The Basis of Everything

by Andrew Ramsey

  Oliphant’s response to what he considered an inexcusable breach of his privacy was typically pragmatic. Come the next morning, he pulled apart the cabinet’s lock in a reprise of his schoolboy tinkering, and reset the security combination without advising the intelligence agency he had done so.

  In mid-1944, Groves further vented his anger about information that Oliphant had shared based on RAF surveillance photographs of a possible atomic production facility in Germany. By that stage of the war, information flowing to the Allies on the Nazis’ uranium fission progress had virtually dried up, partly due to Groves’s secrecy obsession. The general was not prepared to let intelligence officers on the ground in Europe know what an isotope separation plant or bomb research site might look like, for fear those men might be captured by the enemy and their knowledge extracted.

  As a consequence, the information gleaned from studying aerial photographs was tightly held, until Oliphant was shown some of that pictorial evidence and ventured his opinion to colleagues on what it might show. Which brought an immediate scolding from Groves, and an equally combative response from the Australian.

  ‘I would like to say that I am rather tired of these veiled accusations of carelessness or evasion of security rulings,’ Oliphant wrote to Groves, outlining the reasons for his actions and the steps he had taken to ensure he had observed what he considered to be sufficient security protocols. He finished his one-page note to the feared general with a flourish: ‘These considerations seem to matter far more to some people than does getting the job done!’8

  * * *

  ‘Getting the job done’ was, however, proving to be a slow and difficult task. The problems that bedevilled the electromagnetic technique for separating the elusive uranium isotopes were testing Groves’ notoriously febrile temper, and frustrating the scientists and technical staff working around the clock to meet the goal of a bomb.

  Oliphant was one of those who would routinely finish his working day well after midnight. Despite the gruelling hours and the constant stream of technical problems that arose, he remained an upbeat presence, with his hearty laugh – almost Rutherfordian in its rumble – distinctively resonating up and down the hallways and workspaces of Berkeley and Oak Ridge. His warmth of character and preparedness to match words with action meant he was held in high regard, even if some of the ideas he put forward lacked practicality. At one stage, in mid-1944, he advocated that almost every suitable scientist who continued to work in the field of nuclear physics in Britain should be transplanted to the United States to supplement the Manhattan Project.

  His indefatigable zeal, fuelled by an unhealthy reliance on black coffee and cigarettes, stemmed partly from his love of working on intricate machinery such as the calutron, and partly from the keen sense of camaraderie he felt with Lawrence and his team. But just as influential was his nagging fear that, even if the war was beginning to turn against Hitler, Germany’s atomic research ambitions were ongoing.

  It was that shared urgency that saw more British researchers enlisted for the Manhattan Project, including Philip Moon, who joined Oppenheimer and Peierls at Los Alamos. It meant that the Tube Alloys program in Britain essentially ground to a stop as laboratories like Birmingham and the Cavendish saw most of their nuclear physics staff relocate to the United States.

  However, the increase in personnel was not mirrored by a similar upsurge in the production of the crucial uranium-235 at Oak Ridge, as further breakdowns and operational issues dogged the various isotope separation plants. Oliphant continued to call for an expansion of the electromagnetic facility in an effort to increase its output, but again he found no support among the upper echelons of the bomb program.

  Instead, Groves was turning his attention towards an altogether different solution.

  * * *

  Another option as source material for a ‘super-bomb’ – an option the original MAUD Report had dismissed, but which had since been shown to carry significant potential – was the synthetic element 94. It had been discovered during work conducted with Ernest Lawrence’s 60-inch cyclotron at Berkeley, and found to possess a basic chemistry that was very similar to uranium, from which it had been derived.

  When the predominant uranium-238 isotope was bombarded by neutrons slowed down by a moderator, it was found to transmute into uranium-239. This isotope then rapidly transformed into a new unstable element of atomic number 93, which does not exist in nature. After a few days, it decayed into another synthetic product, the stable element 94.

