The primary device was a '' COBRA '' deuterium-tritium gas-boosted atomic bomb made by Los Alamos Scientific Laboratory , a very compact MK 7 device . This boosted fission device was tested in the '' Upshot Knothole '' '' Climax '' event and yielded ( out of 50 – 70 kt expected yield range ) . It was considered successful enough that the planned operation series '' Domino '' , designed to explore the same question about a suitable primary for thermonuclear bombs , could be cancelled . The implosion system was quite lightweight at , because it eliminated the aluminium pusher shell around the tamper and used the more compact ring lenses , a design feature shared with the Mark 5 , 12 , 13 and 18 designs . The explosive material of the inner charges in the MK 7 was changed to the more powerful Cyclotol 75/25 , instead of the Composition B used in most stockpiled bombs at that time , as Cyclotol 75/25 was denser than Composition B and thus could generate the same amount of explosive force in a smaller volume ( it provided 13 percent more compressive energy than Comp B ) . The composite uranium-plutonium '' COBRA '' core was levitated in a type-D pit . '' COBRA '' was Los Alamos ' most recent product of design work on the " new principles " of the hollow core . A copper pit liner encased within the weapon-grade plutonium inner capsule prevented DT gas diffusion in plutonium , a technique first tested in '' Greenhouse Item '' . The assembled module weighed , measuring across . It was located at the end of the device , which , as seen in the declassified film , shows a small cone projecting from the ballistic case . This cone is the part of the paraboloid that was used to focus the radiation emanating from the primary to the secondary
Greenhouse Item
Greenhouse Item
Castle Bravo