Superheavy
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Now in her forties, Shaughnessy cuts a relaxed figure, peppering our chat with quips and the sheer, infectious joy she takes from her research. Her facial expressions switch from seriousness to puckish charm. She wears the loyalties ingrained since childhood – science and Star Wars – on her sleeve. When The Force Awakens came out, her team had a contest to see who’d watch it the most at the cinema. Shaughnessy won by double digits. My geek test was whether I knew who Ahsoka Tano was. My pass for the lab (along with the kind of security clearance you’d expect for a place still at the heart of maintaining the US nuclear deterrent) was a pledge to send her a poster signed by Darth Vader actor David Prowse.
Livermore is an hour and a half on the Bay Area’s metro system from Berkeley. It swings you through downtown Oakland, past the baseball stadium and along the waterfront, before a change in trains sneaks you under the ridges that enclose the Bay and out into the brilliant sunlight of the Livermore Valley. It feels like stepping into a Californian version of Narnia: in an instant, the cloudy cityscapes, chill ocean air and huddled commuters strip away into bucolic peace. Here, basking among gold-spun hills, the pace is relaxed and easy. The mayor, John Marchand, describes it as a city of ‘contrasts and superlatives’. ‘We are the oldest wine region in California – you buy auto parts at Napa, in Livermore we make wine. We have two national labs. We’ve had the world’s fastest computer, we still have the world’s fastest rodeo: a bull ride is 8 seconds, but with 22 gates they keep the thing going for 3 or 4 hours. We even have the world’s longest-burning light bulb. Been burnin’ [since 1901].’
He’s not kidding. The bulb has a direct webcam feed: 24 hours a day, 7 days a week you can tune in to see if it’s still glowing. But the real prize is Lawrence Livermore National Laboratory.
When it was built in 1952, Livermore was merely an offshoot of the Berkeley lab. By the end of the decade, it was developing the Polaris intercontinental ballistic missile. Today it’s the heart of America’s research efforts against bioterrorism, nuclear non-proliferation, energy and environmental security. On 2.5km2 (1 mile2) of campus, 5,800 staff work with a budget of $1.5 billion. In the nuclear science programme, 235 scientists work with $90 million – 80 per cent tied directly to real-world applications, 20 per cent tied to more fundamental research. Livermore honours Ernest Lawrence’s dream of Big Science in action.
None of its staff get to work on superheavy elements completely: it’s a side project to keep them excited. Shaughnessy spends part of her time at Livermore’s National Ignition Facility. The largest, most powerful laser ever designed, it is the size of three football fields, using nearly 40,000 optics to guide 192 laser beams to focus on a target the size of a cotton bud. The result is a beam of more than 100 million °C, or pressures more than 100 billion times the Earth’s atmosphere. When it fires, it uses more energy than the rest of the entire United States. It’s the closest thing Earth has to the Death Star. Small wonder Shaughnessy is all over it.
Shaughnessy completed her PhD at Berkeley in 2000, then moved over to Livermore two years later as a postdoc, where she joined the Dubna–Livermore collaboration.1 By that time, the team had come up with the perfect riposte to anyone who suggested that the Ninov scandal could spiral out and affect more than just Berkeley and GSI. ‘We went about the data upside down,’ Shaughnessy explains. ‘[The Russians] looked for alpha that ended in fission; we looked for fissions and then went looking for alphas. And if you get the same chain, it’s much more convincing.’ At Livermore, chemist and physicist duo Nancy and Mark Stoyer created a Monte Carlo simulation. Taking its name from the Monte Carlo casino (where, according to legend, the uncle of the simulation’s creator used to borrow money from relatives to gamble), the idea was to use randomness against itself. By running hundreds, thousands, millions of scenarios in a computer and aggregating the results, you can quickly find out what you’re looking for. Meanwhile, in Russia, scientists adopted the exact opposite approach and scoured the data for signs of actual events. The results weren’t just being checked by two different people, but by two different labs using completely different methods.
