Finding Suprathermal Tail of Ion Distribution in Fusion Z-Pinch Plasma Using Several Neutron Time-of-Flight Detectors Placed at Different Directions

Neutron diagnostics, not only in z-pinch fusion research, are used mainly as indirect diagnostics of ions. The energy spectrum of produced neutrons corresponds to the velocity distribution of fusing ions and can be reconstructed by a backward technique using fast scintillation detectors that record neutron time-of-flight (nTOF) signals. However, the backward technique has some limitations. Only the neutron spectrum, not the ion distribution, can be reconstructed (basic TOF method). In the case of using several nTOF signals in two opposite directions (extended TOF method [1]), one can obtain the time-resolved spectrum of fusion neutrons or one component of the colliding ions
$(\mathrm{E}_{\mathrm{d}}\cos^{2}(\theta))$
in maximum. It is the limit of the backward technique; the ion distribution cannot be revealed.