Application of Nuclear Emulsion to Neutron Emission Profile Diagnostics in the National Spherical Torus Experiment

The technology for OPERA experiments in neutrino physics was applied to neutral-beam-heated deuterium discharges of NSTX in order to measure d-d neutron emission profile. The diagnostic system consisted of nuclear emulsions named OPERA films and the automatic track scanning system S-UTS developed in Nagoya University. A neutron collimator having three channels was temporarily built for this purpose. The nuclear emulsion indicated peaked neutron emission profiles at the plasma center in NSTX as expected