by Kit Chapman
The element hunters knew how to have a good time. When an element was created and confirmed to Ghiorso’s satisfaction, the team celebrated with a ‘HILAC punch party’ – excessive drinking, joke presentations and a wall-sized game of snakes and ladders. Rumours of crazier exploits still echo in the Berkeley halls to this day; one recounts that Ghiorso used to stuff radioactive material into tennis balls (the rubber was just thick enough to shield the radiation) and bat them between colleagues.
Despite the fun, the search for superheavy elements had run dry. The island of stability and the elements surrounding it seemed like ghosts, and repeated attempts to make them had, like the hunt in nature, failed. The only claims were coming from an Israeli–British team at CERN headed by Amnon Marinov, who were churning out a seemingly endless ream of papers claiming they had discovered element 112. To quote one superheavy researcher: ‘Everyone knew it was bullshit.’2
The problem was neutrons. As mentioned before, the element hunters were using a technique where the nucleus discarded neutrons to stave off fission. This meant that any isotope created would, inevitably, have a relatively low number of neutrons remaining. When looking for the island of stability, this was a disaster. The first viable magic number of neutrons was 184. Even using the best beam and target available, the closest the element makers were likely to get was 173 neutrons: 11 shy of the island. The reactions in the lab were showing a ‘drift to the north’ on the chart of nuclides: instead of approaching the island, they were just making elements too unstable to detect.
The imagined boats navigating the sea of instability had broken rudders – and Ghiorso had run out of ideas.
* * *
Dubna’s JINR had its own scientific rhythms. The teething years had passed, and the institute was proudly claiming scientific victories that won Lenin medals and Nobel Prizes. Staff at Dubna had explained Cherenkov radiation (that blue glow seen in atomic reactors), explored new areas of quantum physics and pioneered Russian computer science. Things were going well.
Even so, life in Russia was vastly different to California, and visitors from the West usually experienced a culture shock on arrival. Scientists would find themselves flanked by stone-faced minders as they walked around town, and tales abounded of how Dubna’s only hotel had an entire floor given over to the KGB, whose spies listened in on the rooms each night. Yet some visitors have also spoken of an incredible, unbreakable bond of companionship away from the prying eyes of the security services. On one research trip, a gaggle of visiting Americans went camping with their Soviet colleagues. Once the group were alone in the woods, the Russians produced a transistor radio and tuned into an illicit frequency. Soon, the entire campsite – Russians and Americans alike – were twisting and jiving to Johnny Rivers’ ‘Secret Agent Man’. ‘Once you get the governments out the way and let scientists speak,’ one American chemist told me, ‘you find that you may have different cultural languages, but the same technical language.’ Johnny Rivers transcends all borders.
Georgy Flerov was still in charge of his laboratory, steering it in his own, inimitable fashion. Heinz Gäggeler laughs as he recalls his first encounters with the Russian element tsar in 1975. ‘He liked to talk,’ Gäggeler says. ‘He was quite often walking up and down in front of his office. If he saw someone, he asked what they were doing.’ Once, after the Swiss researcher briefed him on his project, Flerov asked Gäggeler about his hobbies. ‘I said I was interested in alpinism. Flerov liked mountaineering too. So, I told him I was interested in climbing Lenin Peak [at 7,134m (23,000ft), one of the highest mountains in the Soviet Union]. At that time, you needed the help of the Ministry of Sport in Moscow to go to such an exotic place – I would have had no chance as a foreigner.’ Gäggeler’s passes arrived soon after – and he led a Swiss team to climb the mountain later that year (bad weather prevented them from reaching the summit). ‘Georgy opened the door to the ministry for me. I was a nobody, but he was very famous.’
The person closest to Flerov was Oganessian. By the mid-1970s the duo had worked together for 15 years. Although they weren’t exactly friends, they had formed such a close working relationship that they were, at times, inseparable. ‘He opened me to science, to physics,’ Oganessian told the YouTube channel Periodic Videos. ‘At 6 p.m. I would come home. At 9 p.m. I would get a phone call [from Flerov]: “What are you doing?” I would say I was doing nothing. “Come to me, please.” Every day. And every day, from 9 p.m. to 10 p.m., we’d have an hour’s discussion. Sometimes he called me in the early morning, and he’d just say: “I’m very sorry to call you so early …”’ It was Oganessian’s wake-up call – if Flerov was working, so was he.
