Before the Fallout

by Diana Preston

  The French team had spent a difficult few months. On the outbreak of war in September 1939, Joliot-Curie, a captain in the artillery reserves, had been immediately called up but then given special responsibilities for coordinating government scientific research. This provided cover for his studies of fission. Kowarski and von Halban had quickly been naturalized and then drafted, but, at Joliot-Curie's request, arrangements were made for them to remain with him on special assignment. Joliot-Curie's hope was to demonstrate a self-sustaining chain reaction in natural uranium using slow neutrons, to convince the government that this could provide a potential new source of energy and thereby to win funding to build a nuclear reactor, or "uranium boiler." To do this, he needed not only sufficient quantities of natural uranium but also a suitable "moderator" with which to slow down the bombarding neutrons. Experiments had shown that ordinary water, as used by Enrico Fermi when he had it carried in buckets from the goldfish fountain in the gardens behind his institute in Rome, was not sufficiently effective for his purposes—too many neutrons were lost from the chain reaction. Joliot-Curie decided he must have the denser heavy water.

  Heavy water, though, was scarce and expensive. The only supplier in Europe was the Norsk-Hydro-Electric Company in Norway, of which the German industrial giant IG Farben owned 25 percent. The company's Vemork plant, near Rjukan, manufactured it as a by-product of synthetic ammonia. It was a painfully slow process. Tons of ordinary water were electrolyzed with cheap electricity to release the hydrogen required to manufacture the ammonia. As electrolysis tends to release ordinary hydrogen, this left behind a tiny residue of heavy water. Joliot-Curie briefed the French minister of armaments and Lieutenant Jacques Allier of French intelligence about heavy water's special significance in fission research and pleaded that Norsk-Hydro's entire stock be obtained quickly and brought to France. Allier's interest in the substance had already been raised by reports that IG Farben was demanding without explanation that two tons of heavy water be shipped to Germany. The head of the Norwegian plant, Axel Aubert, a Norwegian of French extraction who was suspicious of its intentions, was stalling but could not fend off IG Farben much longer.

  Consequently, in February 1940, Lieutenant Allier had left Paris secretly by train for Amsterdam, traveling under his mother's maiden name, Freiss. He was carrying a letter from the French president and a credit note for 36 million French francs.* His orders were to bring the entire stock of heavy water to Paris or, if that proved impossible, to render it unusable by contaminating it with cadmium, of which Joliot-Curie had given him a small vial. Despite French precautions, Allier's departure had not gone unnoticed by German agents. French intelligence intercepted a telegram reading, "At any price intercept a suspect Frenchman travelling under the name of Freiss." Nevertheless, by 2 March Allier had reached neutral Sweden, where he made contact with French intelligence agents before slipping into Norway. Upon arrival in Oslo, he had a clandestine meeting with Axel Aubert, who agreed without demur to loan France, free of charge, Norsk-Hydro's entire stock of heavy water—185 kilos—for the duration of the war.

  At the Vemork plant the heavy water was sealed into twenty-six seven-liter cans, specially made by an Oslo craftsman working secretly at home. On 12 March, in a carefully planned exercise, the cans were flown out from under the noses of German agents via Oslo airport. Two airliners on scheduled flights, one to Perth in Scotland and one to Amsterdam, were waiting on the runway. Allier acted as if he intended to board the plane for Holland, paying no attention as the other plane's propellers began to revolve. Suddenly, a large taxi rushed up to the airfield. Inside were both a French agent, enacting a charade about being late for the Amsterdam flight, and the carefully concealed cans of heavy water. The agitated man's taxi was allowed to drive onto the airfield and halted between the two planes, out of sight of the terminal building. The heavy cans were then swiftly manhandled onto the Perth plane, aboard which Allier had meanwhile slipped. It took off almost at once and reached Scotland safely. The subterfuge had been entirely necessary; German fighters forced down the Amsterdam plane, which left soon after, at Hamburg, where it was thoroughly searched but nothing, of course, was found. By mid-March the French had moved their cans of heavy water to Paris, where they were stored in the vaults of Joliot-Curie's College de France.

