, in Workshop on Nuclear Reaction Data and Nuclear Reactors:
Physics, Design and Safety, ed. by P. Oblozinsky, A. Gandini, (ICTP, Trieste, 1998), p. 143,
Feb 23–March 27 1998
8. M. Dupuis et al., Microscopic modeling of direct pre-equilibrium emission from neutron
induced reactions on even and odd actinides. EPJ Web Conf. 146, 12002 (2017)
9. S. Hilaire et al., Comparison between various width fluctuation correction factors for compound nucleus reactions. Ann. Phys. 306, 209 (2003)
10. T. Kawano et al., Statistical Hauser-Feshbach theory with width fluctuation correction including direct reaction channels for neutron induced reaction at low energy. Phys. Rev. C 94,
014612 (2016)
11. A.J. Koning et al., Global and local level density models. Nucl. Phys. A 810, 13–76 (2008)
12. Y. Alhassid, The shell model Monte Carlo approach to level densities: Recent developments
and perspectives. Eur. Phys. J. A 51, 171 (2015)
S. Hilaire and S. Goriely
5 Conclusions
The modelling of a nuclear reaction is a complicated task, sometimes challenging.
Several models and nuclear ingredients have to be linked together to be able
to predict the outcome of a nuclear reaction. Although significant improvements
have been made during the last decades, there are still many challenges to face.
Pre-equilibrium and fission modelling are certainly among these. In the case of
pre-equilibrium, the main reason is that the flexibility of semi-classical approaches
makes it possible to obtain at small computational price results which satisfy the
quality required for applications. It is only recently that the need for better models
has become timely, in particular while studying “subtle” processes such as (n,xnγ)
transitions in actinides [8]. For fission, the problem is more complicated. The
models used are far too simple compared to the most fundamental approaches
which evidence a need to account for multidimensional energy landscapes. If future
developments consist, without any doubt, in adding more and more microscopic
approaches in the nuclear reaction models, this will be a very long-term project.
For now, such microscopic approaches can only provide guidelines for nuclear data
evaluations but offer the only alternative to empirical expressions whose predictive
power far from the valley of stability cannot be trusted given the number of
phenomenological parameters they rely on.
References
1. G. Audi et al., The NUBASE 2016 evaluation of nuclear properties. Chin. Phys. C 41(3),
030001 (2017)
2. A. Sobiczewski, Y. Litvinov, Predictive power of nuclear-mass models. Phys. Rev. C 90,
017302 (2014)
3. G. Audi et al., The AME2003 atomic mass evaluation. Nucl. Phys. A 729, 337–676 (2003)
4. G. Audi et al., The Ame2012 atomic mass evaluation. Chin. Phys. C 36(12), 1287–1602 (2012)
5. A.J. Koning, J.P. Delaroche, Local and global nucleon optical models from 1 keV to 200 MeV.
Nucl. Phys. A 713, 231–310 (2003)
6. E. Bauge et al., Lane-consistent semi-microscopic nucleon-nucleus optical model. Phys. Rev.
C 63, 024607 (2001)
7. A.J. Koning, J.M. Akkermans, in Workshop on Nuclear Reaction Data and Nuclear Reactors:
Physics, Design and Safety, ed. by P. Oblozinsky, A. Gandini, (ICTP, Trieste, 1998), p. 143,
Feb 23–March 27 1998
8. M. Dupuis et al., Microscopic modeling of direct pre-equilibrium emission from neutron
induced reactions on even and odd actinides. EPJ Web Conf. 146, 12002 (2017)
9. S. Hilaire et al., Comparison between various width fluctuation correction factors for compound nucleus reactions. Ann. Phys. 306, 209 (2003)
10. T. Kawano et al., Statistical Hauser-Feshbach theory with width fluctuation correction including direct reaction channels for neutron induced reaction at low energy. Phys. Rev. C 94,
014612 (2016)
11. A.J. Koning et al., Global and local level density models. Nucl. Phys. A 810, 13–76 (2008)
12. Y. Alhassid, The shell model Monte Carlo approach to level densities: Recent developments
and perspectives. Eur. Phys. J. A 51, 171 (2015)