When Science Goes Wrong: Twelve Tales From the Dark Side of Discovery - Simon LeVay (2008)
NUCLEAR CHEMISTRY: The Magic Island
IN AUGUST 1999, NUCLEAR chemists at the Lawrence Berkeley National Laboratory announced the creation of three atoms of a new ‘superheavy’ element, element 118. Two years later they had to retract their claim, and a firefight broke out that cost a star scientist his career and sullied the reputations of several others.
The University of California’s Berkeley campus had been a world leader in the discovery of new elements since 1940, when Edwin McMillan discovered element 93, neptunium. The university’s most famous element hunter was Glenn Seaborg, who discovered plutonium (element 94) in 1941 and followed it up with nine more elements, culminating in 1974 with the one that was named, in his honour, seaborgium (element 106). McMillan and Seaborg shared the 1951 Nobel Prize for Chemistry, but many other Berkeley scientists also played important roles in this work. These included Stanley Thompson, who helped discover most of the new elements up to element 101, and Albert Ghiorso, who shared credit for many of the elements discovered from the mid-1940s onward.
The use of the term ‘discover’ in this context is slightly odd. Darleane Hoffman (also a Berkeley Lab scientist since 1984) and others did discover minute amounts of plutonium and neptunium in natural uranium ores, but none of the other ‘transuranium’ elements exist in the natural world, unless perhaps in some distant supernova. Thus the process of discovery means creating them, not finding them as the term implies. In part, scientists use the term discover simply as a continuation of a tradition that started with the actual discovery of the lighter elements in nature. In addition, however, they probably use the term because they think of the transuranium elements as already existing in a Platonic universe to which their powerful instruments give them entry. They think this way because the properties of each element – even those that don’t exist – were fixed at the beginning of time, when the particles that make up atomic nuclei (the positively charged protons and uncharged neutrons) were endowed with their immutable characteristics.
To some extent, then, nuclear chemists can predict the properties of atomic nuclei that haven’t yet been discovered or created. The most basic theoretical formulation is this: the protons and neutrons are held tightly together by the ‘nuclear force’, which only acts over minute distances. Countering this attraction is the electrostatic repulsion between the protons’ positive charges, which tends to push them apart; this force acts over a much greater distance than the nuclear force. As one progresses to heavier and heavier nuclei, they become less and less stable, because the protons and neutrons cannot crowd closely enough together for the nuclear force to act at full strength between all the particles. Thus the electrostatic repulsion comes to dominate, causing the nucleus to break apart.
If this were the whole story, there would have to be an end to the periodic table of the elements, and that end would lie somewhere in the neighbourhood of element 106, the last element that Seaborg discovered. During the 1980s and 1990s, however, elements 107 to 112 were created – roughly in the sequence of their atomic numbers. Most of these discoveries were made by a group at the Institute for Heavy Ion Research (GSI) in Darmstadt, Germany. A Russian group, the Joint Institute for Nuclear Research in Dubna, near Moscow, was also a player.
The existence of these heavier elements had in fact been predicted by theorists who went beyond the simple model of the atomic nucleus just described. One of these theorists was Seaborg’s Polish-born colleague Wladyslaw Swiatecki, who joined the Berkeley group in 1957. Swiatecki and others believed that, within the nucleus, protons occupy a series of discrete energy levels that can be thought of as concentric shells. A nucleus whose outermost proton shell was completely filled would gain an extra measure of stability beyond that predicted by classical theory. Similarly, neutrons were thought to reside in their own shells and to confer extra stability on the nucleus when their outermost shell was filled. These nuclear shells are analogous to the better-known electron shells outside of the nucleus, which are filled in the inert gas elements helium, neon, and so on.
The numbers of protons and neutrons that conferred stability were said to be ‘magic’, and a nucleus that contained magic numbers of both protons and neutrons were ‘doubly magic’. These might exist in sizes far beyond the limits set by classical theory. In other words, even element 112 might not be the end of the road.
Not everyone agreed on exactly what these magic numbers of protons and neutrons were, or even whether they were meaningful concepts at all. Still, this was the conceptual framework that guided research in the 1990s. And what it meant was that simply going for the next-heaviest undiscovered element on the list might not be the best approach: some elements well beyond the presently achieved limits might actually be more stable and easier to create.
