Speaker
Description
Integrated science and technology efforts in the field of controlled thermonuclear fusion are directed towards the construction and operation of a rector-class machine for electricity production. In the interdisciplinary world of fusion research, the role of particle accelerators is at least five-fold: (i) provision of nuclear data for ion-material interactions; (ii) ion beam analysis (IBA) of plasma-facing materials and components (PFMC); (iii) ion-induced neutron generation for the material irradiation facility; (iv) ion-induced simulation of neutron radiation effects in surfaces of solids; (v) high current units in the neutral beam injection system for plasma (deuterium and tritium: D and T) heating.
Over the years, more than fifty different material characterisation techniques have been used in the PFMC research: ion, electron, neutron, optical, magnetic, sound, mechanical, thermal and their combinations. Compositional analyses must cover a broad range of species which are used in a reactor as fuel, gases injected for auxiliary plasma heating or edge cooling, transport markers, wall and diagnostic components and, those for wall conditioning. As a result, the list extends from H, D, T, 3He, 4He, other noble gases (Ne – Xe), isotopes of Li, Be, B, C, N, O, F, via Al, Si to Cr, Fe, Ni and then to W, Re, and even to Au. Such challenge can be met only by accelerator-based ion beam analysis methods (IBA): RBS, NRA, PIXE, ERDA, MEISS, AMS. Taking into account a range of ion beams, spot size, broad energy spectrum, tens of nuclear reactions and data processing software, the “toolbox” offers a huge number of options.
Quantitative results can only be obtained when based on robust nuclear data sets, i.e. stopping powers and reaction cross-sections. Therefore, the work has three equally important strands: (i) assessment of fuel inventory and modification of PFMC by erosion and deposition processes arising from plasma-wall interactions; (ii) determination of nuclear data for selected ion-target combinations; (iii) equipment development to perform cutting-edge research. In parallel, inter-laboratory comparisons (round robin tests) are carried out.
It is stressed, that the accelerator-based analysis and modification of materials is not an isolated or a passive strand of fusion research. The results directly contribute to decisions regarding the wall composition and diagnostic planning in future devices. This imposes a quest for improvements and developments of analytical capabilities (nuclear data sets, detectors, chambers etc.) to ensure cutting edge research. A brief review of IBA facilities in the fusion research will be presented.
