Experimental and Theoretical Research on the Angular Distribution of Neutrons Produced in 7Li(p, n)7Be Reactions during the Interaction of Intense Laser Pulses with Solid Targets

Experiments to measure the angular distribution of neutrons produced in Li-7(p, n)Be-7 nuclear reactions have been carried out at the "Neodymium" picosecond laser facility. A beam of protons was generated on the rear side of a thin aluminum target irradiated by laser radiation with a maximum flux density of 3 x 10(18) W cm(-2) (lambda = 1.055 mu m). Traces of organic compounds on the target surface were the source of protons. Protons were incident on a massive LiF target in which the above nuclear reactions occurred. Our measurements have shown that the neutron flux is anisotropic with a degree of anisotropy equal to 2. We have analyzed the angular distribution of the neutron flux using numerical calculations. We show that at certain proton beam parameters characterizing the energy and angular spectra of protons, it is possible to reproduce the experimentally measured angular distribution of the neutron flux. There are proton beam parameters at which the degree of anisotropy of the neutron flux can be increased several-fold compared to the experimentally measured one.