Transmutation experiments on 129I, 139La and 237Np using the Nuclotron accelerator

Transmutation experiments have been carried out using the NUCLOTRON, a new accelerator for relativistic particles. The experiments were carried out in the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research in Dubna, Russian Federation. Earlier experiments using an 8 cm O Pb-target of 20 cm length and surrounded by 6 cm paraffin (GAMMA-2 target) have been continued to study the transmutation of 1 3 9 La and the highly radiotoxic radwaste nuclides 1 2 9 I and 2 3 7 Np using spallation neutrons produced by relativistic protons with energies 0.5 GeV ≤ E P ≤ 4.15 GeV. Results of previous experiments were complemented with additional results, thus yielding data systematics with small uncertainties over the probably commercially relevant energy range of 0.5 GeV < E P ≤ 1.0 GeV and also in the scientifically interesting range above 1 GeV. Moreover, neutron density distributions in irradiations with 0.65 GeV, 1 GeV and 3.7 GeV protons were determined on the surface of the paraffin moderator for two energy regimes of slow and intermediate/fast neutrons. A large set of high quality experimental data with small uncertainties has been generated that can serve as benchmark data for modelling purposes.