Tales of the Soviet hydrogen bomb

Abstract

I was one of a very few non-Russian and non-US participants at the fascinating History of the Soviet Atomic Project conference held in May 1996 at the Joint Institute for Nuclear Research in Dubna, north of Moscow. The article “The secret of the Soviet hydrogen bomb” by Alex Wellerstein and Edward Geist (Physics Today, April 2017, page 40) brings up many memories from that meeting.After arriving home from the conference, I wrote an article about it for my institute’s magazine. I think a few details and reflections from that article are worth adding to the international record. They mainly derive from my discussions with Arnold Kramish, a Manhattan Project veteran whom I got to know well during the Dubna meeting and through letters exchanged in the years before his death.After the war Kramish had worked for the US Atomic Energy Commission as a liaison to the Central Intelligence Agency; he provided intelligence estimates on Soviet nuclear capabilities. Shortly before the Teller–Ulam idea was born in early 1951, he had passed on to Stanislaw Ulam intelligence material about Soviet experiments in which extremely strong magnetic fields had been used to compress fusion materials. That information had come from repatriated Austrian physicist Josef Schintlmeister, who, as a victim of the Soviet Alsos operation, was forced to work on the Soviet atomic bomb project and then got insight into work by Peter Kapitza and Andrei Sakharov. Kramish strongly believed that the information Schintlmeister had gathered was the seed of Ulam’s idea of arranging extreme compression of thermonuclear fuel by a physically distinct primary fission charge. Add to that Edward Teller’s idea to employ radiation implosion and the now classical hydrogen bomb was conceived.However, as mentioned in the Wellerstein and Geist article, the concept of radiation implosion stems from a patent filed by Klaus Fuchs and John von Neumann at Los Alamos in May 1946. Fuchs then, like all other British participants in the Manhattan Project, had to go back to the UK in June 1946.Did Fuchs provide the radiation implosion idea to the Soviets? Yes he did, according to former Soviet intelligence chief Vladimir Barkovsky, who spoke at the Dubna meeting. He had collected the documents from Fuchs in London on 13 March 1948; during his talk Barkovsky even showed sketches of the patent. In conversation during the conference banquet, he also said that he thought Fuchs, back in Washington, DC, in 1947 or 1948 for a meeting about UK and US cooperation on nuclear weapons, had gotten new material from an unknown messenger.It is ironic that the development of the H-bomb actually proceeded in a kind of behind-the-scenes de facto cooperation between the two nuclear powers at the time, the US and the Soviet Union. While both nations were struggling to develop thermonuclear weapons, they didn’t realize that the three most important components—compression, staging, and radiation implosion—were already available to be put together. The breakthrough was delayed in the US by Teller’s long inability to give up his belief in his baby, the Classical Super; and in the Soviet Union, by Sakharov’s preoccupation with his baby at the time, the Sloika.A final note on the inflamed relationship between Stan Ulam and Teller: Kramish told me that right after the new H-bomb idea had been conceived, Teller called for a meeting to discuss it. He asked Kramish to take part, and then, after a short pause, Teller added, “Don’t tell Stan!” Section:ChooseTop of page <<CITING ARTICLES© 2018 American Institute of Physics.