138
G. P. A. Nobre et al.
calculated cross sections, with the HFB one generally aligning better with observed
data. Much greater discrepancy was observed in transitions involving states of
opposite parity of that of the ground state, which gives more significance to a more
predictive and internally consistent set of LD, especially when experimental data
are not available.
6 Summary and Conclusions
Even though it is known that cross sections strongly depend on level densities
(LD) there are normally very little direct experimental input in the determination
of their details. In this work we explored this feature by imposing constraints in
extended regions of LD by observing their impact on the agreement of neutron
double-differential spectra with experimental data. This allowed us to extract
experiment-based information about LD that is useful for the structure theory
community which develop microscopic LD models, as well as to increase the
internal self-consistency of models used reaction calculations leading to evaluationlevel quality of cross sections. Additionally, this proved to be a method to obtain
more reliable inelastic gamma cross sections, in particular for those transitions
without measured data or those involving levels with parity opposite of that of the
ground state. One might expect that these effects are more pronounced for the nuclei
close to the shell closures.
Acknowledgments The work at Brookhaven National Laboratory was sponsored by the Office of
Nuclear Physics, Office of Science of the U.S. Department of Energy under Contract No. DEAC02-98CH10886 with Brookhaven Science Associates, LLC. Work at Los Alamos National
Laboratory was carried out under the auspices of the National Nuclear Security Agency of the
U.S. Department of Energy under Contract No. DE-AC52-06NA25396.
References
1. A. Gilbert, A.G.W. Cameron, Can. J. Phys. 43, 1446 (1965)
2. S. Goriely, S. Hilaire, A.J. Koning, Phys. Rev. C78, 064307 (2008)
3. R. Capote et al., Nucl. Data Sheets 110, 3107 (2009)
4. G.P.A. Nobre et al., EPJ Web Conf. 111, 03001 (2016)
5. M. Herman et al., Nucl. Data Sheets 108, 2655 (2007)
6. M. Herman et al., Nucl. Data Sheets 148, 214 (2018)
7. D.A. Brown et al., Nucl. Data Sheets 148, 1 (2018)
8. M.B. Chadwick et al., Nucl. Data Sheets 148, 189 (2018)
9. V.V. Zerkin, B. Pritychenko, Nucl. Inst. Meth. A 888, 31 (2018)
10. A. Negret et al., Phys. Rev. C90, 034602 (2014)
G. P. A. Nobre et al.
calculated cross sections, with the HFB one generally aligning better with observed
data. Much greater discrepancy was observed in transitions involving states of
opposite parity of that of the ground state, which gives more significance to a more
predictive and internally consistent set of LD, especially when experimental data
are not available.
6 Summary and Conclusions
Even though it is known that cross sections strongly depend on level densities
(LD) there are normally very little direct experimental input in the determination
of their details. In this work we explored this feature by imposing constraints in
extended regions of LD by observing their impact on the agreement of neutron
double-differential spectra with experimental data. This allowed us to extract
experiment-based information about LD that is useful for the structure theory
community which develop microscopic LD models, as well as to increase the
internal self-consistency of models used reaction calculations leading to evaluationlevel quality of cross sections. Additionally, this proved to be a method to obtain
more reliable inelastic gamma cross sections, in particular for those transitions
without measured data or those involving levels with parity opposite of that of the
ground state. One might expect that these effects are more pronounced for the nuclei
close to the shell closures.
Acknowledgments The work at Brookhaven National Laboratory was sponsored by the Office of
Nuclear Physics, Office of Science of the U.S. Department of Energy under Contract No. DEAC02-98CH10886 with Brookhaven Science Associates, LLC. Work at Los Alamos National
Laboratory was carried out under the auspices of the National Nuclear Security Agency of the
U.S. Department of Energy under Contract No. DE-AC52-06NA25396.
References
1. A. Gilbert, A.G.W. Cameron, Can. J. Phys. 43, 1446 (1965)
2. S. Goriely, S. Hilaire, A.J. Koning, Phys. Rev. C78, 064307 (2008)
3. R. Capote et al., Nucl. Data Sheets 110, 3107 (2009)
4. G.P.A. Nobre et al., EPJ Web Conf. 111, 03001 (2016)
5. M. Herman et al., Nucl. Data Sheets 108, 2655 (2007)
6. M. Herman et al., Nucl. Data Sheets 148, 214 (2018)
7. D.A. Brown et al., Nucl. Data Sheets 148, 1 (2018)
8. M.B. Chadwick et al., Nucl. Data Sheets 148, 189 (2018)
9. V.V. Zerkin, B. Pritychenko, Nucl. Inst. Meth. A 888, 31 (2018)
10. A. Negret et al., Phys. Rev. C90, 034602 (2014)