Prompt neutron emission in the neutron-induced fission of 239Pu and 235U

A series of experiments has been performed to measure the dependence on the fragment mass and total kinetic energy of the average number and energy of prompt neutrons emitted from U-235 and Pu-239 fission fragments in thermal neutron induced fission. The experiments were carried out using neutrons from the PNPI WWR-M research reactor in Gatchina. For the Pu-239 target the fragment - neutron correlation measurement was also performed at the first resonance. In this case the neutron energy of the strong resonance at 0.296 eV was selected by a Sin filter which was arranged in the neutron flux from the reactor. The description of the experimental set-up and some preliminary results of the average number and kinetic energies of prompt neutrons as a function fragment mass are presented in this article.