Measurement of the Gamma-Ray-to-Neutron Branching Ratio for the Deuterium-Tritium Reaction in Magnetic Confinement Fusion Plasmas
A. Dal Molin, G. Marcer, M. Nocente, M. Rebaı̈, D. Rigamonti, M. Angelone, A. Bracco, F. Camera, Carlo Cazzaniga, T. Craciunescu, G. Croci, M. Dalla Rosa, L. Giacomelli, G. Gorini, Y. Kazakov, E. Khilkevitch, A. Muraro, E. Panontin, E. Perelli Cippo, M. Pillon, O. Putignano, J. Scionti, A. Shevelev, Andrej Žohar, M. Tardocchi
Abstract
At present, magnetic confinement fusion devices rely solely on absolute neutron counting as a direct way of measuring fusion power. Absolute counting of deuterium-tritium gamma rays could provide the secondary neutron-independent technique required for the validation of scientific results and as a licensing tool for future power plants. However, this approach necessitates an accurate determination of the gamma-ray-to-neutron branching ratio. The gamma-ray-to-neutron branching ratio for the deuterium-tritium reaction ^{3}H(^{2}H,γ)^{5}He/^{3}H(^{2}H,n)^{4}He was determined in magnetic confinement fusion plasmas at the Joint European Torus in predominantly deuterium beam heated plasmas. The branching ratio was found to be equal to (2.4±0.5)×10^{-5} over the deuterium energy range of (80±20) keV. This accurate determination of the deuterium-tritium branching ratio paves the way for a direct and neutron-independent measurement of fusion power in magnetic confinement fusion reactors, based on the absolute counting of deuterium-tritium gamma rays.