In April 1945 the New York offices of Detective Comics, Inc. received a visit from the FBI. Polite yet forceful, the agents were taken to meet publisher Harry Donenfeld. It was about the company’s most popular comic strip. The G-men demanded that the latest syndicated story be pulled from publication immediately. Donenfeld called in editor Jack Schiff, who was running the storyline.
Why, the FBI agents asked Schiff, was Superman leaking state secrets?
In the latest strip, Science and Superman, the Kryptonian hero had agreed to undergo a few tests in a particle accelerator for a scientist. ‘No, Superman! Wait! Even you can’t do it!’ his lab-coated ally warned, panicked by the idea of someone being hit by ‘electrons travelling at 100 million miles per hour and charged with three million volts’. The equipment – and the numbers – were a little too on the money to be a coincidence. Fortunately, the FBI soon realised no one was a spy: the writer, Alvin Schwartz, had simply copied the idea of an ‘atom smasher’ from something in a 1935 issue of Popular Mechanics.1 The article had described one of Ernest Lawrence’s cyclotrons.
A particle accelerator is basically a giant gun. Instead of bullets, it fires electrically charged particles down a vacuum tube, which contains a series of electrodes. By flipping the polarity of the electrodes at the right time, researchers can push and pull particles down the tube and make them go faster and faster. It’s a carrot-and-stick approach, using the same idea that makes a TV or X-ray machine work.
The first particle accelerators were ‘linear accelerators’, which shoot particles in a straight line. The problem is that to get a charged particle up to the kind of speed (and therefore energy) needed to punch through a nucleus’s Coulomb barrier requires an accelerator more than 100 metres long. This is far too large to fit into most labs.
Enter Lawrence’s invention. A cyclotron fires particles in a spiral, starting in the centre and looping out through two giant semi-circular electrodes called dees (because of their D shape). The whole thing looks like an oversized zinc battery, sandwiched under a giant magnet that helps the particle to bend around the spiral track due to something called the Lorentz force. With every completed loop the particle gains velocity, before it finally whizzes out of the machine.
Both linear accelerators and cyclotrons have been used to discover elements. Once the ions (atoms stripped of electrons so they have an electric charge) have been accelerated, they are rushed down a ‘beam line’ toward whatever target the researchers are trying to hit. Then all the team can do is sit, wait and hope for the best.
Thanks to their circular shape, a cyclotron is far more compact than a linear accelerator. Lawrence’s first accelerator, the size of his hand, was made out of copper tubes, wires, a vacuum pump, sealing wax and a kitchen chair: the whole thing cost about $25. By 1932 he had built a device 69cm (27in) in diameter, capable of accelerating particles up to energies of 4.8 million electron volts (MeV). This isn’t much in the scheme of things – a neutron produced by fission has an energy of 2MeV – but it was more than enough on the atomic scale. Lawrence’s breakthrough meant you didn’t need a particle accelerator the length of a football field any more.
Not everyone was impressed: you still had to hit the nucleus, something unimaginably small. ‘You see,’ Albert Einstein said dismissively in 1934, ‘it is like shooting birds in the dark in a country where there are only a few birds.’ Einstein was right. Yet even in a dark country, you’ll eventually hit something if you keep going for long enough. The nucleus had been hit before – and the cyclotron effectively gave everyone a super machine gun with an infinite supply of bullets. One of the later element creators, Mark Stoyer, explains it to schoolkids by asking them to throw marshmallows at each other’s mouths from the other side of the classroom. Most of the time they miss entirely; sometimes they get an unwanted reaction and the marshmallow bounces off a nose or an ear. But sometimes – rarely – they get lucky and it goes in. ‘Now,’ Stoyer ends, ‘imagine you’re throwing 6 billion bags of marshmallows a second. For three months. And every bag has 1,000 marshmallows in it. Science gets messy sometimes.’
Lawrence had made larger and larger cyclotrons. By the time the invention won him the Nobel Prize (disturbing his tennis match and annoying his secretary in the process), his latest cyclotron was 150cm (60in) wide, its magnet large enough that the whole Berkeley Rad Lab – 46 people – took a group photo of them sitting on top of it. There were other cyclotrons scattered around the world too: James Chadwick had built one in Liverpool, and the Germans and Russians both had one, as did the Japanese. It was hardly a state secret.
Figure 4 Ernest Lawrence (bottom row, fourth from left) and his team sitting on the magnet of the 60-inch cyclotron, 1939. Among those on top of the machine are Phil Abelson, Luis Alvarez, Edwin McMillan and Robert Oppenheimer.
