A 14 MeV neutron spectrometer for the Joint European Torus deuterium-tritium experiments

A 14 MeV neutron spectrometer, based on the principle of the proton recoil telescope, has been installed as a deuterium-tritium (DT) plasma diagnostic at the Joint European Torus. The device comprises three identical telescop e modules arranged one behind the other, to increase efficiency without wor sening resolution. It views the plasma along a horizontal line of sight. Th e total efficiency is 7.05 X 10(-5) counts per (neutron per cm(2)), and the calculated response function has a full width at half maximum of 2.2% at a n incident neutron energy of 14.1 MeV. The spectrometer was operational thr oughout the recent DT experiment No. 1, and selected neutron spectra have b een analyzed in terms of the contributions from the various neutron product ion mechanisms. (C) 1999 American Institute of Physics. [S0034-6748(99)5650 1-5].