Professor Emeritus of theoretical physics at the University of Sussex Norman Dombey was a scientific expert at the Litvinenko hearing (www.litvinenkoinquiry.org), which took place in London in 2015. The objective scientific expertise was a key factor for the success of the investigation. We publish the interview with Mr Dombey made by Nataliya Demina in London in English on-line and in Russian (*.pdf, *.html).
A: Why did the inquiry ask you to be a scientific expert in this investigation? After all, you are a theoretical physicist, not a radiochemist.B: In 2006 when I heard on the radio that polonium has been used to poison Alexander Litvinenko, I knew that the Russian state must be involved. Polonium-210 was used in early nuclear weapons as a neutron initiator for the weapon: it is only produced by state institutions. I also knew that polonium was an alpha-emitter and that it would not be discovered by normal radiation measurement devices such as Geiger counters which measure beta- and gamma-radiation. So, I wrote an article for the London Review of Books in 2007 about polonium and Litvinenko, saying how the Po-210 was found and explaining why it was not meant to be found.
The Po-210 was only discovered because the poisoning was carried out in London, where Litvinenko was in a very good teaching hospital — University College Hospital — which decided to send samples of Litvinenko’s bodily fluids to Aldermaston, the British nuclear weapon laboratory which knew about polonium from its work in the 1950s and 1960s. There it was determined that it was definitely Po-210 since it emitted both alpha-particles and weak gamma-rays of precisely the right energies. So, I wrote the article and after that I was asked by Marina Litvinenko to write a report for her.
A: Could you tell me more about yourself? Why did you decide to become a scientist, a physicist?
B: I was a scientist from the times when I studied mathematics and theoretical physics in Oxford and the California Institute of Technology in the 1950s and 1960s. I met and was taught by many physicists who were involved in the Manhattan Project which developed the first nuclear weapon. I was interested in the history of nuclear weapons. And I was also involved in the Pugwash movement, which was trying to stabilize the nuclear arms race during the cold war.
I spent a year in Moscow after Caltech. So I knew people who had worked on nuclear weapons in the UK, the US and the USSR. After 1945 most of them tried to prevent nuclear war. And I was involved in Pugwash and similar organizations for many years. So I knew the physicists, the organizations and the uses of polonium. I knew Rudolf Peierls at Oxford very well: he and Frisch wrote the paper in 1940 which showed that nuclear weapons were possible: I was taught quantum mechanics at Caltech by Robert Christie and Richard Feynman who played leading roles at Los Alamos in the Manhattan Project, and I invited Andrei Sakharov to my University, the University of Sussex, to receive an honorary degree in 1989. Sakharov and Zel’dovich (whom I also knew) designed the Soviet H-bomb which was tested in 1955.
A: Are you satisfied by the results of the inquiry?
B: The results of the inquiry were correct as far as I can see. I was a bit surprised that it actually attributed the poisoning to President Putin. It seemed to me that it was clear that it was state sponsored, but the evidence that Putin was responsible was given in secret, so I have no idea what that was.
A: How do you assess the level of those Russian experts who presented evidence?
B: I was not impressed by the Russian experts who gave evidence. But I am impressed by the two Russians who told me what they thought the situation was. They confirmed what I suspected, namely that polonium is only produced in substantial quantities in the Avangard facility in Sarov, and no other country regularly produced polonium in 2006 in such quantities.
A: Is it possible that Litvinenko could have taken polonium by accident or by chance?
B: I don’t think so. There were no traces of polonium in the various places in London which Litvinenko had visited before he was associated with Lugovoy and Kovtun. So, it was clear that Litvinenko had not carried the polonium; but Lugovoy and Kovtun had.
A: Is it possible that Litvinenko could have contaminated Lugovoy and Kovtun, by transferring polonium to them?
B: I can’t see any evidence anything other than Lugovoy and Kovtun taking the polonium and administrating it to Litvinenko. There was a substantial, enormous, amount of polonium discovered in the teapot at the Millenium Hotel. So it was clear where Litvinenko was poisoned. There is no way out of that. And polonium was also discovered in the bedrooms where Kovtun and Lugovoy were staying.A: Do you think that Lugovoy and Kovtun did not know that they used polonium as a poison?
B: Oh, I am sure they did not know. Nobody knew about polonium.
A: And did they know that they were administering a poison?
B: I don’t know, but I suppose that they knew that they were doing something like using poison, but they would not have had any idea what the poison was.
A: Why do you think such a strange poison was used?
B: I think that this poison was used precisely because it was assumed that it would not be identified. There were other cases in Russia where people died under mysterious circumstances with symptoms which looked like radiation poisoning but where no radiation source was identified. Nobody found out why. This would have been the case too in London had the sample not been sent to Aldermaston.
