Superheavy

by Kit Chapman

  The operation isn’t perfect. Sometimes vials slip. Sometimes cables break. Sometimes every atom of an element on Earth ends up in a tiny, radioactive puddle at the bottom of the hot cell. ‘Your eyes go pretty big,’ Bailey confesses. ‘Sometimes it can be several million dollars in your hand. Depends what you’re working with at the time. It’s very hard to put a value on this material.’ The good news is that you can recover every drop by hosing the hot cell down. The bad news is that you have to restart the extraction process from the top. For the more unstable isotopes, the ones with half-lives of only a few days, that means they’re lost forever.

  We head out, leaving Bailey to his work, back through progressively leaner doors, stopping to stick our hands in machines with thick metal grills to make sure we’re not radioactive. A Geiger counter sits nearby, clicking away squeakily. Clean enough. We pass into the less hazardous labs, full of glove boxes, white lab coats and faint caustic aromas. There are machine shops too, ready to spool out the new elements into strips of wire. This is where medical isotopes are made, ready to ship to hospitals across the US for diagnostic tests or to treat cancers. Boll describes this part of her role as being the ‘atom dishwasher’, just purifying the materials. She’s doing herself a disservice. Every moment she applies her skill directly saves lives.

  We pause in front of one fume cupboard, its bottom coated with Teflon to recoup loses if there’s a spill. There’s not much in there save for a small plastic bottle about half-full. ‘We have about two-thirds of the world’s supply right now of thorium-229,’ Boll says off-handedly, before moving on.

  ‘At Oak Ridge?’

  ‘Uh, no. Right there. In that bottle. You’re looking at two-thirds of the world’s supply.’

  * * *

  Thorium is a strange element. It’s named after the Norse god of thunder (incidentally making it the only comic book character on the periodic table), and sits a couple of places before uranium on the periodic table at element 90, between actinium and protactinium. Today, it’s under constant scrutiny as a possible source of more environmentally friendly nuclear power. If you look on a periodic table, it’s part of a row that sits under the lanthanides, away from the rest of the elements. This was Glenn Seaborg’s great innovation in the summer of 1944.

  The periodic table is built on rules: as you look down a column, the elements are supposed to have similar properties. These are based on their electrons. As mentioned before, chemistry is all about the outer shells of electrons and elements trying to fill them. When you reach the lanthanides, their shells are so complicated they all end up reacting in basically the same way as each other, even though electrons continue to be added. This is why, rather than try to put them in the main periodic table, science had condemned them to be the weird bit at the bottom, stuck in a row of their own.

  Up until Seaborg’s epiphany, actinium, thorium, protactinium and uranium were all set out in the main periodic table, placed at the bottom of the area known as the transition metals. It made sense: they behaved much like everything else. But neptunium and plutonium didn’t. What if, Seaborg wondered, there was a second line of elements that acted like the rare earths? This would mean that all the tests they were using to try to isolate element 95 wouldn’t work – the chemical reactions wouldn’t happen and the rules they had assumed wouldn’t be followed. The team realised that they could have been producing the element in their tests but, because they had been looking in the wrong way, they had missed it.

  By now, neutron capture wasn’t enough – instead, Seaborg’s team was trying to achieve fusion (combining two nuclei together to make something larger) by smashing whole elements together with enough energy to get over the Coulomb barrier, but not enough to cause fission. Starting on 8 July 1944, Berkeley’s 60-in cyclotron fired helium ions (two protons, two neutrons) at a plutonium target. Once the sample arrived in Chicago, Seaborg and his three assistants – Ghiorso and a pair of chemists, Ralph James and Leon (Tom) Morgan – began to purify their sample on the new theory, using reactions they knew would separate out elements that behaved like rare earths rather than the transition metals as they had assumed. Soon strange readings were detected: alpha particles at a range never seen before. Instead of transition metals, it became clear that they were dealing with a phenomenon, like the lanthanides, that began with actinium.3

  New element fever took over. It was a world of complex, multidisciplinary science; work that emerged off the back of 80-hour weeks during a hot Chicago summer. Soon, they found evidence of plutonium-238. Working backwards, they mentally added an alpha particle to it. That would make it element 96 with an atomic weight of 242. Soon after, using the chemistry of the lanthanides as a guide, the team found element 95. Seaborg’s actinides were real.