Also, this approach meant that both the number of protons (which defines which element we are talking about) and the number of neutrons (which defines which isotope of that element we are talking about) needed to be considered when thinking about creating superheavy elements. To illustrate this, Seaborg, Swiatecki and others used a chart that plotted the proton number (on the vertical axis) and the neutron number (on the horizontal axis) of all known atomic nuclei. On this chart, the already-known nuclei formed a long, narrow cluster running from the bottom left (a hydrogen nucleus) toward the top right (the currently heaviest element). The cluster resembled the image of the Outer Hebrides as seen on a map. Outside this cluster lay a ‘sea of instability’ in which nuclei could not exist, or not for long enough to be detected. Yet across this sea in a direction farther upward and to the right (corresponding, say, to the location of Shetland), might lie ‘islands of stability’ or ‘magic islands’ – the homes of yet-undiscovered superheavy nuclei with sets of protons and neutrons close to doubly magic numbers. The rumoured existence of these islands offered as powerful a lure to nuclear chemists as the fabled Spice Islands did to the explorers of old.
There seem to have been some differences of opinion within the Berkeley Lab concerning these ideas. Darleane Hoffman and Albert Ghiorso clearly believed in the idea of islands of stability or magic islands, because in a 2000 book they frequently used these phrases when describing their laboratory’s goals. I got a different story from Walter Loveland, a somewhat younger nuclear chemist from Oregon State University who joined the Berkeley Lab for the 1998-1999 year, and who played an important role in the ill-fated search for element 118. ‘I would disabuse you of this idea of the “island of stability”,’ he said in a 2006 interview. ‘Those predictions were made in the 1960s when it was thought that there would be a group of elements with half-lives that were long even relative to the age of the universe, and that they’d form this island. We don’t believe in that anymore – that’s not right. What we know is that there may be nuclei whose half-lives are longer than their neighbours’, but they seem to be connected to the mainland of lighter elements by a peninsula. They are not islands in a sea of instability.’
By 1998, when the effort to detect element 118 began, Berkeley’s glory days of element hunting were long over. Stanley Thompson had died in 1976*. Seaborg was 86, and in August of 1998 he suffered a devastating stroke that led to his death six months later. Ghiorso was 83; Swiatecki and Hoffman, the youngsters, were 72 and 71. Room 307 of Berkeley’s Gilman Hall, where Seaborg identified plutonium, had been a US National Historic Landmark for 32 years. And though much other good work had been done at the Berkeley Lab, not a single new element had been discovered there in more than two decades.
The Berkeley Lab did have the tools to produce superheavy elements, however. One essential tool was the 88-inch Cyclotron – the giant descendant of the hand-held ‘proton merry-go-round’ invented by Ernest Lawrence in the 1920s. The Cyclotron accelerates nuclei of a chosen isotope (let’s say 48Ca, which are calcium nuclei with 20 protons and 28 neutrons, yielding a total mass number of 48) to speeds that can exceed 1,000 kilometres per second, giving them tremendous kinetic energy.
A steady beam of these energetic nuclei emerges from the Cyclotron and enters another piece of equipment, the gas-filled separator. This instrument was built by a Berkeley group led by Ken Gregorich, who belongs to a younger generation; he was one of Seaborg’s last graduate students. Within the separator, the beam passes through a thin foil made from another isotope, such as 244Pu (plutonium with 94 protons and 150 neutrons). The hope is that a very occasional beam nucleus will strike a target nucleus just right. If so, the kinetic energy of the beam nucleus overcomes the electrostatic repulsion between the two negatively charged nuclei (known as the Coulomb barrier) and the two nuclei fuse, yielding a compound nucleus. In this example it has 114 protons (making it the as-yet-unnamed superheavy element 114) plus 178 neutrons.
Because of the kinetic energy of the incoming 48Ca missile, the compound nucleus is put in an excited state, like a drop of water brought nearly to a boil. Most of this excitation energy is carried off almost instantly by the ‘evaporation’ of a few neutrons. The remaining, slightly lighter isotope of element 114 flies onward through the instrument, and a series of magnets deflect it from the main beam and deposit it onto a silicon detector. This nucleus is itself unstable: it breaks down into lighter nuclei over some period of time that might range from microseconds to minutes. The detector identifies the time, location and energy of the particles produced in these sequential breakdown events, and from this data the superheavy nucleus that gave rise to them can be identified. Voila, a new element – element 114 in the case of this hypothetical example – albeit just a single atom and a very short-lived one at that.
That was the basic idea, but up until then it hadn’t worked. Either the energy of the incoming nucleus was too low to overcome the reticence posed by the target nucleus’s Coulomb barrier, or it was too high and the target nucleus simply disintegrated, like a toad struck by a flying princess. There didn’t seem to be any ‘just-right’ level of energy – the gentle kiss that would allow the long-hidden Prince Charming to step forth.
