IFMIF RFQ: an accelerator for a neutron source to test structural resistance of materials
On 21 April 2016 in Rokkasho (Japan) a ceremony was held for the installation of the low energy section of a very powerful accelerator (LIPAc) representing a prototype for the International Fusion Material Irradiation Facility (IFMIF). The aim of IFMIF, and of the LIPAc accelerator, is the production of very high intense fluxes of high energy monoenergetic neutrons which are needed for testing the structural resistance of materials to be employed in Nuclear Fusion Reactors. The IFMIF nominal neutron flux of 1018 m-2s-1 presents a broad energy peak up to 14 MeV, able to simulate the worst situation in a Fusion reactor for energy production. The results of the IFMIF experimental program will be fundamental for the design of DEMO, the reactor generation after ITER.
Cutting-edge technology was developed for this enterprise using know-how developed and shared in several European laboratories (mainly LNL-INFN, IRFU-CEA, CIEMAT and SCK). All of these laboratories are leaders in the construction of a new generation of accelerators with the best performance for beam quality and intensity.
The main component of the low energy accelerator now installed is the RFQ (Radio Frequency Quadrupole) that was constructed by the INFN team composed of 25 physicists and engineers from the LNL laboratory and groups in Padova, Torino and Bologna.
This new RFQ is a unique system, able to produce the highest beam intensities of accelerated particles. It consists of an ultra-pure 10 m long copper structure, manufactured with high mechanical accuracy, able to produce a continuous wave (CW) and very intense deuteron (nuclei of Deuterium) beam with kinetic energy up to 5 MeV. The nominal intensity is a125 mA continuous wave beam, corresponding to 625 kW beam power onto a few square mm beam cross-section. After the design and the development of the prototype and of the most complex parts, to a large extent made within the INFN infrastructures, the construction was assigned to specialised companies dealing with high precision mechanical construction and high power RF electronics.
