Half-Life: The Divided Life of Bruno Pontecorvo, Physicist or Spy

by Close, Frank

  In December 1943, Fuchs traveled from England to New York; for most of the following year he worked on the gaseous-diffusion method for separating the rare U-235 from the dominant, and heavier, U-238. During this period he informed the Soviet Union that the United States had chosen gaseous diffusion as the means to separate the isotopes, and that this was occurring on an industrial scale. However, Fuchs knew nothing of the significance of plutonium, nor of the nuclear reactor pile in Chicago.13 Nonetheless, by the start of 1945 the Soviets had a broad idea of the West’s program and were convinced that an atomic bomb was possible.

  The Anglo-Canadian reactor project also was “penetrated by Soviet agents.”14 We have already seen one of these agents at work: during his time in Canada, Alan Nunn May handed over microscopic samples of U-235 and U-233 to the USSR. Soviet records show that Kurchatov was very excited to receive these samples, and issued a high-priority demand for more, ideally several grams’ worth.

  At some point, blueprints of the heavy-water reactor also made their way to the USSR, but their source is not known.15 If Pontecorvo was responsible, this would substantiate Gordievsky’s claim that knowledgeable KGB officers “rated Pontecorvo’s work as an atom spy almost as highly as that of Fuchs.”16 If this description is justified, it raises questions such as: What was transmitted, to whom, and how? Pontecorvo’s colleague Herbert Skinner shared his thoughts on the third question with MI5 in 1950, remarking on Bruno’s “frequent” visits to the US-Canadian border, “where he could have met someone.”17 Furthermore, it is intriguing that when Pontecorvo was photographed with colleagues during this period, he invariably looked away from the camera. (See Images I.1 and I.2 on the preceding page.) Although it doesn’t constitute evidence, this behavior appears to be quite deliberate and evasive, and unique to this period in his life.

  IMAGES I.1 AND I.2. Two pictures of the senior scientists at Chalk River, with Bruno avoiding the camera. The scientists, from right to left, are Henry Seligman, Bruno Pontecorvo, Bertrand Goldschmidt, Jules Guéron, Hans von Halban, and Pierre Auger. (IMAGE I.1, WITH BRUNO SECOND FROM THE RIGHT, LOOKING AT HIS FEET, COURTESY PAUL BRODA AND ALAN NUNN MAY COLLECTION. IMAGE I.2, WITH BRUNO SECOND FROM THE RIGHT, LOOKING TO THE SIDE, COURTESY AMERICAN INSTITUTE OF PHYSICS.)

  After Nunn May was arrested, scientists at Chalk River, including Pontecorvo, were vetted by Western intelligence agencies once more. The fact that Bruno passed this test is not really significant, as the vetting process seems to have been inefficient or even flawed. For example, Nunn May’s colleagues knew he was a communist, yet this was missed by MI5.18 Fuchs also slipped through the net, yet there were apparently many incriminating clues. The authorities’ desire to have the best experts on call occasionally caused them to turn a blind eye to politics. Fuchs’s case shows that this failing persisted, perhaps unconsciously, even after Nunn May had been exposed. Similarly, the vetting of Pontecorvo also failed to identify his communist affiliation.

  Nonetheless, apart from Gordievsky’s claims, there is no evidence that Pontecorvo was involved in transmitting blueprints, samples of uranium, or indeed any information from the Anglo-Canadian project. However, it is harder to dismiss the hypothesis that at some stage he was approached by the Soviet Union.

  It seems unlikely that the KGB, under active instruction from Kurchatov to recruit agents at North American laboratories, would have been unaware that a member of the Communist Party was working at Chalk River—a leading expert on nuclear reactors and uranium, whose early research in nuclear physics had meshed so well with Kurchatov’s own. Indeed, while Pontecorvo was working in Joliot-Curie’s laboratory, he and Kurchatov had cited each other’s papers. It is improbable that a “penetration by Soviet agents,” resulting from Kurchatov’s initiative, would not have included some approach to Pontecorvo. What reaction he had is unknown.

