The study of an (e,n) reaction based 4-dimensional point neutron source

The TOF (time of flight) technology asks for a short pulse width to reduce the flight distance while keeping a good enough energy resolution for neutrons. To conduct the MeV neutron resonant analysis, the pulse width should be as small as nanosecond or even smaller. In this research, the virtual photons induced (e,n) reaction is investigated for the possibility of realizing a 4-dimensional (x,y,z and t) point fast neutron source. Geant4 was used to simulate the properties of the neutron source, in which a 100 MeV electron beam bombards onto a 1-mm-thick tantalum target. The results show that the root-mean-square size of the neutron source is ~0.23 mm and that of the generation time is ~0.21 ns. Fast neutron resonance analysis can thus be realized within a <; 1 m flight path distance, with negligible optical aberration and the energy resolution of ~0.5 %@2 MeV for light isotopes identification imaging. An experiment with a 100 MeV eLINAC and the thin
¹⁸¹
Ta foil is conducted to confirm the feasibility of realizing 4-dimensional point neutron source. The results will be discussed in this article.