E. Bauge

Neutron Data Evaluation and Validation of Rhodium‐103

Rhodium‐103 is a prominent fission product in nuclear reactors as well as a usual detector in fast neutron activation or dosimetry techniques. The neutron‐induced reactions and the energy regions of interest differ significantly depending on the applications. In this paper, a new evaluation spanning the 0‐ to 30‐MeV energy range is described. The quality of the transitions between the various energy intervals was assessed with the help of statistical techniques to test the resonance parameter distributions and the SPRT method to check optical model calculations. The evaluated nuclear data file was verified and processed. The quality of the data was successfully tested against both differential and integral results for activation, thermal and fast reactor applications. This new file should be part of the upcoming JEFF‐3.1 library.

Topical issue on perspectives on nuclear data for the next decade

Nuclear reaction models, and their computational implementation, have become indispensible in modern nuclear data evaluation. To perform adequate interand extrapolation on the energy and angular grids per reaction channel, technological software (e.g. codes to analyze nuclear reactors) relies on a complete representation of a nuclear reaction in a data file, and not only on the data that happen to be available through measurements. For nuclear model evaluation, future research is seen to proceed in two directions simultaneously: (a) broad scale nuclear model calculations (dripline-to-dripline) and the associated comparison with the experimental database and global parameter determination, (b) precise determination of nuclear data for very important nuclides and reaction channels. For (a), microscopic physics, or trends derived from it, is necessary to obtain a credible prediction for unmeasured reactions, while for (b) the experimental data that are of high quality need to be identified from the existing database, or otherwise, need to be re-measured. For both cases, uncertainties play an important role, and the current abilities to generate covariance data will be demonstrated. Next, an outlook is presented for nuclear models and reaction channels that should become routine in the coming 10 years, such as microscopic optical models, quantum-mechanical multi-step theories, microscopic level densities, fission fragments and their neutron spectra.

Towards Universal Predictions with the TALYS Code

The increasing need for cross sections far from the valley of stability, for astrophysical as well as advanced technological applications poses a challenge for nuclear reaction models. So far, nuclear reaction cross sections calculations have relied on more or less phenomenological approaches, depending on several parameters that are adjusted, to available experimental data, or deduced from systematical relations. While such calculations are expected to be reliable for nuclei not too far from the experimentally known regions, it is clearly preferable to use more fundamental approaches, based on sound physical bases, when dealing with very exotic nuclei. Thanks to the high computer power available today, all the ingredients required to model a nuclear reaction can now be microscopically (or semi‐microscopically) determined starting from a nucleon‐nucleon effective interaction as sole input, and are available to the nuclear physics community. We have recently implemented all these microscopic ingredients in...

Building better optical model potentials for nuclear astrophysics applications

In nuclear astrophysics, optical model potentials play an important role, both in the nucleosynthesis models, and in the interpretation of astrophysics related nuclear physics measurements. The challenge of nuclear astrophysics resides in the fact that it involves many nuclei far from the stability line, implying than very few (if any) experimental results are available for these nuclei. The answer to this challenge is a heavy reliance on microscopic optical models with solid microscopic physics foundations that can predict the relevant physical quantities with good accuracy. This use of microscopic information limits the likelihood of the model failing spectacularly (except if some essential physics was omitted in the modeling) when extrapolating away from the stability line, in opposition to phenomenological models which are only suited for interpolation between measured data points and not for extrapolating towards unexplored areas of the chart of the nuclides.We will show how these microscopic optical...

Interaction potential and reaction cross section of neutron rich nuclei on protons

Proton reaction cross sections were measured on various stable and exotic nuclei, aiming at a better understanding of the potential for neutron rich nuclei.