Diagnostics of Fusion Plasma with D(d,γ)⁴He Gamma-Line Broadening: A Feasibility Study

A novel diagnostic f or ion temperature and density is discussed. The diagnostic, based on the detection of the 24-MeV gamma photon from the D(d,γ)⁴He fusion reaction, appears feasible in reactor-oriented tokamaks. The use of an optimized differential neutron/gamma filter reduces this ratio from 10⁷ at the plasma to ∼1 on the detector. Under these conditions, measurement of the plasma ion temperature and density of a thermonuclear plasma is possible by using a large, high-purity germanium detector as a spectrometer.