Abstract
Measurements have been made of the absolute values of the effective fission cross sections in U233, U235, Pu239 and Pu240, using as photoneutron sources Sb + Be (∼ 30 kev), Na + D2O (∼ 250 kev), Na + Be (∼ 900 kev), a source with a simulated fission-neutron spectrum and Po-α-Be. The fission cross sections for 30 kev-neutrons are 3.06 ± 0.16, 2.21 ± 0.12 and 1.79 ± 0.11 barns for U233, U235 and Pu239, respectively. As the neutron energy Is increased from 30 kev to 250 kev the cross sections in U233 and U235 fall off by approximately 35% and then remain almost constant while the cross section in Pu239 falls off by 12% and then increases. The effective cross sections for fission in Pu240 for 900-kev and 5-Mev neutrons is ∼ 1.4 barns and the threshold for fission in Pu240 lies within the limits 250 and 900 kev.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
