Determination of gaseous fission product yields from 14 MeV neutron induced fission of 238 U at the National Ignition Facility

We determined fission yields of xenon ( 133m Xe, 135 Xe, 135m Xe, 137 Xe, 138 Xe, and 139 Xe) resulting from 14 MeV neutron induced fission of depleted uranium at the National Ignition Facility. Measurements begin approximately 20 s after shot time, and yields have been determined for nuclides with half-lives as short as tens of seconds. We determined the relative independent yields of 133m Xe, 135 Xe, and 135m Xe to significantly higher precision than previously reported. The relative fission yields of all nuclides are statistically indistinguishable from values reported by England and Rider (ENDF-349. LA-UR-94-3106, 1994 ), with exception of the cumulative yield of 139 Xe. Considerable differences exist between our measured yields and the JEFF-3.1 database values.