On the role of secondary pions in spallation targets

Abstract

We use particle-transport simulations to show that secondary pions play a crucial role for the development of the hadronic cascade and therefore for the production of neutrons and photons from a thick spallation target. Considering the spallation target of the n_TOF Facility at CERN, we see that photon and neutron yields are relatively insensitive to large changes of the average pion multiplicity in the individual spallation reactions. We characterize this robustness as a peculiar property of hadronic cascades in thick targets.