Cumulative yields in the 14-MeV neutron fission of 238U

The isotopic abundances of the elements xenon, krypton, and cesium formed in the 14-MeV neutron fission of 238 U have been measured mass spectrometrically. The relative yields of some isotopes of krypton, strontium, zirconium, molybdenum, ruthenium, iodine, xenon, barium, cerium, and neodymium were measured using a Ge(Li) detector. The ratios were normalized through isobaric nuclides, and absolute yields were obtained by normalizing the sum of the heavy-mass yields to 100%.The results indicate that the fine structure persists at this excitation energy. In particular, the peak at A = 134 which is so characteristic of thermal fission is still prominent in 14-MeV fission.