"...Polonium is useful for constructing a real nuclear bomb, however. A small capsule containing Polonium and Berylium in close proximity is placed at the center of the Plutonium core. When the shaped HDX charges surrounding the core are detonated simultaneously, the shock wave compresses the core to a critical mass, and the Polonium is pressed up against the Berylium. The alpha particles from the Polonium dislodge neutrons from the Berylium, ensuring that the chain reaction gets started properly....Modern bombs use other types of neutron sources. The short half life of Polonium creates too much of a maintenance headache..."
Is Cynwoody "the man who knew too much"?
LOL.
Diagram of Fat Man type gadget (from Wikipedia).
The little red dot is the neutron initiator, which used Polonium and Berylium in early designs. Once the chain reaction gets going, it runs through about 80 generations, requiring about 800 nanoseconds elapsed time.
April, 1944 - Monsanto begins delivering polonium for initiator research. The rate is initially 2.5 curies/month.