Despite his friendliness, Flerov – typically referred to just by his initials, GN – was a stickler for rules. He couldn’t abide independent research and ordered his staff not to ‘dabble in zoology’. Anyone who deviated from his instructions was branded a ‘guerrilla’. ‘If guerrillas were found out or, even worse, proved to be successful,’ the Dubna history warns, ‘GN acknowledged the importance of their work in a cool and indifferent manner, without a hint of encouragement or praise.’
At meetings, Flerov kept a gong; once it had been sounded, the topic was settled and it was onto the next item. ‘He was a single-minded, spirited and straightforward man,’ JINR’s history records, ‘a man who would always rush to the charge rather than try outflanking manoeuvres. A man who did not take kindly to meandering or deviating from the task at hand, a man who jealously guarded his flock from straying.’
The Russians had reached the same stumbling block as the Berkeley team. But, unlike the Americans, one researcher did have an idea about how to rekindle the hunt for superheavy elements. Unfortunately, Flerov refused to accept it. Clang. Onto the next topic.
The idea Flerov had discarded was called cold fusion. But Oganessian thought his mentor had made a mistake. As Flerov had done with his letter to Stalin, Oganessian decided his only option was to gamble his career on being right.
The young Armenian turned guerrilla. ‘Cold fusion, my lovely reaction,’ Oganessian remembers. He smiles at its very name. ‘My cold fusion. This … this was something really new.’
* * *
Cold fusion is a term likely to make most scientists roll their eyes. It’s a name that’s also given to a nuclear reaction that would occur at room temperature – pure science fiction that gripped the world in the late 1980s. In element discovery, however, cold fusion is very real.
The idea first emerged in the mid-1960s from Ya. Maly, a Czech scientist working at Dubna. The concept was simple enough. So far, elements had been created by taking a light element and shooting it at something heavier. But now the technology was available to fire heavier projectiles. Why not use elements closer together on the periodic table?
This wasn’t thought to be as simple as it sounds. The Coulomb barrier gets stronger when two similar-sized nuclei are pushed against each other – much like it’s easier to push a small magnet against a large one than two magnets of roughly the same strength. This, everyone thought, meant you needed to fire your projectile at a higher energy to force it through – and higher energy meant a greater chance of fission.
But what if that isn’t what happens at all? Think about two drops of water splashing into each other. As they come together, there is a moment when the new droplet is forced to change its shape to adapt. The same happens to two nuclei. ‘The microscopic correction to the liquid-drop mass,’ wrote US physicist Ken Moody in The Chemistry of Superheavy Elements, ‘acts as a heat sink, stealing excitation energy away from the compound [newly formed] nucleus.’ This means that the energy required to combine two similar-sized nuclei is actually two to three times less than for lighter ion reactions. Less energy required means less need to evaporate neutrons for the nucleus to become stable. More neutrons mean more stable elements.
Cold fusion has its flaws. If light-ion-induced reactions are a bombastic slamming together of two nuclei, a SWAT team kic
king down the atomic door, cold fusion is a surgical ninja strike, stealthily squeezing just under the Coulomb barrier with the minimum energy possible. To succeed, the two nuclei must strike each other perfectly: otherwise, they just end up bouncing off each other. Cold fusion also requires a specific choice of target to make the whole trick work. In practice, this means you can only use targets made of lead or bismuth (lead, especially Pb-208, is doubly magic and thus extra stable; Bi-209 is, obviously, very close and gets some of the same benefits).
Nobody really believed it would work, but in 1973 Oganessian was willing to take the risk. When Flerov went on holiday to Siberia, his right-hand man assembled the team and got to work. ‘He was on a hiking vacation,’ Oganessian remembers, laughing at his mischief. ‘He didn’t believe the idea. But, finding myself in a situation where he was out, I started to do the experiment.’
