CHAPTER 6
THE MANHATTAN PROJECT
… This cloud of radioactive material will kill everybody within a strip estimated to be several miles long. If it rained, the danger would be even worse because active material would be carried down to the ground and stick to it, and persons entering the contaminated area would be subjected to dangerous radiations even after days … the bomb could probably not be used without killing large numbers of civilians …
The Frisch–Peierls Memorandum, the first official document to describe with scientific conviction the means of making an atomic bomb and its effects
THE AMERICAN ATOM BOMB PROJECT exploited discoveries made elsewhere – in Denmark, Britain, Germany and France. They included the influential ‘Paris Group’, whose members (some of whom later worked with the Resistance) made the crucial finding in 1939 that fission in a uranium nucleus liberates the two or three extra neutrons necessary to sustain a chain reaction. And in the late 1930s European scientific advances culminated in two admirably clear reports: the Frisch–Peierls Memorandum of 1940, produced by Otto Frisch and Rudolf Peierls, both of whom had immigrated to Britain and were working at Birmingham University under the Australian scientist and Rutherford protégé, Professor Mark Oliphant; and the Maud Report of 1941, put together by the Maud Committee, a secret scientific-military group headed by James Chadwick.
These developments were complex, close-knit, fast moving and always communicated in strictest secrecy. Every document was marked ‘Eyes Only’ or ‘Top Secret’. Taxpayers, of course, who would finance the project, knew nothing of the great events that led to the creation of the first atomic bomb. The Frisch–Peierls Memorandum was the first statement, in any country, to describe with scientific conviction the practical means of making the weapon. On receiving it, Oliphant, highly impressed, informed Sir Henry Tizard, doyen of the British scientific community and chairman of the Aeronautical Research Committee; in turn Tizard passed it to Britain’s Scientific Survey of Air Defence, which recommended the creation of a special committee to develop the atomic bomb. This would be known as the Maud Committee, so named after a cable sent by Lise Meitner in June 1940 to England, addressed to Cockcroft and ‘Maud Ray Kent’, which subsequent inquiries identified as Bohr’s childhood governess. ‘Maud’ became Meitner’s code for the great man, then working in Britain. The Maud Committee was the predecessor to Tube Alloys, the British atomic project, created in 1941, which subsumed all these discoveries – and scientists – under Churchill’s watchful eye. In time, like a larger fish gobbling up the smaller, America would devour the British program and digest the trans-Atlantic effort as part of the soon-to-be-created Manhattan Project.
The Frisch–Peierls Memorandum probably did more than any other study to spur on this train of events. Both physicists drew heavily on Niels Bohr’s work in concluding that an atomic explosion would require a highly fissile – that is (in the right circumstances) an extremely divisible – substance such as the uranium isotope U235: ‘A moderate amount of U235 would indeed constitute an extremely efficient explosive,’ their memorandum stated. Five kilograms would liberate energy equivalent to several thousand tonnes of dynamite. The Frisch–Peierls Memorandum also warned of the horrors of radiation likely to result from an atomic detonation, the first official document to do so:
The radiations [sic] would be fatal to living beings even a long time after the explosion … This cloud of radioactive material will kill everybody within a strip estimated to be several miles long. If it rained, the danger would be even worse because active material would be carried down to the ground and stick to it, and persons entering the contaminated area would be subjected to dangerous radiations even after days … the bomb could probably not be used without killing large numbers of civilians …
It concluded: ‘It is quite conceivable that Germany is, in fact, developing this weapon.’
The Maud Report expanded on the work of Frisch and Peierls. It was the first Anglo-American governmental paper to explain how an atomic weapon might work, and it recommended Anglo-American collaboration in its construction. Subtitled, ‘Atomic Energy … for Military Purposes’, Maud recognised that the cost and difficulty of extracting U235 placed the job beyond the reach of the British, already overwhelmed by the expense of the war effort. The extraction of 1 kilogram of fissile uranium per day would cost £5 million. Collaboration between the Americans and British was thus ‘the highest priority’.
The Maud Report explained the bomb’s detonation mechanism in terms that politicians could understand: A chain reaction would occur when U235 reached ‘critical mass’ – that is, the point at which neutrons were released from their nuclei – ‘resulting in an explosion of unprecedented violence’. Detonation would result when two pieces of the fissile material – ‘each less than the critical size but which when in contact form a mass exceeding it’ – were smashed together at high velocity, using ‘charges of ordinary explosive in a form of double gun’. Maud envisaged a nuclear blast equivalent in force to 1800 tons of TNT, releasing large quantities of radiation that would make the area ‘dangerous to human life for a long period’.
The great difficulty Maud identified was this: how to extract U235 from common uranium ore? British scientists in Cambridge and Birmingham had gone ‘nearly as far as we can on a laboratory scale’. Only America had the resources to extract supplies of fissile uranium on an industrial scale. It concluded with a sweetener: an atomic bomb would prove cheaper than conventional explosives, ‘when reckoned in terms of energy released and damage done…’.
* * *
Meanwhile, the Americans were making great advances towards an atomic bomb but chose not to share these with their British allies. Roosevelt had approved the development of a bomb in 1939, after receiving Einstein’s letter, and delegated Vannevar Bush and James Conant to drive ‘general policy in regard to the program of bombs of extraordinary power’. Bush, an engineer who directed the Office of Scientific Research and Development, and Conant, an organic chemist who headed the National Defense Research Committee, together oversaw the process that eventually subsumed Britain’s Tube Alloys – and Maud Committee – into S-1, America’s atomic bomb project, and rendered the construction of the weapon an exclusively American enterprise.
