They repeated their experiment in 1970 looking for spontaneous fission.

All these isotopes are characterized by high rates of spontaneous fission.

The first study produced evidence for a spontaneous fission with a 0.3 second half-life and another one at 8 seconds.

This further underwent spontaneous fission with a half-time of about 1.3 h.

Pu-240 has a high rate of spontaneous fission, which can cause a nuclear weapon to predetonate.

The most commonly used spontaneous fission source is the radioactive isotope californium-252.

A fourth decay by direct spontaneous fission was also proposed.

Uranium, for example, constantly undergoes spontaneous fission at a very slow rate.

One possible neutron source is californium-252 which undergoes spontaneous fission.

It was found that the final nucleus undergoes spontaneous fission.