Previously, the Soviet Union allegedly used many of their spies in the U.S. to help them generate methods and ideas for the nuclear bomb.
The creation of the hydrogen bomb required less usage of this method, although they still received help from some spies, most importantly, Klaus Fuchs.
[3] In the same year, Teller postulated a new design for the hydrogen bomb, which he called the "Alarm Clock", which he suggested would use lithium-6 deuteride instead of pure deuterium.
This information resulted in the recruitment of Igor Tamm’s group, whose work helped create the hydrogen bomb.
In early 1950, Klaus Fuchs was arrested in the United Kingdom, and was unable to continue his espionage activity for the Soviet Union.
By spring of 1954, the Soviet scientists began to understand the possibility of releasing radiation from the nuclear-bomb trigger and using it to initiate the fusion part of the bomb.
They subsequently abandoned the single-stage layer-cake and tube designs, and focused entirely on the two-stage bomb project.
After the Bravo Test in March 1954, Soviet scientists started to search for ways to make an effective large-yield thermonuclear bomb.
"[9] The initial alarm-clock method derived by Teller was assessed by Stanislaw Ulam, who decided that it would be more difficult and costlier than expected.
The alarm-clock dilemma lasted until 1951, when Ulam came up with the idea of compressing a thermonuclear secondary with the hydrodynamic shock produced by a primary fission bomb.
The first stage of the hydrogen bomb resembled the layer-cake design, except the main difference is that the initiation is carried out by a nuclear device, rather than a conventional explosive.
The fusion cell itself was not very powerful, coming out to about 17.6 MeV per reaction,[clarification needed] but the quantity of hydrogen fuel can be scaled up to make the weapon as large as desired.
In theory, an atomic initiator would be positioned in the center of a spherical housing that was surrounded by layers of thermonuclear fuel and uranium.
This design was referred to as the "Sloika" by Sakharov's co-workers as it resembled a traditional Russian, multi-layered cake that was tightly held together by a thick cream.
This was refused to minimize the access to intelligence materials but instead on 27 April D–T cross-section measurements were sent to Tamm and Kompaneets without mentioning the origin.
[11] On 24 December 1954, the decision for implementation of the idea of atomic compression was green-lit by Soviet officials in a new project code named RDS-37.
This led to the development of a canonical system in which both the primary and secondary modules were placed into the same compartment to maximize the directional scattering of X-rays.
[11] The technical specifications for the bomb design were completed by 3 February 1955 but were continuously reevaluated and improved up until RDS-37 was delivered to the test site in Semipalatinsk.
[7] In a report written by Yakov Borisovich Zel'dovich and Andrei Sakharov, it was stated that the new principle of atomic compression as seen in the RDS-37 was a "shining example of creative teamwork".
[17] Despite the reduction in yield, much of its shock wave was focused back downward at the ground unexpectedly because the weapon detonated under an inversion layer, causing a trench to collapse on a group of soldiers, killing one.
[18] A group of forty two individuals in Kurchatov were also recorded as having been injured from the glass fragments flying out due to the breaking of the windows (confirmation needed as it is an assumption by common sense) caused by the explosion.
The shock wave of dust and debris caused by the explosion could be seen and heard approaching and reached the viewing station roughly ninety seconds after the thermonuclear detonation.
All viewers were forced to fall down on their faces with their feet pointed toward the explosion to help avoid injury from flying debris.
[8] The RDS-37 tests at the Semipalatinsk Site proved to bring the Soviet Union back into the arms race with the United States.
A large part of this was due to the fact that the Soviet Union was the first nation to successfully employ the use of lithium deuterium as a thermonuclear fuel.
"The test was the culmination of many years of labor, a triumph that has opened the way to the development of a whole range of devices with diverse high-performance characteristics.
Now, 22 November 1955, marked the date where the Soviet Union possessed a weapon that could destroy any target in the United States.
[14] The thermonuclear weapons race between the United States and the Soviet Union exceeded all expectations set out before the scientists who took part.
Two countries creating thermonuclear weapons with such energy yields from two different design methods proved to be the crowning achievement for science in the 1950s [clarification needed].
The Tsar occurred over the southern half of the Arctic polar desert island of Novaya Zemlya, with no similar population centers within hundreds of kilometers at that time.