It was not surprising that some American experts were loath to admit their debt to European science. On receipt of his copy of the Maud Report, the ‘inarticulate and unimpressive’ Lyman Briggs (as Oliphant described him), chairman of America’s Uranium Committee – another secret agency in a web of official US bodies charged with identifying and securing the world’s supply of uranium for military use – promptly locked it in his safe without showing it to the committee. Oliphant, a full-throated champion of US–British collaboration, flew to the US in August 1941 in an unheated Hercules bomber – such was the urgency of his mission – to investigate the fate of Maud, which no US official had responded to for weeks. On his arrival, the Australian was ‘amazed and distressed’ at Washington’s failure to act. Oliphant persuaded Ernest Lawrence, the Nobel Prize-winning Berkeley physicist, to press the report on the US government. He also secured an audience with Conant and Bush. Aloof men conscious of their possession of great power, they were initially disdainful of this zealous emissary, and dismissed Oliphant’s importunate appeal as ‘gossip among nuclear physicists on forbidden subjects’. Conant nonetheless saw the need to act. On 3 October 1941, he obtained a complete copy of Maud and handed it to Bush; on 9 October, Bush placed it under Roosevelt’s nose. Conant later cited Oliphant’s persuasiveness as the ‘most important reason’ the US nuclear program changed direction from an uncertain experiment into an all-out effort to build a bomb.
* * *
In 1942 Conant and Bush worried that progress on the bomb was far too slow. They feared at this time that Berlin would get there first – a view shared by the émigré physicists, who despaired of the prospect of a nuclear-armed Germany.
On 13 June that year Conant and Bush wrote to War Secretary Stimson, Army Chief of Staff General George Marshall, and then Vice President Henry Wallace, urging them to hasten the decision to establish a secret organisation to co-ordinate the development of S-1. Their letter, intended ultimately for the President, conveyed the unanimous belief of several top American physicists that the production of an atomic bomb was possible, and outlined several methods of producing the fissile material (U235), all of which ‘seemed feasible’. They envisaged the production of ‘a bomb a month’ by 1 July 1944 ‘with an uncertainty either way of several months’.
They recommended the physicists Arthur Compton, Ernest Lawrence and Harold Urey as scientific leaders of the operation. All were Nobel laureates, and all were immersed in nuclear physics. A deeply religious man, Compton defined science as ‘the glimpse of God’s purpose in nature’, of which the atom and radiation were manifest signs – he won the Nobel Prize in 1927 for his work on X-rays; the exuberant Lawrence received the prize in 1939 for his invention of the cyclotron atom smasher; Urey, an intensely hardworking man who discovered deuterium, received the Swedish gong in 1934 for his pioneering work on the separation of isotopes. The whole project, Bush and Conant estimated, would cost roughly $85 million (another huge miscalculation). Stimson, Marshall and Wallace sent the recommendation to the White House, from where it was promptly returned, marked ‘OK–FDR’.
The biggest and most expensive industrial operation hitherto launched in America rolled into production. Construction companies were to build, from scratch, enormous factories using industrial processes that had never been attempted; engineers to take new scientific discoveries onto production lines; and scientists to create and test complex mechanisms using chalkboard designs ready for factory application within months.
The ‘Manhattan Engineer District [MED]’, the project’s official title – chosen for its innocuous ambiguity – was always strictly a military operation. It subsumed all civilian research and experimentation in atomic science. The man appointed, on 16 August 1942, to head MED operations was an army engineer, Colonel Leslie Richard Groves. Initially reluctant to accept the job – Groves had hoped for a combat role – once persuaded, the colonel pursued it with characteristic gusto. ‘If you do this job right, it will win the war,’ Lieutenant General Brehon Somervell, commanding general of US Army Service Forces, told Groves. If further persuasion were needed, Major General Wilhelm Styer, a member of the Military Policy Committee that oversaw the development of atomic energy, reassured Groves that his appointment would transform the war effort.
If they meant to fan his ego, they misunderstood the burly engineer. To a man of Groves’ self-worth, success was not the issue – ‘If I can’t do the job, no one man can,’ he later confided in his memoirs. In fact, Groves wanted assurances that the bomb could be built before he accepted the job: the budget was a mere $85 million; the science seemed vague and unformed; and his rank as colonel did not exert the necessary authority. Groves knew more about the Project than he let on, of course, due to his excellent contacts in the Army Construction Division, where he had overseen the building of the Pentagon. He was haggling over terms. The army met his needs immediately: Styer promoted him on the spot to brigadier general, and Groves’ other key demands – top-level security clearance, a virtually unlimited budget, and total operational control – were promptly delivered.
* * *
The portrait of Groves as a great brute of a man, tyrannical and unyielding, has been widely received; his qualities less so. Groves’ mastery of industrial engineering, his iron self-discipline and extraordinary administrative and organisational skills qualified him as possibly the only man willing or able to attempt to build an atomic bomb in the time available. His working hours (around the clock), dismissal of anyone not up to the job, and pachydermal indifference to criticism – as his colleagues often remarked – further recommended him. His superiors wanted a man able to withstand the pressure of surely one of the most difficult jobs of the war effort. To his detractors, Groves seemed more machine than man; to his admirers, such as his deputy and chief engineer Colonel Ken Nichols, he was ‘outstanding’ – ‘extremely intelligent’ and ‘the most egotistical man I know’.
