Studies of the neutron field of the Energy plus Transmutation set-up under 4 GeV deuteron irradiation

The Energy plus Transmutation (EPT) set-up of the Joint Institute of Nuclear Research (JINR), Dubna, Russia is composed of a lead spallation target surrounded by a blanket of natural uranium. The target was irradiated with 4 GeV deuterons. Rates of reactions leading to the production of ²⁰⁶Bi from ²⁰⁹Bi were determined through gamma spectrometry. These were compared with calculated reaction rates determined using the MCNPX code, including the INCL4 intranuclear cascade and ABLA fission/evaporation models along with available cross section data. Close agreement was found for the production of ²⁰⁶Bi. The high threshold energy of neutron induced production indicates that neutrons causing these reactions are most likely to originate in the intranuclear cascade phase of the interaction. This is therefore an important reaction for validation of the computational models used.