Measurement of neutron energy for ICRF heated D-T plasma experiments

In the next large tokamak facility such as the International Thermonuclear Experimental Reactor (ITER), the ion cyclotron range of frequency (ICRF) heating is one of the major techniques to heat the plasma. Due to the existence of the resonance peak for the D-T fusion reaction around 100 keV, the neutron yield of ICRF heated D-T plasma might decrease due to the growth of a high energy tritium ion tail when the temperature of the tail component exceeds similar to 150 keV. On the contrary, the peak width of the D-T neutron spectrum increases monotonically as the tail temperature increases. Therefore, the neutron spectrum measurement could be a useful tool for monitoring the effect of ICRF heating on D-T fusion plasma. In this paper, the necessary performance of a neutron spectrometer will be discussed. (C) 1997 Elsevier Science S.A.