Structural response of the EADF target beam window to beam interruptions: transient thermo-mechanical computations

The operability of a high power proton beam target in an accelerator-driven system (ADS) is inextricably linked to the structural integrity of the beam window. The beam window is undoubtedly the most delicate component in such devices, being exposed to the combined effects of high intensity proton and neutron irradiation, liquid metal corrosion and high thermal stresses induced by the interaction with the beam. It has also recently been highlighted that beam trips may frequently occur in current high power accelerators. Clearly, the definition of the requirements of future accelerators depends on the behaviour of the window under such conditions. For this purpose a numerical study of typical transients has been carried out on the 600 MeV proton beam target that drives the 80 MW demonstration facility of the energy amplifier proposed by C. Rubbia, presently being developed in Italy by Ansaldo, CRS4, ENEA and INFN. (authors)