Things seemed to change in 1998. A young Polish theoretical physicist by the name of Robert Smolanczuk, who was then at the Berkeley Lab’s German rival, GSI, did new calculations of the expected probabilities for the creation of superheavy elements by various fusion reactions. He reported that if atoms of 280Pb (the commonest natural isotope of lead) were bombarded with a beam of 86Kr nuclei (an isotope of the inert gas krypton) that had been accelerated to exactly the right energy, there was a surprisingly good probability of scoring hits that would generate nuclei of element 118 – a superheavy element far beyond what had been created up until then. ‘What Smolanczuk picked up on,’ Gregorich told me, ‘was that you need to bombard at an energy level that’s just over the Coulomb barrier: this happens to be the correct energy needed to make the product.’
Nuclear chemists calculate the probability of such successful hits in units called barns, whose name derives not from some famous scientist named Barn or Barnovsky, but from the phrase ‘can’t hit the broad side of a barn’. Most theorists thought that the probability for such reactions fell off exponentially with increasing atomic number, so that by the time one got to element 118, it might be down in the femtobarn range (one quadrillionth of a barn) or less, making the reaction essentially unachievable even in a lifetime of trying. Smolanczuk, on the other hand, pegged the probability as being many orders of magnitude higher, at 670 picobarns – nearly one billionth of a barn. This was still a challenging proposition but within the realm of possibility.
According to Smolanczuk’s calculations, the compound nucleus formed by the fusion reaction would evaporate just one neutron. The reaction would be a ‘cold fusion’, contrasted with the ‘hot fusion’ reactions in which the compound nucleus was more highly excited and evaporated several neutrons, like the 48Ca/244Pu example described earlier. Thus the reaction would leave an atom of 293118 – a nucleus with 118 protons and 175 neutrons. On the basis of shell theory, this atom seemed to lie on the western shore of a magic island: it could probably exist for a very brief period – a fraction of a millisecond – but it would have too few neutrons to last for longer.
Darleane Hoffman, still a leader of the Berkeley group in spite of having been officially retired for seven years, invited Smolanczuk to join the lab, which he did in October of 1998. His ideas got a very enthusiastic response. Hoffman, along with Albert Ghiorso, urged the junior members of the team to put Smolanczuk’s reaction to the test, and quickly. Smolanczuk had told the German and Russian groups about his ideas, and so the quest for element 118 had suddenly become an international horse race – in Hoffman and Ghiorso’s minds, at least.
Ken Gregorich, the designer of the gas-filled detector, and Walter Loveland, the visitor from Oregon State, took the lead in setting up the experimental apparatus. For the data analysis, they turned to Victor Ninov.
Ninov was born in Bulgaria, but had obtained his doctorate at GSI before coming to Berkeley. While at the German lab he took part in the research that led to the discovery of elements 107 to 112. Darleane Hoffman and Ken Gregorich hired Ninov away from GSI in 1996. Because of his achievements at the German lab, the move was thought to be quite a coup for the Berkeley group – an acquisition that would greatly increase their chances of finding a superheavy element of their own.
At Berkeley, Ninov worked closely with Gregorich on the construction of the gas-filled separator and its associated instruments. His most valuable sphere of expertise, however, was in developing and using the software that analysed the output of the detectors. This software had to search the instruments’ output files, which were binary files recorded on magnetic tape. The software looked for events whose time, location and magnitude corresponded to what would be expected for the breakdown of the nuclei that were being sought.
In the case of element 118, the original 293118 nucleus was expected to decay by giving off a sequence of alpha particles, each of which consisted of two protons and two neutrons. These alpha emissions were what the detector actually detected. The first alpha emission would mark the breakdown from 293118 to 289116 – itself an undiscovered element. The next would mark the breakdown of that nucleus to 285114, and so on all the way down to 269106, which is seaborgium. The entire cascade was expected to take about two seconds. The software was designed to pick this characteristic chain of alpha emissions out of millions of irrelevant events.
Ninov was clearly under a great deal of pressure in the last few months of 1996. ‘We… convinced Victor Ninov that the reaction should be run as soon as possible,’ wrote Ghiorso and Hoffman later, ‘as we greatly feared GSI or Dubna might do it first.’ Whether this pressure came only from Ghiorso and Hoffman, or also from Gregorich and Loveland is not clear. When I talked to the latter two men in 2006, both of them suggested that the experiment was planned more as a shakedown cruise for the new equipment than as a confident attempt to find a new chemical element.
For several months, technical difficulties with the apparatus delayed them. The general level of motivation jumped considerably in January of 1999, however, when a report came in that the Dubna lab had created a single atom of element 114, using the calcium-plutonium reaction described earlier.
