The fission cross sections of 233U, 234U, 235U, 236U, 237Np 239Pu, 240Pu and 241Pu for 24 keV neutrons

Abstract The fission cross sections of various nuclides have been measured using 24 keV neutrons from an SbBe photoneutron source. The neutron flux from this source was determined either directly or indirectly by means of three independent absolute flat response detectors; namely the NPL manganese bath, the AWRE oil bath and the AERE boron pile. The values of the cross sections obtained, in barns, are as follows. 233 U 2·73 ± 0·11, 234 U 0·015 ±0·004, 235 U 2·36 0·06, 236 U ⩽ 0·004, 237 Np 0·11 +- 0·002, 239 Pu 1·66 ± 0·007, 240 Pu 0·106 ± 0·018, 241 Pu 2·83 ± 0·21. These results are compared with previous measurements at or near this energy.