  THE OTTAWA SPY RING

  In June 1943, in response to Kurchatov’s intervention with Stalin, the Soviet military intelligence agency, the GRU, sent a new team to Ottawa. Its head was Colonel Nikolai Zabotin, who ended up in a labor camp following the defection of the team’s cipher clerk, Lieutenant Igor Gouzenko. Other members included Lieutenant Pavel Angelov, who made contact with Nunn May, and Colonel Pavel Motinov, who later transported Nunn May’s uranium samples to Moscow.

  At the time, the head of the KGB was Lavrenti Beria, who also became overlord of the Soviet atomic bomb project. Under Beria’s watch, atomic espionage was deemed so important that the KGB recruited its own agents using the Comintern.19

  The KGB was also responsible for counterintelligence at Soviet embassies. Their operations in Ottawa, overseen by resident agent Vitaly Pavlov, were on a smaller scale than the GRU’s, but were important nonetheless. The KGB kept a watch on the GRU. The GRU, for its part, had no access to KGB communications.

  Stalin usually required agents of both the GRU and the KGB to supply information independently before he would trust it. For example, information about the bomb work at Los Alamos, sent by Ted Hall, confirmed the information sent by Klaus Fuchs, and vice versa. Stalin “distrusted intelligence” until it was received from “at least two independent sources.”20

  This is significant if one accepts Gordievsky’s claims about Pontecorvo. Bruno’s cousin Emilio Sereni was well connected in the Comintern, which the Soviets used as a vehicle to recruit contacts. If Pontecorvo was passing information on behalf of the KGB, Gouzenko—a GRU operative—would not have known. And, as we shall see later, the KGB used a uniquely successful courier in Canada whose history had some intriguing overlap with Pontecorvo’s own.

  The GRU’s Colonel Zabotin had not been in Ottawa long before he had earned a reputation as a lover of the high life, an eager party host, ever ready to charm the wives of diplomats. Boisterous and charismatic, he became a great favorite on the diplomatic circuit. As a means of getting to know the inner secrets of a community, this was ideal. This frenetic pace slowed, however, when the wives of the team members arrived from Russia. The presence of the KGB also sobered the GRU team, at least metaphorically.

  The Soviets became aware of the Chalk River laboratory but were unable to penetrate its security, and so initially had no real idea of its purpose. Nunn May’s evidently communist sympathies were known in Moscow, since the GRU chief in Moscow, Fyodor Kuznetsov, instructed Zabotin to make contact with the scientist. Zabotin assigned Angelov to be Nunn May’s contact, and Nunn May was given the code name Alek, which was a somewhat transparent cover for his real name, Alan.

  Following Nunn May’s exposure, the Canadian Royal Commission that investigated the matter noted, “In view of his background and the position he occupied, he was a logical person from whom the Russians could expect to obtain the available knowledge on atomic energy.”21 Nunn May himself told his stepson, Paul Broda, that he was approached by the Soviets early in 1945. At that stage, Angelov was completely unaware of the Chalk River laboratory’s role in nuclear physics, and erroneously thought it to be a factory for making conventional explosives.22 Even allowing for the firewalls between the GRU and the KGB, this makes it unlikely that anyone, let alone Pontecorvo, had been passing significant information since 1943.

  Over several weekends, Nunn May borrowed reports from the Chalk River library on Friday evenings. He would hand them to Angelov, who would hand them back on Sunday evening, enabling Nunn May to return them to the library on Monday morning. In this way, they worked through much of the “basic material” on the chemistry of uranium and plutonium, the design of the Chicago graphite reactor, and basic nuclear data.23 Nunn May did not pass any specific details or blueprints of the heavy-water reactor, however. As we saw earlier, Kurchatov had decided to pursue graphite rather than the heavy-water approach. At the time, ZEEP was near completion, while the NRX was still three years away.

  Nunn May delivered the fateful samples of U-233 and U-235 to Angelov in the first week of July 1945.24 The Soviet embassy informed Moscow by telegram: “ALEK [Nunn May] handed over to us
. . . 162 micrograms of uranium 233 in the form of oxide in a thin lamina.” The news must have caused a sensation in Moscow, because Colonel Motinov—the assistant military attaché in Ottawa—was ordered to bring them from Canada to Moscow personally.

