The Manhattan Project Heritage Preservation Association, Inc.

"Preserving, Exhibiting, Interpreting and Teaching the History of the Manhattan Project"

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The Dragon Experiments


"Tickling the Tail of the Dragon"


The so-called Dragon Experiments derived their name from a common joke that the Los Alamos scientists were "Tickling the Tail of the Dragon" whenever they were working on criticality calculations at the Omega Site.  These were the first attempts to create a temporarily critical mass of fissionable material by sliding a slug of Uranium-235 hydride through a larger mass of the same substance. (See Photo Above).  These manual experiments continued with the hemispheres of plutonium used in the Trinity test bomb, the Fat Man bomb dropped on Nagasaki, and the bombs used at Operation Crossroads in 1946. There were numerous "criticality accidents" with run-away output of energy and radiation. Within a year of the Trinity test, these accidents would claim the lives of two members of the team that assembled the plutonium core at Trinity: Harry Daghlian and Louis Slotin.

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