Oganessian decided his proof of concept would be to make fermium-244, an unstable isotope that has a half-life of around four milliseconds before it completely self-destructs in spontaneous fission. ‘Normally, fermium is produced by neutron capture, through uranium,’ Oganessian continues. ‘We wanted to fire argon into lead. It was thought to be impossible – argon was supposed to be too heavy for fusion. But I made a set-up that allowed me to adjust the intensity of the ion beam.’
Argon pummelled a lead target for five days. ‘The result was amazing and stunning,’ the JINR lab records report. ‘The detectors were riddled with fission fragments.’ As predicted, the fermium had undergone spontaneous fission. But the half-life Oganessian detected wasn’t four milliseconds. It was 1.1 seconds – more than 250 times longer. The team had created an entirely different isotope.
‘It was so big!’ Oganessian exclaims. ‘It was seconds! I was very surprised and excited. Even at the intensity I had to use for the beam, the cross section was a thousand times greater … at that moment, I knew we had cold fusion!’
On Flerov’s return to the lab, he gave Oganessian the same treatment as any other guerrilla. ‘Not only did he not show that he was particularly glad,’ JINR’s records state, ‘but he actually looked indifferent.’ Flerov ordered the lab to go back to its previous programme. Don’t dabble in zoology.
A short time later, the president of the USSR’s Academy of Sciences visited the laboratory. Flerov summoned Oganessian up to his office and motioned to him. ‘He produces [elements beyond uranium] in their tens of thousands,’ he told his visitor, almost offhand. The president realised what it meant and grabbed the physicist by the shoulders. ‘He gave the lucky beggar three kisses on his cheeks,’ the JINR history records. ‘That was his reward for insubordination.’
* * *
With cold fusion, a whole new realm of possibility had opened. In 1974 Oganessian used the technique to shoot chromium ions into lead. The result was spontaneous fission – and the first signs of element 106. Excitedly, the Russians prepared to announce the element at an upcoming conference in Nashville. Although they didn’t say why, they made it known to the world that Georgy Flerov himself would attend.
Almost simultaneously, the Berkeley team were also preparing to announce the discovery of element 106. By now, the team’s composition had changed. Ghiorso was still in charge, with Nurmia at this side, but Harris and the Eskolas had departed. In their place were German-born physicist Mike Nitschke and another married couple, this time from Yale University: Carol and Jose Alonso. Joining them in the chase were a group from Lawrence Livermore National Laboratory led by Ken Hulet and Ron Lougheed. Hulet had been a health chemist at Berkeley and had been drawn into the superheavy world as one of Glenn Seaborg’s post-war apprentices.
Livermore was no longer just an offshoot of Berkeley; it was one of the US Department of Energy labs where the US designed its nuclear weapons. Hulet’s interest in superheavy elements wasn’t a full-time pursuit – it was a side hobby, something the government was happy to support if it meant they kept the brightest minds working for them.
The US team’s attempt to find element 106 had started off well. Hulet and Lougheed prepared a californium target, while Ghiorso ran checks on his oxygen-18 beam. Meanwhile, Jose Alonso tested the team’s latest computer by asking it to run over some data from 1971. To his surprise, the computer suggested that the Americans had made element 106 already and failed to notice. This time, when the machine produced an alpha chain that chimed perfectly with known isotopes, the Berkeley–Livermore team spotted it immediately.
Almost simultaneously, the Russians and Americans had discovered the same element – and both wanted to announce it first. The Nashville conference attendees could sense something was happening. Rumours of a new element started to swirl. Tennessee had become the set for a Cold War thriller.
The only member of the Berkeley team in Nashville was Carol Alonso – the rest had stayed home to get more data. On the second day of the conference, she and the other speakers were invited to take a cruise down the Cumberland River on a paddle wheel boat – a majestic floating palace straight from the pages of Mark Twain. Alonso, the only woman on the boat, soon found herself besieged by researchers eager to know if the rumours of element 106 were true. She confirmed them, and, taking position next to the giant wheel at the back of the boat, turned spymaster. From her hiding place, she sent four friends to subtly ask Flerov if the Russians had also made element 106. Flerov was wise to them. ‘No,’ he’d teased one researcher. ‘[We’re announcing] 108!’