  Just as uranium – element 92 – was named in honour of Uranus, the seventh planet from the sun, after being discovered in 1789, these manufactured elements that followed on the periodic table took on the equivalent solar system sequence. Element 93 became neptunium, and 94 plutonium.

  The latter was found to be even more fissionable than uranium-235, and released a greater store of neutrons when it split. It also boasted a critical mass smaller than the difficult to extract uranium-235, and therefore offered the decided advantage that less of it would be needed to fuel a nuclear weapon.

  When clandestine word reached Oliphant – through the supposedly impermeable silo walls of the Manhattan Project – that plutonium was being viewed as the preferred core for the war-ending bomb, his disillusionment was palpable.

  Three nuclear reactor ‘piles’ were now taking shape within a 2000-square-kilometre site on the Columbia River at Hanford. If the plutonium they produced became the heart of bomb plans, then the years of work Oliphant had dedicated to uranium separation would prove wasted. Given the problems that had plagued the electromagnetic plants under his direction, while Lawrence continued his work back at Berkeley, the lack of support for his push to have more resources allocated to them, and now the possibility they might even be mothballed in favour of reactors churning out plutonium, Oliphant’s previously unsated appetite for the project began to wane.

  Not that his scepticism was rooted purely in the threat of repudiation of his area of expertise. The imperative that had drawn him into military work was to devote whatever scientific insights he possessed to ending the hellish war. And it was doubts about the unproven weapons capability of plutonium that worried him most.

  Those reservations were laid bare in a memo he sent to Lawrence from Washington in mid-February 1944, spilling details that he had absorbed from confidential conversations with Chadwick and Niels Bohr, now that the Dane had also joined the Manhattan Project’s ordnance research team at ‘Y’ in Los Alamos.

  Both . . . [Bohr] and Chadwick tell me that at ‘Y’ they are very pessimistic about ever getting sufficient [uranium] 235 for a weapon and hence, are giving all their attention to 94 [plutonium]. It is this assumption that leads to all the ordnance difficulties . . . there are practically none with 235. Chadwick had endeavoured to persuade them that there is at least some chance of 235 being available, but he says they are only half convinced. You will appreciate that the information which I have given you about things, which I have heard here, is ‘off-the-record’ but I feel it essential that you should have it and that you should draw your own conclusions.9

  As had been established from the time of Frisch and Peierls’s memorandum three years earlier, once a critical mass of uranium-235 was achieved, the detonation of an atomic weapon was comparatively simple. The two sub-critical components were kept safely separate within the bomb to prevent premature detonation, then fired together using a gun-like mechanism at the desired moment, setting loose the chain reaction. And annihilation.

  Although the critical mass needed for a plutonium weapon was much smaller – around one-third the amount of uranium-235 – triggering an explosion would be infinitely more complex. The highly fissionable plutonium core was not suited to ‘gun’ detonation due to the high risk of untimely explosion.

  Following furious theoretical calculation and investigation at Los Alamos, it was agreed that implosion was the most feasible way to achieve ignition. The sub-critical masses of plutonium would be sur
rounded by high explosives which, when set off, would force the two sections of the core violently together to trigger the fission reaction. It was a method so speculative that it would require test firing before any weapon could be considered suitable for use in combat.

  Oliphant’s unease was therefore not primarily caused by questions over the bomb’s key ingredient. Most of his anxiety stemmed from his pragmatist’s view that, once completed, the device must work. The risk posed by a prematurely exploding nuclear bomb was unconscionable. And the repercussions of dropping a fully formed device on enemy territory and having it land harmlessly intact, as a gift-wrapped make-your-own-bomb kit, were potentially worse.

  As it turned out, Oliphant’s misgivings were shared by Oppenheimer, who was now having to deal with the realities posed by the highly enriched plutonium beginning to emerge from the Hanford reactors. As a synthetic element whose existence had been known for barely four years, its chemical, physical and metallurgical properties remained largely a mystery.