  The chemists immediately grasped what was happening. Ghiorso, predominantly a tinkerer, was a little slower on the uptake. ‘[The report] read “observed and understood by Albert Ghiorso”,’ he would later comment at a talk celebrating the discovery 25 years later. ‘I am sure I observed it … I am sure I didn’t really understand it.’

  Ghiorso wasn’t alone. The actinides changed how chemists thought of the periodic table, and have been the source of never-ending arguments ever since. In 1955, for example, Seaborg used his knowledge of the actinides to predict which of element 95’s electrons would form partly covalent bonds with chlorine. While this may sound technical, this is crucial to understanding how to recycle and recover spent nuclear fuel rods in reactors. Seaborg, it turns out, was right – but scientists couldn’t prove it until 2017.

  Another lab event Ghiorso became involved with would have an even more dramatic effect, even if no one realised it at the time. One day, playing with plutonium, Ghiorso set up his detectors to look for evidence of fission – big ‘kicks’ as atoms broke apart. Soon the kicks came, appearing every 15 minutes like clockwork. Ghiorso rushed around the lab telling everyone – evidence of spontaneous fission! He was detecting newly-formed isotopes by recording them as they broke apart.

  ‘Then I happened to notice a strange thing,’ Ghiorso later wrote in the book The Transuranium People. ‘You know, those things were just like a train.’ Science is full of uncertain noises and surprises – his punctual, 15-minute fissions were a little too neat. After investigating his equipment, Ghiorso realised that all the alpha radiation flooding out of his sample was charging up a plate in his equipment; the plate was just discharging and creating a false reading. ‘It was a pretty good joke on me … perhaps ever since then I have had it in for spontaneous fission.’

  It was a small moment, forgotten by most almost immediately. But it had sown a doubt in Ghiorso’s mind about how reliable spontaneous fission was when confirming an element had been discovered. It was a worry that would eventually cause a schism throughout the nuclear world.

  * * *

  In August 1945, two atomic bombs fell on Japan. The death toll was staggering, the damage beyond measure. It was a human tragedy that bought the bloodiest conflict in history to a close. All the scientists could do was put the horror of their creation to the back of their mind and keep working.

  Although neither of the two new elements, 95 and 96, had any military purpose, their creation via plutonium meant they still had to be kept a secret. They were also an elusive nightmare to isolate – so much so that Morgan wanted to call them ‘pandemonium’ and ‘delirium’. But, by the end of 1945, the team felt confident to announce their discovery. Neptunium and plutonium were no longer secrets (after a plutonium bomb had been dropped on Nagasaki, how could they be?) and Seaborg decided to reveal the new elements at the American Chemical Society’s national meeting. There, in front of his fellow chemists, the great element magician, still only 33 years old, planned to announce his latest trick to the world.

  Fate intervened. On 11 November 1945, Armistice Day, Seaborg was asked to come on Quiz Kids. This was a popular Sunday night radio show – a pure slice of wholesome Americana in which children with high IQs trie
d to win a $100 bond toward their education. The categories varied from spelling to nature, science to literature, all met with saccharine phrases like ‘that’s swell’ or ‘gee whiz’ as the precocious minds came up with the answer. Usually the special guest was a comic, but the producers wanted someone to talk about this new, exciting thing called atomic power. Seaborg happily obliged.

  Ding ding! The makers of Alka-Seltzer present the Quiz Kids: five bright youngsters ready to match wits with each other and you! Seaborg sat as the intro music played. Here, behind a row of school desks, was the next generation – the children he had been fighting to protect. To his left was Sheila, aged five; beyond her, the slightly older Bob. The giant Swedish-American cut an almost ridiculous figure at the edge of the class.

  As Seaborg was the guest, the kids got to ask him a few questions. At first, they were relatively easy. Then, just as the cross-examination finished, one of the kids, Richard Williams, caught Seaborg off guard.

  ‘Oh, and another thing,’ Williams asked innocently. ‘Have there been any other new elements discovered, like plutonium and neptunium?’

