Passage: The first attempt to exploit the symbiotic relationship between fission and fusion was a 1940s design that mixed fission and fusion fuel in alternating thin layers. As a single-stage device, it would have been a cumbersome application of boosted fission. It first became practical when incorporated into the secondary of a two-stage thermonuclear weapon.The U.S. name, Alarm Clock, came from Teller: he called it that because it might "wake up the world" to the possibility of the potential of the Super. The Russian name for the same design was more descriptive: Sloika (Russian: Слойка), a layered pastry cake. A single-stage Soviet Sloika was tested on 12, 1953. No single-stage U.S. version, but the August 26, 1954, Operation Union Castle yielded a two-stage nuclear device.
6.9 megatoni