The First War of Physics (33 page)

British Nobel laureate Paul Dirac had acted occasionally as a consultant to the MAUD Committee on aspects of isotope separation and bomb physics. Keen to have such an eminent physicist in the delegation, Anderson telephoned Dirac in Cambridge and asked him to call into his office when next in London. Dirac agreed. As an afterthought, Anderson asked how often Dirac actually came to London. He replied: ‘Oh, about once a year.’ Dirac, too, refused to join the British mission.

All selections were subject to scrutiny by Groves, who had insisted that only British citizens would be accepted, and that they should arrive with full security clearance. Frisch’s enthusiasm for British citizenship was not shared by Rotblat, however, who was adamant that he would remain a Polish citizen and return to Poland to rebuild physics there when the war was over. Rotblat judged this mission to be more important to him than working on the Anglo-American bomb programme. Chadwick made personal representations to Groves on Rotblat’s behalf, giving assurances of Rotblat’s integrity. By this time Chadwick had managed to build something of a rapport with the notoriously blunt, anti-British head of the Manhattan Project. Groves accepted, and Rotblat joined the delegation as a Polish citizen.

Chadwick, Frisch and Rotblat were to go to Los Alamos, with British physicists William Penney and James Tuck. Oliphant was to join Lawrence’s team at the Rad Lab in Berkeley. Peierls and Fuchs were to head for New York to join the work on gaseous diffusion.

Fuchs had already pledged his oath and taken British citizenship a year earlier. British intelligence gave him a security clearance after a rudimentary background check. He advised his Soviet contact Sonja of his impending move. NKVD and GRU atomic intelligence activities had been consolidated with the NKVD First Chief Directorate under the umbrella of ENORMOZ just a few months earlier. Sonja moved quickly. At their next meeting she advised him that his controller in New York would have the cover name Raymond, and gave him a series of coded recognition signals he should use to make contact.

Barely a week after being approached by Chadwick, Frisch found himself at Liverpool docks, part of a group of about 30 scientists, some with
their families. They were to board the
Andes
, a luxury liner that had been converted to bring American troops to Britain. Frisch had forgotten his ticket but Akers waved him through. He found he had an eight-berth cabin all to himself. ‘Some of us got seasick,’ Frisch wrote after the war about the delegation’s journey to America, ‘but otherwise the journey was uneventful, and the ship arrived safely, with perhaps the greatest single cargo of scientific brain-power ever to cross the ocean.’

And in their midst was a Soviet spy.

Niels and Aage Bohr headed for America on the
Aquitania
, early on the morning of 29 November, accompanied by an armed detective. When they arrived they were given the cover names Nicholas and James Baker.

Arlington Hall

In June 1942, the US Army Signals Security Agency had moved into new premises, a former private girls’ school set in 100-acre grounds on Arlington Boulevard, Arlington, Virginia. The school had been named the Arlington Hall Junior College for Women, and the name Arlington Hall (or, sometimes, Arlington Hall Station) was retained. In many respects, Arlington Hall was the American equivalent of Britain’s Bletchley Park.

By October 1943 the analysts at Arlington Hall had identified at least five different variants of the Soviet cipher system. One was used primarily for trade messages originating from Amtorg, the Soviet trade agency, and the Soviet Purchasing Commission which supervised Lend-Lease aid from America. A second was used by Soviet diplomats. The remaining three systems were being used by Soviet spies belonging to the NKVD, the GRU and the Naval GRU.

Lieutenant Richard Hallock had worked as an archaeologist and had studied the ancient languages of Babylonia before joining Arlington Hall. Now he was charged with studying a vast pile of paper consisting of about 10,000 coded Soviet trade and diplomatic messages – page upon page of apparently random and meaningless groups of five letters. But, of course, the groups of letters were not meaningless. Penetrate the cipher system and the coded messages would be revealed. Acquire a codebook or somehow
break into the code and the messages themselves could be read. He confronted the stubborn question: where to begin?

He figured that at the beginning of each message there might be a reference to the subject matter that followed, a pattern that would, perhaps, be repeated for every message, much like addressing conventions in personal or business letters. He arranged for the clerks at Arlington Hall to produce punch cards containing the first five five-letter groups, converted to fivenumber groups, for all 10,000 messages. When these punch cards were run through a sorter, he noticed that seven messages conformed to a pattern. Although unrelated, the messages appeared to have been encrypted using the same cipher key.

For some unknown reason, some of the one-time pads had in fact been used more than once.

¹
Which the German physicists had not dared to touch.

²
This was a convention that dated back to Mansfield Cumming-Smith, the first head of the SIS, who would initial papers that he had read with a ‘C’, written in green ink. Ian Fleming would later adopt a similar convention for his fictional ‘M’.

³
More recent estimates put the death toll at over 21,000.

⁴
It seems the author of the letter was Mironov himself. He also sent a letter to Stalin denouncing Zarubin as a double agent, and both Zarubin and his wife were recalled from Washington in the middle of 1944. Zarubin was able to demonstrate that all his contacts with Americans were legitimate and both he and his wife were cleared. Mironov was then recalled to face charges of slander, but was discovered to suffer from schizophrenia and was subsequently discharged from the NKVD.