The Russians had run through more than a million dollars’ worth of 48Ca to achieve that one seemingly successful strike. If superheavy nuclei are defined as those with an atomic number greater than 112 – the usage favoured by Hoffman and Ghiorso – then this was the first superheavy nucleus ever created. What’s more, the nucleus stayed intact for all of half a minute before breaking down. If this finding was genuine, the Russians had already landed on or near an island of stability. ‘[W]e felt happy that at last the Magic Island had been found,’ wrote Ghiorso and Hoffman in their 2000 book, ‘and we redoubled our efforts to get our own experiment under way.’
On April 8, 1999, the Berkeley experiment finally began. Over a period of four days, the lead foil target was bombarded with 700,000,000,000,000,000 krypton nuclei, each of them boosted to an energy of nearly half a million electron volts. When Ninov applied his software to the resulting data, he found two alpha-decay chains. The energies of the alpha emissions and the time intervals between them were remarkably close to the values predicted by Robert Smolanczuk. It seemed clear that the run had produced two atoms of element 118, which had decayed into another never-before-seen element element – 116 – and then into element 114 and even lighter elements.
To be sure of the result, the group ran another experiment a couple of weeks later, in which they hurled more than twice as many krypton atoms at the target as they had done during the first run. The researchers were therefore expecting that they might see four or more alpha chains. In fact they only saw one, but it was a beauty, again confirming Smolanczuk’s predictions. So the research team assumed that the lower yield on the second run was just a statistical fluctuation, and they added the one sighting to the previous two, meaning that three atoms of element 118 had now been created.
‘Does Robert talk to God or what?’ exclaimed Ninov, according to Ghiorso and Hoffman’s memoir. There was general amazement at the close fit between the observations and Smolanczuk’s theory. Clearly there was some initial worry about this among the researchers, but the worry eventually gave way to jubilation. ‘It was such a startling discovery that strenuous efforts were made to find out if anything had gone wrong,’ wrote Ghiorso and Hoffman, ‘but nothing obvious was uncovered… Now there is no question, the Super-Heavy Island actually exists!’
The findings were quickly written up and submitted to Physical Review Letters, a journal that specialises in rapid publication of newsworthy findings. The paper appeared in print on August 9, 1999, only three months after the experiments were completed. The paper had 15 authors. First came Ninov, Gregorich, and Loveland – the central players – followed by a group of other faculty members who had played at least a peripheral role, including Ghiorso, Hoffman and Swiatecki. The list was rounded off with a gaggle of graduate students who, as Loveland put it, ‘took shifts minding the separator in the middle of the night and stuff like that.’
The paper described the observation of the three alpha decay chains and the evidence that these had originated in three nuclei of the new element 118. From their data, the authors calculated that the probability of production of element 118 by the krypton-lead fusion reaction was about 2 picobarns – well shy of Smolanczuk’s estimate of 670 picobarns, but still an amazingly efficient reaction compared with what most nuclear chemists would have predicted.
The publication of the paper was accompanied by excited pronouncements from the scientists involved. ‘We jumped over a sea of instability onto an island of stability that theories have been predicting since the 1970s,’ said Ninov, according to the Berkeley Lab Research Review. In June, Hoffman and Ghiorso added a bubbly epilogue and some more exclamation marks to their already overloaded book. ‘We have convincing evidence for elements 114, 116, and 118!!’ they wrote. They mentioned their sadness that Seaborg had not lived to witness the discovery. (Seaborg was a posthumous co-author of the book, however.) All the major US newspapers carried stories about the discovery, often on their front pages. It was an American flag, after all, that the Berkeley group had planted on the Magic Island.
Very quickly, rival laboratories geared up to duplicate the feat of Ninov and his colleagues – but they couldn’t. Over a period of a year or so, GSI, GANIL (a French laboratory) and later RIKEN (in Japan) all announced their failure to create even a single 118 nucleus by the krypton-lead reaction, even with levels of bombardment that made the Berkeley Lab’s efforts seem like a mild peppering.
Meanwhile, back in Berkeley, the researchers were tearing down and rebuilding their equipment, including the gas-filled separator, in preparation for new studies. It was a time of great optimism. ‘It was clear that once this reaction worked, there were many other reactions you could open up – you could almost discover the other chemical elements one by one in a straightforward manner,’ Loveland told me. Loveland himself wrote a whole new suite of analytical software in preparation for the new work.
The Berkeley group’s reaction to the negative reports from overseas was fairly dismissive; they believed that the equipment in those other laboratories didn’t have the requisite sensitivity to replicate their own findings. In March of 2000, Darleane Hoffman was awarded the American Chemical Society’s Priestley Medal. In her acceptance lecture, she gave pride of place to the discovery of element 118.
