Клаус Фукс: Атомный шпион и физик-теоретик

German born British physicist and atomic spy (1911–1988)

Klaus Emil Julius Fuchs (29 December 1911 – 28 January 1988) was a German theoretical physicist and atomic spy who supplied information from the American, British, and Canadian Manhattan Project to the Soviet Union during and shortly after World War II. While at the Los Alamos Laboratory, Fuchs was responsible for many significant theoretical calculations relating to the first nuclear weapons and, later, early models of the hydrogen bomb. After his conviction in 1950, he served nine years in prison in the United Kingdom, then migrated to East Germany where he resumed his career as a physicist and scientific leader. The son of a Lutheran pastor, Fuchs attended the University of Leipzig, where his father was a professor of theology, and became involved in student politics, joining the student branch of the Social Democratic Party of Germany (SPD), and the Reichsbanner Schwarz Rot Gold, the SPD's paramilitary organisation. He was expelled from the SPD in 1932, and joined the Communist Party of Germany (KPD). He went into hiding after the 1933 Reichstag fire and the subsequent persecution of communists in Nazi Germany, and fled to the United Kingdom, where he received his PhD from the University of Bristol under the supervision of Nevill Francis Mott, and his DSc from the University of Edinburgh, where he worked as an assistant to Max Born. After the Second World War broke out in Europe, he was interned in the Isle of Man, and later in Canada. After he returned to Britain in 1941, he became an assistant to Rudolf Peierls, working on "Tube Alloys"—the British atomic bomb project. He began passing information on the project to the Soviet Union through Ursula Kuczynski, codenamed "Sonya", a German communist and a major in Soviet military intelligence who had worked with Richard Sorge's spy ring in the Far East. In 1943, Fuchs and Peierls went to Columbia University, in New York City, to work on the Manhattan Project. In August 1944, Fuchs joined the Theoretical Physics Division at the Los Alamos Laboratory, working under Hans Bethe. His chief area of expertise was the problem of implosion, necessary for the development of the plutonium bomb. After the war, he returned to the UK and worked at the Atomic Energy Research Establishment at Harwell as head of the Theoretical Physics Division. In January 1950, Fuchs confessed that he had passed information to the Soviets over a seven year period beginning in 1942. A British court sentenced him to fourteen years' imprisonment and he was subsequently stripped of his British citizenship. He was released in 1959, after serving nine years, and migrated to the German Democratic Republic (East Germany), where he was elected to the Academy of Sciences and became a member of the Socialist Unity Party of Germany (SED) central committee. He was later appointed deputy director of the Central Institute for Nuclear Physics in Dresden, where he served until he retired in 1979.

Klaus Emil Julius Fuchs was born in Rüsselsheim, Grand Duchy of Hesse, on 29 December 1911, the third of four children of a Lutheran pastor, Emil Fuchs, and his wife Else Wagner. In the March 1932 German presidential election, the SPD supported Paul von Hindenburg for President, fearing that a split vote would hand the job to the Nazi Party (NSDAP) candidate, Adolf Hitler. However, when the Communist Party of Germany (KPD) ran its own candidate, Ernst Thälmann, Fuchs offered to speak for him, and was expelled from the SPD. That year Fuchs and all three of his siblings joined the KPD. Fuchs and his brother Gerhard were active speakers at public meetings, and occasionally attempted to disrupt NSDAP gatherings. At one such gathering, Fuchs was beaten up and thrown into a river. When Hitler became Chancellor of Germany in January 1933, Fuchs decided to leave Kiel, where the NSDAP was particularly strong and he was a well known KPD member. He enrolled at the Kaiser Wilhelm Institute for Physics in Berlin. On 28 February, while on a train to Berlin for a secret KPD meeting, he read a newspaper article on the Reichstag fire. Fuchs correctly assumed that opposition parties would be blamed for the fire, and surreptitiously removed his hammer and sickle lapel pin. Fellow party members urged him to continue his studies in another country. He went into hiding for five months in the apartment of a fellow party member. In August 1933, he attended an anti fascist conference in Paris chaired by Henri Barbusse, where he met an English couple, Ronald and Jessie Gunn, who invited him to stay with them in Clapton, Somerset. He was expelled from the Kaiser Wilhelm Institute in October 1933.