  The French mission had been timely. On 9 April 1940, a month later, German troops invaded Norway and ended the phony war. However, Paris was not for long a safe home for the heavy water either. On 1 o May the Germans attacked neutral Belgium and Holland. The latter quickly capitulated after heavy bombing raids on Rotterdam that killed 814 civilians. The German blitzkrieg swiftly overran Belgium too. By the end of May, with the evacuation of British troops from Dunkirk under way, and with German forces advancing on Paris, where French government ministries were burning their papers, Joliot-Curie found a temporary hiding place for the drums of heavy water in the death cell of the central prison at Riom, near Clermont-Ferrand. A few days later, von Hal­ban and Kowarski loaded a truck with scientific equipment and fled there from Paris with their families. The Joliot-Curies joined them soon after.

  On 16 June, two days after the fall of Paris to the Germans, Allier arrived with orders for the French scientists to withdraw to Bordeaux for evacuation to England aboard the Broompark. Early the next day, 17 June—the same day Marshal Petain broadcast to the French people that he had assumed control of their government and had applied to the Germans for an armistice—von Halban and Kowarski, a refugee once more, loaded the heavy water onto a truck and, with their wives and children, joined the frightened stream of people heading for the coast. Joliot-Curie followed after leaving Irene, who was suffering from a combination of respiratory problems and anemia, at a sanatorium.

  The port was in chaos, under aerial attack, and crammed with more than five hundred thousand refugees, troops, and abandoned military and civilian vehicles. Von Halban and Kowarski managed to find the Broompark and embarked with the heavy water. Despite the earl of Suffolk's assurances that his wife and children would be brought safely to England, Joliot-Curie decided to remain in France—a decision his mother-in-law, Marie Curie, would have wholeheartedly endorsed. As Irene later told a friend, "My mother would never have abandoned her laboratory." However, it meant that Joliot-Curie would have no further contact with von Halban and Kowarski until the war ended.

  Joliot-Curie never revealed his motivation for staying. Some friends thought that Irene, with her powerful personality that dominated their marriage, was a major factor. Bertrand Goldschmidt, who worked with him again after the war, believed that worries about his poor English and the status and facilities that the British would accord him may have swayed a difficult decision. Joliot-Curie's daughter Helene later suggested that he stayed to help keep French science alive during what he thought would be a long occupation. If such was his main motivation, it had some resemblance to Heisenberg's reasons for remaining in Germany. His decision would certainly confront him with similar moral dilemmas: How far, for instance, should he collaborate with the Nazis to preserve his beloved research facilities for his nation's science?

  The collier was the last cargo ship to sail from Bordeaux. According to Kowarski, Suffolk, who had not shaved for days and whose bare arms were covered with tattoos—symbols of his exuberant eccentricity—"had got the crew too drunk to sail until the machinery and ourselves were aboard." The bemused Russian thought "Suffolk was straight out of Wodehouse. . . . There was sea-sickness: there were 25 women aboard. Suffolk was pouring them champagne. 'This is the perfect remedy,' he said."* When the ship docked at Falmouth, the heavy water, which had been strapped to a raft in hopes it could be salvaged if the Broompark was torpedoed, was transferred first to Wormwood Scrubs prison and then—perhaps most incongruously of all—to the custody of the royal librarian at Windsor Castle.

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  Otto Frisch

  As Otto Frisch had feared, Denmark too had quickly fallen. On the evening of 8 April 1940
, while Niels Bohr was being entertained by King Haakon of Norway at the Royal Palace in Oslo, Nazi forces were preparing to invade his homeland as well as Norway. Unaware of what was about to happen, Bohr boarded the night train for Copenhagen. As the train was shunted off the ferry that had carried it across the Kattegat, Bohr was awakened by Nazi warplanes streaking overhead and shouts that the Germans were coming. At 4:20 a.m. that morning Hitler had presented the Danish government with an ultimatum: accept the protection of his Third Reich without resistance or face all-out attack. While the Danish king and his government agonized, Nazi aircraft flew very low over Copenhagen, their roaring engines emphasizing the Danes' lack of choice. By noon on 9 April, Denmark was an occupied country.