Still, the Berkeley group eventually realised that it might be a good idea to repeat their own work before venturing further. So in early 2000 they conducted two more runs, totalling about the same length as the successful runs of the previous year. Not a single element 118 nucleus was spotted – a statistically very improbable result, assuming that the earlier runs were authentic. The group put together a committee of nuclear science specialists from other Berkeley labs to examine the problem, and in January of 2001 that committee wrote a report that focused on possible problems with the equipment during the 2000 runs, as well as on ways to resolve them. It seemed likely that Gregorich and his colleagues just needed to retune everything and they would soon get back to their winning ways.
Following the unsuccessful 2000 runs, the group did in fact spend about a year checking and improving their equipment. The next run began in April of 2001. This run, in Loveland’s phrase, was ‘massive’: the beam, the detectors and many other aspects of the experiment had been so thoroughly upgraded that the researchers expected to reap a rich harvest of element 118 atoms. Yet several days went by with no signal. Then, finally, Ninov announced success: he had found just one alpha decay chain with the unambiguous signature of an element 118 nucleus.
‘Victor came up with the chain,’ said Loveland, ‘and Don Peterson – who was the post-doc working with me – and myself were there, and we said, “Victor, we want to be able to see that chain,” because we now had our own software to analyse the data. We said, “Let’s go ahead, tell us where it is on the tapes, we’ll look at it.” We tried; it was an eventful weekend. We tried very, very hard and had absolutely no success. We couldn’t find this event at all… We talked to Victor and said, “There’s a terrible problem, we can’t find this.” He said, “Oh, I’ll show you,” and he pulled it up on his computer screen, and I said, “Oh my God, this is really tough, because now we’re caught in a situation where it depends whose software we’re using, and there’s something terribly wrong at that point.”’
So far, it looked as if the problem was a technical one involving the data-analysis software. Either Ninov’s software was finding events that didn’t exist, or Loveland’s was failing to find events that did exist. A second investigatory committee was formed in June of 2001, headed by Darleane Hoffman. The committee delegated a post-doc and Victor Ninov to independently search for the reported decay chains in the output files from both the 1999 and the 2001 runs: neither of them could find any of the chains. Meanwhile, Ken Gregorich got into the act. He wrote an entire data-analysis program from scratch in an attempt to resolve the conflict. When he applied this program to the data, he again failed to see any sign of the four decay chains that Ninov had reported.
Because the problem now seemed to be in the data-analysis software rather than the equipment, a third committee was assembled, this time consisting of Berkeley computer experts, including Gerald Lynch, Augusto Macchiavelli and two others. At some point in this process, some of the magnetic tapes that carried the original output from the detectors went missing, and they have remained missing ever since. The Lynch-Macchiavelli group also found that some of the crucial files from Ninov’s own computer were missing. Loveland had copied all of Ninov’s directories onto his own computer, however, and the investigators relied in part on those copies in their further studies.
One thing that greatly aided the computer sleuths in their investigations was the existence of a ‘log file’ in the data-analysis software. This file was a record of all the activities that had taken place during the process of analysis, as well as who had performed them. The log file showed that Ninov had indeed run an analysis on the data from the 2001 run and that it had come up with the element 118 decay chain, just as he had told his colleagues. However, another similar analysis run later with the same software had not shown any such decay chain. The sleuths went through these two files, checking every tiny detail, and they found evidence that the first file had been manipulated – some of the details, such as the timing of the supposed events, just didn’t make sense, and the lengths of the pages were not what would have been generated during normal operation. They then showed that the apparent record of a decay chain in this file could easily have been inserted by cutting and pasting code from elsewhere in the software. When the investigators turned their attention to the records from the 1999 runs, they found similar evidence of manipulation. In all cases, the suspect manipulations had been made from Victor Ninov’s computer account. Furthermore, in 1999 at least, Ninov was the only person in the group who knew how to run the data-analysis software.
Once they realised that the alpha decay chains were not in the data, Gregorich and Loveland hastened to let the scientific community know – Loveland mentioned it at a research conference in New Hampshire in late June of 2001, for example, and the Berkeley group also put out a news release on the topic at the end of July. They knew that it was also necessary to send an official retraction to the journal in which the original report had appeared, and Gregorich sent off the retraction statement at the beginning of October. But Victor Ninov sent his own letter to the journal, in which he asked for his name to be removed from the retraction statement. This put the editors of Physics Review Letters in a quandary. They sat on the letter for a year, while correspondence went to and fro between the editors, Ninov and the other authors. Finally, in July of 2002, the journal announced that ‘all but one’ of the authors had requested a retraction – they didn’t name Ninov as the standout. That put the paper into a kind of permanent vegetative state in which it still lingers today, although everyone knows that the Berkeley Lab’s claim to have discovered element 118 is dead.
