Private enterprises in fusion: an opportunity for innovative nuclear diagnostics

The goal of nuclear fusion research is energy production by using the heat generated by fusion reactions of light isotopes. The most promising results have been attained with a hydrogen gas fuel in the state of a plasma made of deuterium (D) and tritium (T) ions, which, when confined and kept hot for a time long enough, produce energy with the reaction D+T->?+n +17.6 MeV; the fusion born 3.5 MeV alpha particles being confined can provide the required plasma self-heating. The research in the field of nuclear fusion based on magnetic confinement has been carried out so far since the early 50's mainly via public funding. In the second half of 2021 the JET tokamak in United Kingdom achieved a record of 11 MW of power for 5 seconds. These results have provided a unique opportunity to validate the performance of the nuclear diagnostics in the high 14 MeV neutron yields (up to 4.7·1018 n/s). The next step in the fusion roadmap is the ITER reactor in construction in France which aims to demonstrate the scientific and technological feasibility of fusion by around 2040. In the last five years, the need for decarbonization to mitigate the global warming has motivated important efforts by private enterprises. We can count over 25 private funded companies in the world that are developing different concept of fusion reactors [1], with a raised capital in 2021 over 2 billion dollars. Common aim is to accelerate the path towards the first commercial fusion reactor and make it possible within one or two decades. While some of the developed concepts are still undemonstrated, the most promising efforts come from exploitation of high temperature superconducting magnets (>10T), which could be the potential game-changer by making possible to build tokamaks of compact sizes. This contribution will outline the opportunities which these projects open up for developing innovative nuclear diagnostics based on neutron and gamma ray spectroscopy. One of such example would be the first high resolution spectroscopic neutron camera which, by tomographic reconstruction of the 14 MeV neutron emission, measure in real time the fuel ion plasma temperature and its radial profile.