by P. D. Smith
You wouldn’t have guessed it from what Simons said, but in the 1940s fissile elements such as plutonium and uranium-235 were more precious than gold to the atomic bomb project. They were the result of a vast expenditure of money and effort. Whole cities of workers laboured to produce these lethal elements in vast industrial complexes built specifically for the Manhattan Project. Each gram was the product of thousands of working hours. It was not unusual to see scientists down on their hands and knees, sweeping the floor with Geiger counters, hunting for any stray pieces of metal that might have been dropped. Sometimes the Geiger counter would crackle furiously as it passed over a tiny orange or black speck on someone’s lab coat, revealing the telltale signs of radioactivity. Even the smallest particle of fissionable matter was extremely valuable, and lab coats were routinely treated with chemicals to reclaim these elements.
Research scientist Sanford Lawrence Simons – the ‘plutonium collector’ – in the custody of two US Marshals in Denver, August 1950.
Sanford Simons hid the stolen plutonium under his house. He had good reason to. Plutonium has been called the most dangerous element on earth. The glass vial and its deadly contents remained in its hiding place for four years. The FBI became aware of its presence there only after they were tipped off. Simons had let slip in conversation with a friend that he had some plutonium. In the year that Joe McCarthy stoked fears about a Communist fifth column infiltrating American society, to admit that you had a key ingredient for the atomic bomb stashed in your home was simply asking for trouble.
Outside the courtroom, a reporter put it to Agent Kramer that taking plutonium as a ‘souvenir’ was a rather corny excuse. The FBI man nodded in agreement and said, without a trace of humour, ‘He’s a pretty corny guy.’
During his trial the defence pointed out that Simons had never been in trouble with the police. More importantly, he was not a ‘Red’ and had no ‘Communist connections’. The defence attorney based his case on the popular image of the scientist. He argued, somewhat unconvincingly, that scientists are ‘all darned fools’ when it came to experiments. He claimed that scientific curiosity alone had prompted Sanford Simons to take the samples of plutonium and uranium in 1946. It was a case of the irresistible allure of forbidden knowledge, Your Honour, and, as everyone knew, no scientist worth his slide-rule could resist that. But Judge Lee Knous was not particularly impressed by this argument. For taking a pinch of plutonium, the disgraced scientist was sentenced to eighteen months in a Federal prison.1
The ‘plutonium collector’, as the press dubbed the unfortunate Simons, was driven by a dangerous fascination for the deadly element. Its discovery at the beginning of 1941 marked the point where science could claim to have exceeded the dreams of the alchemists. Plutonium was first identified by chemist Glenn Seaborg, who bombarded uranium with deuterons (the nuclei of heavy hydrogen atoms) and painstakingly separated out the resulting transmuted elements. He recalled that the critical chemical identification took place on the ‘stormy night’ of 23 February 1941, in Room 307, Gilman Hall at the University of California, Berkeley. Twenty-five years later the room was dedicated as a National Historic Landmark. The 28-year-old son of Swedish immigrants to the United States was a dynamic and ambitious scientist, the only person to have an element named after him during his lifetime – element 106, seaborgium.
An alchemist would probably have felt quite at home in Seaborg’s laboratory. It was usually dense with fumes and steam from the processes used to isolate the microscopic amounts of this new matter. By March, he and his co-worker Joseph W. Kennedy had managed to isolate half a microgram of the new artificial element. Talking about this and his subsequent work identifying other new elements heavier than uranium, Seaborg commented:
When you are working with invisible amounts of a new substance, the task of identification is immensely difficult. In one instance, we had only five atoms and a few hours to make a positive identification through chemical analysis. The difficulty can be understood when one realizes that the ink in the dot of an ‘i’ on this page you are reading contains something on the order of a billion atoms.2
From 1942, Glenn Seaborg worked for the Manhattan Project at the University of Chicago. This part of the programme to build the world’s first atomic superweapon was code-named by the military ‘Met Lab’. Here too, Leo Szilard worked with Enrico Fermi to develop CP-1, the first nuclear reactor. In the storm of neutrons unleashed within this graphite and uranium pile, the new element, plutonium, would be born. Seaborg was put in charge of developing the chemical process to extract plutonium after it had been created in the reactor.