That night, back on dry land, Alonso phoned Ghiorso for orders. The maverick decided to hold off announcing the US discovery, telling her ‘it would be better to let the Russians go out on a limb and just watch to see if it got chopped off’. The next day, Alonso – still playing superspy – managed to sneak an advanced copy of Flerov’s paper from the conference organiser and confirm his plans. When Flerov’s speech was delivered and the Russian discovery of element 106 was revealed, Alonso was able to play it cool and ignore the claim entirely. It was a dirty trick – depriving the Russians of the oxygen of the publicity and credibility from the US’s own results – but it worked.
A week later, the Russians visited Berkeley. There, both teams told each other of their element 106 experiments in full. The Russians were impressed by the thoroughness of the US team; the American team were less impressed by the Russian effort, but had no obvious grounds to object to the validity of their claim. For the first time, the discovery of an element had ended in a stalemate.
Figure 9 The Russian and US teams meeting in Dubna, USSR, 1975. From left to right: Yuri Oganessian, Georgy Flerov, V. A. Druin, Al Ghiorso, Glenn Seaborg, Ken Hulet.
The teams had been competing for 15 years. Neither side – Seaborg and Ghiorso, Flerov and Oganessian – had any interest in continuing to fight. Both Berkeley and Dubna agreed that nobody would suggest a name until the results were confirmed.
Element 106 had been discovered, but its space on the periodic table would remain blank. The hot phase of the transfermium wars was over.
Notes
1 He was not the last. In 2009 Clarice Phelps aided in the purification of berkelium, which led to the discovery of element 117 and confirmation of element 115. You can read more about that in Chapter 20.
2 Marinov later claimed to have discovered evidence of element 122 (‘or a nearby element’) in nature from a sample of thorium – a feat of detecting one atom in a trillion. Once again, the superheavy community dismissed his paper.
CHAPTER THIRTEEN
The Atoms That Came in from the Cold
Two cars rushed through the San Francisco countryside at breakneck speed, wheels almost touching as they jockeyed for position on the road. At the wheel, Al Ghiorso battled to keep his supercharged Volkswagen straight, his team clutching onto their seats as he revved the engine past its supposed limits. Next to him, packed like sardines into their own vehicle, Flerov, Oganessian and impassive KGB agents raced past, barging out in front and blocking the Americans’ path.
Ghiorso focused and twist
ed the wheel, the smell of burning rubber permeating the air as he bobbed and weaved, trying to squeeze his way around the Soviets. Finally, teeth gritted in sheer determination, he pulled the Beetle out onto the shoulder and floored the accelerator. Rubble, smoke, dirt and dust plumed out from behind the car as the Americans, slowly but surely, overhauled their Russian counterparts. Ghiorso cast a glance over at his defeated rivals, smiling in triumph before turning to look ahead. There was nothing but a solid brick wall. Ghiorso hit the brakes, but they didn’t work. The Berkeley boys were hurtling to certain doom, out of control …
Ghiorso woke up, the nightmare fresh in his mind, out of breath from his imagined panic. He was safe in his home in Berkeley, Wilma at his side. It was 17 July 1976. Climbing out of bed, he went and had a shower. Out of control. He closed his eyes and groaned. His subconscious had just shot down the greatest discovery of his career.
For the past 18 hours, Ghiorso had been convinced that his team had found the island of stability. Partnering with Livermore, the Berkeley team had been bombarding curium (19 years since the HILAC explosion, Ghiorso was happy to use the radioactive material again) with a new beam – calcium-48. This was a brilliant idea. Natural calcium is a bad isotope for element hunting – it doesn’t have enough neutrons. But a quirk of nature means that around 0.19 per cent of natural calcium is Ca-48, with eight extra neutrons – plenty to evaporate and try to stabilise the newly formed element. Even better, Ca-48 is ‘doubly magic’: both 20 (protons) and 28 (neutrons) were in Goeppert Mayer’s list of ‘magic numbers’. The only problem was the cost. Today, 1g of Ca-48 costs $200,000. An accelerator uses 0.5mg an hour. In the glory days of Berkeley, elements could be produced with only a few hours of bombardment. By the 1970s the new elements had cross sections so low an experiment had to be run for weeks or months at a time just to get one atom. The cost of calcium soon mounted up. Even so, if Berkeley found the island of stability, it would have been worth every penny.