Investigation of neutron emission by n-n correlation function in fission process using an array detector

An experimental set-up designed to investigate the origin of the prompt scission neutrons in fission processes by using an array neutron detector is modeled. Quantities of interest as the correlation function strength in the momentum space within a model of independent one-particle pointlike sources, with a Gaussian distribution for the neutron generation points are obtained in a preliminary investigation. Two working hypothesis are used: i) the scission neutrons are emitted from the neck between fragments, in the final stage of the fission process, and ii) the post-scission neutrons are emitted from the accelerated fission fragments. For the scission neutrons emitted from the neck, a n-n correlation strength significantly larger than that obtained for neutrons emitted from the fission fragments is obtained. The results indicate that it is possible to discriminate scission and post-scission neutrons within an time-of-flight experimental set-up consisting from an array neutron detector combined with a VME acquisition system, using (p,xnf) reactions on actinide targets at the Bucharest Tandem. (authors)