  Seaborg could have bluffed. For five years he had helped keep the greatest secret in the world; he could easily have kept quiet about elements 95 and 96 for a few days more. There were also other answers he could have given. Teams across the world had been creating radioactive elements, filling in all of the known gaps in the periodic table. He could have mentioned how francium had been found by the French physicist Marguerite Perey shortly before war had broken out, or spoken of Emilio Segrè’s technetium and astatine. Although it wouldn’t be announced for another two years, Oak Ridge scientists had even discovered the last missing piece of the periodic table, element 61, which they would call promethium. The jigsaw puzzle of the periodic table had no gaps – only an edge that was Seaborg’s to explore.

  But the chemist couldn’t resist a chance to showboat. ‘Oh yes, Dick,’ he replied with a toothy grin. ‘Recently there have been two new elements discovered – elements with the atomic numbers 95 and 96 out of the Metallurgical Laboratory, here in Chicago. So now you’ll have to tell your teachers to change the 92 elements in your schoolbook to 96 elements.’

  It is the only time news of new elements was announced on a quiz show.

  Notes

  1 There are several versions of this story; I’m taking as a basis Schiff’s word, although doubt has been cast on whether the strip was cut, replaced or monkeyed with in any way. In April 1948 Harper’s published a secret memorandum from the time, which insisted that the strip was harmless and ‘will considerably de-emphasise any serious consideration of the apparatus to many people’.

  2 This wasn’t the last word in DC Comics’ brush with the FBI. In 1983 a new villain was retroactively added to its continuity: Cyclotron. And if that wasn’t enough to stick it to the Feds, DC also introduced Cyclotron’s grandson Nuklon – who was later renamed Atom Smasher.

  3 Technically speaking, both the lanthanides and actinides (officially ‘lanthanoids’ and ‘actinoids’) are transition metals too, but here it’s much easier to think of them as separate entities. There’s currently massive debate as to which lanthanide and actinide pair (if any) belongs on the main bit of the periodic table, and an international group of chemists are trying to sort it out.

  CHAPTER FIVE

  Universitium ofium Californium Berkelium

  In 1946 the scientists of the Manhattan Project scattered back to civilian life. Some, like Enrico Fermi, stayed in Chicago to found the Argonne National Laboratory; some headed to the East Coast, some along the West. Some never returned at all. In September 1945 an accident with a plutonium core had killed a promising scientist, Harry Daghlian. A few months later, the same core had gone on to kill again. Louis Slotin – the man who had assembled the Gadget in the McDonald bedroom – had been fiddling with the so-called ‘demon core’ in Los Alamos, the lab where the nuclear bomb was designed. He had been performing his party piece, something his colleagues described as ‘tickling the tail of a sleeping dragon’. Protected by little more than jeans and cowboy boots, Slotin would lower the two halves of the core together, using a screwdriver to keep them apart and prevent a fission chain reaction. With the inevitability of a health and safety training video, the screwdriver had slipped. Slotin had been engulfed in a blue flash as the air around him ionised, and died in agony nine days later. The new elements were not toys.

  Most of the Berkeley researchers – including Luis Alvarez, Edwin McMillan, Emilio Segrè and Glenn Seaborg – opted to return home. In their absence, the San Francisco Bay had moved on. The new federal prison was showing its age, with its cell house damaged by grenades and gunfire after a failed escape attempt known as the Battle of Alcatraz; past that, at the base of the Golden Gate Bridge, beachcombers had unearthed an unexploded Japanese torpedo. Life would not be the same.

  The men who came home, now in their late twenties and early thirties, had changed too: they were already far beyond full professors in terms of raw experience. ‘We had gone away as boys, so to speak, and came back as men,’ Alvarez wrote in his autobiography Alvarez: Adventures of a Physicist. Lawrence set them free to work on whatever interested them. ‘Ernest,’ Alvarez noted, ‘was always a wise scientific parent.’

  Alvarez had seen more than his share of nuclear horror. He had been in a B-29 bomber high above the Trinity test as a scientific observer, and had repeated the experience over Hiroshima. His friend Lawrence Johnston, working with him, had been present at the bombing of Nagasaki, and thus was the only person to complete the nuclear hat-trick of witnessing every atomic explosion in the Second World War. Within a month, the US would drop yet more of these deadly creations, setting them off in the waters around Bikini Atoll in the Pacific. Those who witnessed the tests, lacking protection and bathed in radioactive spray, would have their life expectancy slashed by an average of three months.1 Seaborg would later call it the world’s first nuclear disaster.

