The triple beam facility
JANNuS-Saclay offers the rare possibility to simultaneously deliver three concurrent ion beams on a single target allowing for a wide range of irradiation and implantation conditions for well-controlled modelling-oriented experiments.
Ion beams are employed to understand neutron-induced effects in nuclear materials for decades as they can produce nuclear recoil damage and implant a large variety of elements mimicking helium and hydrogen from nuclear reactions, transmutation products, fission products and gasses [G.S. Was, and R.S. Averback : Radiation Damage Using Ion Beams. Comprehensive Nuclear Materials 1, 195 (2012)]. Among the most stringent reasons for using electrostatic ion accelerators are the scarcity of neutrons sources and the ease of use : a high damage level either as implanted ions and/or as dpa is obtained over a very short time –typically a few hours– and the irradiated sample has no residual radioactivity. Ion beams allow also to perform well controlled experiments in terms of energy, dose, flux, temperature… with little variation during the irradiation. This is of great value in an analytical approach.
At CEA Paris-Saclay, a triple beam facility has been installed for simultaneous ballistic damage, gas implantation and/or electronic excitation. Samples can be irradiated in the wide temperature range from liquid nitrogen to 850K. Evolution in the ion-irradiated material microstructure and changes in the service properties (mechanical, thermal…) are then characterized by on line Raman spectrometry or post mortem. Simulation can greatly help in validating the transposition of material laws derived from ion irradiations –formation and evolution of defect loops and of cavities, segregation, amorphization– to in-reactor conditions.
Together with JANNuS-Orsay at CSNSM, it forms since 2005 the multi-ion beam irradiation platform JANNuS for Joint Accelerators for Nanosciences and Nuclear Simulation.