Delayed Neutrons from the Spontaneous Fission ofCf252

The periods and absolute yields of delayed neutrons emitted following the spontaneous fission of ${\mathrm{Cf}}^{252}$ have been measured. Delayed-neutron periods of ${\tau }_{\frac{1}{2}}=0.5\mathrm{}\pm 0.4, 2.0\pm 0.4, \mathrm{and} 20.0\pm 0.5$ sec with respective absolute yields of 0.35, 0.29, and 0.22% were found. The experimental results have been correlated with delayed-neutron emission from other fission processes and with existing precursor systematics.