The third son of four children to an austere Presbyterian army chaplain, ‘for whom thrift was one of the godliest of virtues’, and a gentle, sickly woman worn down by the weight of constant travel and hard work, Leslie was a good little boy, by all accounts, whom family and friends preferred to call ‘Dick’. Biblical remonstrations pursued the boy’s youth and Sunday Sabbaths were strictly observed. The family was constantly on the move following Chaplain Groves’ service itinerary. Illness stalked their peripatetic rounds of the nation: the chaplain suffered recurring bouts of malaria, which he had caught in Cuba on a visit in 1898; Groves’ crippled sister undertook strenuous exercises to straighten her hunched spine; and his mother, Grace, suffered from a chronic heart condition. The Groves home had the atmosphere of a ‘family hospital’, noted the general’s biographer.
The boy grew into a tall, athletic young man who, as a student at Massachusetts Institute of Technology, kept his own counsel; he was self-absorbed, diligent and friendless. The premature death, from pneumonia, of his elder brother Allen, his parents’ favourite, stung young Leslie to action. He defied his father’s wishes and enrolled in the US Military Academy at West Point in 1916, where his arrogance won him few friends. He had inherited his father’s tight-fistedness and refused to pay for his laundry, earning him the nickname ‘Greasy’, an appellation that pursued him through life. Lonely and unpopular, he rose through sheer grit and intelligence unrelieved by the personal charm or good humour that eased the advancement of less talented men.
He never shouted or swore. He led by quiet intimidation; those who angered him received ‘the silent treatment’. As a young captain, he ‘gave the impression of a man of great latent power, who was biding his time,’ observed the historian Robert Norris. His baleful stare and his snap decisions left a trail of anxiety.
The general travelled tirelessly around his secret empire, which grew rapidly during 1942–44 to embrace city offices, university laboratories and secret factories on remote prairies, from the Midwest to Manhattan. Weekly, his private train shot through the dark fields of the Midwest towards another trembling recipient of his wrath. Everything he did was shorn of clutter, time-wasters and verbiage; all fine-tuned to the task ahead. He had no time for small talk or pleasantries. His memos were brief and abrupt, regardless of the seniority of the recipient; he closed meetings when he decided, even with superiors. At his first meeting with President Roosevelt, he impertinently announced that he had to leave early. An example of the Groves style was the following memorandum:
GEN GROVES TO DR V BUSH, REAR ADMIRAL WR PURNELL, MAJGEN WD STYER: On 11 May 1943, the MED entered into a fixed-fee ($1.00) cost contract with Union Mines Dev Corp to determine the world resources of uranium and, to the extent possible, bring such resources under the control of the US Government.
Groves thus commandeered the world’s available supplies of yellowcake.
If knowledge is power, Groves was among the most powerful people in America at this time. His security clearance matched the highest levels of the military and political establishment. He knew the fate of the earth – insofar as nuclear weapons might decide it – ahead of senior politicians and military commanders. The State Department was unaware of the bomb until February 1945 when Groves decided to let them in on the secret; General Douglas MacArthur was not officially informed until mid-1945; and Fleet Admirals Ernest King and Chester Nimitz, respectively Commander in Chief United States Fleet, and Commander in Chief Pacific Fleet, were only informed, on Groves’ recommendation, in early 1945.*
By then, Groves had been working on the bomb for three years. His power over the weapon was complete. Anyone who opposed the general – and by extension, the bomb’s purpose – found themselves mysteriously removed (irritating scientists, notably Szilard, were smoothly sidelined). Few questioned the intent of the project; their very awareness of it assured their approval. And Groves had powerful champions, chief among them Bush, Conant and, of course, the new President. His thinking was thoroughly in line with that of Truman and Byrnes, who believed that Japan was the immediate target, but Russia was America’s ultimate future enemy: ‘There was never … any illusion on my part but that Russia was our enemy, and the [Manhattan] Project was conducted on that basis.’
In time, he would exert a disproportionate influence over senior politicians; his unique position and mastery of the project’s detail made him indispensable to its success, and they bowed to his demands. It was on Groves’ insistence, for example, that in 1943 Byrnes, then head of the Office of War Mobilization, was told to abandon an inquiry into the $2 billion spent on the Manhattan Project because it might damage security. The President quashed the Byrnes review; and while Byrnes would become a staunch supporter of the bomb, at the time he was anxious to know why, and on what, so much public money was being spent. Stimson, too, felt the shadow of this granite presence: Groves surreptitiously drew attention to the War Secretary’s doom mongering and negativity, and would gradually help to marginalise him.
Groves’ first actions were eminently practical. In 1942 he moved to secure control of the world’s largest uranium supply, in the Belgian Congo, through negotiations with Edgar Sengier, the managing director of the mining giant Union Minière du Haut Katanga. Sengier, a discreet Belgian banker and engineer, was relieved: the State Department, then under Edward Stettinius, had previously misunderstood the importance of uranium and rebuffed his approaches. Groves understood all too well: in a meeting with Colonel Nichols, the chief engineer of the Manhattan Project, on 18 September 1942, Sengier agreed to supply 1250 tons (1134 tonnes) of ore that had been imported from the Congo and was stored in some 2000 steel drums in a Staten Island warehouse. More would follow.
An equally pressing priority after his appointment was personnel: the general needed better than the best; failure was not an option. If the Project fails, General Somervell had joked, he and Groves might as well buy houses next to the Capitol, ‘because you and I are going to live out our lives before Congressional committees’. Most importantly, Groves needed a lab leader. The exacting résumé narrowed the field to a handful: Ernest Lawrence, however, could not be spared from his work on the cyclotron at Berkeley and Arthur Compton was inseparable from the Metallurgical Laboratory (a codename) of Chicago University, where he co-led the work on nuclear fission with Fermi and Szilard. That left Robert Oppenheimer.