As Berkeley recovered from the fallout and GSI found its programme curtailed, the Dubna–Livermore group hit success after success. With both Russian and American expertise – and the doubly magic, neutron-rich calcium-48 beam – the elements were just waiting to be found. By 2002 the team had clear evidence for fusion of elements 114, 116 and 118 (even-numbered atomic elements are easier to make). By 2003 the team had created 115;2 there was even evidence for 113, as an alpha decay product. All of the elements showed longer half-lives than would have been possible without the island of stability. But, again, none of the elements could land on it. There were too few neutrons.
With hot fusion, Dubna were once again leading the charge into the unknown. And once again, the atmosphere lingering from the transfermium wars began to rear its head. Bitter sentiments about the Cold War and mistrust began to leak out in once-civil conversation. ‘When we first announced our 114 discovery there were some very complimentary comments,’ recalls Nancy Stoyer. ‘But once Berkeley announced their 118 discovery, all of a sudden everything became very negative. Blackball isn’t quite the right word, but there was this attitude: “You’re working with the Russians, you can’t do anything right.” Granted, the first atom we saw, the chance it was random was high. But we were honest in presenting that.’
Inevitably, tensions boiled over. In 2003, at a conference in the Napa Valley, Yuri Oganessian was giving a talk on element 114 when Hoffman rose and added her own acetate to the projector: ‘None of this has been confirmed.’ (‘Never put that community of scientists near that much wine,’ one heavy element researcher told me, only half-joking.)
Hoffman had a point. As with all element discoveries, any results would be single atoms, produced in a whirlwind of radioactive background, fissions and ions flying everywhere. Inevitably, half-lives are going to differ, isotopes are going to be misidentified and gently corrected and supposed discoveries are going to fade in favour of the right results. It’s why science thrives on repetition, repetition, repetition. As the theoretical physicist Witold Nazarewicz put it in the New York Times: ‘One has to be extremely careful […] this is not because one is doing something wrong, it’s because these are very difficult measurements. They are playing on the edge of statistics.’
‘The rest of the community did not buy 114 at all,’ Shaughnessy remembers. ‘Like, forever. I thought it was never going to get confirmed. We’d done so many experiments, and repeats, and excitation functions within our group, and it was so consistent. We weren’t really going “Dang it, we need to get these confirmed!” because we felt we had done real science.’
In March 2009 Livermore scientist Ken Moody attended the American Chemical Society meeting in Salt Lake City to collect the highest honour the nuclear chemistry and technology division gives out – named after (who else?) Glenn T. Seaborg. The division chair at the time was Mark Stoyer (‘it’s the only time Ken has ever worn a tux’) and Shaughnessy had organised a programme on Moody’s behalf. ‘So here comes a surprise,’ Shaughnessy recalls. ‘Ken Gregorich came up to us, and said: “Here’s some data, hot off the press, no one has seen it. We’ve just confirmed your discovery of element 114.”’
Putting aside their differences, Berkeley had focused on the science. While they didn’t have the resources or beam time to hunt for elements themselves, confirming a reaction was easier: they could calibrate their equipment to match the energy the discoverers claimed, run the reaction and see what happened. Finding a spare moment in their own research programme, Gregorich’s team had run the Dubna–Livermore hot fusion reaction and come up with the same numbers. ‘I fell off my chair,’ Shaughnessy remembers. ‘Nobody knew it was coming. You had an element where someone had confirmed someone else’s data for the first time in decades.’ The Cold War, the transfermium wars, were finally over for good.
But something even more important
was happening at Livermore and Dubna. The superheavy scientists had worked out how to perform chemistry on their fleeting children … and it seemed like the new elements broke all the rules.
* * *
At 5 a.m. on 14 October 2016 Robert Eichler got up, donned his warmest jacket and set off into the Dubna night to fix an experiment. Tall, broad-shouldered and imposing, the giant trudged through the sub-zero climes toward the JINR gates. Eichler had virtually grown up in the city – his father was a visiting scientist from East Germany – but this was a new experience even for him.
