shake

shake

Timeexact by definition

A shake is exactly 10 nanoseconds. It is a real unit of nuclear engineering, sized to the interval between generations in a fission chain reaction, which makes the multiplication of a chain conveniently countable in whole shakes.

1 shake 1.0000000e-08 s
Where the unit came from

The name comes from "two shakes of a lamb's tail", coined during the Manhattan Project, and appears to have started as a joke that turned out to be too useful to drop.