As soon as Ninov’s onetime collaborators in Germany heard of what had transpired, they were concerned that similar invalid data might have been used to document the discovery of some of the elements he had worked on there. So the GSI scientists went back and examined all 34 decay chains that had been used to document the discovery of elements 110, 111, and 112. They found that two of the chains – the second of the chains reported in the element 110 study of 1994, and the first of those reported in the element 112 study of 1996 – were based on ‘spuriously created’ data. Sigurd Hofmann, the team’s leader, told the Berkeley group about this, and in due course the GSI group published a retraction of those specific chains. This did not put their claims for discovering elements 110 and 112 into doubt, however, because additional, genuine chains were observed in the same and subsequent experiments. Although the published retraction did not go into details, Sigurd Hofmann told colleagues and reporters that the spurious chains had been created intentionally – by Victor Ninov.
‘That was the killer,’ said Walter Loveland. The world was now closing in on Ninov. The university convened a fourth and final investigative committee, headed by Rochus (‘Robbie’) Vogt, a retired Caltech physicist. The committee surveyed the results of all the prior investigations and interviewed the participants – except for Ninov, who declined to attend committee meetings after the first introductory session. In March 2002 the committee issued its report, which named Victor Ninov as a perpetrator of scientific fraud.
The other investigators took some heat too – not for faking data, but for failing to independently analyse the data before publication. ‘The Committee finds it incredible,’ Vogt wrote, ‘that not a single collaborator checked the validity of Ninov’s conclusions… The claim of an important discovery demanded no less.’
Neither Gregorich nor Loveland was very happy with this part of the report. Gregorich told me that he first set eyes on the report when it was sent to him by a journalist, and he felt aggrieved that he hadn’t been given the chance to ‘check it for accuracy’. Loveland took issue with the general notion that scientists are obligated to validate the authenticity of their colleagues’ work. ‘In theory the answer is, yes, we should do this,’ he said, ‘but in practice the way science is carried out in large collaborative experiments is that people have assigned responsibilities, and if they’re reliable and there’s no question about their work, that kind of double- and triple-checking doesn’t occur. There’s just not enough time for anyone to do that sort of thing, so you trust people to do various portions of the experiment.’
Of course, the main focus was on Ninov. In November of 2001, even before the Vogt committee met, he was put on paid leave and banned from the Berkeley Lab. In May of the following year he was fired.
After Victor Ninov left Berkeley, he took a teaching position at the University of the Pacific in Stockton, California. When I tried to reach him there in the fall of 2006, I was told that he had left the college and that no one knew how to contact him – something that turned out not to be quite true, as (unknown to me) Ninov’s wife was still a professor at the college. Eventually I was able to track him down, and he agreed to a telephone interview, which took place late one evening in December of 2006.
I started the interview, as I usually do, by asking whether I could tape the conversation. Ninov said that I could not, because previous journalists had twisted his words; the only journalists who had treated him fairly, he said, were Germans. Casting about for something that might change his mind, I offered to conduct the interview in German if I could use the recorder. To my surprise he agreed, and our conversation proceeded in that language for a few minutes. Unfortunately, I soon found that my German – which has been languishing in a dark corner of my cerebellum since my student days in that country – wasn’t up to the technicalities we were discussing, so I lapsed into English. Ninov quickly pounced. ‘Are you still taping the conversation?’ he demanded. ‘Yes,’ I said. ‘So you have already broken your word,’ he replied, and he demanded that I stop the tape and erase what I had already recorded.
At that point I thought the interview was about to come to a premature end, but in fact Ninov kept talking for an hour longer. He talked fast, sometimes about highly technical matters, and he didn’t always pause to deal with my requests for clarification. Thus I don’t claim to have understood everything he said, and I certainly wasn’t able to write much of it down. However, I did take home a number of key points.
Most importantly, Ninov emphatically rejected all the accusations that have been made against him. ‘I did not do anything wrong,’ he said. ‘I stand by the integrity of everything I’ve done in my scientific life.’ And he denied he was ever less than frank in his dealings with his colleagues. ‘I presented everything openly to everyone; I never tried to hide anything.’
Ninov told me that he had never liked the Berkeley Lab. The intellectual atmosphere was stuck in the 1950s, he said, and he didn’t trust anyone there except Gregorich. The equipment was outdated and the resources meagre. In building the gas-filled separator, for example, he had been forced to recycle decades-old magnets that he found in a storeroom. The main thing that kept him at Berkeley was its coastal location: he kept an ocean-going sailing boat in the Berkeley marina, and since leaving Berkeley he has sailed it across the Pacific. (The GSI, he said disdainfully, is surrounded by forest.) In addition, he married an American soon after his arrival.
