Los Alamos scientists devised two designs for an atomic bomb--one
using the uranium and another using the plutonium. The uranium bomb
was a simple design and scientists were confident it would work
without testing. The plutonium bomb worked by compressing the
plutonium into a critical mass which sustains a chain reaction. The
compression of the plutonium ball was to be accomplished by
surrounding it with lens-shaped charges of conventional explosives.
They were designed to all explode at the same instant. The force is
directed inward, thus smashing the plutonium from all sides.
In an atomic explosion, a chain reaction picks up speed as atoms
split, releasing neutrons plus great amounts of energy. The escaping
neutrons strike and split more atoms, thus releasing still more
neutrons and energy. In a nuclear explosion this all occurs in a
millionth of a second with billions of atoms being split.
Project leaders decided a test of the plutonium bomb was essential
before it could be used as a weapon of war. From a list of eight
sites in California, Texas, New Mexico and Colorado, Trinity Site was
chosen as the test site. The area already was controlled by the
government because it was part of the Alamogordo Bombing and Gunnery
Range which was established in 1942. The secluded Jornado del Muerto
was perfect as it provided isolation for secrecy and safety, but was
still close to Los Alamos.