  The complexities of designing a safe (to the deployers) means by which a plutonium bomb might be detonated even led Oppenheimer to consider resigning his commission as director of the project’s main site. However, that outcome was averted through the application of the program’s definitive feature and enduring strength: its sheer volume of willing personnel.

  As the Los Alamos facility’s technical history would note: ‘The Laboratory had at this time [mid-1944] strong reserves of techniques, of trained manpower and of morale. It was decided to attack the problems of the implosion with every means available, “to throw the book at it”.’10

  To bring the vision of a plutonium bomb to fruition, the number of full-time staff in the Los Alamos laboratory, which had been around 1200 in mid-1943, would double, and then double again by the end of 1944.

  As the Manhattan Project continued to grow exponentially into the largest science endeavour the world had known, the other unstinting constant was the obsessive secrecy in which Groves enshrouded it. When President Franklin D. Roosevelt died suddenly in April 1945, with the weapon nearing finalisation, his successor Harry S. Truman came to office with no inkling that an atomic bomb project had even been in operation for more than three years.

  By that time, plutonium production had increased after nuclear fission had become self-sustaining at the largest of the three reactors at Hanford in September 1944. At Chalk Hill, under John Cockcroft’s leadership, Canada’s first nuclear reactor was also taking shape. And at Oak Ridge, the three different methods of uranium isotope separation that had been effectively competing against each other were now operating in harness to churn out low-grade uranium-235 that could then undergo further enrichment in Lawrence’s calutrons. It was over these racetracks that Mark Oliphant continued to maintain a watchful eye, despite his broader unease.

  And it was during those long, late-night ‘owl watch’ shifts at Oak Ridge that his restless mind began to turn to other things.

  * * *

  As he had shown through his earlier endeavours, Oliphant needed to be where the action was. The reason why he had decided, at age twenty-three, to pack his academic life and young wife off to England was to join Ernest Rutherford’s atomic revolution. He had been central to the golden era of Cambridge physics that had followed, then had sought to engineer his own at Birmingham after Rutherford’s death.

  He had overseen the radar innovation that had helped Britain endure its ‘darkest hour’, and through sheer force of character had rallied American scientists in their commitment to the bomb. But now, after his belated introduction into the Manhattan Project and the dilution of his influence upon its secretive, labyrinthine structure, Oliphant felt himself to be on the periphery.

  Ultimately, it was his allegiance to Lawrence and to seeing the project through that kept him in the United States throughout 1944. He remained crucial to trouble-shooting at Oak Ridge’s electromagnetic plants, and he revelled in the incremental success of each team milestone. But by the beginning of 1945 – as a completed bomb came closer with every enriched atom painfully extracted from uranium in Tennessee, and every microgram of plutonium from the high desert of Washington State – he began to feel his continued usefulness to the project was limited.

  Never one to linger when he was not at the heart of the action, Oliphant eventually decided his time with the Manhattan Project had come to an end. On 22 January 1945, he wrote a succinct, one-page memo to General Groves, advising his plans – already communicated to Akers and other British authorities – to return permanently to Birmingham in mid-March.

  Chadwick, upon seeing its detail when it was shared by Oliphant as his direct subordinate, sent an immediate follow-up to Groves in an attempt to mitigate any ill will the premature departure might spark. Chadwick was fully aware of Groves’ lingering suspicions that British scientists would use the information gleaned from their involvement in the Manhattan Project for the commercial benefit of Tube Alloys.

