Gadget

"Gadget" was the code name given to the first atomic device tested. It was called a device because it was not yet a deployable weapon and words like "atomic" or "bomb" were avoided for security reasons. The Gadget was an implosion-type plutonium bomb similar in design to the Fat Man bomb used three weeks later in the attack on Nagasaki.

Due to the complicated design of the device, it was decided that a test would be necessary prior to deployment. The Gadget was tested on July 16th, 1945, at the Trinity Site near Alamogordo, New Mexico. The initial assembly took place at the George McDonald Ranch House. For the test, the Gadget was raised to the top of a hundred-foot steel tower.

J. Robert Oppenheimer made one final inspection, as described in the book The Making of the Atomic Bomb, by Richard Rhodes: "Sometime early that evening Oppenheimer climbed to the tower platform to perform a final ritual inspection. There before him crouched his handiwork. Its bandages had been removed and it was hung now with insulation wires that looped from the junction boxes to the detonator plugs that studded its dark bulk, an exterior ugly as Caliban's. His duty was almost done."

This mock-up of the gadget was developed by a team of volunteers and staff. The brass-colored objects represent the detonators, with silver-colored cones representing strain gauges used to measure the expansion of the aluminum sphere to determine deficiencies should the device not work as planned.

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