Neutron spectrometry diagnosis of DT fusion experiments

High-flux, high-count-rate (HFC) neutron spectrometers devised for diagnosis of burning fusion plasmas (Q → ∞) of tokamaks are discussed in view of their potential use on Q ∼ 1 plasmas obtainable with present tokamaks (JET). A figure of merit based on counting statistics is introduced as a means to judge the quality and scope of neutron spectrometry on different tokamaks (ITER, Ignitor and JET) and for different plasma conditions. The opportunities for prototype testing of new HFC diagnostic methods on JET and for making essential diagnostic contributions are discussed. (author)