Wide-range neutron energy spectra that are produced when an ultraintense laser with an intensity of 3 × 1018 W cm−2 is focused on a CD2 target have been studied. The experimentally observed spectra and numerically calculated ones, by a three-dimensional Monte Carlo code, indicate that the energy range of the emitted neutrons is larger than that of the D(d,n)3He reaction. The reactions that can participate in neutron production and their relative importance have been analysed. An explanation for the measured spectra is introduced by taking into account the 12C(d,n)13N and D(12c,n)13N reactions. These reactions strongly participate in neutron production due to their high cross sections. Moreover, the neutrons from these reactions will overlap the neutrons from the D(d,n)3He reaction, including the 2.45 MeV neutrons, with increasing energy of the accelerated ions under higher irradiances.
High efficiency focus neutron generator