PART III

WAR

Chapter 11

UNCLE NICK

November 1943–May 1944

P
ash and de Silva were convinced of Oppenheimer’s guilt, but in the months of intensive surveillance following the taped conversation in Berkeley they could uncover no further evidence of espionage. Lansdale was equally convinced that Oppenheimer was telling the truth, though not all the truth that could be told. Groves, who was himself convinced that Oppenheimer was already irreplaceable, began to weary of Pash’s stubborn and fruitless pursuit. When the decision was taken in November 1943 to commission a secret intelligence mission in Europe, Groves supported the appointment of Pash to lead it. Pash left San Francisco for London.

Pash was gone but the surveillance continued. Oppenheimer was still under considerable suspicion. Groves and Lansdale had challenged him on a couple of occasions to volunteer the name of Eltenton’s intermediary but Oppenheimer had refused. He would yield up a name only if ordered to do so, he said. Groves rationalised this as a childish desire on Oppenheimer’s part not to ‘rat’ on a friend. His inclination was to let the matter rest.

But Groves could not let it rest for long. The investigation into Eltenton’s involvement in suspected Soviet espionage against the Manhattan Project clearly could not progress much further without the name of his
intermediary. In mid-December, Groves finally ordered Oppenheimer to co-operate. Reluctantly, Oppenheimer now gave up Chevalier’s name, but insisted that his friend was merely an innocent messenger. Telegrams naming Chevalier were despatched to the Manhattan Project’s chief security officers the next day. Oppenheimer had had little choice, but he was all too aware of the likely consequences of this revelation for his friend’s career.

Chevalier had taken a year’s sabbatical from Berkeley in July 1943, and in September moved to New York expecting to receive an assignment with the Office of War Information (OWI), which had been split off from the Office of Strategic Services (OSS)
¹
the year before. He waited for news of his application for security clearance through the final months of 1943. In January 1944 he finally received word about his clearance. It was not good. His contact at the OWI had seen his FBI file in Washington. ‘Someone obviously has it in for you’, he said.

There remained the question of the identities of the three physicists whom, according to Oppenheimer, Chevalier was meant to have approached. Groves did not ask and Oppenheimer chose not to elaborate his lie any further. When the FBI pressed for more information, Groves ignored the requests.
²

Pash had identified Jean Tatlock as a prime espionage suspect, most probably the all-important link in the intelligence network between Oppenheimer and the Soviet
rezidentura
in San Francisco. However, here again FBI surveillance turned up no further evidence.

In the first days of January 1944, Tatlock had descended into the blackness of depression. She visited her father on 3 January in a despondent mood and promised to call him the next day. She returned to her apartment and called a female friend, Mary Ellen Washburn, and invited her to come over. But Washburn could not come that night.

After dining alone, Acock took a quantity of sleeping pills. She wrote a short note on the back of an envelope, wishing love and courage to all those who had loved her and helped her, declaring that she had wanted to live but ‘got paralyzed somehow’. The note tailed off into illegibility, as the sleeping pills began to take effect. She partly filled the bathtub and may at this point have taken chloral hydrate – knock-out drops.
³
She passed out, slipped beneath the water, and drowned.

When she didn’t call the next morning her father became concerned. After climbing through a window to gain access to her ominously silent apartment early the following afternoon, he discovered her body in the bath. He didn’t call the police, however, and after carrying his daughter’s body through to the living room and laying it on the sofa, he proceeded to search her apartment. Only when he had burned some of her private correspondence and photographs did he call a funeral parlour. Someone at the funeral parlour alerted the police.

Whatever it was that John Acock did not want discovered about his daughter, it is unlikely that this was anything to do with her activities as a Communist. Although the reasons for Jean Tatlock’s suicide remained obscure,
⁴
her psychoanalysis had revealed latent homosexual tendencies. There were hints of lesbian affairs, including one with Washburn. It may have been denial of her homosexuality that had led her to take so many male lovers.

Whatever the reason, the woman whom Oppenheimer had loved – still loved – and had very nearly married, was now gone. Her death was a bitter blow and he was deeply grieved. On hearing of her death he took a long, quiet and contemplative walk in the woods surrounding Los Alamos.

Little Boy

The Italian physicist Emilio Segrè had found a little haven away from the bustle of the main Los Alamos compound. In December 1943 he had retreated to a small log cabin in secluded Pajarito Canyon, a few miles from the main laboratory. It was here that Segrè repeated experiments on the rate of spontaneous fission in natural uranium, experiments he had earlier performed in Berkeley. The results were much the same, but they hinted at a higher rate for U-235 than he had measured previously. Segrè wondered why.

His conclusion represented a significant discovery, one that was to bring a U-235 bomb much closer to realisation. It was simply a question of altitude, he reasoned. High up on the mesa, 7,300 feet above sea level, Segrè’s samples were so much closer to the constant wash of neutrons that results from cosmic ray bombardment in the earth’s upper atmosphere. The rate of spontaneous fission in U-235 was being affected by these stray neutrons. The closer the sample was to the upper atmosphere, the greater the number of stray neutrons and the higher the rate. At Berkeley, much closer to sea level, the density of stray neutrons was much lower.