A TOF neutron spectromet er for measurement of the fuel ratio on ITER

The possibility of measurement of the fuel ratio with a neutron spectrometer for ITER was studied. In a neutronics calculation on the model of ITER, the possibility of separating the DD component from that of the DT reaction was examined. The separation in a neutron spectrum is possible at an appropriate measurement position with a collimator 1–3 cm in diameter. Design parameters of a TOF spectrometer for this purpose were considered. The optimum-scattered angle for geometric energy resolution is 35 degrees. The optimum thickness of the first scintillator and the optimum distance between first and second detectors are 0.8 cm and 80-120 cm, respectively, to cover the dynamic range of 10 4 .