  It was something Seaborg understood all too well. As one of the leading chemists in the Manhattan Project, Seaborg had been part of the committee that had discussed how the bomb should be used. He had counselled restraint, though he never regretted the choice to use his element in an act of war: he had cousins who were stationed in the Pacific islands, dreading the inevitable invasion of Japan. ‘For years after the war, at family reunions,’ he recalled in his autobiography, ‘they made a point of thanking me … they were convinced that the bomb had saved their lives.’ Even so, Seaborg felt an almost overwhelming responsibility to control his creation.

  Seaborg returned to Berkeley as head of nuclear chemistry. He was the obvious choice; the boy who had grown up with nothing was suddenly one of the most important men in America. The element maker had been tempted by an offer from Chicago ($10,000 a year, about $140,000 today and four times his pre-war salary), but the lure of home was too strong. At his side, as ever, was Helen. Ten days after their return, she gave birth to twins. ‘Two fragments,’ Seaborg announced to his colleagues. ‘But not fission.’

  Seaborg had followed up his Quiz Kids appearance with another radio show, Adventures in Science. There, he was asked what his two new elements would be called. ‘Well, naming one of the fundamental substances of the universe is, of course, something that should be done only after careful thought,’ he hedged. ‘Naming neptunium after the planet Neptune, and plutonium after the planet Pluto, was rather logical. But so far, the astronomers haven’t discovered any planets beyond.’

  Listeners were asked to offer suggestions. Some wanted Latin titles such as ‘proxogravum’ and ‘novium’; others focused on the cosmos with ‘sunian’, ‘cosmium’ and even ‘bigdipperean’; yet more wanted ‘washingtonium’ and ‘rooseveltium’ after US presidents; one listener even suggested, given 96 was the offspring of another element, ‘bastardium’. But Seaborg was morphing into a canny diplomat: he was going to use the names to cement his actinides on the periodic table.

  The actin
ides were now appearing in a row below the rare earths in chemistry labs around the world. To push the association beyond all doubt, Seaborg paired them up with their rare earth equivalent or homologue (group mate). Element 63 was ‘europium’, after Europe – the element beneath it, 95, would be ‘americium’. Element 64 was ‘gadolinium’, after Johan Gadolin, an eighteenth-century Finnish chemist who had discovered the element yttrium – Seaborg decided element 96 would be ‘curium’, after the legendary radiation pioneers Marie and Pierre Curie. It was the first element named, even in part, after a woman.

  The new elements needed exploration. Fortunately, Seaborg brought with him the kernel of his Chicago team. Among them was Stanley Thompson, who had given up the oil industry and decided to complete his PhD at Berkeley under Seaborg’s guidance; Al Ghiorso was back too, although this time his talent wouldn’t be wasted making Geiger counters. It was a team that had been forged in a crucible, and their skills were unmatched in the world. Seaborg was the leader who could play politics and get the experiment approved; Ghiorso the mad inventor whose equipment could do it; Thompson the brilliant chemist who could prove what they had done.

  It was the dawn of a golden age at Berkeley.

  * * *

  ‘So, there was this guy, Seaborg ... he was one of the most famous scientists ever. Fun fact: his name is an anagram of “Go Bears!”.’ The tour guide chirps away cheerily as she takes the new university intake past Gilman Hall, full of pep and team spirit. Science and the Golden Bears – Berkeley in a nutshell.

  I’m back on campus. The chill of the Bay Area mist still permeates the air. I still wish I’d picked up one of those cheap ‘I heart San Francisco’ sweaters. Fortunately, this time I have a stiff climb to keep me warm. Berkeley Lab sits on the slopes of the hills above campus. At its top is a massive dome, today housing the Advanced Light Source, shooting bright beams of X-rays around in a circle to understand how the universe works. It was a sight that would have greeted the Berkeley boys on their return to the lab: while they were off in Chicago, Ernest Lawrence had been busy making ever-larger machines. In 1944, under the dome, he finished a 470cm (184in) cyclotron, eclipsing the 150cm (60in) machine used to create the new elements. This was never used for war work, but the director of the Manhattan Project, General Leslie Groves, still chipped in $170,000 (about $3 million today).