  Bohr hurried to the chancellor of the University of Copenhagen and to members of the Danish government to seek protection for the Jewish scientists at his institute, some of them refugees from Nazi racial persecution elsewhere in Europe, and to urge them to resist the imposition of race laws. In turn, officials from the U.S. Embassy sought out Bohr to offer him and his family sanctuary in the United States. Bohr knew that with a Jewish mother he was in personal danger but insisted he must remain to look after his staff. Somehow he found time to send an urgent telegram to Otto Frisch, warning him to remain in England.

  Another telegram to England caused some puzzlement. It was from Lise Meitner, who had arrived in Copenhagen just twelve hours before the German occupation began and had been wakened by the noise of airplanes. Since the Germans initially allowed the Danes to retain a degree of self-rule in return for their bloodless surrender, Meitner was able to remain in Copenhagen unmolested for three weeks and to meet Niels Bohr. On her return to neutral Stockholm, she dispatched, at Bohr's request, a telegram to one of his friends, the British physicist Owen Richardson, reassuring him that the family was all right. The text read, "Met Niels and Margrethe recently both well but unhappy about events please inform Cockcroft and Maud Ray Kent." John Cock­croft jumped to the conclusion that Meitner's words contained a hidden warning. He wrote anxiously to James Chadwick, suggesting that the final three words—Maud Ray Kent—were code for "uranium taken." Others speculated that they were an anagram for "Make Ur Day Nt"—"Make Uranium Day and Night." Only later did they learn the simple truth that Maud Ray had been the Bohr children's governess. She lived in Kent, and her address had mistakenly been omitted from the telegram.

  However, the telegram solved one problem: that of choosing a suitably coded name for the group set up in April 1940 by the British government in response to Otto Frisch and Rudolf Peierls's memorandum to consider the possibility of constructing a uranium bomb. The group decided to call themselves the "Maud Committee"—formally the "M.A.U.D. Committee." Many who became associated with it were convinced that the letters stood for "Military Applications of Uranium Disintegration."

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  The Maud Committee was chaired by George Thomson of Imperial College, London, and members included Mark Oliphant of Birmingham University and James Chadwick of Liverpool University, who was to coordinate the laboratory research across the various universities. The committee did not, however, include Otto Frisch or Rudolf Peierls, who had been anxiously awaiting a reaction to their memorandum. While they waited, Frisch was summoned by the police as an enemy alien and interrogated. Security concerns meant that by this time many aliens were being interned—some in camps on the Isle of Man and others overseas in countries such as Canada. Even though Frisch was sent home, he felt that "all those questions really added up to the simple question 'Is there any reason not to intern that chap?'" Genia Peierls, who, according to Frisch, "ran her house with cheerful intelligence, a ringing Manchester voice and a Russian sovereign's disregard of the definite article," was so convinced that the impractical Frisch was about to be locked up that she bought him "some shirts of sea-island cotton which could be washed by a bachelor" like himself.

  Frisch was spared internment, but at first it did seem that he and Peierls would be barred from working on the project they had initiated. Mark Oliphant told the incredulous pair that the government was grateful to them for their analysis but that, since enemy aliens and recently naturalized British citizens could not be employed on sensitive war work, they would not be consulted further. The normally quiet, equable Peierls was angered by such idiocy, certain that he and Frisch had "the answers to important questions" likely to perplex and delay the committee. Peierls wrote politely but firmly to Thomson, who acknowledged the logic of his arguments and won agreement for Peierls and Frisch to be consulted on the Maud Committee's progress and later to become members of a technical subcommittee.

