  The Deep Underground Neutrino Experiment (DUNE) is a leading-edge,
international experiment for neutrino science and proton decay studies. This
experiment is looking for answers regarding several fundamental questions about
the nature of matter and the evolution of the universe: origin of matter,
unification of forces, physics of black holes. Two far detector prototypes
using two distinct technologies have been developed at CERN. The prototypes are
testing and validating the liquid argon time projection chamber technology
(LArTPC). In neutrino physics, as well as in any experiment with rare
interaction rate, the good knowledge of the radioactive backgrounds is
important to the success of the study.
  Unlike most of the charged particles or short lived neutral particles, muons
and neutrons represent the main sources of background for this kind of
experiments. In this paper, we have considered two sources of neutrons: cosmic
neutrons and neutrons coming from the accelerating tunnel. Also, cosmic muons
are taken into account. The contribution of these particles to the production
of radioactive isotopes inside the active volume of the detector in comparison
to the one corresponding to muons is shown. Also, simulations of nuclear
reactions for the processes of interest for investigating the radioactive
background due to the lack of measurements or insufficient experimental data
are presented. The results presented are of interest for the future underground
DUNE experiment.
