A well-established knowledge of nuclear phenomena including fission, reaction cross sections, and structure/decay properties is critical for applications ranging from the design of new reactors to nonproliferation to the production of radioisotopes for the diagnosis and treatment of illness. However, the lack of a well-quantified, predictive theoretical capability means that most nuclear observables must be measured directly and used to calibrate empirical models, which in turn provide the data needed for these applications. In many cases, either there is a lack of data needed to guide the models or the results of the different measurements are discrepant, leading to the development of evaluation methodologies to provide recommended values and uncertainties. In this review, we describe the nuclear data evaluation process and the international community that carries it out. We then discuss new measurements and improved theory and/or modeling needed to address future challenges in applied nuclear science.

${}^{72}\mathrm{As}$ is a promising positron emitter for diagnostic imaging that can be employed locally using a ${}^{72}\mathrm{Se}$ generator. However, current reaction pathways to ${}^{72}\mathrm{Se}$ have insufficient nuclear data for efficient production using regional 100–200 MeV high-intensity proton accelerators. In order to address this deficiency, stacked-target irradiations were performed at LBNL, LANL, and BNL to measure the production of the ${}^{72}\mathrm{Se}/{}^{72}\mathrm{As}$ positron emission tomography (PET) generator system via ${}^{75}\mathrm{As}(p,x)$ between 35 and 200 MeV. This work provides the most well-characterized excitation function for ${}^{75}\mathrm{As}(p,4n){}^{72}\mathrm{Se}$ starting from threshold. Additional focus was given to report the first measurements of ${}^{75}\mathrm{As}(p,x){}^{68}\mathrm{Ge}$ and bolster an already robust production capability for the highly valuable ${}^{68}\mathrm{Ge}/{}^{68}\mathrm{Ga}$ PET generator. Thick target yield comparisons with prior established formation routes to both generators are made. In total, high-energy proton-induced cross sections are reported for 55 measured residual products from ${}^{75}\mathrm{As}, {}^{\mathrm{nat}}\mathrm{Cu}$, and ${}^{\mathrm{nat}}\mathrm{Ti}$ targets, where the latter two materials were present as monitor foils. These results were compared with literature data as well as the default theoretical calculations of the nuclear model codes talys, coh, empire, and alice. Reaction modeling at these energies is typically unsatisfactory due to few prior published data and many interacting physics models. Therefore, a detailed assessment of the talys code was performed with simultaneous parameter adjustments applied according to a standardized procedure. Particular attention was paid to the formulation of the two-component exciton model in the transition between the compound and preequilibrium regions, with a linked investigation of level density models for nuclei off of stability and their impact on modeling predictive power. This paper merges experimental work and evaluation techniques for high-energy charged-particle isotope production in an extension to an earlier study of this kind.

Background: A number of accelerator-based isotope production facilities utilize 100- to 200-MeV proton beams due to the high production rates enabled by high-intensity beam capabilities and the greater diversity of isotope production brought on by the long range of high-energy protons. However, nuclear reaction modeling at these energies can be challenging because of the interplay between different reaction modes and a lack of existing guiding cross-section data.

Theoretical models often differ significantly from measured data in their predictions of the magnitude of nuclear reactions that produce radionuclides for medical, research, and national security applications. In this paper, we compare a priori predictions from several state-of-the-art reaction modeling packages (CoH, EMPIRE, TALYS, and ALICE) to cross sections measured using the stacked-target activation method. The experiment was performed using the Lawrence Berkeley National Laboratory 88-Inch Cyclotron with beams of 25 and 55 MeV protons on a stack of iron, copper, and titanium foils. Thirty-four excitation functions were measured from 4–55 MeV, including the first measurement of the independent cross sections for $$^{\mathrm{nat}}\hbox {Fe}$$nat Fe (p,x) $$^{49,51}\hbox {Cr}$$49 , 51 Cr , $$^{51,{\mathrm{52m}},{\mathrm{52g}},56}\hbox {Mn}$$51 , 52 m , 52 g , 56 Mn , and $$^{{\mathrm{58m,58g}}}\hbox {Co}$$58 m , 58 g Co . All of the models, using default input parameters to assess their predictive capabilities, failed to reproduce the isomer-to-ground state ratio for reaction channels at compound and pre-compound energies, suggesting issues in modeling the deposition or distribution of angular momentum in these residual nuclei.