  Frederick Lindemann, professor of experimental philosophy (physics) at Oxford—later Lord Cherwell—also attended the technical subcommittee. He was both friend and adviser to Winston Churchill, who had replaced Neville Chamberlain as prime minister in the crisis of May 1940. Churchill, who always referred to him as "the Prof," appreciated Lindemann's ability "to decipher the signals from the experts on the far horizons and explain to me in lucid, homely terms what the issues were." The British son of a naturalized Franco-Alsatian father and an American mother, Lindemann had studied physics in England and Berlin. He was also an ace tennis player who competed at Wimbledon. During the First World War, disturbed that pilots had no guidance on what to do if their planes went into a spin, he had studied the mathematics of spin until he believed he had the solution. Determined to test his conclusions without hazarding the lives of others, he learned how to fly, put his plane through a systematic series of spins, and, applying his theory, succeeded in straightening it out again. His work saved many lives. Like Churchill, he doubted that Germany was working on atomic weapons, but thought it vital that Britain was not outflanked.

  The Maud Committee worked quickly, aware that with Britain battered, devoid of European allies, and facing invasion, time was not on their side. They were also aware of the desirability of greater contact with the United States. Since the start of the war there had been few scientific exchanges between Britain and the neutral United States. However, in the late summer of 1940 Winston Churchill decided to send a scientific delegation under Sir Henry Tizard to woo America by revealing Britain's technical secrets. His team, which included John Cockcroft, sailed with a black-metal steamer trunk packed with tempting models and blueprints.

  Once in the United States, they briefed American scientists on subjects from the design of the Rolls-Royce Merlin engine—powering the Spitfires currently confronting the Luftwaffe in the skies over southern England in the Battle of Britain and later used in the American P-co Mustang and the British Lancaster bomber and Mosquito intruder—to the cavity magnetron vital for enhancing radar performance, to the emerging evidence of the feasibility of an atomic bomb. The Tizard mission also attended a meeting of the Uranium Committee—the body set up by President Roosevelt in the aftermath of Albert Einstein's warning. It was chaired by Lynam J. Briggs, originally a government soil scientist who had become director of the National Bureau of Standards. The other members were experts in military ordnance with little expertise in nuclear physics.

  The British mission returned home and reported to the Maud Committee that America was not pursuing nuclear research with any great urgency. It was, however, impressed by the evidence it had seen of the United States' great productive capacity for costly experimental work. This reinforced the view expressed by Mark Oliphant and shared by many British scientists that "if things go really badly with this country there is a great deal to be said for investigating any possibility which offers a chance of hitting back from the New World."

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  Nuclear research was being pushed forward in Britain but under increasingly difficult conditions. In July 1940 Otto Frisch joined Chadwick's team in Liverpool to work on isotopic separation. Soon after his arrival he heard "the wailing of air-raid sirens" for the first time in his life. Within weeks the city began suffering heavy air raids, and nighttime was dominated by the "pop
ping of anti-aircraft guns" and the "clatter of falling shrapnel." The bombing intensified when, in November 1940, Hitler ordered a series of bombing raids on British cities.

  Liverpool was badly hit, but a worse sufferer was Coventry, where many of the city's buildings, including the cathedral, were destroyed or badly damaged and _ ;68 people were killed. The Germans invented a new word, Koventrieren—"to Coventrate" or raze to the ground. Some of the fires joined together to produce greater intensity of heat, a fact not lost on the future air marshal Arthur "Bomber" Harris, then working in the Air Ministry. He would later recall that Coventry taught British planners the "principle" of the firestorm, igniting "so many fires at the same time." It was, nevertheless, the Japanese who a year earlier, in 1939, could be said to have begun strategic bombing of undefended civilian cities and the creation of firestorms by dropping numerous incendiaries on the Chinese provisional capital, Chungking. A Times reporter described how the timber houses "burned like tinder. . . . the phosphorus kept the fires raging and a breeze extended them, three quarters of a square mile of houses were in flames."