  On July 28, 1945, “The Director” in Moscow sent a telegram to Colonel Zabotin in Ottawa: “Try to get from him [ALEK] before [his return to England] detailed information on the progress of the work on uranium. Discuss with him: does he think it expedient for our undertaking to stay on the spot; will he be able to do that or is it more useful for him and necessary to depart for London?”

  In August, Zabotin visited a friend who lived near Chalk River, and took a cruise along the river so as to take a look at the plant himself. He reported back to Moscow. His superiors replied on August 14, asking him if the friend had contacts in the plant. They followed up on August 22 with the instruction, “Take measures to organize acquisition of documentary materials on the atomic bomb! The technical process, drawings, calculations.”

  So far, Zabotin had not received any assessment from Moscow about the value of the information that he had already sent, so he telegraphed his superiors as follows: “I beg you to inform me to what extent have ALEK’s materials on the question of uranium satisfied you and our scientists (his reports on production etc.). This is necessary for us to know in order that we may be able to set forth a number of tasks on this question to other clients.”25 (Italics added.) The GRU clearly had identified Chalk River as a priority. It is inconceivable that the KGB had not done so also.

  Igor Gouzenko’s defection from the Ottawa embassy in September 1945 had a huge impact in Moscow. Stalin ordered Lavrenti Beria to initiate damage limitation. Both the GRU and KGB immediately severed contact with their agents, without explanation.26 Better to preserve agents for the long term, even if it meant experiencing a slump in intelligence for a while.

  According to Gordievsky, Gouzenko’s defection did not compromise all the Soviet agents in Canada. Nunn May had been working with the GRU network. This was shut down by the Soviets following his exposure. A network of KGB agents remained, however, relatively unscathed.27 Gordievsky’s contacts in the KGB insist that one of these was Bruno Pontecorvo.28

  THE UBIQUITOUS KIM PHILBY

  Gouzenko’s defection, which occurred just three days after the Japanese signed the documents of surrender, was the moment when the Western powers knew for sure that their former ally had become an adversary.29 The most surprising and important name that Gouzenko revealed was that of Bruno’s colleague, Alan Nunn May. The news emerged around this time that Bruno was weighing offers from Harwell and various American institutions. Whether or not his decision was influenced by these events, there is one common thread between them: the role of the infamous double agent Kim Philby.

  At the time, Philby was the head of Soviet counterespionage in London—or at least this was his official job. In reality, Philby was a double agent who worked for the Soviet Union but was paid by the British and would not be exposed until the 1950s.30 When he learned of Gouzenko’s defection and its aftermath, Philby alerted Moscow that Nunn May was under suspicion.31 We know this because later decrypts32 of Soviet diplomatic cables show that, on September 17, Pavel Fitin, a high-ranking NKVD official in Moscow, sent a message to the NKVD resident in London, asking for verification of Philby’s news about the “GRU in Ottawa.”33

  Nunn May was due to return to the United Kingdom in the fall of 1945, and take up a position at King’s College London. In addition to his duties at the university, one of his tasks would be to advise the government on the incipient British nuclear research program, including the new laboratory at Harwell. This would have placed him in a powerful position, with significant interest for the Soviets. At that stage the British did not have solid enough evidence to prosecute Nunn May, so, following his return to England on September 16, security officers from MI5 followed him, hoping to catch him in the act of passing information to a contact.34 Philby was aware of this. He succeeded in alerting the Soviets, who canceled a meeting between Nunn May and his Soviet contact, planned for October 7 in London.35 This was the first of three crucial interventions that Philby would make with regard to atomic scientists, as we shall see. It wasn’t until March 1946 that the British felt confident enough to arrest and prosecute Nunn May.

  Following Gouzenko’s explosive revelations, Western authorities were worried that the Soviets might have targeted other scientists. Pontecorvo was vetted again, along with others at Chalk River. However, these inquiries produced no evidence that anyone else had collaborated with the Soviets, or shared any secret information with unauthorized people—at least, as far as the Canadian team was concerned. As we have seen, Pontecorvo had been weighing various attractive job offers from American institutions during the latter half of 1945, only to turn them down in favor of Harwell, a fact that Segrè later regarded with suspicion. If Segrè’s worries have any basis in fact, then the timing of this choice, which came just as Philby had made the Soviets aware of Nunn May’s exposure, is intriguing. And these weren’t the only pieces moving on the chessboard of Pontecorvo’s destiny at this time.