Wearily, Eichler made his way through the armed checkpoint, up into the guts of the Flerov Laboratory of Nuclear Reactions. Up a flight of stairs, past the neat and ordered halls of Oganessian’s office, into the concrete maze of the accelerator labs. Down dusty halls with cracked tiles and marked with Cyrillic warnings, past twirling alarm bulbs and humming lab set-ups, out to an experiment resting on a small metal platform – a balcony – suspended over the gloomy darkness of an interior shaft.
Eichler had travelled to Dubna from the Paul Scherrer Institut. His team of Swiss, Russian and Japanese scientists had won a month’s beam time to conduct an experiment using element 114. Three hours before it was due to shut down, the system had failed. Eichler knew nothing had been lost – his team had been packing up to go home, so all their logs were safe and secure. He also knew that element 114 was produced at around a single atom a week; it was unlikely he’d get another hit anyway. But for superheavy researchers, hours, minutes and even seconds matter. Beam time is the most precious commodity, the source of all life and stress. Eichler wasn’t going to let personal comfort cost him any more than necessary. Not with stakes so high.
Eichler’s experiment was, for a chemist, one of the most tantalising prospects possible: he was looking for the collapse of the periodic table.
The periodic table is based on trends. If you follow the columns down, the properties of the elements stay similar, but some become more pronounced and some become less. Sulfur, for example, stinks – but it’s nothing compared with the stench of its homologues selenium or tellurium. Fluorine, on the other hand, is far more reactive than its homologues chlorine and bromine. Chemistry is, largely, about understanding how this works.
The problem is that as you increase the charge of the nucleus, some of the electrons – the part of an atom that controls its chemistry – gain velocity and begin to edge closer to the speed of light. That, thanks to Einstein’s most famous rule, the theory of relativity, means they gain mass and change the radius of their orbit. It’s a quirk called a ‘relativistic effect’. It’s why mercury is a liquid at room temperature, gold is golden, and lead–acid batteries work but tin–acid batteries don’t. When it comes to the superheavy elements, the charge of the nucleus is so large that the trends the periodic table is supposed to follow – the whole point of deducing the properties of the elements by their position – may no longer apply.
The first superheavy elements, for the most part, behave as everyone expects. But once you get up to the outer reaches, things change. In the two decades since the first glimpse of 114, researchers have been probing, prodding and trying to perform chemistry on it. Because of its instability, typical lab experiments are out of the question (you can barely titrate a pipette before the atom decays or fissions). That meant Eichler had to do something fast and simple. When his experiment made element 114, instead of being caught by hitting something solid, it was imprisoned inside an inert gas filling a quartz bulb, flushed through a capillary (coated with Teflon so atoms wouldn’t stick) and into an array of 16 selenium-coated detectors followed by 16 gold-plated ones. Eichler’s kit was stuck out on the precarious balcony because it was the closest spot possible to the target – shorter beam line, less time wasted. Even so, from the moment an atom fused, to it running through Eichler’s array, took about two seconds; by that time, it had probably decayed into copernicium (element 112).
Eichler’s array had a temperature gradient, getting colder and colder the further along an atom travelled. Elements in copernicium’s group all form amalgams with gold at different temperatures or occur in nature bound to selenium. By looking at which detector pings with an alpha decay, Eichler could tell at which temperature copernicium had formed a compound with either selenium or gold. Once he knew that, he could calculate the element’s thermodynamics.
Eichler’s experiment hints that something strange is going on. His results found he got pings at room temperature and at extreme colds. This, on its own, is unusual. But it becomes even weirder when you think about the basic rules of chemistry. Following a group of elements down the periodic table, you should get a neat trend for their thermodynamics when you plot the figures on a graph. Eichler’s data show that both elements 114 and 112 don’t appear to sit where they are supposed to on the curve for their respective groups. The research is only in its early stages – nothing about the superheavy elements is guaranteed until you repeat it – but it suggests that relativistic effects are already playing a part.
Jacklyn Gates at Berkeley sums Eichler’s findings up neatly. ‘We have a weird situation. Element 114 sticks to gold at room temperature, and it sticks to gold at near the temperature of liquid nitrogen, but not really in between. Those are two very different behaviours, and I don’t think we have a good, coherent theory to explain it.’