* * *
Few people have experienced a more controversial rise and fall in the public eye than Julius Robert Oppenheimer. A tall, thin, lanky man with blue eyes and a shock of dark hair, he walked, or rather advanced, on the balls of his feet, giving the impression that he floated by. His baggy suits and porkpie hat created a faintly clown-like effect. Oppenheimer was a Jew; his former girlfriend, Jean Tatlock, a communist; his brother, Frank, a Jewish communist. Those facts placed Oppenheimer outside the East Coast Anglican establishment. His communist associations deeply compromised him, decided the FBI and the security services, which initially refused to clear him for work on the Manhattan Project.
Oppenheimer’s exceptional intellectual and, as it proved, administrative, gifts overrode the security risk, Groves believed. That he was related to, or slept with, communists did not mean he shared their beliefs. Groves, who had read everything he could about ‘Oppie’, saw a distinction that eluded the secret services. On 20 July 1943, the general confirmed the scientist as ‘absolutely essential to the Project’. Thus began one of the oddest and most effective working partnerships in American history: Groves, immense, boorish and demanding; Oppenheimer, frail, cultured and intellectual.
Oppenheimer was born in 1904 to a wealthy, liberal New York family, and his early correspondence conveys the impression of an extremely clever young man in the thrall of his transcendent intellectual gifts. At Harvard (where he attended Bohr’s lectures in 1923) and, as a Rhodes scholar at Oxford, he applied his prodigious mind as a tool for rapid self-advancement. At Harvard he explained his desire to jump straight to advanced physics on the grounds that he received ‘a 96’ in his physics entrance exam, grade As in all his subjects, and his ‘partial’ reading then involved four volumes on kinetic theory, thermodynamics, statistical mechanics and quantum theory; James Crowther’s Molecular Physics; Henri Poincaré’s La Physique Moderne and Thermodynamique; James Walker’s Introduction to Physical Chemistry; Wilhelm Ostwald’s Solutions; J. Willard Gibbs’ On the Equilibrium of Heterogenous Substances; and Walther Nernst’s Theoretische Chemie. These were advanced texts; Oppenheimer read them in English, French and German. He also read Ancient Greek and Latin. A few months earlier he had completed his freshman year, with top grades in French prose and poetry (Corneille through to Zola), the history of philosophy, and courses in maths, chemistry and physics. ‘Whatever reading or work you may advise, I shall be glad to do…’ he added. He was 19.
The young Oppenheimer styled himself a philosopher-aesthete who affected an interest in literature ahead of science. A La Recherche du Temps Perdu by Marcel Proust left a deep impression on him. He quoted a favourite passage from memory: ‘Perhaps she would not have considered evil to be so rare, so extraordinary, so estranging a state, to which it was so restful to emigrate, had she been able to discern in herself, as in everyone, that indifference to the sufferings one causes, an indifference which, whatever other names one may give it, is the terrible and permanent form of cruelty.’
He would be an occasional poet, as this example of his student juvenilia (1923) intimated:
… When the celestial saffron
Is faded and grown colourless,
And the sun
Gone sterile, and the growing fire
Stirs us to waken,
We find ourselves again
Each in his separate prison
Ready, hopeless
For negotiation
With other men.
And an art critic: ‘The three things you sent me,’ he wrote that year of sketches by a friend, ‘… show a good deal more care and inspiration in their design than the van Dyke and Giotto things you defend – I like immensely your abstract, particularly, I think, for its obvious but skillful repetition of color and texture, and the corresponding dramatic rapidity. Best of all, though, I like the nude, in spite of its technical scraggliness…’
Harvard’s recognition of his talents did not surprise him. He drolly wrote at the end of another superb semester, ‘The work goes much as before: frantic, bad and graded A.’ He graduated with distinction – summa cum laude – within three years, and celebrated privately with two friends and a bottle of laboratory alcohol: ‘Robert, I think, only took one drink and retired,’ remarked his friend, Fred Bernheim.
In his mid-20s he suffered from depression, hallucinations and suicidal feelings – ‘a tremendous inner turmoil’. He self-diagnosed a schizoid personality and seems to have recovered through sheer hard work and strength of mind. At one point, in London, he dismissed his Harley Street psychiatrist as ‘too stupid’: ‘[Robert] knew more about his troubles than [the doctor] did,’ wrote a friend. ‘Robert had this ability to … figure out what his trouble was, and to deal with it.’
There was nothing rebellious or dissipated in the young Oppenheimer; rather something joyless … a space of pure intellect in his ‘separate prison’ from other men. ‘Conrad’s Youth,’ he wrote, dismissively, ‘is a beautiful novelette on the futility of youthful courage and idealism.’ Perhaps, but were not the futile pursuits of ideals a rite of passage in the young? Oppenheimer, on the contrary, strove for perfection: of what use were ideals if one failed in their pursuit? His overriding psychological impulse was a fear of failure. In this he had something in common with Groves. ‘Ambitious’ is too crude, too obvious, a term for such complex men; they acted in defiance of, or in spite of, the voices in the wings as surely as they pursued the laurels of success.