He also told me that he had never wanted to participate in the search for element 118. ‘I resisted to the bitter end to do the experiment,’ he said. His reasons had partly to do with the fact that the gas-filled separator wasn’t ready – it wasn’t yet possible to accurately measure the number of krypton atoms impinging on the target, for example. This criticism is substantiated to some extent by what I read in Hoffman and Ghiorso’s book: they spoke of modifications being made to the setup even after the runs got under way. They also wrote of having to put pressure on Ninov to do the experiment, as mentioned earlier.
He was also unenthusiastic about the experiment because of his scepticism about whether Robert Smolanczuk’s reaction would work. He told me that he asked Smolanczuk how far off base his ‘670 picobarn’ estimate might be, and Smolanczuk replied, ‘Three orders of magnitude’ (a thousandfold); this could put the actual figure around 1 picobarn. Again, Ninov’s statement is substantiated by others. ‘Everybody expected this [670 picobarn] estimate to be wrong,’ Loveland told me. ‘Robert himself thought it would be wrong.’
What about the three alpha decay chains that he reported finding in the data? Ninov denied that he had ever referred to them as decay chains. He called them ‘events’, and he said that they could equally well have been artefacts caused by ‘damped oscillations’. A damped oscillation would be a series of waves in the electronic equipment that rapidly diminished in amplitude. He suggested that each wave might cause a signal resembling an alpha emission, and the decreasing heights of the waves would cause the appearance of decreasing alpha energies, as expected for a decay chain. Even if they were actual decay chains, he said, there was no way to tell whether they arose from the decay of element 118 nuclei, because it was impossible to answer the key question – how many protons they possessed.
As far as I could tell from the Vogt report, Ninov never brought up his damped-oscillation explanation during the investigations. I asked him how such phenomena could give rise to precisely the half-lives and energies that were predicted by Smolanczuk’s theory. His answer was that the electronic filters were set to only accept the predicted events out of a huge sea of candidate events, so it wasn’t surprising that a few would match the requirements. Ninov emphatically denied that he had ever said, ‘Does Robert talk to God or what?’ as claimed by Hoffman and Ghiorso.
Of course, I asked Ninov why he had gone ahead and published the claim for element 118 if, in his own mind, the data was so suspect. This is where he really surprised me. He told me that Gregorich and Loveland had jumped to the conclusion that the ‘events’ were alpha decay chains, and that they had submitted the paper to Physics Review Letters without his knowledge or consent. He himself wrote an entirely different paper, he said, but the other two men rejected it, citing his poor English. (In speaking with me, Ninov’s English was flawless – which is remarkable, considering that it is probably his fourth language.)
These claims don’t square very well with the quotation cited earlier from the Berkeley Lab’s magazine, in which Ninov reportedly talked in enthusiastic terms about the findings at around the time the paper appeared. Nor do they square with Ninov’s refusal to sign the retraction letter. If he had been as sceptical about the authenticity of the data as he now claims, he should have been the first to call for a retraction. I didn’t ask Ninov about these apparent contradictions. When I asked Gregorich to comment on Ninov’s version of events, he sent me three excerpts from Ninov’s draft of the paper, all of which interpreted the findings as detections of element 118. With regard to the investigations that led to his identification as the person who had inserted the evidence for decay chains into the computer files, Ninov denounced the committees as biased against him and politically motivated. His colleagues also betrayed him, he said, especially Gregorich. With regard to the Lynch-Macchiavelli committee, he expressed contempt. ‘You know already from their names what’s up,’ he said, implying that they were a lynch mob and were following the cynical recommendations of Macchiavelli’s 15th-century namesake. ‘The investigation was absolutely political,’ he said.
I asked Ninov about the allegations that he had created spurious data at GSI before he came to Berkeley. Ninov denied it, and suggested that the Germans’ statements were made in response to pressure from Ken Gregorich, who needed something to bolster the believability of his own allegations. Ninov criticised the Germans for cutting off communications with him, and was particularly bitter that he was not invited to participate in the choice of a name for element 111, which he helped discover. (The final choice was roentgenium.)
The persecution continued after he was ousted from Berkeley, Ninov said. An anonymous caller, whom he suspected was Augusto Macchiavelli or one of his colleagues, called the administration at the University of the Pacific and complained about his presence there. As a result, Ninov said, his appointment there was not renewed and he had to seek work at a different institution. He would not tell me where he was currently working, because he feared further persecution of the same kind. He did tell me that he had put the Berkeley episode behind him, however. ‘I’ve just moved on with my life and left the little animals to do what they want,’ he said.