This is exactly what Shaughnessy’s team at Livermore is looking at. While element 114 is the extreme of what’s possible to look at with modern chemistry, elements such as rutherfordium and seaborgium – once the far fringes of what was possible – are within reach, even if the experiments themselves are still tricky. ‘Doing chemistry [on superheavy elements] is an extremely challenging enterprise,’ Shaughnessy once told Chemistry World. ‘There’s theories that elements could actually alter their bonding based on what we’d predict just going down the periodic table. If that’s the case, we could be revolutionising how we think of the periodic table.’
Shaughnessy’s colleague (Padawan?) is John Despotopoulos. Young, with a scruffy stubble and long jet hair slicked back in a ponytail, he’s one of the researchers looking at element 114 – and knows just how bizarre it can be. ‘When you get to element 114, the chemistry is starting to behave more dissimilar to its direct homologue, lead, and behave more like mercury, which is in an entirely different group. By doing this chemistry, you might be changing the landscape of the periodic table.’
Despotopoulos is focused on the elements he can play with for longer than two seconds at a time. He’s checking out lead and tin (both supposedly in element 114’s group), as well as mercury (which isn’t), looking at ways to separate them as fast and as accurately as possible. Currently he’s creating traps for metals called ‘thiacrown ethers’, effectively cages made from carbon–sulfur rings. Again, the chemists are using their knowledge of the periodic table: sulfur is known for forming strong bonds with metals like lead and mercury. Once he perfects the technique, the next step is to try it on element 114. ‘From that, you’d get some idea of whether it belongs in group 14 [with lead] or some of the more exotic predictions, like group 12 [with mercury]. Quantum mechanics … it’s still just chemistry.’
Chemistry, yes – but chemistry that could potentially change how we think about the world.
* * *
On 30 May 2012 IUPAC agreed that there was enough evidence for elements 114 and 116 (the rest, it decided, needed a little more). Livermore and JINR agreed to split the names down the middle.
Element 114 was named ‘flerovium’. To avoid any arguments about Flerov’s relationship with Kurchatov and the Russian atomic bomb project, the team were careful to stress that it was named after the Flerov Laboratory as well as the man himself. Finally, Flerov had joined Seaborg on the periodic table. The two giants of twentieth-century element discovery – the men who had led their teams, led the world, into the unknown waters of nuclear instability – would be remembered forever.3
Thank
s to a suggestion from Shaughnessy, so would Livermore. ‘We chose the name “livermorium” for Lawrence Livermore National Laboratory, the city and all of the nuclear scientists that worked to make new elements,’ Mark Stoyer recalls. ‘We never could discover enough elements to name them after all of the important scientists.’
When Glenn Seaborg had phoned up the mayor of Berkeley to tell him that there would be an element named after his city, the man on the other end of the line hadn’t been interested. When Mayor John Marchand found out the news Livermore would have its own element, it was the highlight of his career. Marchand is a chemist; he just got into politics to fix the local water supply.
Marchand and I are enjoying lunch, tucking into burnt ends on a table outside the stickiest rib joint in town, the effervescence from our soft drinks cooling the air. No need for ‘I heart San Francisco’ hoodies here; just golden sun to match the serene lustre of the hills. Directly across from us is a small park, wooden benches daubed with artwork from local graffiti artists. Each backboard celebrates a different aspect of chemistry – one depicts the Bohr model of the atom; another shows researchers with particle accelerators.
‘Peet’s Coffee is 122 Livermore Avenue,’ Marchand tells me. ‘That plaza is number 116 – so we named it Livermorium Plaza. I wanted public art there, so people could understand it’s a special place. When the mayor of Dubna came out here to name Livermorium Plaza, he made a good point. There may come a time when Livermore or Dubna no longer exist; but as long as there is human knowledge, we will exist on the periodic table of elements.’ The bond extends out into the district schools; in 2012, when the discovery team were awarded a $5,000 grant, they donated it to the Livermore High School chemistry department instead. Shaughnessy remembered the empty cabinets at El Segundo High; there was no way she was going to let the next kid potentially miss out on a career in science.