On 17 October 1931, Oppenheimer’s mother died. ‘I am the loneliest man in the world,’ he wrote somewhat disingenuously, as he had long felt estranged from her and compensated for this with excessive displays of somewhat contrived affection. After her death he immersed himself in his work: ‘On the Stability of Stellar Neutron Cores’, ‘On Massive Neutron Cores’ and ‘Behavior of High Energy Electrons in Cosmic Radiation’ were among his (co-written) scientific papers of the 1930s, unimpressive alongside the output of Lawrence, Compton and Fermi. Yet Oppenheimer was an intellectual dilettante, a modern Rennaissance man. He took up the study of Sanskrit: ‘I have been reading the Bhagavad Gita with … two other Sanskritists,’ he told his brother in 1933. If any single mind has attempted to reconcile Eastern and Western cultures and bridge the Sciences-Arts divide, it was his.
The precocious student grew into a loyal friend, excellent teacher and inspiring leader. Along the way, at Harvard and in the 1920s at Cambridge and Göttingen in Germany, he met the greatest physicists of the day and formed close relations with Max Born, his professor at the University of Göttingen with whom he wrote ‘On the Quantum Theory of Molecules’, his most cited work. In the 1930s in California, as a professor at Berkeley University and later at Caltech, his students became his admiring disciples. The physicist Hans Bethe, one of his most staunch friends – who would work with him on the atomic bomb – said of him: ‘Probably the most important ingredient he brought to his teaching was his exquisite taste. He always knew what were the important problems, as shown by his choice of subjects. He truly lived with those problems, struggling for a solution, and he communicated his concern to the group … He was interested in everything, and in one afternoon they might discuss quantum electrodynamics, cosmic rays, electron pair production and nuclear physics.’ His mature attributes – the rare fusion of scientific excellence, self-discipline and organisational flair – marked him for leadership of the Manhattan Project.
Another lure was his deep yearning to belong; to be inside the tent. A longing to know the world and the people who presumed to know and control him possessed Oppenheimer. He wanted not so much to share the nest of the American establishment as to feel able to share it, and then take or leave it. His family’s wealth could buy yachts, ranches and horses but not this – the coming and going of a welcome insider. His sheer brilliance would force admission to the gilded enclave: it convinced Groves, and Groves persuaded the innermost sanctum of American power.
* * *
In the late 1930s Oppenheimer worked closely with Ernest Lawrence and the cyclotron pioneers at Berkeley, ushering him into the orbit of work on the bomb project. On 21 October 1941, at a meeting at General Electric’s Schenectady laboratories, New York, Oppenheimer calculated the critical mass of U235 that would be required for a chain reaction – and an effective weapon. Conant, who had been one of Oppenheimer’s lecturers, invited him to conduct further work on ‘fast neutron’ calculations that were critical to a chain reaction, and that year Oppenheimer opened a ‘summer school’ in bomb theory at Berkeley. His appointment to the Manhattan Project briskly followed in September 1942.
Oppenheimer and Groves chose Los Alamos, New Mexico, as the site for the bomb’s laboratory. An unlikely horseman, Oppenheimer knew the terrain; he owned a ranch in the nearby Sangre de Cristo Range. The site sat atop a red-earth mesa, the Pajarito Plateau, near White Rock Canyon and the Valles Caldera, within an hour’s drive of Santa Fe and Albuquerque, within easy reach of water, and near the train line and flight paths to major cities. To the cosmopolitan scientists housed in an erstwhile boys’ boarding school, which the US government had bought, it seemed impossibly remote.
Here the finest physicists and chemists came willingly, or were persuaded to come. Oppenheimer plundered the nuclear physics departments of the most prestigious universities in the country, and the world – to those institutions’ intense irritation. Most of the scientists were in their 20s and 30s; some had just finished their degrees. They gathered on the ‘Hill’, as they named Los Alamos, rather like Swift’s Laputans on their floating island. Their ambitions went further than extracting sunbeams from cucumbers, however. They were attempting ‘a far deeper interference in the natural course of events than anything ever before attempted’, Bohr told Churchill on 22 May 1944 (Bohr had been smuggled out of German-occupied Denmark in 1943). Even at this stage Bohr consistently warned of an impending arms race and urged openness with the Russians. This little impressed Churchill, who scolded the physicist at their May meeting (‘I did not like that man with his hair all over his head,’ the Prime Minister later told Lord Cherwell), and afterwards cautioned Roosevelt that Bohr be monitored as a security risk: ‘It seems to me Bohr ought to be confined,’ Churchill said, ‘or at any rate made to see that he is very near the edge of mortal crimes.’
Many of Los Alamos’ boffins were Jews exiled from Nazi-occupied Europe, and motivated by hard personal experience – chiefly the physicists Bethe, Peierls and Edward Teller, and the astonishingly gifted mathematician John von Neumann, to name a few; Jewish émigrés also had prominent roles at Chicago University and in other parts of the Manhattan Project. These scientists included Szilard and the Nobel laureate James Franck, who had left Germany in 1933. Their job, as they initially saw it, was to build a weapon to defeat Germany. In the pursuit of victory they shared a personal motive: to avenge family members and friends persecuted by the Nazis. Enrico Fermi, who left fascist Italy to protect his Jewish wife, shared their determination; Oppenheimer sympathised; as did Einstein. They scorned ‘Aryan scientists’ such as Heisenberg who remained in Germany.
