Measurement of the Variance of the Number of Neutrons Emitted in Fission ofCf252as a Function of the Fragment Mass and Total Kinetic Energy

We have measured the variance of the number of neutrons emitted by individual fragments in fission of ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ as a function of the fragment mass and the total kinetic energy released. The variance does not show pronounced "sawtooth" structure as a function of the fragment mass. We deduce from this that the correlation coefficient between the excitation energies of complementary fission fragments is substantially less than unity for at least some portions of the fragment mass-ratio distribution.