Direct evaluation of high neutron density environment using reaction induced by laser-driven neutron source

Abstract

We demonstrate that reactions are induced by a high-flux pulse of fast neutrons ( neutrons in ) provided from a laser-driven neutron source (LDNS). The maximum energy of the broadband neutrons reaches a few tens MeV. Several kinds of metal targets are exposed to the fast neutrons. As a result, unstable isotopes, such as , and are produced by reactions and , and are produced by reactions. We evaluate the neutron fluence and energy spectrum using the activation method in conjunction with a time-of-flight measurement. The neutron fluence is determined to be in the energy range from approximately 8 to 20 MeV at 8-mm downstream of the neutron source. The present scheme provides a method to evaluate high-density neutrons seen in stellar environments, which are expected to be generated from future LDNSs.