* * *
In 1942–43 the Manhattan Project scientists came under great pressure from Groves to meet his stringent schedule. Events were progressing in several locations, chiefly Chicago, where the scientists’ priority was to demonstrate that a self-sustaining nuclear reaction might work. While the theory was sound, and pointed with certainty to this outcome, nobody had yet achieved it. The man responsible for the breakthrough was Enrico Fermi, nicknamed ‘the Pope’ in deference to his nationality and reputation for omniscience. Fermi, a professor of physics at the Univerity of Rome at the age of 24, received the Nobel Prize in 1938 (aged 37) for his ‘demonstrations of the existence of new radioactive elements produced by neutron irradiation, and for his related discovery of nuclear reactions brought about by slow neutrons’, according to the citation. That year Fermi and his wife, Laura, immigrated to America. He worked first at Columbia University in New York and from 1940 with Franck, Szilard and Compton at the University of Chicago’s ‘Metallurgical Lab’, where he focused his energy on achieving a nuclear chain reaction.
On 2 December 1942, in a squash court beneath the West Stands of Stagg Field football stadium, near the Metlab, Fermi and his team put the finishing touches on the first ‘atomic pile’ of graphite blocks embedded with uranium. The dozen or so scientists present included Compton, Szilard and Wigner, who gathered on the spectator stand 2 metres above the court floor, whereupon the young George Weil prepared to remove the last rod that held the reaction in check.
In theory, the reaction was capable of flying out of control and consuming much of Chicago along with the footballers on Stagg Field. In practice, this was highly unlikely. Cadmium rods were inserted in the pile to absorb overeager neutrons, to stop or slow the bombardment process and to avoid a conflagration: ‘The same effect might be achieved,’ Fermi later wrote, ‘by running a pipe of cold water through a rubbish heap; by keeping the temperature low the pipe would prevent the spontaneous burning.’ If the rods failed, a three-man ‘liquid control squad’ on a platform overhead stood ready to drench the pile with buckets of cadmium salt solution.
Always cool under pressure, Fermi gave the signal to initiate the neutron bombardment. George Weil removed the rod. The team above fastened on their indicators, which measured the neutron count and ‘told us how rapidly the disintegration of the uranium atoms … was proceeding’. The first attempt failed – the pile’s safety threshold was set too low. ‘Let’s go to lunch,’ Fermi said. After lunch and several adjustments, they resumed their places and made a second attempt. The neutron storm rose ‘at a slow but ever increasing rate’; shortly the reaction was self-sustaining. It was unspectacular – ‘no fuses burned, no lights flashed,’ Fermi wrote. ‘But to us it meant that release of atomic energy on a large scale would be only a matter of time.’ Compton made a coded phone call to Conant, in Washington:
Compton: The Italian navigator has landed in the New World.
Conant: How were the natives?
Compton: Very friendly.
An elated Eugene Wigner presented Fermi with a bottle of chianti. They drank from paper cups, in silence.
* * *
Meanwhile, in the valley below the Hill in New Mexico, ordinary Americans went about their business in morlock-like ignorance of the goings-on above them, where great experiments were advancing to meet harsh deadlines.
Oppenheimer arrived at Los Alamos on 16 March 1943 with his wife, Kitty – senior scientists were permitted the company of their wives. Their home was a log-and-stone house built in 1929 at the end of Bathtub Row, named because the homes thereon had one. He started work at 7.30am. Periodically the couple entertained. His ‘dark moods’, ‘savage sarcasm’ and knack for the brutal riposte were more restrained in the company of his peers. He charmed his staff and endowed his colleagues with ‘rare qualities and facets they did not know they possessed’.
Groves and Oppenheimer worked like two cogs in a machine. Oppenheimer met the engineer’s demands; Groves respected the scientist’s brains. Oppenheimer accepted the militarisation of his bomb-making laboratory; Groves held back at insisting that scientists wear military uniforms. They shared an overweening ambition for the Project, and ‘saw in each other the skills and intelligence necessary’ to fulfil it. Oppenheimer looked the part – groomed, business-like and efficient; Groves responded with rare empathy, treating the scientist, as the historian Norris observed, ‘delicately, like a fine instrument that needed to be played just right’.
On arrival, senior staff – who had ‘Secret Limited’ level security clearance – received a copy of The Los Alamos Primer, a digest of a series of lectures, ‘On How to Build an Atomic Bomb’, given by the physicist Robert Serber, one of Oppenheimer’s colleagues at Berkeley. The Primer, edited by Edward Condon, the lab’s associate director, was the first, detailed explanation of why they were there. It was issued only to the most senior scientists and lab technicians, many of whom reacted with euphoria at this final confirmation of their mission.
The Primer was an exposition not a cookbook: ‘The object of the Project,’ it informed the new arrival, ‘is to produce a practical military weapon in the form of a bomb [Condon used the word ‘gadget’] in which the energy is released by fast neutron chain reaction…’ (his emphasis). Serber ran through the process and risks, sprinkling his text with equations of interest to the specialist.
Serber left little to the physicists’ imagination in his section on ‘Damage’: intense radiation (‘a very large number of neutrons’) would saturate everything to ‘a radius of 1000 yards [900 metres]’ from the explosion – ‘great enough to produce severe pathological effects’; a million curies of radiation would remain ‘even after 10 days’. The blast wave’s destructive radius would extend to ‘about two miles [three kilometres]’. He concluded with a discussion of the detonation methods.
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Far bigger and more dangerous facilities than Los Alamos were being erected around the country throughout 1943 and 1944; they were neither dark nor Satanic, but clean to a curlicue and hermetically sealed. Among the most important were Oak Ridge and Hanford, whose employees were primarily engineers and technicians, rather than scientists.
