Neutron emission study of DT plasmas heated with tritium neutral beams

The neutron emission energy spectrum from deuterium-tritium fusion reactions has been measured in experiments carried out at the Joint European Torus for plasmas heated with high power neutral beam (NB) injection of tritium beams at E-b approximate to 150 keV using a magnetic proton recoil neutron spectrometer. High quality data were obtained in which up to three spectral components due to different ion reactions could be distinguished with the help of dedicated model calculations of the fusion neutron emission based on Monte Carlo simulations. The analysis model involved neutrons from reactions of NB ions on passing and trapped orbits interacting with thermal bulk ions. Moreover, a narrow Gaussian component, due to neutrons from thermal d + t --> alpha + n reactions, could be resolved in some cases. Results are presented and the plasma information obtained is discussed as an illustration of the capabilities of neutron emission spectroscopy diagnostics. (C) 2001 American Institute of Physics.