A: What do you think about the technical expertise of the administration of polonium?
B: It was very high. First of all, you had to produce polonium. Aldermaston found that the polonium used was very pure. No impurities, such as bismuth, were found even though bismuth would have been irradiated in the reactor at the Mayak facility in Ozersk which supplied Avangard. And the polonium has to be dissolved in some solvent in order to be able to use it. I understand that the most likely way to administer it is to make a capsule of the liquid containing the polonium in some gelatin so that it looks like a medicinal pill.
We are talking about extremely small amounts of polonium here: micrograms of polonium. The amount used to poison Litvinenko was about 50 — 100 micrograms. The amount of polonium in his blood was about 30 micrograms: remember one microgram is one millionth of a gram. Yet where polonium is concerned It can be considered a large amount because you can measure picograms of Po-210 and a picogram is one millionth of a microgram. Since you can measure such exceedingly small quantities, it was easy to track where Lugovoy and Kovtun had been when they travelled around London.
A: Do all the facts that you are aware of demonstrate that the Russian state provided this polonium or are there are other places where it could be produced?
B: Well, in principle you can make polonium at any nuclear reactor. But in practice you would need to make a substantial amount of polonium: at least 100 micrograms and probably more. For that you will need to irradiate a bismuth target of mass of a kilogram or so, the size of a reactor fuel rod. This used to be done in a few places: Harwell in the UK; Oak Ridge in the US; Chalk River in Canada, and in China, as well as in Russia. In all these places it was possible to insert a bismuth rod into the reactor core. But by 2006 polonium production had ceased in those sites apart from Avangard in Russia.
If you used a small reactor, you would only use about a gram of bismuth and irradiate it in a peripheral chamber of the reactor. So the amount of polonium produced would be about one thousand times smaller. Also Aldermaston found that the polonium used was very pure, so it could not have been produced at a facility where it has not been produced before. Therefore, the amount of polonium used together with the its purity indicate that the polonium was produced at the Avangard facillity at Sarovwhere it has been produced for over 60 years and which provides over 95% of all polonium produced worldwide. Furthermore, this is the only place where it is produced regularly, because the polonium produced at Avangard is shipped from Russia to the US every month. A few tens of micrograms or whatever could be siphoned off for nefarious purposes without any problems.
A: What is polonium used for? Is it space research?
B: Polonium is not used in space satellites anymore. About 40 years ago it was used as a thermoelectric power source in satellites. But its half-life is only 138 days, so now plutonium-238 is used. It is not used as a neutron source any more: tritium is used. It not used as an antistatic device in photography any more as no one uses photographic film these days. It is not used anymore as an antistatic in paper mills because that is not necessary. So now it is not produced anywhere other than in Sarov on a regular basis. In Britain we used to make it but stopped in the 1960s; in the US production stopped in the 1970s; in Canada it stopped by the 1980s and in China it stopped in the 1990s. By 2006 there were no known sources of Po-210 other than Sarov.
A: You mentioned that there is a contract between Russia and the USA for the supply of polonium. Why does the USA need polonium?
B: They do not really need polonium. In the early 1990s after the Soviet Union broke up, the US was worried about nuclear weapon scientists being unemployed and going to Iran, Libya, North Korea and so on. So the US tried to find ways for Russian nuclear scientists to be usefully employed in civil projects. For example, there was an American-Russian collaboration led by colleagues of mine in Princeton who suggested that polonium production could be usefully continued at Sarov. So the US government encouraged polonium production at Sarov and arranged for American industry to use Po-210 as an anti-static on a regular basis. No one else produces it except occasionally in very small amounts. You have to work hard to find a use for it. The only use I know of is as an antistatic in the motor industry to help with the painting of cars.
A: Do you think that there were several attempts to poison Litvinenko? Reading the inquiry documents, I was not sure that the first attempt really occurred.
B: Well, I don’t know the details. But according to the inquiry there was three attempts. Maybe in one of the attempts too little polonium was used. I don’t know. This is not my field. But it seems from the analysis of Litvinenko’s hair that there was more than one attempt. Probably there were three attempts.
A: During the inquiry you presented evidence that polonium was produced in Russia. Why in the final report of the inquiry this is not confirmed?
B: In my evidence I stated that it was highly likely that the polonium was produced at Sarov. I think that scientist A1 from Aldermasten was an expert in analyzing alpha-particles, but she knew very little about the production of polonium and where it is produced. All her evidence on polonium production is from the 1960s. It is very unlikely that polonium at Sarov is produced in the way that she outlined. She did not know anything about how and where it is produced now. She simply said that somebody could in principle produce it somewhere else. That was true but highly unlikely.