Although Ninov’s Berkeley colleagues experienced direct injury to their reputations as a result of being associated with an apparently fraudulent study, their expressed reactions have been more of puzzlement than anger. ‘He had nothing to gain,’ said Loveland. ‘He was a very successful scientist.’ Quite a few people have brought up possible medical explanations – perhaps something related to a head injury that Ninov suffered years ago. ‘There were a lot of discussions on whether there was an issue of painkillers involved, or issues of mental illness,’ said Loveland. And he recounted something that seemed to strengthen such ideas in his own mind. ‘I remember sitting out on the patio of the Cyclotron and asking him, “Hey, Victor, what’s going on?” He spun off some comments to me about conspiracies, and I thought, Oh dear, we have a real problem here, when people start talking about conspiracy theories and so forth.’
Both Ninov and his wife (in a brief conversation I had with her) strongly rejected such ideas. (‘Painkillers?’ retorted Ninov. ‘Aspirin, maybe.’) Both of them interpreted these speculations as indications of malevolence on the part of the people who expressed them. To me, they seemed more like attempts on the part of Ninov’s onetime colleagues to construct explanations that removed some of the blame from a person they had once liked and admired.
One idea that many writers have stressed when considering scientific fraud is that the perpetrator fabricates data to prove an idea that he or she is already convinced is correct: this way, the perpetrator is unlikely to be found out, because future genuine findings will confirm the fraudulent ones. The spurious data in the GSI studies could be taken in support of this idea. The first apparently fraudulent decay chain only cropped up after one genuine chain was detected. Thus Ninov, presuming that he was the perpetrator, might have thought that he was merely hurrying the process of discovery along a little by adding a spurious chain. Once that fraud passed muster, perhaps committing further frauds became easier – maybe even addictive.
One thing stuck in my mind that Ninov told me in passing. ‘I was never interested in nuclear chemistry,’ he said. At first, I thought that this was just a bitter comment on a career that had culminated in such ignominy. Then I wondered. Ninov clearly has an exceptionally brilliant and restless mind. Could his real passion have been not to discover things about the natural world, but to pursue ideas, to solve intellectual challenges – the harder the better? And then I recalled that, as far as the superheavy elements were concerned, there was nothing to discover in the natural world. Those elements don’t exist, they have to be created in the image of an idea about how matter should behave. So did Ninov, for all his labours on the detectors and the data-analysis software, see the challenge more in terms of philosophy than science? We may never know, but Walter Loveland holds out hope for an answer. ‘It would be interesting at some point in my life to sit down with Victor over a beer and talk candidly for a while,’ he said. ‘I don’t know what I would hear.’
Several weeks after my interview with Ninov, I received a message that shone an intriguing new light on the story. In the interview I had asked Ninov to suggest a scientist I might talk to who would support his point of view. He mentioned his former graduate advisor at GSI, Peter Armbruster, himself a renowned element hunter.
But Armbruster did not support Ninov’s point of view. In an email that he sent me in January 2007, he agreed with his German colleagues that Ninov fabricated two decay chains while he was at GSI. ‘I certainly feel deceived, and I can in no way justify what he has done,’ Armbruster wrote.
Perhaps more telling from a psychological perspective was this detail: Armbruster told me that Ninov’s first fabricated decay chain occurred at 11:17 a.m. on November 11, 1995. November 11 marks the beginning of the south German carnival season known as Fasching, when people like to play all kinds of pranks. In Germany, the number 11 (elf) is known as die närrische Zahl – the fool’s number. For this reason, the exact beginning of Fasching is am elften elften elf Uhr elf, which is to say ‘at 11:11am on November 11’. Thus Ninov’s first spurious decay chain occurred just six minutes after the official opening of Germany’s practical-joke season.
‘I suppose this chain… was composed by Victor Ninov as a joke for Fasching,’ wrote Armbruster. ‘Victor must have been very surprised that it was accepted and published. This success certainly encouraged Victor to go on, playing games with the group.’ Of course, there is no independent evidence that this was Ninov’s motivation, and Ninov himself did not reply to an emailed request for a comment on Armbruster’s theory.
A footnote: in 2006 the Dubna group, assisted by scientists from the Lawrence Livermore Laboratory (a separate institution from the Lawrence Berkeley Lab), announced that they had succeeded in creating three atoms of element 118. This they did by a completely different reaction from the one attempted at Berkeley. It was a hot fusion reaction between calcium and californium, so the results said nothing about the validity of Smolanczuk’s theory.
Both Gregorich and Loveland expressed some caution about the reported finding; they mentioned that most of the Russians’ reported discoveries still await independent verification. But if the finding is verified, the Dubna group will get to name the new element. They may name it oganessium after their leader, Yuri Oganessian. They may name it after some historical Russian physicist – cherenkovium or zeldovium or even sakharovium. But they are unlikely to pick the name that seemed like a front-runner in 1999 – ninovium.