The Fission Yield ofXe133and Fine Structure in the Mass Yield Curve

A mass spectrometer investigation of the xenon isotopes formed from ${\mathrm{U}}^{235}$ fission has been made and the fission yield and half-life of ${\mathrm{Xe}}^{133}$ determined. The fission gases were extracted, purified, and the mass spectrometer abundance data obtained within two weeks of the end of the irradiation period. The fission yield of ${\mathrm{Xe}}^{133}$ was found to be 6.29±0.01 percent, which is 20 percent higher than that expected from the mass yield curve. This is further evidence of fine structure in the mass fission yield curve. The half-life value of ${\mathrm{Xe}}^{133}$ was found to be 5.270±0.002 days.