Until August 1942, Seaborg had just millionths of a gram of plutonium to work with. The day when he was able to display the first sample of a visible amount of a plutonium compound to his fellow scientists was ‘the most exciting and thrilling’ he had experienced at Chicago: ‘It is the first time that element 94 – or any other synthetic element, for that matter – had been exposed for the eye of man to behold… my feelings are akin to a new father engrossed in the development of his offspring since conception.’3
Showing off the newborn element to his colleagues set a precedent, and afterwards visitors to the Met Lab insisted on being shown it. Seaborg later confessed, with a mischievous twinkle in his eye, that due to plutonium’s value and toxicity, most people only ever saw a solution of green ink in a test tube. The man who beat the alchemists at their own game was awarded the 1951 Nobel Prize in Chemistry, while arguably his most diehard fan, Sanford Simons, was still locked up in jail.
Glenn Seaborg shared the prize with his University of California colleague Edwin McMillan, whose discovery of element 93, the shortlived neptunium, had led Seaborg to his lethal chemical child. Neptunium has 93 protons in its nucleus, which is why it is number 93 in the periodic table of the elements. An atomic nucleus consists of protons and neutrons. Many elements, uranium among them, can exist in several different forms, depending on how many neutrons the atom’s nucleus has. These different forms of the element are known as isotopes. Plutonium, element 94, has fifteen isotopes. They range from the lightest, plutonium-232 with 138 neutrons, to the heaviest, plutonium-246 with 152 neutrons. In his career, Seaborg helped to identify over a hundred different isotopes.
When uranium-238 captures a neutron it becomes the unstable isotope uranium-239. Within minutes this transmutes into neptunium-239, which just over two days later becomes plutonium-239. This is the reaction that took place inside Szilard and Fermi’s prototype reactor, CP-1. It is now known that minute traces of plutonium do occur naturally in uranium ore, created by the release of neutrons.
In its solid form, plutonium is a silvery metal which quickly turns yellow when exposed to air. It is warm to the touch – it feels alive, and in a sense it is, constantly emitting a stream of alpha particles (helium nuclei, consisting of two protons and two neutrons). A large piece of plutonium placed in water, would radiate enough heat to bring the water rapidly to the boil. Indeed, this heat has been utilized to produce electricity to power everything from cardiac pacemakers to spacecraft. But bring together too much plutonium in one place and it will go critical, creating a potentially explosive chain reaction. The Nagasaki bomb contained just 13 lb of plutonium and produced the explosive power of 20,000 tons of chemical high explosive. A mere 1 lb can yield 10 million kilowatt-hours of energy. As Seaborg quickly realized, ‘element 94 is almost twice as fissionable as uranium-235’, a finding of huge importance for the atomic bomb project.4 Uranium-235, the rare isotope of natural uranium used in the Hiroshima bomb, was difficult to separate. Seaborg’s discovery meant that bombs could be built with less fissionable material.
Just after the ‘Fat Man’ plutonium bomb was dropped on Nagasaki, a Los Alamos scientist, Harry Daghlian, was fatally injured while assembling pieces of plutonium for an experiment to determine plutonium’s critical mass. A chunk of the warm, silvery metal slipped from his fingers into the assembly, causing it to go prematurely cr
itical. In the fraction of a second before he could scatter the blocks to stop it exploding, he saw the air around the assembly glow with an eerie blue light as it was ionized by lethal radiation. The nuclear scientist died twenty-five days later. Each stage of Daghlian’s radiation sickness was documented by his fellow scientists, eager for knowledge about the lethal new element. The official record states that they obtained ‘most spectacular pictures’.5
Plutonium is aptly named after the god of the underworld and death. According to Seaborg, plutonium is ‘one of the most deadly substances known, it has unusual – and unreal – properties’.6 It is highly toxic. At Los Alamos the chemists had a policy of ‘immediate high amputation’ if plutonium entered a cut.7 Once inside the body it accumulates at bone surfaces, from where it irradiates surrounding tissues and fatally destroys bone-marrow cells. There is nothing that can be done once it is absorbed into the body: plutonium-239 has a half-life of over 24,000 years. Plutonium remains in your bones long after you are dead and buried.