Oak Ridge was the administrative heart of the Manhattan Project; and the site of the world’s largest factory, Clinton Engineering Works, built on a 24,000-hectare government reservation on the Tennessee Valley floor, 30 kilometres northwest of Knoxville. General Electric, Westinghouse and Allis-Chalmers supplied the main equipment; Stone & Webster designed and constructed it; and Tennessee Eastman, a subsidiary of Eastman Kodak, handled the operations. Oak Ridge’s job was essentially to separate the highly fissile U235 uranium isotope from the ordinary U238, and manufacture enough U235 for use in a bomb; Hanford’s, in Washington state, was to produce an atomic bomb using the alternative weapons-grade material plutonium, a highly fissile, extremely toxic new element, the discovery of which Lawrence had reported in May 1941. Both projects ran in tandem as an insurance policy should the other fail. Both involved huge amounts of electricity, water, equipment, space and manpower.
Oak Ridge grew into a secret city employing, at the height of construction, almost 70,000 people for whom, at one point, 1000 homes were being built per month (in peacetime the town held 3000 inhabitants). All the social requirements of an inland American city accompanied them: schools, a hospital, a dental clinic, cinemas and sports facilities. By June 1945 Oak Ridge had one high school, eight elementary schools and a grammar school built or under construction, with 317 teachers and 11,000 pupils; nine drugstores; 13 supermarkets and seven cinemas. Seventeen different religious bodies catered for the workers’ spiritual needs.
The site at Hanford, which at its peak would employ 45,000 workers, was designed and built by the DuPont Corporation. At first, the task seemed impossible and DuPont demurred. Groves’ argument – ‘if we succeed in time, we’ll shorten the war and save tens of thousands of American lives’ – persuaded the company’s president, Walter Carpenter. He attached two conditions: that DuPont made ‘no profit whatever from the work it did’; and that ‘no patent rights growing out of DuPont’s work on the project should go to DuPont’. ‘Our feeling,’ Carpenter told employees (after the war), ‘was that the importance to the nation of the work on releasing atomic energy was so great that control, including patent rights, should rest with the Government.’
Construction of Hanford involved the use of 8500 major pieces of construction equipment, and the building of 550 kilometres of permanent roads and 1200 kilometres of railroad; 36,000 tonnes of steel, 38,000 cubic metres of lumber, and 11,000 poles for electric power were also required. Reports that salmon were dying in the nearby Columbia River drew Groves’ concern, and he asked his medical chief Dr Stafford Warren to commission a study on the effects of radiation on aquatic organisms. The study, by Dr Lauren Donaldson, concluded that, as far as could be ascertained, radiation emanating from the factory would not harm salmon. Groves was acutely aware of the dangers of radiation to humans, too – ‘a serious and extremely insidious hazard’, he recalled in his memoirs. He insisted on enclosing the huge reactors in heavy metal walls and concrete tanks to protect workers, and set the safe tolerance dose at one-hundredth of a roentgen per day (that is, 0.12 rems; the current annual US occupational limit in adults is 0.005 rems, according to the MIT Radiation Protection Office).
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The greatest challenge facing Oak Ridge was how to extract the highly fissile but extremely rare isotope U235 from common uranium. Of several methods, Groves directed his empire to pursue two: electromagnetism and thermal/gaseous diffusion.
The electromagnetic method utilised Canadian scientist Arthur Dempster’s 1918 invention of the mass spectograph in conjunction with Ernest Lawrence’s cyclotron (nicknamed the slingshot). The process is based on the principle that electrically charged atoms (ions) describe a curved path when accelerated through a magnetic field. With the speed and magnetic field at constant levels, atoms of different mass (for example, the uranium isotopes U235 and U238) will follow different ‘flight’ paths: heavier atoms have longer radii than lighter atoms. In this way, two kinds of uranium could be separated, neutralised and collected in specially designed containers. It sounds simple; in practice it involved the construction of the world’s largest magnet in a facility covering 200 hectares. The electrical conductors required 86,000 tons of silver since the war’s demand for copper exceeded national supply. The silver was borrowed from the US Treasury, whose tight-lipped reply to Colonel Ken Nichols’ request was, ‘Colonel, in the Treasury we do not speak of tons of silver; our unit is the Troy ounce.’
The thermal diffusion method works on the principle that two gases will diffuse through a porous membrane at rates inversely proportional to the square root of their molecular weights. For example, if gas X has a molecular weight of 4, and gas Y has a molecular weight of 9, when they pass through a membrane, the lighter gas diffuses at a rate of three volumes to the heavier gas’s diffusion rate of two volumes. To separate the uranium isotopes this way proved exceptionally difficult, however, as their molecular weights differed only slightly. The gaseous ore uranium hexafluoride had to be forced through a cascading network of ‘barriers’ – or atomic ‘sieves’. Each pass yielded a gaseous residue containing a greater proportion of U235 than the previous stage. To visualise this in operation, one could imagine a gigantic tube snaking around a football-stadium-sized facility punctuated along its path by thousands of huge membranes. Everything inside had to be kept spotlessly clean to avoid polluting the enriched gas at any stage of the journey. The challenge involved building membranes with gaps small enough to faciliate the passage of U235 gas molecules: the holes in the screens, or sieves, eventually delivered were one-hundredth of a micron, or four ten-millionths of an inch, in diameter. ‘They won’t believe it when the time comes when this can be told,’ James Conant said of the Oak Ridge site. ‘It is more fantastic than Jules Verne.’