Fuchs arrived in England on 24 September 1933. Jessie Gunn was a member of the Wills family, the heirs to Imperial Tobacco and benefactors of the University of Bristol. She arranged for Fuchs to meet Nevill Francis Mott, Bristol's professor of physics, and he agreed to take Fuchs on as a research assistant. Fuchs earned his PhD in physics there in 1937. A paper on "A Quantum Mechanical Calculation of the Elastic Constants of Monovalent Metals" was published in the Proceedings of the Royal Society in 1936. By this time, Mott had a number of German refugees working for him, and lacked positions for them all. He did not think that Fuchs would make much of a teacher, so he arranged a research post for Fuchs, at the University of Edinburgh working under Max Born, who was himself a German refugee. Fuchs published papers with Born on "The Statistical Mechanics of Condensing Systems" and "On Fluctuations in Electromagnetic radiation" in the Proceedings of the Royal Society. He also received a Doctorate in Science degree from Edinburgh. Fuchs proudly mailed copies back to his father, Emil, in Germany. In Germany, Emil had been dismissed from his academic post, and, disillusioned with the Lutheran Church's support of the NSDAP, had become a Quaker in 1933. He was arrested for speaking out against the government and was held for a month. His daughter, Elisabeth, married a fellow communist, Gustav Kittowski, with whom she had a child they named Klaus. Elisabeth and Kittowski were arrested in 1933, and sentenced to 18 months imprisonment but were freed at Christmas. Emil's son, Gerhard, and his wife Karin were arrested in 1934 and spent the next two years in prison. Gerhard, Karin, Elisabeth and Kittowski established a car rental agency in Berlin, which they used to smuggle Jews and opponents of the government out of Germany. After Emil was arrested in 1933, his other daughter, Kristel, fled to Zurich, where she studied education and psychology at the University of Zurich. She returned to Berlin in 1934, where she too worked at the car rental agency. In 1936, Emil arranged with Quaker friends in the United States for Kristel to attend Swarthmore College there. She visited her brother, Klaus Fuchs, in England en route to America, where she eventually married an American communist, Robert Heineman, and settled in Cambridge, Massachusetts. She became a permanent resident in the United States in May 1938. In 1936, Kittowski and Elisabeth were arrested again, and the rental cars were impounded. Gerhard and Karin fled to Czechoslovakia. Elisabeth was released and went to live with her father, Emil, while Kittowski, sentenced to six years, later escaped from prison and also made his way to Czechoslovakia. In August 1939, Elisabeth died by suicide by throwing herself from a train, leaving Emil to raise her young son, Klaus.

At the request of Norris Bradbury, who had replaced Robert Oppenheimer as director of the Los Alamos Laboratory in October 1945, Fuchs stayed on at the laboratory into 1946 to help with preparations for the Operation Crossroads weapons tests. The US Atomic Energy Act of 1946 (McMahon Act) prohibited the transfer of information on nuclear research to any foreign country, including Britain, without explicit official authority, and Fuchs supplied highly classified U. S. information to nuclear scientists in Britain and to his Soviet contacts. as of 2014, British official files on Fuchs were still being withheld. as of 2020, the National Archives listed one dossier on Fuchs, KV 2/1263, including the "Prosecution file. With summary of early interrogations and details of the scientifical/technical information passed to the Russians". The date of release of this material was not stated. According to an October 2020 book review, author Nancy Thorndike Greenspan "appears to have had access to some of the Fuchs files that have been withheld at Kew, such as the AB/1 series, which has been closed for access for most human beings". Fuchs was highly regarded as a scientist by the British, who wanted him to return to the United Kingdom to work on Britain's postwar nuclear weapons programme. He returned in August 1946 and became the head of the Theoretical Physics Division at the Atomic Energy Research Establishment at Harwell. From late 1947 to May 1949 he gave Alexander Feklisov, his Soviet case officer, the principal theoretical outline for creating a hydrogen bomb and the initial drafts for its development as the work progressed in England and America. Meeting with Feklisov six times, he provided the results of the test at Eniwetok Atoll of uranium and plutonium bombs and the key data on production of uranium 235. Also in 1947, Fuchs attended a conference of the Combined Policy Committee (CPC), which was created to facilitate exchange of atomic secrets at the highest levels of governments of the United States, United Kingdom and Canada. Donald Maclean, another Soviet spy, was also in attendance as British co secretary of CPC.

