Proposed neutron diagnostics for Wendelstein 7-X stellarator

Deuterium plasmas in the Wendelstein 7-X stellarator are estimated to generate 1012–1016 neutrons per second. At this level, information on ion velocity distributions, ion densities, reaction fluctuations, and thermal reaction fractional contribution can be revealed from the neutron emission rate and energy distribution. A system of neutron counters, activation system, neutron spectrometer, and a profile monitor, as well as computer codes for interpretation and analysis are envisaged.