Plutonium from the Nevada Desert nuclear tests in 1952 and 1953 drifted out of America and settled invisibly on Great Britain within days. Tests on soil samples gathered in Hertfordshire have only recently revealed this chilling fact. It is estimated that our biosphere contains several tons of plutonium, a legacy of atmospheric weapons testing in the 1950s and 1960s.8 Leo Szilard’s vision of global doomsday through nuclear poisoning was happening sooner, but more gradually, than anyone realized. It would not be until the mid-1950s that concerns were voiced about the health effects of the fallout from nuclear tests.
It was this deadly element that so intrigued the 24-year-old Sanford Simons that he was prepared to risk his liberty to possess it. Otto Frisch, whose calculations of critical mass were crucial in the early stages of the bomb project, understood this dangerous fascination with these deadly new elements. When the silvery blocks of highly fissionable uranium-235 were first delivered to Los Alamos in April 1945, he felt an overwhelming ‘urge to take one’.9 They were the first pieces ever made of uranium-235 metal, the element that would blast the heart out of Hiroshima. Somewhat incongruously, Frisch thought that the heavy metal would make a nice paperweight.
Precious elements such as gold have long exerted an almost mystical power over human minds. Gold, the sun-like metal that never rusts or corrodes, promised its owner earthly riches but also eternal life. Alchemists have walked a weary path down through the centuries in their fruitless quest for the secret of this metal. They believed the discoverer of the philosopher’s stone would be able to speed up the natural processes by which, according to alchemistic lore, metals evolve beneath the earth’s surface from base lead to noble gold. Their search was in vain, but there was a nugget of truth in their belief: elements can be transmuted, both in the laboratory and in the earth’s interior, where it has been happening since our planet was first formed. Tragically, however, once we gained this elemental knowledge of the secrets of matter it gave us the key not to eternal life, but to mass destruction on an almost unimaginable scale.
In a lecture delivered one year after the atomic bombing of Japan, Leo Szilard told a Chicago audience that the ‘first and only successful alchemist’ had been God. But when plutonium was created, fulfilling the dream of the ancient alchemists, the first use that humankind found for the new element was to create a bomb to destroy a city. ‘I sometimes wonder,’ said Szilard, ‘whether the second successful alchemist may not have been the Devil himself’.10
The foundations of the Atomic Age were laid at the beginning of the twentieth century, creating both a new science and popular dreams of a utopia in which humankind had access to unlimited power. Szilard and his fellow atomic scientists grew up in this age of the atom. The hopes and fears provoked by this revolutionary science, expressed in fiction, newspaper articles and films, tell us as much about ourselves as they do about our understanding of the physical world. At times in this fantastic story, in which the dreams of the alchemists are realized and Strangelovean fantasies give birth to the ‘Hell Bomb’, science and fiction seem almost indistinguishable. To trace the roots of what Leo Szilard termed ‘the tragedy of mankind’ we need to follow the dream of the superweapon back to its origins in both scientific discovery and popular culture.11
The story of atoms begins in the fifth century BC. The Greek philosophers Leucippus and Democritus believed that matter was made up of unchanging, indestructible atoms. These were the smallest things in the physical world. Our word ‘atom’ comes from the Greek word atomos, meaning ‘indivisible’. In 1803 John Dalton, a Manchester Quaker, revived atomism. In his hands it became a powerful tool in the dominant science of the nineteenth century – chemistry.
Dalton proposed a theory in which elements could be distinguished from one another by the relative weights of their atoms. The atoms of each element were unique, he said, and had the same weight. They could not be created nor destroyed, merely rearranged to form new compounds. It was impossible, said Dalton, for lead to change into another element, such as gold. To believe otherwise meant following in the footsteps of the alchemists.