  Oliphant’s position is not so uncompromising as it is put . . . Oliphant says he has urgent reasons not connected with T.A. [Tube Alloys] which demand his return to England. He believes also that he cannot contribute much more to the E.M. [electromagnetic] work as far as the war effort is concerned, and he is naturally anxious to be where he can be most useful.11

  Chadwick’s official correspondence with Groves was suitably conciliatory, but from the private conversations he had held with Oliphant – via letter and telephone, and when their paths occasionally crossed in Washington – his opinions differed. That’s because, in his own mind, James Chadwick was beginning to feel similarly vexed. The health problems he had endured since his internment at Ruhleben ensured he appeared forever gaunt and stern, and his workload throughout the bomb project – compounded by his almost daily dealings with the combustible Groves – meant he appeared older than his fifty-three years as the war entered its final phase. As his good friend and regular confidant mulled over plans to return to England, Chadwick assured Oliphant he retained his full support.

  Given the innate understanding and fondness they had developed for one another since their first meeting at the Cavendish almost two decades earlier, Oliphant knew that Chadwick shared some of his own doubts but, unlike the Australian, was too habitually diplomatic to air them publicly.

  An old-fashioned British patriot, Chadwick was wholly devoted to all that the United Kingdom represented. He admired and liked many Americans, but he did not trust their political, system nor its ‘way of life’. He felt strongly that the nuclear weapons could not be left in American hands alone, and it was Britain’s duty to possess the weapons as soon as possible, and thereby to have at least one sane and experienced nation with some say in its development and use.12

  In Oliphant’s mind, there was no equivocation. The bomb that had for so long been an experimental exercise was now glaringly imminent. And the project to which he had been personally attached since the Frisch–Peierls Memorandum landed in his hands was now grinding inexorably to its climax. And whether he remained in the United States or returned to his laboratory at Birmingham, that same sobering outcome would be delivered.

  He was not interested in personal wealth or scientific status. Instead, he wanted to utilise his now vast knowledge of nuclear physics to benefit Great Britain.

  * * *

  As foreshadowed in his note to Groves, Oliphant returned home to his family and to his Birmingham office in late March 1945.

  His first priority upon resuming the Poynting Chair of Physics was to reclaim the laboratory that he had not occupied for almost two years. The vision he had formed during the ‘owl watch’ stints at Oak Ridge was to lead the development of a large-scale electromagnetic plant in Britain. But before he could devote himself to that ambition, he needed to restore some order within the physics department.

  In his absence – and that of his former colleagues who had also joined the Manhattan Project – his laboratory had been occupied by a team from Oxford Univers
ity. They formed part of what remained of Tube Alloys. Before he had departed the United States, Oliphant had demanded of Tube Alloys boss Wallace Akers that the interlopers be evicted from Birmingham as a priority. He had also advised his laboratory would no longer be available to Tube Alloys, given its threadbare form. Emboldened by Chadwick’s reassurances, he foresaw that Britain’s nuclear industry would thrive in the post-war world and therefore imagined Tube Alloys in its current moribund state would be subsumed into a much larger entity.

  It was an exchange that prompted angst and ill feeling at senior levels of Tube Alloys and within the British bureaucracy before Oliphant got his way. As Vice-Chancellor Raymond Priestley was moved to note in his diary: ‘Oliphant and the Admiralty Research Department have parted brass-rags and there is a great deal of feeling unfortunately. The more brilliant the scientist, the more gently he has to be handled.’13

  * * *

  Even though Oliphant’s attention was turning to Britain’s role in the peacetime nuclear landscape, he remained an enthusiastic advocate for the Manhattan Project and the impending realisation of its mission. As he saw it, the completion of an atomic bomb would bring the exclamation mark needed to end the ongoing war. With the same display of harrowing force, it would also announce a new era of peace, in which the full potential of nuclear energy could be harnessed for the betterment of civilisation.

  Shortly before leaving for Birmingham, he had written an optimistic parting letter to Lawrence:

  There is no doubt we have been associated with the birth of a new industry. This is not a passing phase in the intensive development of a new military weapon but a permanent contribution to science and technology of the future.

  It will not be long before we see demonstrated the first fruits of our labours. Though war has brought the opportunity to do these things, and although the immediate result will be incalculable destruction, we know that in the ultimate analysis this aspect will be overshadowed by the benefits wrought for mankind.14