- The gadget
"The gadget" was the code-name given to the first nuclear explosive developed under the
Manhattan Project duringWorld War II , which was tested at the "Trinity" test site onJuly 16 ,1945 . It was so called because it was not a deployable weapon, and because revealing words like "bomb" were not used during the project for fear ofespionage . It was an implosion-typeplutonium device, similar in design to the "Fat Man " bomb used three weeks later in the atomic bombing of Nagasaki, Japan.Design
A subcritical sphere of plutonium was placed in the center of a hollow sphere of
high explosive . Numerous detonators located on the surface of the high explosive were fired simultaneously to produce a powerful inwardpressure on the core, squeezing it and increasing its density, resulting in a supercritical condition and a nuclear explosion.[
Fat Man article for details.]The initial design, based on work done on cyclotron-supplied plutonium would have envisioned a gun-type device, akin to
Little Boy . However, mass-produced plutonium emitted enough neutrons to make it likely that it would pre-detonate with low yield, making this design, known as "Thin Man", unusable.Subsequently, an implosive design was selected, resulting in the design known as
Fat Man . Both Fat Man and the gadget are not strictly "Fat Man type", as the design was modified into a production design, and both were strictly one-off prototypes.Test
The "gadget" was tested at
Trinity Site ,New Mexico , nearAlamogordo . It was feared by some that theTrinity test might "ignite" the Earth's atmosphere, eliminating all life on the planet, although a classified report produced several years earlier had demonstrated that this was not possible [ [http://www.fas.org/sgp/othergov/doe/lanl/docs1/00329010.pdf Report LA-602, "Ignition of the Atmosphere With Nuclear Bombs"] ] . Less wild estimates thought that New Mexico would be incinerated. Calculations showed that the yield of the device would be between 0 (if it did not work) and 20 kilotons (metric, equivalence of TNT). In the aftermath of the test, it appeared to have been a blast equivalent to 18 kt of TNT. It was also a highlycovert operation .References
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