Ralf Kaiser’s research has been focused on the fundamental structure of matter and on the design and construction of radiation detectors. Currently, he is most interested in the practical applications of nuclear technology, in particular with a view to mitigating climate change. He has served as Head of Physics at the International Atomic Energy Agency in Vienna, which included the responsibility for the IAEA programmes on nuclear fusion and nuclear instrumentation, as well as numerous missions to Fukushima. Lynkeos Technology, the company he founded in 2016, deployed the worldwide first muon imaging system for nuclear waste containers at Sellafield in 2018. At present he is the Head of Programmes at the International Centre for Theoretical Physics (ICTP) in Trieste, Italy.