  Klaus Fuchs, for example, was still at Los Alamos, free from suspicion. In September 1945, Fuchs told his Soviet controller that he would return to England after the war. In November he was interviewed for a position at Harwell, and his appointment there was arranged. Fuchs then prepared to leave the United States, which he did in June 1946, eventually starting work at Harwell in August.

  In the meantime, with the Nunn May affair known to the authorities, but not yet to the public, Chadwick agreed to hire Pontecorvo at Harwell, with no constraints on his travel. In response, Bruno suddenly announced that he wanted to stay in Canada, at least for a while.36

  As the facility at Harwell was still under construction, and many decisions about its personnel were being made, it is possible that these intermingled events were nothing more than chronological coincidences. However, if one gives credence to the claims that Pontecorvo had been working for the Soviets since 1943, the timing becomes more tantalizing. In any event, the role of Philby—who first alerted the Soviets about the Western intelligence community’s interest in Nunn May, then later tipped them off about Fuchs, and later still, as we shall see, about Pontecorvo—will become central to the whole affair.

  LONA COHEN A.K.A. HELEN KROGER

  Nunn May had worked exclusively with the GRU. Meanwhile, the KGB had its own ring of spies. At Los Alamos these included the brilliant young prodigy Ted Hall. Hall had entered Harvard at age sixteen, and two years later joined the team at Los Alamos, where he was one of the youngest scientists to work on the bomb. Unknown to his colleagues, discussions with his roommates at Harvard had crystallized Hall’s interest in Marxist ideology. He felt that it was essential for the USSR to build a bomb, to prevent a US monopoly.

  Hall probably had a deeper knowledge of the bomb’s dynamics than Klaus Fuchs.37 Fuchs is well known because in 1950 he was exposed and then convicted with much publicity. Hall’s name is not as well known. He was only identified as a result of VENONA decrypts that mentioned an agent code-named MLAD, Russian for “youngster.” The decoded messages also revealed the details of MLAD’s travels, which enabled his true identity to be pinpointed in the spring of 1950.38 Nonetheless his name only became public knowledge in the 1990s.

  The reasons Hall was never prosecuted are complex, but a crucial factor was that he refused to confess, unlike Fuchs and Nunn May. Another key to his success was his KGB contact: the American Lona Cohen. Lona Cohen and her husband, Morris, were arguably the most successful of all the couriers and organizers that the Soviets had in North America, and were later celebrated as “heroes of Soviet intelligence.”39

  Born in Connecticut just four months before Bruno in 1913, Lona was born to Jewish immigrants, the fifth of ten children, just as Bruno was number four out of eight. Lona’s parents worked in textile mills, whereas Bruno’s father owned one. Bruno l
ed a life of relative privilege, leaving at age twenty-three for Paris, where his intellectual curiosity led him to communism. Lona grew up in the hard reality of the Great Depression, and watched her parents scrimp and save to raise the children. Lona left home at age thirteen to find work in New York, where she witnessed social injustice firsthand, became a committed leftist, and in 1935 joined the US Communist Party.

  Bruno met Marianne in 1936, and the course of their lives was ultimately determined by his commitment to communism. Lona met Morris in July of 1937, and was later recruited by her husband as an agent for the Soviet Union.40 She was given the code name Helen, which would later have ironic resonance.

  When the United States entered the war, Morris was drafted into the US Army, so “Helen” took over his network of seven agents. She was one of the mules of Soviet espionage. Her job was to pick up clandestine copies of documents that had been smuggled out of research centers, carry them secretly across the country, and deliver them to the central controller—in her case, the Soviet resident in New York. This separated the source of information from the central controller, who would know the source’s nom de guerre but not always his or her true identity. Lona was so successful that the resident soon assigned her more sources; in the spring of 1945, she was put in contact with the young Los Alamos physicist Ted Hall.

  Some of the most important atomic papers received by the Soviets originated with Hall, and were couriered by the woman he knew only as Helen.41 The fact that Hall remained undetected for so long (and ultimately refused to confess) also protected the identity of the Cohens throughout the war and for nearly two decades thereafter.