By September 1949, information from the Venona project indicated to GCHQ that Fuchs was a spy, but the British intelligence services were wary of indicating the source of their information. The Soviets had broken off contact with him in February. Fuchs may have been subsequently tipped off by Kim Philby. After a great deal of research for his 2019 biography, Trinity, Frank Close confirmed that while MI5 suspected Fuchs for over two years, "it was decrypters at GCHQ who supplied clear proof of his guilt not the crack American team that is normally given all the credit", according to a review of the book. Under interrogation by MI5 officer William Skardon at an informal meeting in December 1949, Fuchs initially denied being a spy and was not detained. According to Nancy Thorndike Greenspan, author of a 2020 book, Atomic Spy: The Dark Lives of Klaus Fuchs, Skardon told Fuchs that if he admitted his earlier espionage activity, he could be permitted to continue to work at Harwell. In October 1949, Fuchs had approached Henry Arnold, the head of security at Harwell, with the news that his father had been given a chair at the University of Leipzig in East Germany, and this information became a factor as well. In early January Fuchs was informed that he must resign his position at Harwell because of his father’s appointment in East Germany. He was offered help in finding a university post. Meeting with Skardon for a fourth time on 24 January 1950, Fuchs voluntarily confessed that he had shared information with the Soviets. According to Nancy Thorndike Greenspan, Skardon’s report on their meeting “made no mention of his promise to Fuchs to stay on at Harwell if he confessed,” but at the subsequent debriefing it was agreed “to maintain FUCHS in his present state of mind, and for this state of mind to be in no way disturbed”. To make it possible to prosecute Fuchs, Skardon proposed that Fuchs be asked to prepare a signed statement, which he then did at the War Office in London. The document included the statement “I was given the chance of admitting it and staying at Harwell or clearing out.”

Three days later, he also directed a statement more technical in content to Michael Perrin, the deputy controller of atomic energy within the Ministry of Supply. Fuchs told interrogators that the NKGB had acquired an agent in Berkeley, California, who had informed the Soviet Union about electromagnetic separation research of uranium 235 in 1942 or earlier. Fuchs's statements to British and American intelligence agencies were used to implicate Harry Gold, a key witness in the trials of David Greenglass and Julius and Ethel Rosenberg in the United States. Fuchs later stated that he passed detailed information on the project to the Soviet Union through courier Harry Gold in 1945, and further information about Edward Teller's unworkable "Super" design for a hydrogen bomb in 1946 and 1947. Fuchs also stated that "The last time when I handed over information [to Russian authorities] was in February or March 1949". Fuchs, however, was not told how the Soviets would or would not use his information, and though certain questions from his espionage contacts suggested to him that the Soviets had additional sources within the Manhattan Project, he was unaware of their identities and knowledge. He told Perrin that he was himself "extremely surprised" at the speed at which the Soviets developed their own atomic bomb, "as he had been convinced that the information he had given could not have been applied so quickly and that the Russians would not have had the engineering design and construction facilities that would be needed to build large production plants in such a short time." The head of the British H bomb project, Sir William Penney, visited Fuchs in prison in 1952. While imprisoned, Fuchs was friendly with the Irish Republican Army prisoner Seamus Murphy with whom he played chess and helped to escape. Fuchs was released on 23 June 1959 after he had served nine years and four months of his sentence (as was then required in England where long term prisoners were entitled by law to one third off for good behaviour in prison) at Wakefield Prison and promptly emigrated to the German Democratic Republic (GDR).

On arrival at Berlin Schönefeld Airport in the GDR, Fuchs was met by Grete Keilson, a friend from his years as a student communist. They were married on 9 September 1959. In the GDR, Fuchs continued his scientific career and achieved considerable prominence as a leader of research. He became a member of the SED central committee in 1967, and in 1972 was elected to the Academy of Sciences where from 1974 to 1978 he was the head of the research area of physics, nuclear and materials science; he was then appointed deputy director of the Central Institute for Nuclear Physics in Rossendorf, Dresden, where he served until he retired in 1979. From 1984, Fuchs was head of the scientific councils for energetic basic research and for fundamentals of microelectronics. He received the Patriotic Order of Merit, the Order of Karl Marx and the National Prize of East Germany. In The Nuclear Express: A Political History of the Bomb and Its Proliferation (2009) by Thomas Reed and Daniel Stillman, it is argued that a tutorial Fuchs gave to Qian Sanqiang and other Chinese physicists helped them to develop the first Chinese atomic bomb, the 596, which was tested five years later. Three historians of nuclear weapons history, Robert S. Norris, Jeremy Bernstein, and Peter D. Zimmerman, challenged this particular assertion as "unsubstantiated conjecture" and asserted that The Nuclear Express is "an ambitious but deeply flawed book".

Fuchs died in Berlin on 28 January 1988. He was cremated and honoured with burial in the Pergolenweg Ehrengrab section of Berlin's Friedrichsfelde Cemetery.

Robert C. Williams collection of Klaus Fuchs biography material, 1943–1989, Niels Bohr Library & Archives