About the poster

Bombs, Spies and Physics

The background on the poster is page from the physics lectures given to the newcomers at Los Alamos at the beginning of the project in 1943. They were told that “The object of the project is to produce a practical military weapon in the form of a bomb in which the energy is released by a fast neutron chain reaction in one or more of the materials known to show nuclear fission.”

The person reading the Times newspaper is Klaus Fuchs, the spy who gave a detailed account of what was going on at Los Alamos to the Soviets. But in effect, he defies any standard definition of a spy. Having fled Germany as a communist student of physics, he got involved in the British effort to build a nuclear bomb in 1941. He moved with the British team to the USA and was a prominent physicist there. After the war the British-US alliance broke up and he moved back to the UK taking his knowledge with him, including that on a possible H-bomb. There is no doubt that Klaus Fuchs was a great boon to the Soviets, living, by means of the Soviet secret service, under the desk of Kurchatov, the father of the Russian bomb. Having helped three powers making the bomb, he was the foremost proliferator of nuclear weapons. On the photograph he is in East Germany, after serving nine years in prison in Great Britain. As more and more files become declassified our perspective on Fuchs is still shifting.

The bottom of the poster shows a modified photograph, taken in the USA in 1939 just before the outbreak of war. On the left is the Dutch-American physicist Samual Goudsmit and on the right two Nobel prize winners, Werner Heisenberg and Enrico Fermi. The latter two would head the efforts to produce a nuclear reactor in Germany and the USA, respectively. Fermi’s reactor became operational at the end of 1942. With that it became possible to have two types of material for a fission bomb: ²³⁵U and ²³⁹Pu. Goudsmit was the scientific leader of the mission to round up the German nuclear physicists. In the “Atomkeller” under a cliff in Haigerloch in the Black Forest he found in April 1945 the remains of a last attempt of Heisenberg to obtain a working reactor. The German effort was dwarfed by the American effort; the Germans had put their money on rocket science. Heisenberg also missed the fact that it is fast neutrons that makes the bomb work. Samual Goudsmit always said this, but his arguments were classified. With all evidence available now Goudsmit appears to be right.