[Vinnie_Vidi_Vici]

"Little Boy" did not have a fast neutron trigger and it seemed to work OK.

[El Gato]

"Little Boy" did not have a fast neutron trigger and it seemed to work OK.

True, but it wasn't a boosted subcritcal device either. In fact it was a uranium device, using a gun type mechanism to ram two subcritical masses together to create a critical mass. They were so sure it would work, they never tested it before dropping one on Japan.