Although there were lingering doubts as to whether atoms really existed, by the mid-nineteenth century Dalton’s theory had been widely accepted. But exactly 100 years after Dalton’s influential 1803 lecture, a new scientific era dawned. His axiom that no man would ever split an atom was about to be challenged.
Ernest Rutherford followed his wife, Mary, out into the night air. He was relieved to feel a slight breeze on his face. It was a sultry June evening and everyone was feeling uncomfortably warm – the women laced into constricting corsets, their husbands buttoned into starched collars and dinner jackets. It was a blessed relief to step out of the dining room and into the garden.
Earlier that day, Rutherford, who was visiting Paris, had called unannounced at Marie Curie’s laboratory in the rue Cuvier. He had been surprised to find that for once she was not working at her bench. Instead, she was defending her doctoral thesis in the students’ hall of the Sorbonne. Her four-year quest for new elements had been successful, and today, 25 June 1903, the examiners had given their scientific seal of approval to her arduous research.
Rutherford also called on his old friend Paul Langevin, whom he had known as a research student at Cambridge eight years earlier. Langevin immediately invited the Rutherfords to a celebratory dinner with the Curies at his villa opposite the Parc Montsouris, together with Sorbonne physicist Jean Perrin and his wife. Now, as they stood in Langevin’s garden, Marie’s husband, Pierre, suddenly drew a small glass vial from his waistcoat pocket. As he held it up against the night sky between his thumb and forefinger, a bright new star suddenly shone from the heavens. A soft, blue-green light illuminated their upturned faces. It was the new, luminous element that had made headline news around the world – radium.
Ernest and Mary would remember the moment for the rest of their lives. The vial was partly coated with zinc sulphide and contained a relatively large quantity of priceless radium in solution. ‘The luminosity was brilliant in the darkness and it was a splendid finale to an unforgettable day,’ wrote Ernest.12 The dinner guests were transfixed by the ethereal radiation. It was as if they were seeing a light from another world, a strange realm that nobody yet fully understood.
The light of transmutation shone brightly in the Paris night. Rutherford and his co-worker Frederick Soddy had explained the previous year that in watching the glow they were seeing atoms of radium disintegrate, as the element transmuted down through Dmitri Mendeleev’s periodic table towards dull, inactive lead. It was something everyone had thought was impossible. In the eerie light of the radium, Ernest could see that Pierre’s hands, like those of his wife, were painfully swollen and scarred from constant exposure to the penetrating rays emitted by the radioactive element. He even seemed to have difficulty holding the tiny vial steady between his fingers.
The Curies had led the world in isolating the new radiant element and identifying its propertie
s. Ernest Rutherford’s work on the causes of radioactivity was similarly groundbreaking, but as yet his ideas, though published, were just hypotheses. So when Mary Rutherford asked over dinner where radium’s energy came from, Pierre’s reply was frank: ‘We just don’t know.’ Had it absorbed the rays of the sun? Or did its energy come from some force within the element itself? No one could say for certain. ‘We have made a discovery of forces and power beyond present knowledge, quite beyond imagination,’ said Pierre solemnly. ‘It is a revolution… we are walking into strange territory, a no man’s land of scientific mystery.’
Marie and Pierre Curie pictured in a chromolithograph by ‘Imp’ from Vanity Fair (1904).
At 44, Pierre Curie was twelve years older than Ernest Rutherford. A tall and dignified man with a dark, neatly trimmed beard, he looked genuinely worried as they discussed the future uses to which their discovery might be put. Would the human race benefit from knowing these ‘secrets of nature’? Looking round at the faces of his fellow diners that June evening, he asked a question that has since tormented many scientists: ‘What if such a dangerous force falls into the hands of warring men?’13
Within a mere forty years, the power of the atom, revealed in the Curies’ glowing vial of radium, would be released by a group of scientific refugees from Europe working in – of all places – a squash court on the campus of Chicago University. When the first plutonium bomb was detonated in the Nevada desert just before dawn on 16 July 1945, the flash of atomic light was so bright that it could have been seen from the moon. It was as if a second sun had risen in the sky, a new and terrible morning star, lighting the way to an uncertain future.
