Figure 4: Observation of emission of beta delayed neutrons as a unique signature of material undergoing nuclear fission.
From: Uncovering Special Nuclear Materials by Low-energy Nuclear Reaction Imaging
The interrogating beam is turned off at time = 0 s. (a) Temporal profile of delayed neutrons with a natural uranium target observed using a low-threshold composite fast neutron detector is in good agreement with a common parameterization into six delayed neutron groups (red line). (b) Temporal profile of delayed neutrons with a tungsten target using a low-threshold composite fast neutron detector shows no emission of delayed neutrons. More information on the neutron measurements is provided in Supplementary Materials.