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Security was a paramount priority in the Manhattan Project. Important arrivals at Los Alamos set mouths aflutter. Groves insisted that celebrity scientists use aliases when visiting. Niels Bohr became Mr Baker; the Fermis – Mr and Mrs Farmer; Harold Urey – Hiram Upton; and Arthur Compton – Mr Comstock. Codenames permeated the whole enterprise. The main industrial plants, the plutonium bomb-making factory at Hanford and the uranium enrichment plan at Oak Ridge were Sites W and X, and Los Alamos Site Y. Various key words were forbidden, chiefly ‘bomb’ and ‘uranium’. Wives were kept in the dark: ‘I can tell you nothing about it,’ husbands would say, before their departure for Los Alamos. ‘We’re going away, that’s all.’ Only Groves was permitted a diary, which said little and poorly. A sign in Groves’ offices, the mysterious Rooms 5120 and 5121 of the War Department Building in Foggy Bottom, Washington, said, ‘O Lord! Help me to keep my big mouth shut!’ The loquacious found themselves on long-term assignments in the Pacific.
Ordinary employees – engineers, factory hands, clerical staff – were carefully screened and worked in cordoned-off ‘compartments’, or silos. Workers in one silo had no idea what their counterparts were up to in another: ‘Compartmentalisation of knowledge, to me, was the very heart of security,’ Groves later said. ‘My rule was simple … each man should know everything he needed to know to do his job and nothing else.’ When addressing employees, Groves said nothing of the bomb, or the fact that it might ‘win the war’, only that their work was of ‘extreme importance to the war effort’. This charter throbbed in the minds of hundreds of thousands of carefully processed employees, none of whom knew what he or she was making; nor did they see any result for their effort: ‘They would see huge quantities of material going into the plants, but nothing coming out.’ The rows of young women at Oak Ridge sitting at their calutrons – mass spectrometers used for separating uranium isotopes – had ‘no idea what they were doing’ or what the machines did; ‘merely that they were making some sort of catalyst that would be very important in the war’, observed Theodore Rockwell, an engineer at Oak Ridge. Unions were banned: ‘We simply could not allow [them],’ Groves wrote, ‘to gain the overall, detailed knowledge that a union representative would necessarily gain…’ Black workers were segregated, paid little and housed in poor conditions; racial discrimination against African-Americans and Hispanics did not pause for the war effort.
Notwithstanding the tightest security net, several spies infiltrated the Project, the most damaging of whom was Klaus Fuchs, a German émigré who began spying for the Soviet Union from Britain in August 1941 (two other, relatively insignificant spooks were the technicians David Greenglass and Ted Hall). Having established contacts in Moscow, and insinuated himself into the British scientific community, Fuchs came highly recommended to Los Alamos, where he worked in the most sensitive department dealing with detonation: specifically, the extremely complex implosion system of the plutonium bomb, sketches of which he sent to his Soviet-run handler, Harry Gold. Fuchs was also deeply involved in research on the hydrogen bomb. Unusually hardworking, he drew no attention to himself and made a strong impression on Hans Bethe and Robert Oppenheimer. Washington would learn the extent of his damage after the war: the Russian bomb project drew extensively on Fuchs’ information, which had ‘great value’, according to Soviet physicist Igor Kurchatov, who headed the Soviet atomic program. Indeed, Fuchs informed Moscow of ‘essentially everything we were doing at Los Alamos’ from August 1944, the physicist Edward Teller wrote in his memoirs. It enabled the Soviet Union to define the dimensions of an atomic bomb as early as April 1945, three months before the test of the weapon codenamed Trinity at Alamogordo in New Mexico.*
Fears of Soviet penetration of the atomic secret coalesced in Washington, where Truman quickly grasped that he had inherited the reins of a clandestine race – initially against Germany: ‘They may be ahead of us by as much as a year,’ James Conant, who headed the National Defense Research Committee, had warned in 1942. The Allies were then unaware of the woeful state of the Nazi atomic industry, which US intelligence (Project Alsos) would reveal as a miserable failure after the German surrender in May 1945. Albert Speer would later complain of Hitler’s inability to grasp the ‘revolutionary nature’ of ‘Jewish physics’ (an exception concerned the brilliant Austrian Lise Meitner, whom Hitler had been prepared to exempt from the anti-Jewish laws, an offer she refused). Nor did Japan’s atomic research pose any threat, as US intelligence would accurately conclude in early 1945. In fact, Japan had abandoned any hope of making a bomb in March 1943, when a colloquium of scientists concluded that it would take them ten years. The mysterious Soviet nuclear program under Igor Kurchatov was considered further advanced than Germany’s or Japan’s but well short of the United States’.
‘This country has a temporary advantage, which may disappear or even reverse if there is a secret arms race,’ Bush and Conant warned War Secretary Stimson in a letter of 30 September 1944. It was ‘the height of folly’ for the US and Britain to believe they could sustain their supremacy in nuclear technology, they added – and apprised the War Secretary of the consequences for the world were Russia and America to build secret nuclear arsenals. If Russia beat the US to the development of a ‘super-super bomb’ – the thermonuclear hydrogen bomb – ‘we should be in a terrifying situation if hostilities should occur’. The ‘expanding art’ of nuclear war might, within a year, involve weapons equivalent to 10,000 tons of high explosive, enabling one nuclear-armed B-29 to inflict damage equivalent to that of 1000 conventionally armed B-29s. In place of the current policy of blanket secrecy, Bush and Conant recommended a ‘free interchange’ of all nuclear information, under the auspices of an international body, when the war ended. The two scientists’ proposals were ignored. The Russians were not to be trusted and strictest secrecy would prevail – a policy that hardened after Soviet deceit at Yalta. America thus entered the last year of the war as the only country to possess the theory, brains and resources to produce atomic bombs, the first test of which was scheduled for the coming July.