A: Why the inquiry didn’t want to conclude that the polonium came from Russia?
B: I don’t know but I suspect for two reasons. First, the judge did not understand probability. He is a lawyer and he must have thought that if there is a possibility that something could happen, that was a reason to say it may well have happened. I presented evidence that the polonium produced at Sarov amounted to more than 99% of worldwide production in 2006. So, it is not completely certain but it is highly probable --I would say it is beyond reasonable doubt -- that the polonium used to poison Litvinenko came from Sarov. The second reason is that the judge would have been reluctant to criticize scientist A1 because her main evidence was crucial for his conclusions. My evidence did criticize her but only criticized her knowledge of the production and uses of polonium at the present time. Her work on alpha-spectroscopy and its application to track the presence of polonium in London was first rate.
A: Do you think that if the judge had a good scientific adviser or had a scientific background, the results and conclusions of the inquiry would have been different?
B: My evidence stated I hope pretty conclusively, that the Russian state had ordered this poisoning because only the Russian state has access to polonium. The judge reached the same conclusion but preferred to rely on secret evidence given in closed session.A: Do you think that the polonium discovered in the Pine Bar where the poisoning had happened may be dangerous for other people?
B: In principle, yes. Quite substantial amounts of polonium were discovered in London and there was even some in Hamburg, though in Hamburg there was much less. If there had been a spillage of polonium in the Millennium Hotel, it could have given rise to a serious public health problem. The British organization which dealt with safety and public health was really worried when they saw that polonium was involved.
A: When you read the documents of the inquiry, were you surprised by the actions of Lugovoy and Kovtun? They did not seem to handle the polonium very well…
B: Not really. Their mistake was to carry out the poisoning in London. The main difficulty for the British authorities was to identify polonium as the poison. It was unlikely that it could have been identified anywhere else other than in London, since Aldermastonis only about 100 km from London. Maybe it could have been identified in New York, since the Brookhaven National Laboratory is situated in Long Island, or in Paris, where the nuclear laboratory at Saclay is only 20 km away, or in San Francisco since the Lawrence Livermore laboratory is nearby. Anywhere else it would have resulted in a mysterious death and no polonium would have been found.
Those responsible for sending Lugovoy and Kovtun made a serious error in choosing London. First of all, there was a range of consultants in the relevant disciplines at University College Hospital, which is a major teaching hospital in London which has a strong medical physics department and a strong medical radiation department. Litvinenko was transferred there from a small suburban hospital because of his mysterious symptoms and because he had been a Russian FSB agent. Radioactive thallium was first suspected as the poison. That was shown not to be possible and polonium was suggested. So a sample of Litvinenko’s bodily fluids was sent to Aldermasten to test for polonium. The polonium was identified since it strongly emits alpha-particles of energy 5. 3 MeV together with a weak gamma-ray of energy 803 keV. Both the alpha and the gamma with those energies were found.
A: How did you hear about this case first?
B: I remember listening to the BBC radio news on a Sunday in November or December 2006 and heard that Po-210 had been identified at Aldermaston as the poison. That was enough for me to suspect Russian state involvement. Then I asked a colleague, who had spent quite some time in Russia whether he knew of anyone who had died in similar mysterious circumstances in Russia. If the Russian state authorities had decided to carry out a poisoning abroad, they would have wanted to try out the poison in Russia first.
So I was interested to discover whether there were cases of mysterious deaths in Russia which seemed to be the results of radiation, in particular, with hair loss and damage of the immune system, but where no radiation source had been discovered. And within a few days my colleague had three possible cases, one of which involved a person who had been imprisoned by the Russian authorities, had been given a cup of tea and had died with symptoms of radiation poisoning shortly after. That person was the Chechen Lecha Islamov.
A: I heard about this. There was also the case of Yuriy Schekochikhin. Nobody knows why did he die.
B: Yes, he was the second possibility.
A: Would it possible to identify the cause of their deaths?
B: It is very difficult. I suggested this myself at 2007. You could in principle exhume their bodies and look for traces of polonium. In 2007 this may have been possible but 9 years later it is not. The half-life of Po-210 is 138 days, so less than one millionth of any polonium present in 2007 remains. That would be too small to measure.
A: Do you see any uninvestigated problems in the case? Do you think that the scientists and the other people involved know now what happened in detail?
B: I don’t see much to learn now. There was clearly a lot to learn initially, in particular, you had to be able to test for alpha-radiation as well as for beta- and gamma-radiation. Ten years ago that was difficult and you needed the proper equipment. Now it is straight forward. So we have learned lessons.
A: Thank you very much for the interview.