Back to Superman at the Manhattan Project. Schiff had refused the FBI’s request to pull the offending panels, only to be overruled by his publisher, who had a ghost writer come in and make changes. The storyline was quickly wrapped up: the hero survived his encounter with the cyclotron (‘never felt better!’) and the strip was quietly changed to something more all-American, where the Man of Steel played a baseball game single-handed. As Newsweek commented after the war, ‘Superman could take [a cyclotron bombardment] and did. What he couldn’t take was the Office of Censorship.’2
A year before Clark Kent’s accidental espionage, Seaborg’s hand-picked unit of element hunters had already started to try and make element 95 with a cyclotron. In a host of locations – including Berkeley, St Louis and Oak Ridge – the team bombarded Pu-239 with deuterons and neutrons to try and induce neutron capture. The results were all negative. Perhaps there was a problem with detection? Al Ghiorso began to come up with new, innovative instruments to try to coax out any sign of a new element.
Finally, in July 1944, as the Allied forces began to break out of Normandy following the D-Day landings, an idea broke out of Glenn Seaborg’s mind. What if the chemistry was all wrong?
* * *
Summer in Oak Ridge is hot. The hot labs at Oak Ridge’s Radiochemical Engineering Development Center (REDC) are, paradoxically, cool. The ‘hot’ in the name is a reference to the deadly amounts of radiation that lurk inside. Fortunately, in 50 years the Oak Ridge team have never broken containment. ‘You notice the doors are getting harder and harder to open as we get deeper?’ one of my guides, nuclear engineer Julie Ezold, comments. ‘The walls here are 54-inch concrete, each window has three panes of leaded glass that range between 3 to 8 inches and in between each of those is a mineral oil. Even then, the mineral oil needs replacing every 5 to 10 years. The radiation just eats it away.’
Ezold is accompanied by Rose Boll. Both are carrying on Seaborg’s legacy of separating out the newly formed elements. Ezold is a 26-year Oak Ridge veteran who started out studying iodine, one of the most common uranium fission products. You also find iodine in your thyroid gland, which is why fallout exposure is treated with potassium iodide – you don’t want the radioactive version taking up residence in your neck. Boll came to Oak Ridge via working in a hospital as a medical technologist before going back to college and specialising in medical isotopes. There doesn’t seem to be one route to Oak Ridge’s hot labs, but once you get there, few choose to retire.
I took a car up to the hot labs from HFIR. The newly created elements come up from the reactor via the ‘Q-ball’, a massive shielded container, painted white, that is usually suspended in water above the unloading pool floor. When the products are ready, it gets loaded on a tractor trailer and taken up the hill. It’s hard for anything to escape 25t of protective metal.
I’m taken deeper into the hot labs’ interior. Turning a corner, suddenly we’re in a long gallery, where a row of chemical technicians are staring deep into inky, oily boxes in the wall – a series of enclosed chemistry stations called ‘hot cells’. Their hands are gripped to giant steel rods that vanish up into the roof. From there, the rods – manipulators controlled by flexible metal tape – reach down into the boxes with metal claws, allowing the operators to puppeteer the experiments concealed inside. It’s hypnotic to watch: a cross between the brute force of a power loader from Aliens and Tom Cruise’s graceful hand flicks in Minority Report. The workers don’t even blink as, with a twist of their wrist and a flick of their thumb, the metal claw grabs a flask of whatever they need.
The hot labs operators work 12-hour shifts, 24 hours a day. First the aluminium is trapped in a matrix and stripped away. ‘Aluminium dissolves in base, whereas the target forms a hydroxide,’ explains Boll. ‘That’s solid. You filter it out and gather it up.’ Ezold’s eyes gleam. ‘It’s pure chemistry. Just with a bit of radiation added to it.’
I approach and look over an operator’s shoulder, a big guy wearing a loose T-shirt and baseball cap. Trucker chic. How he can even see inside is amazing, let alone tell where the variety of leads, pipes, buttons and wires are all supposed to go. ‘It’s like spaghetti,’ I mutter, staring deep into the vortex above his station.
‘Yeah,’ the operator, Porter Bailey, agrees, his reply given in a deep Tennessean drawl. ‘It gets difficult sometimes. But we have maps, procedures.’ Another whirring click and a flick of his wrist, and the robot arm on the other side of the glass comes to a halt. Even with the aluminium gone, the process isn’t done. You still have to separate out the uranium, plutonium and anything else there. That means taking all the solid bits that remain and throwing them in a column of acid, where the newly made elements separate out. ‘We just dissolved 32 plutonium targets,’ Bailey says. Whirr. Click. ‘We’re giving it an acid digest for about 24 hours.’
From this point on, nothing is wasted. Even if it isn’t the element you want, the smallest bead of it is worth more than my house. ‘We’ve been able to get material out of the hot cells in nanogram [a millionth of a milligram] quantities,’ Ezold says. ‘They [the hot labs staff] do magic … it’s science and an art.’
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 tried 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.