Properties of radiation from portable pulsed neutron generators

The results of computational studies of the effect of the building materials used in ING-031, -06 pulsed neutron generators, produced by the Dukhov All-Russia Research Institute of Automatics, on the properties of the neutron and photon fields in the air near them are presented. The studies showed that in the real structures of the generators both the angular and energy distributions of the neutrons and photons change considerably. An isotropic angular distribution of the neutrons emanating from the target becomes anisotropic. Low-energy neutrons, which are not present in a pure target with no structural elements, appear in the energy distribution of the neutrons leaving the surface of the generator. The energy range extends to the thermal region. High-energy photons from inelastic scattering and radiative capture, which are absent in pure targets, appear as a result of the interaction of the neutrons with the structural elements. The building elements in a pulse generator distort the shape of the neutron pulse because of the appearance of moderated neutrons. The regularities found must be taken into account when solving practical problems arising with the use of neutron generators.