Proton-induced reactions on Fe, Cu, & Ti from threshold to 55 MeV

Abstract

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 LBNL 88-Inch Cyclotron with beams of 25 and 55 MeV protons on a stack of iron, copper, and titanium foils. 34 excitation functions were measured for 4 < Ep < 55 MeV, including the first measurement of the independent cross sections for nat Fe(p,x) 49,51 Cr, 51,52m,52g,56 Mn, and 58m,58g Co. All of the models 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.